1、 Surface stereoscopic printing (water transfer printing)

Water transfer printing - is the use of water pressure and activator to dissolve and transfer the stripping layer on the water transfer carrier film. The basic process is:

1. Film printing: printing various patterns on polymer films;

2. Spray primer: Many materials must be coated with a layer of adhesive, such as metal, ceramics, etc. To transfer different patterns, different base colors must be used, such as brown, coffee, earth yellow for wood grain, white for stone grain, etc;

3. Extension of membrane: Lay the membrane flat on the water surface and wait for the membrane to extend smoothly;

4. Activation: Using a special solvent (activator) to activate the pattern of the transfer film into an ink state;

5. Transfer printing: Using water pressure to print the activated pattern onto the printed object;

6. Water washing: Wash the remaining impurities of the printed workpiece with water;

7. Drying: Dry the printed workpiece at a temperature that depends on the material's quality and melting point;

8. Spray topcoat: Spray transparent protective paint to protect the surface of the printed object;

9. Drying: Dry the surface of the object after spraying the topcoat.

There are two types of water transfer printing technology, one is water mark transfer printing technology, and the other is water cover transfer printing technology. The former mainly completes the transfer of text and photo patterns, while the latter tends to complete the transfer printing on the entire product surface.

Cubic Transfer technology uses a water-based film that is easily soluble in water to carry images and text. Due to the excellent tension of the water covered film, it is easy to wrap around the product surface to form a graphic and textual layer, giving the product a completely different appearance just like spray painting. Covering transfer printing technology can cover color patterns on any shape of workpiece, solving the problem of three-dimensional product printing for manufacturers.

Curved covering can also add different patterns on the surface of the product, such as leather, wood, jade, and marble patterns, while also avoiding the common voids in general board printing. And in the printing process, as the product surface does not need to come into contact with the printing film, it can avoid damaging the product surface and its integrity.

2、 Metal wire drawing

The surface drawing process of aluminum alloy: Drawing can be made into several types according to decorative needs, such as straight lines, random lines, threads, ripples, and spiral lines.

1. Straight wire drawing refers to the process of machining straight lines on the surface of aluminum plates using mechanical friction. It has a dual function of brushing away scratches on the surface of aluminum panels and decorating the surface of aluminum panels. There are two types of straight wire drawing: continuous and intermittent.

Continuous silk patterns can be obtained by using a cleaning cloth or stainless steel brush to continuously and horizontally rub the surface of the aluminum plate in a straight line (such as manually grinding or using a planer to clamp a steel wire brush on the aluminum plate). Changing the diameter of the steel wire of the stainless steel brush can obtain different thicknesses of patterns. Intermittent silk patterns are generally processed on a brushing or wiping machine.

Production principle: Two sets of differential wheels rotating in the same direction are used. The upper group is a fast rotating grinding roller, and the lower group is a slow rotating rubber roller. Aluminum or aluminum alloy plates pass through the two sets of rollers and are brushed with delicate intermittent straight lines.

2. Random pattern wire drawing is a type of irregular and non obvious matte wire pattern obtained by rubbing the aluminum plate forward, backward, left, and right under the high-speed running copper wire brush. This type of processing requires high surface requirements for aluminum or aluminum alloy plates.

3. Ripples are generally made on a brushing or wiping machine. By utilizing the axial motion of the upper group of grinding rollers, a wavy pattern is obtained by grinding and brushing on the surface of aluminum or aluminum alloy plates.

4. Rotational pattern, also known as optical rotation, is a type of silk pattern obtained by rotating and polishing the surface of aluminum or aluminum alloy plates using cylindrical felt or grinding nylon wheels mounted on a drilling machine, kerosene mixed with polishing paste. It is mostly used for decorative processing of circular signs and small decorative dials.

5. Thread is a small motor equipped with a circular felt on the shaft, which is fixed on the desktop at an angle of about 60 degrees to the edge of the table. In addition, a mop with a fixed aluminum plate for pressing tea is made, and a polyester film with a straight edge is pasted on the mop to limit thread competition. By utilizing the rotation of the felt and the linear movement of the drag plate, a thread pattern with a consistent width is formed on the surface of the aluminum plate.

