Rapid Prototyping | Low-Volume Manufacturing

scanning:263 author:John Kino time:2017-04-10 classify:Latest News
High precision metal parts, almost all need cnc machining, sure, for some function parts also can make by mold, some bending parts also by metal sheet processing,if you want rapid prototyping parts ,we can choose cnc ,3D printing,silicone mold, and we also can offer assembly services, if you have 1sets products give us, we can assembly ship to you .

CNC machining is the process of removing the edge material by pushing the workpiece through the tool rotation. This can change the direction, head speed and pressure on one or more axes.

CNC machining covers a wide range of operations and machines, from small individual parts to large heavy-duty combined milling operations. It is one of the most common processes for machining custom parts to precise tolerances.

Milling can be carried out using a variety of machine tools. The original type of machine used for milling is a milling machine (often called a milling machine).

After the emergence of computer numerical control (CNC) in the 1960s, milling machines gradually developed into CNC machining centers: through automatic tool changers, tool magazines or turntables, CNC functions, cooling systems and casing reinforcement milling machines.

CNC machining centers are usually divided into vertical machining centers (VMC) or horizontal machining centers (HMC).

The number of slave axes of CNC machining center can be divided into three-axis machining center, 4-axis machining center, five-axis machining center and other multi-axis machining centers. The higher the number of axes, the more secondary clamping can be avoided, and the multi-angle machining is easy to cause data deviation. Problem. However, due to the high price and high technical requirements of the 5-axis machining center, most of China's CNC processing plants are mainly 3-axis machining centers.

The parts produced are mainly simple and the data requirements are not strict. Some of the pursuit of high-precision CNC processing plants use imported 5-axis equipment to meet customer needs.

This type of factory often has decades of experience and services in the communications industry, optical industry, medical industry, automotive industry, aerospace industry and other industries with extremely high requirements for components.

3D printing (3DP) is a rapid prototyping technology. It is a technique for constructing an object by layer-by-layer printing based on a digital model file and using an adhesive material such as powder metal or plastic.

3D printing is typically accomplished using a digital technology material printer. It is commonly used in mold making, industrial design, etc., and is used in the direct manufacture of certain products. Parts that have been printed using this technique have been used. The technology is used in the fields of jewelry, footwear, industrial design, architecture, engineering and construction (AEC), automotive, aerospace, dental and medical, education, geographic information systems, civil engineering, firearms and more.

On January 14, 2019, the University of California, San Diego, used rapid 3D printing to create a spinal scaffold that mimics the structure of the central nervous system, successfully helping the rat to restore motor function.

There are many different techniques for 3D printing. The difference is that components are created in different layers and in different layers.

Common materials for 3D printing are nylon fiberglass, durable nylon material, gypsum material, aluminum material, titanium alloy, stainless steel, silver plated, gold plated, rubber material.

Technology: fused deposition (FDM) electron beam freeform fabrication (EBF) direct metal laser sintering (DMLS) electron beam melting (EBM) selective laser melting (SLM) selective thermal sintering (SHS) selective laser sintering (SLS) gypsum 3D printing (PP)) Layered solid state manufacturing (LOM) stereolithography (SLA) digital light processing (DLP).

Injection molding is a method of producing plastic products. The products are usually injection molded with rubber and plastic. Injection molding can also be divided into injection molding and die casting.

Injection molding machine (referred to as injection machine or injection molding machine) is the main molding equipment for making thermoplastic or thermosetting materials into plastic products of various shapes by using plastic molding die.

Injection molding is achieved by injection molding machines and molds.

Main type

1. Rubber injection molding: Rubber injection molding is a production method that injects rubber directly into the mold from the barrel. The advantage of rubber injection is that although it is intermittent operation, the molding cycle is short and the production efficiency is high, eliminating the blank preparation process. , labor intensity is small, product quality is excellent.

2. Plastic injection molding: Plastic injection molding is a method of plastic products. The molten plastic is injected into the plastic product mold by pressure, and the plastic molding is obtained by cooling molding. There is a mechanical injection molding machine specially used for injection molding. The most commonly used plastic is polystyrene.

3. Molding: The resulting shape is often the final product. No additional processing is required before installation or use as a final product. Many details, such as bosses, ribs, and threads, can be molded in one step of injection molding. come out.

Advantages Disadvantages

Injection molding is also the machine made of shoes. After the upper surface is attached to the aluminum crucible, the rotary disc machine is directly injected with PVC, TPR and other materials to form the sole at one time. Nowadays, there is also PU (chemical name polyurethane) injection molding (machine and mold with The general injection molding is not the same).

Advantages: Because it is machine-made, the output is large, so the price is low.

Disadvantages: If there are many styles, it is more troublesome to change the mold, the shoe is difficult to shape, and there is no cold-stick shoes to work fine, so it is generally suitable for a single order of the sole style.

Process basis

●The purpose of temperature, pressure, speed and cooling control, operation and results

●How the adjustment of the injection molding machine affects the process and quality

●Optimize screw control settings

●Multi-stage filling and multi-stage pressure control; effects of crystallization, non-crystallization and molecular/fiber discharge on process and quality

●Intrinsic stress, cooling rate, plastic shrinkage on the quality of plastic parts

●Plastic rheology: how plastic flows, discharge and change viscosity, shear and molecular/fiber orientation

●The relationship between the casting system, the cooling system, the mold structure and the injection molding process

Problem analysis

Shrinkage, shrinkage, underfill, burrs, welds, silver, spray marks, burnt, warp deformation, cracking/cracking, dimensional oversize and other common injection molding problems, cause analysis, and in mold design, forming Process control, product design and plastic materials, etc.

●The lack of glue around the injection molded parts, the reason for the failure of the mold and the solution

●Analysis of the reasons for the front (burr) and countermeasures

●The reason for the shrinkage of the surface of the injection molded part and the shrinkage hole (vacuum bubble) and the solution

●Silver pattern (flower flower, water flower), charring, gas pattern analysis and solution

● Analysis of the causes of water ripples, flow patterns (flow marks) on the surface of injection molded parts and solutions

●The reason for the water mark (welding mark) and the spray pattern (snake) on the surface of the injection molded part and the countermeasures

●Analysis of the causes of surface cracks (cracks) and whitening (top explosion) of injection molded parts and solutions

●The color difference of the surface of the injection molded parts, poor gloss, color mixing, black bars, black spots and the countermeasures

● Analysis of the causes of warping deformation and internal stress cracking of injection molded parts and solutions

●Cause analysis and solution for the dimensional deviation of injection molded parts

●Injection mold sticking, towing (strain), analysis of the reasons for dragging and solving countermeasures

●Insufficient transparency and insufficient strength (brittle breaking) of injection molded parts and countermeasures

●Cause analysis and solution for cold spot on the surface of injection molded parts and peeling (layering)

●Analysis of the causes of poor metal inserts in injection molded parts and solutions

●Nozzle flow (flowing), leakage of glue, nozzle drawing, nozzle blockage, analysis of the reasons for difficulty in mold opening and improvement measures

●Using CAE mold flow analysis technology to quickly and effectively solve the problem of injection molding site

Optimized design

●The structure, composition, classification and function of the injection mold;

●Optimization design of gating system (gate, runner, cold well, etc.)