3、 Anodizing

As a light metal, aluminum and its alloys have become more and more popular in industrial design. MP3 players, DSC, mobile phones, NB, and even desktop computers can all see the shadow of light metal (magnesium alloy and aluminum alloy are the mainstream). The proportion of magnesium alloy used in NB (including internal and external components) has exceeded 50%. Apple's MP3 players, desktop computers, Sony's DSC, and even a large number of aluminum alloy materials are used. The oxidation coloring of aluminum alloy is a commonly used surface treatment process for small electromechanical products, which mainly enhances the corrosion resistance of the product surface (such as blackening and blueing) and gives the product a decorative effect (such as uniform and consistent colors).

The oxidation coloring effect is related to the material composition and process parameters of aluminum alloys. After the oxidation and coloring of the aluminum alloy surface, there is usually a subsequent treatment process to make the entire product more aesthetically pleasing. Another point is that coloring is not a post-treatment of oxidation, it is carried out simultaneously with oxidation.

There are several commonly used oxidation coloring treatment methods:

1. Colored anodic oxide film The anodic oxide film of aluminum is colored by adsorbing dyes.

2. Spontaneous colored anodic oxide film This anodic oxide film is a colored anodic oxide film spontaneously generated by the alloy itself in a suitable electrolyte (usually based on organic acids) under electrolysis.

3. Electrolytic coloring of anodic oxide films is achieved by electrodepositing metal or metal oxides through the gaps in the oxide film.

4、 Aluminum plate diamond carving

Aluminum plate diamond carving: It can maintain good compressive strength, high hardness, high mechanical strength, good wear resistance, light specific gravity, and a relative heat index of up to 80c at low temperatures. It can also maintain good dimensional stability, fire resistance, simple process, good glossiness, and easy coloring at high temperatures. Compared to other thermoplastic plastics, it has lower costs. Typical uses include electronic consumer goods, toys, environmental protection products, automotive dashboard, door panels, and outdoor protective barriers.

5、 Electroplating process

Electroplating process: Electroplating refers to a surface processing method in which the cations of the metal to be plated in the plating solution are deposited on the surface of the substrate metal through electrolysis in a salt solution containing the metal to be plated. The performance of the coating is different from that of the base metal and has new characteristics. According to the function of coatings, they are divided into protective coatings, decorative coatings, and other functional coatings.

Electroplating process: generally includes three stages: pre-treatment before electroplating, electroplating, and post-plating treatment. Requirements for electroplated coatings:

1. There should be good adhesion between the coating and the base metal, as well as between the coating and the coating.

2. The coating should be finely crystallized, flat, and of uniform thickness.

3. The coating should have a specified thickness and as few pores as possible.

4. The coating should have specified indicators such as brightness, hardness, conductivity, etc.

6、 Nickel plating

Nickel is a silver white slightly yellow metal with ferromagnetism, a density of 8.9/g.cm-2, and a melting point of 14530C. Nickel metal is easily soluble in dilute nitric acid, but difficult to dissolve in hydrochloric acid and sulfuric acid, and is in a passive state in nitric acid. In the air, nickel reacts with oxygen to quickly form an extremely thin passivation film on the surface, which can resist the corrosion of atmosphere, alkali, and some acids. Nickel does not react with strong alkalis.

The standard electrode potential of nickel is -0.25V, and nickel plating has a wide range of applications, which can be divided into two aspects: protective decoration and functionality. As shown in the figure below, the radiator has a black or yellow appearance

7、 Chrome plating

Chromium is a silvery white metal with a slight sky blue. Although the electrode potential is very negative, it has strong passivation performance and quickly passivates in the atmosphere, showing the properties of precious metals. Therefore, the chromium plating layer on iron parts is a cathodic coating. The chromium layer is very stable in the atmosphere and can maintain its luster for a long time. It is very stable in corrosive media such as alkali, nitric acid, sulfide, carbonate, and organic acid, but soluble in hydrogen halide acids such as hydrochloric acid and hot concentrated sulfuric acid.

The chromium layer has high hardness, good wear resistance, strong reflective ability, and good heat resistance. There is no significant change in gloss and hardness below 500OC; When the temperature exceeds 500OC, oxidation and discoloration begin; Only when it is greater than 700OC does it begin to soften. Due to the excellent performance of the chromium plating layer, it is widely used as an outer layer and functional coating for protective and decorative coating systems.

Other electroplating

Copper plating: The copper plating layer is pink in color, soft in texture, and has good ductility, conductivity, and thermal conductivity. It is easy to polish, and after appropriate chemical treatment, decorative colors such as bronze, copper green, black, and natural color can be obtained. Copper plating tends to lose its luster in the air, and reacts with carbon trioxide or chloride to form a basic copper carbonate or copper chloride film on the surface, which will generate brown or black copper sulfide under the action of sulfide. Therefore, as a decorative copper plating layer, it needs to apply an organic coating on the surface.

Cadmium plating: Cadmium is a silver white glossy soft metal, harder than tin and softer than zinc, with good plasticity and easy forging and rolling. Cadmium has chemical properties similar to zinc, but it does not dissolve in alkaline solution, but in nitric acid and ammonium nitrate. It dissolves slowly in dilute sulfuric acid and hydrochloric acid.

The vapor of cadmium and soluble cadmium salts are both toxic, and cadmium pollution must be strictly prevented. Due to the significant harm and high cost of cadmium pollution, galvanized or alloy coatings are usually used to replace cadmium plating. At present, the commonly used types of cadmium plating solutions in domestic production include ammonia carboxyl complex cadmium plating, acidic sulfate cadmium plating, and cyanide cadmium plating. In addition, there are cadmium plating with pyrophosphate, cadmium plating with alkaline triethanolamine, and cadmium plating with HEDP.

Tin plating: Tin has a silver white appearance, with an atomic weight of 118.7, a density of 7.3g/cm3, a melting point of 2320C, and atomic valences of divalent and tetravalent. Therefore, the electrochemical equivalents are 2.12g/A.h and 1.107g/A.h, respectively. Tin has advantages such as corrosion resistance, non-toxicity, easy soldering, softness, and good ductility.

Tin plating has the following characteristics and uses:

1. High chemical stability;

2. In the electrochemical process, the standard potential of tin is positive, which is a cathodic coating for steel. Only when there are no pores in the coating can the substrate be effectively protected;

3. Tin has good conductivity and is easy to solder;

4. Tin begins to mutate when crystallized from -130C, and by -300C, it will completely transform into an allotrope of a crystalline form, commonly known as "tin blast". At this point, the properties of tin have been completely lost;

5. Tin, like zinc and cadmium coatings, can grow into whiskers under high temperature, humidity, and enclosed conditions, known as long hairs

6. After tin plating, it can be remelted in hot oil above 2320C to obtain a glossy patterned tin layer that can be used as a decorative coating for daily necessities.

In terms of electroplating single metals, there are also lead plating, iron plating, silver plating, gold plating, etc. In terms of electroplating alloys, there are: electroplating copper based alloys, electroplating zinc based alloys, electroplating cadmium based alloys, indium based alloys, electroplating lead based alloys, tin based alloys, electroplating nickel based alloys, cobalt based alloys, electroplating palladium nickel alloys, etc. In terms of composite electroplating, there are nickel based composite electroplating, zinc based composite electroplating, silver based composite electroplating, and diamond embedded composite electroplating.

8、 Surface spraying (plastic parts)

The four main elements that make up coatings include:

1. Resin;

2. Pigment;

3. Solvent;

4. Other additives.

There are several types of paint drying:

1. Evaporation drying (using diluent evaporation drying);

2. Fusion drying (molecular and phase resistant polymerization due to volatilization);

3. Oxidative drying (unsaturated fat acid combines with oxygen in the air);

4. Using bridging reaction to dry (using bridging agent, also known as hardening agent to form bridging and harden);

5. UV hardening (unsaturated polyester additives are used to harden molecules after irradiation with UV wavelengths of 300-400mn).