●Optimization of cooling system (waterway, water-blocking, roller, etc.)

●Setting and adjustment of shrinkage rate

●The relationship between the casting system, the cooling system, the mold structure and the injection molding process

●Mould installation, commissioning and maintenance

●Control of the process by using chiller and mold temperature machine

●Using CAE mold flow analysis technology for mold optimization design

Sheet metal processes generally include basic equipment such as Shear Machine, CNC Punching Machine/Laser, Plasma, Cutting Machine, Bending Machine, Drilling Machine and various Auxiliary equipment such as: unwinder, leveling machine, deburring machine, spot welding machine, etc.

Usually, the most important four steps of the sheet metal process are shearing, punching/cutting, folding/rolling, welding, surface treatment, etc.

Sheet metal is sometimes used as a gold plate. The word comes from the English platemetal. Generally, some metal sheets are plastically deformed by hand or die to form the desired shape and size, and can be further welded or a small amount of machining. Form more complex parts, such as the chimneys commonly used in the home, the iron stove, and the car shell are all sheet metal parts.

Sheet metal processing is called sheet metal processing. For example, the use of sheet metal to make chimneys, iron barrels, fuel tank oil pots, ventilation ducts, elbow heads, round spaces, funnels, etc. The main process is cutting, bending and buckle, Bending, welding, riveting, etc., requires a certain amount of geometric knowledge.

Sheet metal parts are thin-plate hardware, that is, parts that can be processed by means of stamping, bending, stretching, etc. A general definition is - parts with constant thickness during processing. Corresponding to casting parts, forging parts , machining parts, etc., for example, the outer iron shell of the car is a sheet metal piece, some of the stainless steel cabinets are also sheet metal parts.

Modern sheet metal processes include: filament power windings, laser cutting, heavy machining, metal bonding, metal drawing, plasma cutting, precision welding, roll forming, sheet metal bending, die forging, water jet cutting, precision welding, etc. .

The surface treatment of sheet metal parts is also a very important part of sheet metal processing, because it has the function of preventing parts from rusting and beautifying the appearance of the product. The surface pretreatment of sheet metal parts is mainly to remove oil, scale and rust. Etc., it prepares for surface post-treatment, and the post-treatment is mainly spray (baked) paint, spray and rust-proof layer.

In 3D software, SolidWorks, UG, Pro/E, SolidEdge, TopSolid, CATIA, etc. all have sheet metal parts, mainly through the editing of 3D graphics to obtain the data needed for sheet metal processing (such as unfolding, bending) Lines, etc.) and provide data for CNC Punching Machine/Laser, Plasma, Water Jet Cutting Machine/Combination Machine and CNC Bending Machine .

 

Stamping is a method of forming a workpiece (stamping part) of a desired shape and size by applying an external force to a plate, a strip, a pipe, a profile, etc. by a press and a die to cause plastic deformation or separation.

Stamping and forging are the same plastic processing (or pressure processing), collectively called forging. The blanks for stamping are mainly hot-rolled and cold-rolled steel sheets and strips.

60-70% of the world's steel is sheet metal, most of which are stamped into finished products.

Automobile body, chassis, fuel tank, radiator, boiler steam drum, container housing, motor, electrical iron core silicon steel sheet, etc. are all stamping processing. Instrumentation, household appliances, bicycles, office machinery, living utensils In the products, there are also a large number of stamping parts.

Stamping processing is the production technology of product parts with certain shape, size and performance by means of the power of conventional or special stamping equipment, which directly deforms and deforms the sheet in the mold.

Sheet, mold and equipment are the three elements of stamping processing. According to the stamping processing temperature, it is divided into hot stamping and cold stamping. The former is suitable for sheet material processing with high deformation resistance and poor plasticity;

The latter is carried out at room temperature and is a common stamping method for sheet metal. It is one of the main methods of metal plastic processing (or pressure processing) and is also part of material forming engineering technology.

The mold used for stamping is called stamping die, referred to as die. Die is a special tool for batch processing materials (metal or non-metal) into required punches.

Die is very important in stamping. There is no die that meets the requirements. Batch stamping production is difficult to carry out; without advanced die, advanced stamping process cannot be realized.

Stamping process and die, stamping equipment and stamping materials constitute the three elements of stamping processing, only they can be combined to obtain stamping parts.

Processing characteristics

Compared with castings and forgings, stampings are thin, uniform, light and strong. Stamping can produce ribs that are difficult to manufacture by other methods.

Ribs, undulating or flanging workpieces to increase their rigidity. Due to the use of precision molds, the accuracy of the workpiece can reach micron level, and the repeatability is high, the specifications are the same, and the holes, bosses, etc. can be punched out.

Cold stamping parts are generally no longer machined, or only a small amount of cutting is required. The precision and surface condition of hot stamping parts are lower than that of cold stamping parts, but still better than castings, forgings, and less cutting.

Stamping is an efficient production method, using composite molds, especially multi-station progressive molds, which can perform multiple stamping operations on one press (single or multi-station).

It realizes automatic production of unwinding, leveling, blanking, forming and finishing of strips. High production efficiency, good working conditions and low production cost, generally can produce hundreds of pieces per minute.

Compared with other methods of machining and plastic processing, stamping processing has many unique advantages both technically and economically. The main performances are as follows.

(1) The stamping process has high production efficiency and is easy to operate, and it is easy to realize mechanization and automation. This is because stamping relies on die and stamping equipment to complete the process.

The number of strokes of ordinary presses can reach dozens of times per minute, the high-speed pressure can reach hundreds or even thousands of times per minute, and each punching stroke may get a punch.

(2) Since the die guarantees the size and shape accuracy of the stamping part during stamping, and generally does not damage the surface quality of the stamping part, and the life of the die is generally long, the quality of the stamping is stable, the interchangeability is good, and it has “the same”. Characteristics.

(3) Stamping can process parts with large size range and complicated shape, such as small needles as small as clocks, as large as car longitudinal beams, covering parts, etc., plus the cold deformation hardening effect of materials during stamping, the strength of stamping and The stiffness is high.

(4) Stamping generally has no chip scraps, less material consumption, and no need for other heating equipment, so it is a material-saving, energy-saving processing method, and the cost of stamping parts is low.

Due to the superiority of stamping, stamping processing is widely used in various fields of the national economy. For example, in aerospace, aviation, military, machinery, agricultural machinery, electronics, information, railways, post and telecommunications, transportation, chemicals, medical equipment, household appliances And light industry and other departments have stamping processing.

Not only is it used by the entire industry, but everyone is directly connected to stamping products. There are many large, medium and small stamping parts on airplanes, trains, cars and tractors.

The body, frame and rim of the car are all stamped and processed. According to relevant statistics, 80% of bicycles, sewing machines and watches are stamped parts; 90% of TV sets, tape recorders and cameras are stamped. Piece

There are also food metal cans, steel-fired boilers, enamel bowls and stainless steel tableware, all of which are stamped and processed products using molds; even the hardware of the computer is not lacking in stamping parts.

Silicone mold is a special mold for making crafts. The raw materials of plastic tools can be divided into ordinary silica gel and meteorological silica gel according to their performance. The characteristics of silica gel are high temperature resistance, corrosion resistance, strong tear resistance and high simulation.

It is a mold for making various handicrafts.

Silicone mold raw materials

Silicone is more and more popular because of its good environmental performance. To understand the knowledge of silicone mold, we must start with silicone raw materials.

1, ordinary silica gel, also known as precipitated silica gel

Color: translucent, milky white, light yellow, gray, etc.

Hardness: 30 °, 40 °, 50 °, 60 °, 70 °, etc., commonly used between 40 ° -70 °.

Density: 1.1-1.12g/cm3

Elongation: 400%

Uses: More use of mobile phone buttons, miscellaneous pieces, conductive adhesives and other low-end silicone products.

Meteorological glue, also known as pure silica gel

Color: transparent.

Hardness: 30 °, 40 °, 50 °, 60 °, 70 °, 80 °, etc., commonly used between 40 ° -60 °.

Density: 1.1-1.12g/cm2

Elongation: 600%-700%

Features: Due to the transparency of this material, strong tensile strength and high cost

Uses: silicone tube, protective sleeve and other high-end products that require high elasticity.

2, silica gel raw materials can be divided into solid silica gel and liquid silica gel according to physical properties.

Solid silica gel is mainly used for molded products. For example: silicone sleeve, silicone tableware, silicone mold, silicone button, etc. Liquid silicone is mainly used for extrusion molding products, such as silicone nipples, silicone tubes, etc.

Insulation silicone pad, excellent high temperature resistance, silica gel (food grade silica gel) can withstand high temperature of 200 ° C and can be used for a long time. The raw materials of this product meet food grade standards, passed FDA food grade test, tasteless and non-toxic, manufacturers rely on Production, color, shape can be customized.

shed at least three layers of silica gel. The thickness of each layer of silica gel is 1mm. In the process of brushing silica gel, each layer is required to be cured before brushing another layer. When brushing the third layer, add one layer to the second layer. Layer gauze to increase the strength of the silica gel.

The thickness of the silicone part of the whole mold is controlled to 3-4mm according to the size of the product, and the width is not more than 60 mm of the product width. The solidification time of the silica gel is 20 minutes.

1. Wash and dry the master mold for smoothing (can apply a layer of release wax or apply a mold release agent)

Mold picture

Mold picture

2, 500-1000 grams of mold silicone rubber (mold silicone, mold glue, silicone rubber, silicone) as a plastic basin spare;

3, the hardener is weighed by weight ratio (generally 1.5-2.5%), then added to the container for mixing, fully stirred;

4, depending on the situation (especially the first layer) add a certain amount of silica thinner. Until the mixing is uniform, usually 3-5 minutes.

5. The mold silicone rubber (mold silicone, mold glue, silicone rubber, silica gel) is mixed with the hardener and reacted at room temperature to release low molecular weight alcohol.

In order to remove the alcohol molecules from the colloid, it is necessary to discharge the bubbles under negative pressure for 1-3 minutes. It is also possible without the aid of equipment (mainly depending on the operation experience of the molder)

6, multi-layer brushing die, should be followed by internal, medium and external curing is appropriate. When the amount of curing agent is relatively small, the reaction time is longer, the reaction is sufficient, the colloid is good, so the curing agent dosage is preferably less inside and outside.

When painting, wait for the first layer (inner layer) to dry and then brush the second layer. The operation time is 30-50 minutes, the mold removal time is 10-15 hours. The curing time is 24 hours. Pay attention to the first and second layers. Add a mold cloth,

This can greatly improve the service life of the mold (but the glass fiber cloth can not be used, otherwise it will easily cause delamination and the entire mold will be scrapped)

7, three-dimensional perfusion mold, generally 10-15 hours of curing as well.

8. After the soft mold is finished, a plaster or fiberglass jacket should be made to support the silicone soft mold. Note: 1. Die line selection: choose the position that does not affect the appearance of the product;

Choose the position that is easy to process after grouting; choose the position where the mold itself is easy to demolish; select the position where the product is not easily deformed 2, and must not blindly increase the amount of hardener for the production schedule.

Otherwise it will greatly reduce the service life of the silicone mold.

common problem

1. Why does mold silicone have fewer molds?

In the process of making the mold, too much silicone oil is added. The silicone oil destroys the molecular weight of the silica gel, so the mold will have fewer times of mold turning and less durability. If it is a product with a relatively small product pattern,

When the mold is opened with a hard silicone, the number of times of mold turning will be small, because the time when the silica gel is too hard will be very brittle and easy to break.

On the contrary, if you build a product and use a low-hardness silica gel to make the mold, the result will be unsatisfactory. Because the silica gel is too soft, its tensile strength and tear strength will be reduced, and the resulting mold will be deformed.

Therefore, the number of molds will be reduced. The quality of the mold glue itself is very good, the silica gel is not good or bad, only suitable and not suitable.

We don't have to use a silicone that is suitable for the hardness of the product to make the mold.

2. Why does the mold silicone show a burning phenomenon?

Because the unsaturated resin and the resin product are added with a peroxide curing agent, a large amount of heat is generated when the resin reacts. Generally, the curing time of the resin is 3 minutes, so it is necessary to demold the mold as soon as possible after 3 minutes to prevent the silicone mold from being prevented. Produce the phenomenon of burning.

3. Molding method and mold of mold silicone:

Slicing mold or sheet mold operation method: the vacuum-coated silica gel is applied by brushing or infusion method. If you are using a sheet mold or a split mold, there is a brushing method.

Apply a layer of release agent or release agent to the product or model you want to copy before painting, then apply silicone to the product (note: be sure to apply evenly) for 30 minutes.

Apply a layer of gauze or fiberglass cloth to the surface to increase the strength, and then apply a second layer of silica gel. After the silica gel is dried, the outer mold can be used. The outer mold can be made of gypsum or resin.

The operation method of filling or pouring mold: filling or pouring mold, which is used for relatively smooth or simple products, which is the product or model that you want to copy.

Wrap the rubber or glass plate, pour the vacuumed silica gel directly onto the product, and after the silica gel is dried, take out the product.

The mold is formed (Note: the casting mold is generally made of soft silicone with a softer hardness, so that the mold release is easier and does not damage the product inside the silicone mold).

The above is the whole process of the use and operation of the mold silicone.

4. Why does the mold silica gel appear to be dry in the stem?

Mold silicone is a kind of condensation type silica gel. It is solidified by absorbing water in the air. During the process of making the silica gel, the water is evaporated to dryness without adding proper amount of water.

This phenomenon will occur. Solution: This phenomenon is not a product quality problem, but because there is no control of water, the storage period of the silica gel is improved, and the shelf life is long.

As long as you use silica gel, add 0.05% water in an appropriate amount, and evenly stir it to solve some problems.