UV process introduction:

UV coatings can be applied by dipping, showering, painting, spin coating, or even vacuum coating methods, and then cured into a film by irradiation with ultraviolet photons. Compared with general solvent based coatings, the characteristics of UV coatings are as follows:

1. Fast curing speed;

2. Curing at room temperature;

3. Energy conservation;

4. Save land area;

5. Not polluting the environment;

6. Improve product performance.

9、 Transfer printing

Transfer printing refers to the process in which the substrate is an irregularly shaped surface (such as instruments, electrical parts, toys, etc.), and a copper or steel concave plate is used to cast a hemispherical transfer printing head through silicone rubber, which presses the printing ink onto the substrate to complete transfer printing. Pad printing technology is a special printing technology that was introduced to China in the 1980s. Because of its obvious advantages in printing on small area, concave and convex products, it makes up for the lack of screen printing technology.

In the early 1990s, with the further opening of the Chinese market, a large number of foreign-funded enterprises mainly engaged in traditional industries such as electronics, plastics, gifts, toys and so on entered the Chinese market one after another. The pad printing technology and screen printing technology, as the main decoration method, have achieved extraordinary development. According to incomplete statistics, the application of pad printing technology and screen printing technology in the above industries has reached 27%, 64%, 51% and 66% respectively.

Applicable industries for transfer printing machines:

Plastic industry, toy industry, glass industry, metal industry, electronics industry, sports goods industry, stationery industry, optical industry, IC packaging industry, etc.

Scope of application of transfer printing machine:

Printing of rulers, pens, spherical objects, doll eyes, watches, cameras, hair dryers, ceramic magnets, medical equipment, rackets, audio tapes, electronic parts, ICs, CPUs, DRAMs, computer casings, buttons, decorative logos, and phone cases.

Overall, the technological content of pad printing technology is not high, and it is difficult to continue developing in developed countries with high production costs. Therefore, the transfer of the pad printing industry to low labor cost developing countries like China is an inevitable trend. Currently, in addition to a few foreign companies that also manufacture highly automated pad printing production lines, most of them have moved their production bases to China.

10、 Heat transfer printing

Heat transfer printing is a technique of printing patterns or patterns onto heat-resistant adhesive paper, and then applying heat and pressure to print the pattern patterns of the ink layer onto the finished material. Even for patterns with multiple colors, as the transfer process is only a process, customers can shorten the printing process and reduce material (finished product) losses caused by printing errors. By using heat transfer film printing, multi-color patterns can be formed into a single image without the need for color matching. Simple equipment can also print realistic patterns.

Heat transfer printing equipment is used for decorating aluminum shaped materials and various metal plates, which can achieve the effect of wooden products or marble. The heat transfer printing equipment operates based on the principle of thermal sublimation. It can quickly transfer the desired wood or marble grain to the surface of the aluminum powder coating within 3-5 minutes and can penetrate into the interior of the coating by 40-60 microns.

Aluminum transfer printing production process:

1. Use a film machine to roll and cut the heat transfer film to the required size.

2. Use transfer ultrasonic packaging machine to weld the cut transfer film into a workpiece package bag with ultrasonic welding according to the size of the workpiece.

3. Insert the workpiece into a packaging bag made of transfer film on the packaging platform.

4. Place the workpiece with the transfer film wrapped on the platform of the heat transfer machine trolley, where 18 aluminum pieces can be placed in sequence. Connect the vacuum taps on both ends of the aluminum material and lock them tightly. Turn on the vacuum switch, and at this time, the transfer film is tightly attached to the aluminum material.

The car automatically sends the aluminum material to the baking furnace, which automatically heats up to 220 degrees and keeps it warm for 3 minutes. The car automatically exits the baking furnace. Fifth, loosen the vacuum tap and remove the workpiece. Six is to remove the transfer film and check the quality of the workpiece.