5. Why does the mold silicone have a poor pull?

Because the customer in the process of making the mold, in order to reduce the viscosity of the silica gel, the silica gel is easy to operate and a large amount of silicone oil is added to the silica gel, which will make the silica gel become soft and produce non-resistance.

The tear strength is reduced and the tensile force is deteriorated, resulting in a phenomenon that the mold is not durable, the service life is short, and the number of times of overturning is small.

6. Why does the mold appear to be in a fuel condition?

The mold silicone itself does not oil, and oil is produced because the compound silicone oil (complex of silicone oil and white mineral oil) is added during the operation, because white mineral oil is a petrochemical product, not a silicone oil.

7. Why does the mold produce acid and alkali resistance and is not resistant to aging?

In the process of making silicone molds, we recommend that customers do not add any silicone oil, if necessary, do not add more than 5% to 10% silicone oil.

Because the addition of silicone oil will destroy the molecular weight of silica gel, the resulting mold will produce acid and alkali resistance and aging resistance.

8. Why do molds made from mold silicone have traces, streaks, and matte surfaces?

This phenomenon occurs because the product or model to be copied is not polished or polished. Because the model or the product itself is not smooth or perfect.

Therefore, if the product or model to be copied is not polished or polished, the mold made of the best silica gel will be unsightly and not smooth enough. There is also a case where the mold release agent is used.

Without even brushing, the mold will not be smooth.

9. Wonderful use of mold silicone you know?

Mold silicone is mainly used in the toy gift industry, craft gift industry, furniture decoration and decoration industry, character reproduction, architectural decoration and decoration industry, resin crafts industry,

Unsaturated resin crafts industry, candle technology, plastic toy industry, gift stationery industry, gypsum craft gift industry, mold manufacturing industry, Boli industrial products,

Simulation of animal and plant sculpture, Buddha carving crafts and other product reproduction and mold making.

Mainly used in toys, gifts, fine patterns, for mold, perfusion mold products, glass crafts, lighting, candles, character reproduction molds,

Large-size products, open split molds, reliefs, Buddha statues, craft gift making molds, sole models, infusion molds, sand casting.

The specific operation of the different types of mold silicone is also different. To meet the requirements, it must be operated according to various parameters.

How to clean

In general, we clean the molds by sandblasting. First, we choose the appropriate washing sand (according to the shape of the silicone product mold).

Then, the washing sand is introduced into the sand blasting machine, and then the silicone product production mold is placed in the sand blasting machine, and the blasting head is used to align the silicone product to the cavity of the mold.

Then step by step in the order of the cavity.

The principle of aluminum anodization is essentially the principle of water electrolysis. When the current passes, the following reactions will occur:

On the cathode, H2 is released as follows: 2H + + 2e → H2

On the anode, 4OH - 4e → 2H2O + O2, the oxygen evolved is not only molecular oxygen (O2), but also atomic oxygen (O), and ionic oxygen (O-2), usually expressed as molecular oxygen in the reaction. .

The aluminum as the anode is oxidized by the oxygen deposited on it to form an anhydrous Al2O3 film: 2AI + 3[O] = AI2O3 + 1675.7KJ It should be noted that the generated oxygen does not all act on the aluminum, and a part is precipitated in the gaseous form. .

The anodizing type of anodizing has long been widely used in industry. There are many methods for different names, and the following classification methods are summarized:

According to the current type: DC anodizing, alternating current anodizing, and shortening the production time to the required thickness, the film is thick and uniform, and the corrosion resistance is significantly improved by pulse current anodization.

According to the electrolyte, sulfuric acid, oxalic acid, chromic acid, mixed acid and natural colored anodizing with organic sulfonic acid solution.

According to the nature of the film layer: ordinary film, hard film (thick film), porcelain film, bright decoration layer, semiconductor layer barrier and other anodizing.

The application of direct current sulfuric acid anodization is most common because it has anodizing treatment for aluminum and most aluminum alloys;

The film layer is thick, hard and wear-resistant, and can obtain better corrosion resistance after sealing; the film layer is colorless and transparent, the adsorption capacity is strong and easy to color; the processing voltage is low, and the power consumption is small;

The process does not have to change the voltage cycle, which is conducive to continuous production and practical operation automation; sulfuric acid has less harm to the human body than chromic acid, wide supply and low price.

Anode structure

1) Structure of anodized film Anodized film consists of two layers. The outer layer is called porous layer. It is thick, loose and porous, and has low electrical resistance. The inner layer is called barrier layer (also known as active layer), which is thin, dense and resistant. High.

The porous outer layer is grown on a dense inner layer having dielectric properties. In general, the anodized film is an array of hexagonal cylinders, each of which has a star-shaped pore filled with a solution.

Shaped like a honeycomb structure, the thickness of the pore wall is twice the diameter of the pore.

(1) Barrier layer The barrier layer is composed of anhydrous AI2O3, which is thin and dense, has high hardness and prevents the passage of current.

(2) Porous outer layer oxide film porous outer layer mainly consists of amorphous AI2O3 and a small amount of r-AI2O3.H2O also contains electrolyte anion.

The pore size of the oxide film is between 100 nm and 200 nm, the thickness of the oxide film is about 10 μm, the porosity is about 20%, and the pore spacing is between 300 and 500 nm.

The cross-sectional view of the oxide film shows that the pores of the oxide film are basically tubular structures, and the film-dissolving reaction of the oxide film occurs substantially at the bottom of the pores. The pore diameter of the general sulfuric acid DC anodized film is about 20 nm.

If it is a 12 micron oxide film, how deep is the thin tubular structure! Assuming that this is a 1m diameter well, its depth will be 600m deep.

Most of the excellent properties of the oxide film, such as corrosion resistance, wear resistance, adsorption, insulation and other properties are determined by the thickness and porosity of the porous outer layer, but the two are closely related to the anodizing conditions.

Therefore, the film layer can be obtained by changing the anodizing conditions to meet different use requirements. The film thickness is a very important performance indicator of the anodized article, and the value of the value directly affects the corrosion resistance and wear resistance of the film layer.

Insulation and chemical coloring ability. In the conventional anodizing process, the film layer thickens with time. After the maximum thickness is reached, it gradually becomes thinner as the processing time increases.

Some alloys such as AI-Mg and AI-Mg-Zn alloys are particularly noticeable. Therefore, the oxidation time is generally controlled within the maximum film thickness time.

2) Properties and application of anodized film Anodized film has high hardness and wear resistance, strong adhesion, strong adsorption capacity, good corrosion resistance and electrical insulation and high thermal insulation.

Due to these specific properties, it has been widely used in various aspects. The main uses are:

(1) Improve the wear resistance, corrosion resistance and weather resistance of parts.

(2) The transparent film formed by oxidation can be colored into various color films.

(3) As a capacitor dielectric film.

(4) Improve the adhesion with the organic coating. For the coating of the bottom layer.

(5) for electroplating, the bottom layer of enamel.

(6) Other uses under development, solar absorption panels, ultra-high hard membranes, dry lubricating membranes, catalytic membranes, nanowires, magnetic alloys deposited in porous membranes as memory components.