The production process of flat heat transfer printing involves using a film cutting machine to cut the heat transfer printing paper roll into the required size. The second is to attach the heat transfer paper film to the surface of the workpiece and place it on a flat plate heat transfer machine. The third is to push the flat plate to the heating area of the flat plate heat transfer machine, press the pressure plate switch, and the pressure plate tightly presses the heat transfer paper onto the workpiece, heating and keeping it warm for one minute. The fourth is to raise the pressure plate, push the workpiece to the section, remove the transfer film, remove the workpiece, and inspect it.

Heat transfer printing technology is widely used in electrical appliances, daily necessities, building materials decoration, etc. Due to its properties such as corrosion resistance, impact resistance, aging resistance, wear resistance, fire resistance, and non discoloration after 15 years of outdoor use, almost all products are labeled using this method.

For example, when you open the phone case, you can see densely packed labels with barcodes inside. Many labels require that they can withstand the test of time, remain unchanged for a long time, do not fade, do not wear out due to contact with solvents, and do not deform or change color due to high temperatures. Therefore, it is necessary to use a special material printing medium and printing material to ensure these characteristics, which is not achievable with general inkjet and excitation printing techniques.

11、 Sandblasting

The application of sandblasting treatment on metal surfaces is very common. The principle is to impact accelerated abrasive particles onto the metal surface to achieve rust removal, deburring, oxidation layer removal, or surface pretreatment. It can change the smoothness and stress state of the metal surface. Some parameters that affect sandblasting technology need to be noted, such as abrasive type, abrasive particle size, spraying distance, spraying angle, and speed. In addition to sandblasting, shot blasting is also a good choice.

The sandblasting process can be divided into two types: air pressure spray gun and impeller shot blasting. The advantage of sandblasting process is that it can remove burrs after die-casting, stamping, flame cutting, and forging. It has a better effect on thinner workpieces and burrs with pores. It can clean residual sand particles during the sandblasting process, clean rust stains on cast iron or steel, clean heat treatment, burn, hot forging, rolling, and other thermal processes to remove oxide skin.

In addition, in coating applications, it can remove existing coatings or protective layers, cover defects such as cracks or cold lines on castings, and provide a glossy surface. In addition, in terms of surface stress, it can provide a consistent roughening surface, oiling, and spraying effect. When high stress metal parts such as springs and connecting rods are continuously struck locally, they will deform and show strengthening phenomenon. This strengthening effect requires the use of circular abrasives such as stainless steel balls in high-energy shot blasting machines or specialized powerful sandblasting machines. To determine the surface strengthening effect of the machine, the test workpiece can be shot blasted or sandblasted, and then the deformation amount can be measured to see if it meets the requirements.

12、 Laser engraving

A surface treatment process using optical principles, commonly used on buttons in mobile phones and electronic dictionaries. Simply put, it's like this: For example, I want to make a keyboard with characters in blue, green, red, and gray on it, and the key body is white. When laser engraving, spray the corresponding colors of blue, green, red, and gray first, and be careful not to spray them on other keys. This will make it look like there are blue, green, and other keys, and then spray a layer of white on the whole, making it a whole white keyboard, Each blue and green is wrapped underneath.

At this point, laser engraving can be carried out. Using laser technology and ID generated key maps, the film is made by carving off the white oil on top, such as processing the letter "A". If the white on the stroke is carved off, the blue or green underneath will be exposed, forming various color letter buttons.

At the same time, if you want light transmission, use PC or PMMA to spray a layer of oil and carve out the font part. If there is light below, it will be transparent, but at this time, the adhesion performance of various oils should be considered. Because each color key needs to be sprayed with different oils, it is necessary to consider this when making the structure. Each key should be separated to avoid unnecessary spraying. There are also areas with high losses, so it is better to make two or more, so that multiple can be matched.

The color difference of each color should be slightly larger, with the largest being black and white. This way, the machine can easily distinguish and carve clean, so as not to carve unclean and affect the appearance quality. Additionally, the fonts of different colors should not be too close together.