Closed process

The aluminum oxide film is a porous film. Whether it is colored or not, it must be sealed before being put into use, so as to improve its corrosion resistance and weather resistance. There are three types of treatment methods, namely high temperature hydration reaction closure, inorganic salts. Closed and closed organic matter.

(1) High temperature water sealing

This method uses a hydration reaction of an aluminum oxide film with water to change the amorphous film into a hydrated crystalline film:

The hydration reaction can be carried out at both normal temperature and high temperature, but at high temperatures, especially at the boiling point, the resulting hydrated crystalline film is a very stable and irreversible crystalline film. Therefore, the most commonly used aluminum oxide film is closed. Method or steam treatment.

(2) Inorganic salt closure

Inorganic salt method can improve the fastness of organic dyes, so it is commonly used in chemical coloring.

1 acetate method

2 silicate method

(3) Organic sealing method

This is the immersion, immersion or painting of the aluminum oxide film. Because of the high cost and increased process flow, it is not used much, and the two types of methods mentioned above are used, and the first type is used. Water law is the mainstream.

 

Electroplating is the process of plating a thin layer of other metals or alloys on some metal surfaces by electrolysis. It is a process of attaching a metal film to the surface of metal or other materials by electrolysis to prevent metal oxidation ( Such as rust),

Improve wear resistance, electrical conductivity, light reflectivity, corrosion resistance (copper sulfate, etc.) and enhance the appearance of beauty. The outer layer of many coins is also electroplated.

Basic meaning

During electroplating, the plated metal or other insoluble material is used as the anode, and the workpiece to be plated is used as the cathode. The cation of the plated metal is reduced on the surface of the workpiece to be plated to form a plating layer. To eliminate the interference of other cations, the plating layer is uniform and firm.

A plating solution containing a plating metal cation is required to maintain the concentration of the metal cation of the plating layer. The purpose of the plating is to plate a metal plating on the substrate to change the surface properties or size of the substrate.

Electroplating can enhance the corrosion resistance of metals. (The coating metal is mostly made of corrosion-resistant metal), increase the hardness, prevent wear, improve conductivity, smoothness, heat resistance and surface beauty.

Related role

The technique of electrolytic cell is used to deposit a well-attached technology with different properties of the metal coating on the mechanical product. The plating layer is uniform than the hot-dip layer and generally thin.

From a few microns to a few tens of microns. By electroplating, it is possible to obtain decorative protective and various functional surface layers on mechanical products, as well as to repair worn and mishandled workpieces.

In addition, there are different roles depending on various plating requirements. Examples are as follows:

1. Copper plating: used for primers to improve adhesion of plating layer and corrosion resistance. (Copper is easily oxidized, after oxidation, patina is no longer conductive, so copper plating products must be protected by copper)

2. Nickel plating: base or appearance, improve corrosion resistance and wear resistance, (where chemical nickel is more resistant to chrome plating in modern processes). (Note that many electronic products, such as DIN head, N head, Nickel is no longer used,

Mainly due to the magnetic nature of nickel, it will affect the passive intermodulation in the electrical performance)

3. Gold plating: Improve the conductive contact resistance and improve signal transmission. (Gold is the most stable and most expensive.)

4. Palladium-plated nickel: Improve the conductive contact resistance, improve signal transmission, and wear resistance is higher than gold.

5. Tin-plated lead: Improve the welding ability, and be replaced by other substitutes (because lead is mostly changed to bright tin and matte tin).

6. Silver plating: Improve the conductive contact resistance and improve signal transmission. (The best silver performance, easy oxidation, conductive after oxidation)

4. Electroplating is a method of laying a layer of metal on a conductor using the principle of electrolysis.

In addition to electrical conductors, electroplating can also be used on specially treated plastics.

The process of electroplating is basically as follows:

Plating metal at the anode

The substance to be plated is at the cathode

The anode and cathode are connected by an electrolyte solution composed of plated metal positive ions.

After passing through the DC power supply, the metal of the anode will oxidize (loss electrons), and the positive ions in the solution will be reduced at the cathode (to get electrons) into atoms and accumulate on the surface of the cathode.

The appearance of the electroplated object after electroplating is related to the current level. The smaller the current, the more beautiful the object to be plated; otherwise, some uneven shape will appear.

The main uses of electroplating include preventing metal oxidation, such as rust, and decorating. The outer layers of many coins are also electroplated.

Sewage from electroplating (such as electrolytes that are ineffective) is an important source of water pollution. Electroplating processes have been widely used in semiconductor and microelectronic component leadframe processes.

VCP: Vertical continuous plating, the new machine used in the circuit board, better quality than traditional suspension plating.

Partial silver plating

Aluminum parts plating solution formulation process:

High-temperature weak alkali etching→cleaning→acid washing→cleaning→zinc-plating→cleaning→secondary zinc immersion→cleaning→pre-plating copper→cleaning→pre-silvering→cyanide bright silver plating→recycling washing→cleaning→silver protection→cleaning → Drying.

From the process flow, the selected protective material must be resistant to high temperatures (about 80 ° C), alkali resistance, acid resistance, and secondly, the protective material can be easily peeled off after silver plating.

Commercially available protective materials include peelable rubber, peelable paint, general adhesive tape and tape, etc. Test the acid resistance, alkali corrosion, high temperature resistance (the maximum temperature of the alkali etching solution is about 80 °C) and peelable. Sex.

Material requirements

The coating is mostly a single metal or alloy, such as titanium palladium, zinc, cadmium, gold or brass, bronze, etc.; also has a dispersion layer, such as nickel-silicon carbide, nickel-fluorinated graphite, etc.; and a laminate layer, such as steel Copper-nickel-chromium layer, silver-indium layer on steel, etc.

In addition to iron-based cast iron, steel and stainless steel, electroplated base materials are non-ferrous metals, or ABS plastics, polypropylene, polysulfone and phenolic plastics, but must be specially activated and sensitized before plastic plating.

Plating method

Electroplating is divided into hanging plating, barrel plating, continuous plating and brush plating, etc., mainly related to the size and batch size of the parts to be plated. Hanging plating is suitable for general size products, such as bumpers of automobiles, handlebars of bicycles, etc.

Barrel plating is suitable for small parts, fasteners, washers, pins, etc. Continuous plating is suitable for batch production of wire and strip. Brush plating is suitable for partial plating or repair.

The plating solution is acidic, alkaline and acidic and neutral solution with chrome mixture. Regardless of the plating method, the plating tank and the hanging device which are in contact with the product to be plated and the plating solution should have a certain degree. Generality.

Partial plating

Usually, according to the plating area, electroplating can be divided into all kinds of plating and partial plating. Many parts that need to be partially electroplated should be insulated and protected from non-plated surfaces, which requires different local insulation methods to meet the construction technology. Requirements to ensure that the non-plated parts of the parts will not be plated, especially those with special requirements.

According to the daily work experience, several local plating methods commonly used in electroplating are introduced.

Bandaging

This method is to protect the non-plated surface with tape or plastic strips, tapes, etc. The method of dressing depends on the shape of the part. The dressing method is suitable for simple parts, especially circular parts with regular shapes. 4. The dressing method is the simplest method of insulation protection.

Special fixture method

Special fixture method, also known as profiling fixture method. That is to say, for some complex shapes, special insulation fixtures can be designed according to the shape of the parts, which can greatly improve production efficiency, such as bearing inner diameter or outer diameter. For partial chrome plating, a special bearing chrome-plated fixture can be designed, and the fixture can be used repeatedly.

Wax protection

The characteristic of insulation with wax preparation is that it has good bonding performance with parts, wide temperature range of use, and the end edge of insulation layer will not be lifted. Therefore, it is suitable for parts with high dimensional tolerance of insulation end and complicated shape.

In addition, the wax preparation can also be reused, and the loss is small, but the method of use is complicated and the cycle is long. When the wax preparation is applied, the parts should be preheated to 50-70 ° C, and then the melted wax preparation is applied, first coated. a thin layer covering the entire surface to be insulated,

At this time, the wax should not be solidified in the middle, and then repeatedly applied to the required thickness. After the coating, before the temperature is not cooled to room temperature, the insulating edge is trimmed with a knife, and then the cotton ball is repeatedly rubbed with gasoline. Plated surface, this operation should be very careful.

After plating, the wax preparation can be melted and recovered in hot water or special wax barrel, and then the parts are cleaned with a solvent such as gasoline or a water-soluble cleaning agent.

Coating insulation method

Insulation protection is often used in galvanizing insulation coatings. This insulation protection method is easy to operate and can be applied to complex parts. Commonly used insulating coatings are perchloroethylene anticorrosive varnish, PVC insulation coating, nitro glue, etc.

 

Powder spraying refers to a coating process in which a powder coating is adhered to a workpiece by corona discharge. After spraying, it is successfully subjected to thermal coating. In 1962, the French company Semes Company invented powder electrostatic spraying, powder coating Just begun.

Overview

Powder spraying is to use the corona discharge phenomenon to adsorb the powder coating on the workpiece. The process of spraying powder is: the powder gun is connected to the negative electrode, the workpiece is grounded (positive electrode), and the powder coating is fed into the spray gun by the compressed air gas.

The high pressure generated by the high-voltage electrostatic generator is added to the front end of the spray gun. Due to the corona discharge, a dense charge is generated in the vicinity of the spray gun. When the powder is ejected from the nozzle, the loop forms a charged paint particle.

It is absorbed by the electrostatic force and sucked onto the workpiece with the opposite polarity. As the powder sprayed increases, the charge accumulates more. When a certain thickness is reached, the adsorption does not continue due to the electrostatic repulsion.

Therefore, the entire workpiece is obtained with a certain thickness of the powder coating, and then the heat is melted, leveled, and solidified, that is, a hard coating film is formed on the surface of the workpiece.

use

Powder spraying is an indispensable process in the modern high-speed multi-color offset printing process. Its main function is to prevent the back of the printed matter from sticking to the dirt, improve the printing quality and efficiency. The powder is made from pure natural plants and refined by modern science.

Printing dusting is an indispensable tool in offset printing! Its main function is to prevent the printed matter from being sticky and dry during the printing process. The good dusting particles are smooth, excellent in assimilation with ink, and evenly distributed after spraying.

It is of great help to improve the printing quality and printing efficiency! It is widely used; in addition to color printing, film, rubber, nylon, composite can be used. The powder particles are spherical; the surface is smooth; the particle size is 10-25μm (number of meshes) 300-450);

Uniformity of powder; excellent fluidity and dispersibility; assimilation with ink, excellent lipophilicity. It can be completely and effectively spread on the surface of printed products, so that the printing quality can be guaranteed.

Powder type

Plastic dusting

Sprayed on low temperature materials on plastic, similar to paint-like coatings, but domestic powder suppliers have not developed them.

Chemical fiber dusting

Powder spraying, also known as powder coating, is a new type of coating process that has developed rapidly in recent decades. The raw materials used are plastic powder. Some countries began to study experiments in the early 1940s, but the progress was slow.

In 1954, James of Germany successfully applied polyethylene to the fluidized bed method. After the invention of the electrostatic spraying of the powder in France in 1962, the powder coating began to be officially adopted in production, due to the importance of environmental protection in various countries. ,

Powder coatings that are not polluted by water and the atmosphere have developed rapidly.

Work safety

1, the scope of the dusting area

a) dusting room, powder feeding device (including powder conveying device of circulating powder feeding device, powder storage bin and its discharging device), recycling device, fan, purification device and powder conveying pipeline connected thereto.

b) the area at the opening of the powder chamber is 3m horizontally and 1m vertically;

c) where the powder coating is stored or deposited on the aluminum coating site;

d) inside the exhaust duct, air circulation filter and its maintenance structure and other areas that may produce explosive suspended dust or accumulated dust.

2, dustproof area fireproof and explosion-proof grade

2.1 The fire danger zone in the dusting area is zoned 22.

2.2 The dusting area shall be classified as 11 areas according to the explosive dust environment. Those who meet the requirements of GB 50058 may be classified as non-explosive hazardous areas.

3, design

3.1 Powder electrostatic spraying process design, powder electrostatic spraying equipment and equipment development, design and manufacture should comply with the provisions of GB 7691.

3.2 The safety and hygiene indicators of the dusting room should meet the following requirements:

a) Except for the local area such as the outlet of the spray gun, the average concentration of suspended powder in the spray chamber (ie, the concentration in the exhaust duct of the spray chamber) should be less than half of the minimum explosive concentration of the powder. The lowest explosive concentration (MEC) is unknown.

The maximum concentration is not allowed to exceed 15 g/m3. If there is a blasting device in the system, the concentration of suspended powder in the outlet vent of the dusting chamber is allowed to exceed 50% of the minimum explosive concentration;

b) The use of electrostatic powder guns and their auxiliary devices shall comply with the requirements of GB 14773;

c) the allowable concentration of total dust in the workplace air is 8 mg/m3;

d) The wind speed of the opening surface of the powder spraying chamber should be 0.3-0.6 m/s.

4. Location

4.1 Powder electrostatic spraying and painting operations should not be set in the same working area. If it is set in the same working area, its explosion danger area and fire danger area should be divided according to the painting area.

4.2 The dusting operation area should be arranged in a single-storey factory building; if it is arranged in a multi-storey factory building, it should be arranged on the top floor of the building. If it is arranged in a multi-span factory building, it should be arranged in the side span and meet the relevant provisions of GB 6514.

4.3 The dusting operation shall be carried out in the dusting room complying with the provisions of Chapter 5.

4.4 The dusting chamber shall be arranged in an azimuth that does not cause interference airflow, and shall be arranged to be arranged with devices that generate or dissipate water vapor, acid mist and other media with adhesion, corrosiveness, flammability and explosiveness.

It should be isolated from the area where the above medium is produced.

4.5 The dusting room should not double as a spray booth.

5, fire, explosion-proof

5.1 The surface of the workpiece entering the dusting chamber shall have a surface temperature 28 ° C lower than the ignition temperature of the powder used.