The composition of the paint required for laser carving is different from that of ordinary plastic shell spray painting, called double leaf paint, which has a softer texture and is suitable for carving. In addition, before spraying exterior paint, a layer of black should be sprayed on the surface of the raw material, otherwise the color cannot be carved out.

Usually, laser engraving machines can carve the following materials: bamboo and wood products, organic glass, metal plates, glass, stone, crystal, Corinne, paper, dual color plates, aluminum oxide, leather, plastic, epoxy resin, polyester resin, and spray metal. Silk screen print.

13、 Screen printing - is the process of attaching a template with images or patterns to a screen for printing.

(Applicable to situations where the drop between flat, single curved, or curved surfaces is relatively small)

Usually, silk mesh is made of nylon, polyester, silk, or metal mesh. When the substrate is directly placed under the screen with a template, the screen printing ink or coating passes through the mesh hole in the middle of the screen under the compression of the ink scraper and is printed onto the substrate (there are two types of ink scraper: manual and automatic).

The template on the screen seals a portion of the small holes in the screen so that the pigment cannot pass through the screen, and only the image part can pass through. Therefore, only the image part has imprints on the substrate. In other words, screen printing actually uses ink to penetrate the printing plate for printing, which is why it is called screen printing instead of silk screen printing or silk printing, because not only silk is used as a screen material, nylon, polyester fiber, cotton fabric, cotton cloth, stainless steel, copper, brass, and bronze can all be used as screen materials.

14、 Ultrasonic welding

It is a high-tech technology for welding mature plastic products, and various mature plastic adhesive parts can be processed using ultrasonic welding without the need for solvents, adhesives, or other auxiliary materials. Its advantages include increasing productivity multiple times, reducing costs, and improving product quality.

The principle of ultrasonic plastic welding is that a generator generates a high-pressure and high-frequency signal of 20KHZ (or 15KHZ), which is converted into high-frequency mechanical vibration through an energy conversion system. The signal is applied to the plastic product workpiece, and the temperature from the transmission point to the interface is increased through friction between the surface and internal molecules of the workpiece. When the temperature reaches the melting point of the workpiece itself, the working interface quickly melts, and then fills the gaps between the interfaces. When the vibration stops, The workpiece is simultaneously cooled under a certain pressure to form a perfect welding.

15、 Pressure injection molding

Injection molding, also known as injection molding, is a molding method that involves both injection and molding. The advantages of injection molding method are fast production speed, high efficiency, automated operation, and the ability to shape complex shaped parts. The downside is that the mold cost is high and cleaning is difficult, so this method is not suitable for forming small batch products.

The products formed by this method include: TV casing, semiconductor radio casing, electrical connectors, knobs, coil framework, gears, car lampshades, tea cups, rice bowls, soap boxes, bathtubs, sandals, and so on.

At present, injection molding is suitable for all thermoplastic materials, with a short molding cycle, a wide variety of designs, shapes that can vary from simple to complex, and sizes that can vary from large to small. Moreover, the product size is precise and easy to update.

16、 Dual color injection molding

Double injection molding mainly uses a double injection molding machine with two material pipes and two sets of molds to form double injection products through two molding processes in sequence. Compared to traditional injection molding, the dual material co injection molding process has the following advantages:

1. Core materials can use low viscosity materials to reduce injection pressure.

2. From an environmental perspective, recycled secondary materials can be used for core materials.

3. According to different usage characteristics, such as using soft materials for thick finished products, hard materials for core materials, or foam plastics for core materials to reduce weight.

4. Lower quality core materials can be utilized to reduce costs.

5. The use of expensive materials with special surface properties, such as electromagnetic interference resistance and high conductivity, can be used to enhance product performance.

6. The appropriate combination of skin and core materials can reduce residual stress in the formed product, increase mechanical strength or surface properties of the product.

7. Produce products with marble patterns.

The characteristics and applications of multi-color injection molding and dual material co injection molding indicate a trend towards gradually replacing traditional injection molding processes in the future. The innovative injection molding technology not only improves the precision of the injection molding process, provides high difficulty process technology, but also expands the scope of the injection molding process field. Innovative injection equipment and processes are sufficient to meet the increasingly diverse, high-quality, and value-added product demands.