5.2 The following regulations should be followed in the dusting area:

a) Fire sources, open flames and equipment and apparatus that generate sparks are not allowed;

b) prohibiting the impact or friction from generating sparks;

c) heating equipment that does not ignite powder or powder gas mixture should be used;

d) Fire extinguishing fire extinguisher according to GB 50140, but it is not suitable to use fire extinguisher which is easy to make powder coating fly or pollute.

5.3 In the automatic dusting room, a reliable alarm device and an automatic fire extinguishing system should be installed. In the event of a fire, the gas supply system and power supply can be automatically cut off.

6. Ground

The ground of the dusting area should be laid with non-combustible or flame-retardant anti-static materials. The ground should be smooth and seamless, with grooves to facilitate cleaning of the powder.

7. Lighting

The dust-spraying area should be illuminated by dust-proof cold light source lamps. The illumination should meet the requirements of Article 4.3.1 of GB 12367-2006. When using transparent materials for diaphragm lighting, the following requirements should be met:

a) using a fixed luminaire as the light source;

b) Separate the luminaire from the dusting area with a partition, and the installation and sealing shall ensure that the dust does not enter the luminaire;

c) The partitions shall be of non-flammable or non-combustible materials that are not easily damaged;

d) the thickness of the deposit on the partition is not allowed to affect the specified illuminance;

e) The surface temperature of the separator does not exceed 93 ° C.

product inspection

Inspection of dusting products

1. Test conditions

Arctic dawn or indoor high-efficiency two-source fluorescent lamp (illuminance 1000 lumens)

Visual distance: A-level surface 300MM, B-face 500MM, C-face 1000MM, 3 m/min speed gaze scanning.

2. Inspection criteria:

All surfaces are not exposed, peeling, no scratches, blistering, wrinkling, pinholes, powder

Film thickness: outdoor powder 60-120; indoor powder 50-100; spray paint generally 40-70 (film thickness gauge 1 point five times, take the average, the whole face takes four corners and the middle five points and then average).

3. Production of paint swatches

A: When baking, make two color plates per furnace for testing (one test, one archive). After the furnace is finished, mark the powder number, curing condition, time, and sign by QE.

B: The swatch is stored for two years, the humidity at room temperature is 70±15%, and no direct sunlight is irradiated.

4. Performance requirements

Non-destructive testing.

Film thickness test.

Luminance test: The gloss meter has an incident angle of 60 degrees, and the error of ±5% is acceptable. Some customers require gloss ≥90%.

Color difference test: A surface color difference of 0.8, the remaining side color difference of 1 or less, or swatches.

5. Destructive testing

Hundreds of tests: In the area of 100mm2, draw a line every 1mm with a utility knife (the depth must see the substrate), cross-cut 100 squares, and stick it with 3M#600 Scotch tape 10~13mm or compatible with it. Characterize the test area,

The tape is instantly and quickly peeled off the paint on the test surface in the vertical direction, and can not fall off 5%.

Bending test: The swatch is bent 180 degrees with r=t or repeated 90 degrees, and the coating does not fall off.

Hardness test: 2H pencil is applied with a force of 1KG at a 45-degree angle to push forward 15-30MM along the ruler. After the eraser is erased, no leakage is allowed, allowing slight marks; or pencil hardness H or more, cutting the tip of the pencil into a right angle. For the test surface along the 45 degree direction,

Apply 1KG force to draw 8CM straight line on the surface of the paint, the surface can not be damaged, scratched, allowing slight trace paint. Refer to room temperature hardness: 3H or more.

Resistance to solvent test: 99.8% of anhydrous alcohol cotton sticks, 50 times with 1KG force, except for a slight change in gloss, the coating should not change color, rise, peel off; or clean cotton, clean solvent (industrial alcohol) 95%);

Apply 50g force to the test surface to wipe back and forth 50 times. The test surface can not be discolored, peeling paint, floating, or losing luster, the gloss can be changed a little.

Impact test: 500 gram weight with a cross-sectional area of 1/4 is free to fall from 500 meters, the film does not fall off, and the crack is qualified. It is also useful for the ball drop test: ball drop test (using a solid ball with a diameter of 1.5CM and a length of 1.5M hollow 竿,

Test the strength and adhesion of the paint). Or on the QCJ type film impactor, (1Kg weight is free to fall at a height of 500mm, no cracks and sprayed layer peeling).

Abrasion resistance test: brush with a sponge brush, 5000 times, can not expose the material with a sponge brush hard side, plus a width of 30mm, 500g load, 55mm distance, 60 times / min back and forth brush; or Great Wall rubber 500g Force back and forth 50 times without leaking bottom.

Moisture resistance: 24H in 60°C relative humidity 90%, the film surface is not abnormal.

Boiling water resistance: boiling water, 1hr soaking, no abnormality.

Resistance to fading: Use a wavelength of 2800A ° ~ 3000A °, a 15W UV lamp. Continuous irradiation for 72 hours at a distance of 625px, and then compared with the comparative sample, the test surface can not have leg color, peeling paint, floating or tarnishing.

Alkali resistance: 5% NaOH, no change in 240hr.

Acid resistance: 3% HCl, no change in 240hr.

Solvent resistance: xylene, no change in 24hr.

Pollution resistance: Lipstick, no abnormality at 24 hr at room temperature.

Corrosion resistance: salt spray resistance 1000hr no change; heat and humidity resistance 500hr no change; or salt spray can not have bubbles, rust occurs (5% salt water 35 degrees Celsius, continuous spray 400 hours).

 

Laser marking technology is one of the largest application areas of laser processing. Laser marking is a chemical reaction that uses a high-energy-density laser to locally irradiate a workpiece to vaporize or color change the surface material.

Therefore, a marking method that leaves a permanent mark. Laser marking can produce various characters, symbols and patterns, and the character size can be on the order of millimeters to micrometers, which has special significance for product anti-counterfeiting.

Fundamental

The basic principle of laser marking is that a high-energy continuous laser beam is generated by a laser generator, and the focused laser acts on the printing material to instantaneously melt or even vaporize the surface material by controlling the path of the laser on the surface of the material.

Thereby forming the required graphic mark.

Laser marking is characterized by non-contact machining, which can be marked on any irregular surface, the workpiece will not be deformed and generate internal stress, suitable for marking metal, plastic, glass, ceramic, wood, leather and other materials.

The laser can mark all parts (such as pistons, piston rings, valves, valve seats, hardware tools, sanitary ware, electronic components, etc.), and the marking is wear-resistant. The production process is easy to automate, and the marked parts are less deformed.

The laser marking machine adopts the scanning method to mark, that is, the laser beam is incident on the two mirrors, and the scanning motor is controlled by the computer to drive the mirrors to rotate along the X and Y axes respectively, and the laser beam is focused and falls onto the marked workpiece.

Thereby forming traces of laser marking

In the Pearl River Delta, the laser translation of laser marking in the Hong Kong and Taiwan regions is called laser laser processing.