17、 Blow molding

Blow molding - is a method of using gas pressure to blow and expand a hot billet closed in a mold into a hollow product, or to blow and expand a tube blank into a tube film without a mold. This method is mainly used for the manufacturing of various packaging containers and tubular films. All hollow blow molding materials with a melt index of 0.04~1.12 are relatively good, such as polyethylene, polyvinyl chloride, polypropylene, polystyrene, thermoplastic polyester, polycarbonate, polyamide, cellulose acetate, and acetal resin, among which polyethylene is the most commonly used.

1. Injection blow molding - Using injection molding method, plastic is first made into a bottomed mold, and then the mold is moved into a blow molding mold to blow into a hollow product.

2. Extrusion Blow Molding - Using the extrusion method, plastic is first made into a bottomed mold, and then the mold is moved into a blow molding mold to blow into a hollow product.

The difference between injection blow molding and extrusion blow molding is that the method of manufacturing the blank is different, and the blow molding process is basically the same.

Blow molding equipment, in addition to injection machines and extruders, is mainly used for blow molding molds. Blow molding molds are usually composed of two lobes, which are equipped with coolant channels and small holes on the parting surface for inserting compressed air blowing pipes.

3. Stretch Blow Molding - Stretch Blow Molding is a type of blow molding that involves biaxial directional stretching. The method involves first stretching the blank longitudinally, and then blowing it with compressed air to achieve lateral stretching. Stretch blow molding can greatly improve the transparency, impact strength, surface hardness, and rigidity of products, making it suitable for blow molding of polypropylene and polyethylene terephthalate (PETP).

Stretch blow molding includes: injection molding oriented stretch blow molding, extrusion molding oriented stretch blow molding, multi-layer oriented stretch blow molding, compression molding oriented stretch blow molding, etc.

4. Blow molding film method - a method of forming thermoplastic films. Using the extrusion method, the plastic is first extruded into a tube, and then continuously expanded to a certain size of tubular film by blowing air into the tube. After cooling, it is folded and wound into a double-layer flat film. Plastic films can be manufactured using many methods, such as blow molding, extrusion, casting, rolling, and so on, but blow molding is the most widely used method. This method is suitable for the manufacturing of films such as polyethylene, polyvinyl chloride, polyamide, etc.

18、 Stamping

Stamping is a pressure processing method that uses a mold installed on a press to apply pressure to a material at room temperature, causing separation or plastic deformation, in order to obtain the required parts.

Characteristics of stamping processing:

1. High stamping productivity and material utilization.

2. The produced parts have high precision and complexity

3. The mold has high precision, high technical requirements, and high production costs.

Materials used for stamping:

The shapes of materials used for stamping include various specifications of sheet, strip, and block materials. The size of the sheet metal is relatively large and is generally used for stamping large parts. For small and medium-sized parts, most of the sheet metal is cut into strips and used.

Belt material (also known as coil material) comes in various specifications of width, with an unfolding length of several thousand meters. It is suitable for automatic feeding in mass production, and even when the material thickness is very small, it can be supplied as a belt material. Block materials are only used for stamping a few steel grades and expensive non-ferrous metals. Common stamping materials include: black metal: ordinary carbon structural steel, high-quality carbon steel, alloy structural steel, carbon tool steel, stainless steel, electrical silicon steel, etc.

Stamping process:

1.The stamping process varies depending on the shape, size, and accuracy of the workpiece.

2. According to the deformation characteristics of materials, the cold stamping process can be divided into two categories: separation process and forming process.

Separation process - refers to the process where the stress in the deformed part of the billet reaches the strength limit ob under the action of punching pressure, causing the billet to fracture and produce separation. The separation process mainly includes cutting and punching.

Forming process - refers to the stress in the deformed part of the billet under the action of punching pressure reaching the yield limit os, but not reaching the strength limit. The processing process that causes plastic deformation of the blank to become a workpiece with a certain shape, size, and accuracy. The main forming processes include bending, deep drawing, flanging, spinning, etc.