Advantage

The focused ultra-fine laser beam is like a tool, which can remove the surface material of the object point by point. Its advanced nature is that the marking process is non-contact processing, without mechanical extrusion or mechanical stress, so it will not damage the processed object;

Due to the small size of the laser after focusing, the heat-affected area is small and the processing is fine, so that some processes that cannot be realized by conventional methods can be completed.

The “tool” used in laser processing is the spot after focusing. No additional equipment and materials need to be added. As long as the laser works normally, it can be processed continuously for a long time. The laser processing speed is fast and the cost is low.

Laser processing is automatically controlled by a computer and requires no human intervention during production.

What kind of information can be marked by the laser is only related to the content designed in the computer. As long as the artwork marking system designed in the computer can identify it, the marking machine can accurately restore the design information to the appropriate carrier.

Therefore, the function of the software actually determines the function of the system to a large extent.

 

Screen printing refers to the use of a screen as a substrate, and through the photosensitive plate making method to produce a screen printing plate with graphics. Screen printing consists of five major elements, screen printing plate, scraper, ink, printing table And the substrate.

The mesh of the screen printing plate can be permeable to the ink, and the non-image part of the mesh can not be printed through the basic principle of the ink. When printing, the ink is poured into one end of the screen printing plate, and the screen is used with the squeegee. Applying a certain amount of pressure to the ink on the plate,

At the same time, the other end of the screen printing plate moves at a constant speed, and the ink is pressed by the squeegee from the mesh of the graphic part to the substrate during the movement.

Process origin

The most convenient stencil printing was written at the end of the 19th century. This printing was made on a special stencil paper, made of a stencil graphic version by a typewriter or a stylus, and printed on a wax paper plate with an ink roller.

The ideal printing effect can be obtained on the substrate. In stencil printing, the most widely used is screen printing.

Screen printing is to stretch silk fabric, synthetic fiber fabric or metal mesh on the frame, using manual engraving film or photochemical plate making method to produce screen printing plate. Modern screen printing technology,

The screen printing plate is formed by photolithography by using a photosensitive material (so that the screen hole of the graphic part on the screen printing plate is a through hole, and the screen hole of the non-graphic part is blocked), oil painting, printmaking, Poster, business card,

Binding cover, commodity packaging, commodity signs, printing and dyeing textiles, glass and metal plane carriers, etc.

Plate making method

Direct plate making

Method: The method of direct plate making is to first place the photosensitive film coated with the photosensitive material on the surface of the work surface in the plate making process, and place the stretched wrist frame on the base.

Then put the photosensitive paste in the net frame and apply pressure coating with a soft scraper. After drying, remove the plastic base, and attach the photosensitive film to the screen, which can be used for printing, developing and drying. Screen printing screen.

Process: stretched net - skim - drying - peeling film base - exposure - development - drying - revision - sealing network

Indirect plate making

Method: The indirect plate making method is to expose the indirect film first, harden it with 1.2% H2O2, develop it with warm water, and dry it to make a peelable graphic film. When making the plate, the film film surface is tightly attached to the stretched wire mesh. ,

The film is adhered to the wet wire mesh by extrusion, the film base is peeled off, and the screen printing screen is made by drying with the wind.

Process flow:

1) Stretched net - skim - drying

2) Indirect film - exposure - hardening - development

1and2 - fit - blow dry - revision - seal net

3) Straight intermixing method a

First, the photosensitive adhesive layer is pasted on the screen frame with water, alcohol or photosensitive glue. After drying by hot air, the base of the photographic film is removed, and then the plate is printed, and the screen plate is formed after development.

working principle

Screen printing consists of five major elements, namely screen printing plate, squeegee, ink, printing table and substrate. The basic principle of screen printing is to use the screen printing part of the mesh to penetrate the ink.

The basic principle of the non-image part of the mesh is not ink-permeable. When printing, the ink is poured on one end of the screen printing plate, and a certain pressure is applied to the ink portion on the screen printing plate by the squeegee blade.

Simultaneously moving toward the other end of the screen printing plate. The ink is squeezed from the mesh of the graphic portion onto the substrate during the movement. The ink is fixed within a certain range due to the viscosity of the ink.

During the printing process, the squeegee is always in line contact with the screen printing plate and the substrate, and the contact line moves with the movement of the squeegee, because a certain gap is maintained between the screen printing plate and the substrate,

The screen printing plate at the time of printing generates a reaction force against the squeegee by its own tension. This reaction force is called resilience. Due to the resilience, the screen printing plate and the substrate are only in mobile line contact.

The other parts of the screen printing plate are separated from the substrate. The ink and the screen are broken, which ensures the printing dimensional accuracy and avoids the dirty substrate. When the scraper scrapes across the entire surface, it is lifted and screen printed. The version is also raised,

And the ink is lightly scraped back to the initial position. This is a printing stroke.

advantage

Advantages of screen printing:

(1) Not limited by the size and shape of the substrate

Generally, printing can only be carried out on a flat surface, and the screen printing can not only print on a flat surface but also on a special shaped molding such as a spherical surface, and the shape can be screen printed.

(2) The layout is soft and small

The screen is soft and flexible.

(3) Strong ink coverage

It can be printed on pure black paper with a strong white effect.

(4) Suitable for all types of inks

(5) Strong resistance to optical rotation

The gloss of the printed matter can be kept unchanged (no effect on temperature and daylight). This makes it unnecessary to apply additional film and other processes when printing some stickers.

(6) Flexible printing methods

(7) Easy plate making, low price, easy to master technology

(8) Strong adhesion

(9) can be hand-printed silk screen or machine-printed

(10) Suitable for long-term display, outdoor advertising is expressive

UV glazing

Partial UV glazing refers to the UV varnish on a certain pattern on the original black print. After the UV varnish is finished, the glazing pattern is brighter and brighter than the surrounding printing effect. Strong.

Because the screen printing ink layer is thick, it will bulge after curing, and it looks like an indentation. Screen printing UV glazing is higher in height, leveling and thickness than offset UV, so it has been favored by foreign merchants.

Screen printing partial UV glazing has solved the problem of adhesion on black film after printing BOP or PETPPOPP, and it can also be convex and scratch resistant, folding resistant and low odor. This creates a large market space and can be applied in packaging. ,trademark,

Books, propaganda and other printing fields, to achieve the finishing touch.

Screen printing local UV glazing equipment used for low interest, a small amount of production will not cause waste (each version of the outsourcing production costs between 50--150 yuan, and can be reused repeatedly) required equipment: drying version, Printing, UV curing.

The whole set of equipment investment can be completed as long as tens of thousands of yuan. For example, the production of the printing plate can reduce the investment in the printing equipment. The electricity consumption is about 9kw, and the staff can be simple and easy to understand. 30 square meters area.

With the above hardware, you can easily have local UV glazing, UV glazing area up to 1500pxX2250px wide paper, thickness up to 125px.

If you already have hardware, it is easier to develop. Just pay attention to the choice of UV varnish according to the substrate. Select the mesh parameters according to the concentration of UV varnish and the ink return of printing. Select the thickness of the photoresist during the printing process according to the thickness of the customer. And the mesh is sparse and dense,

Generally between 350 mesh - 420 mesh.