1. Injection molding
(1) Injection molding
Injection molding: also known as injection molding, the principle is to add granular or powdered raw materials to the hopper of the injection machine, the raw materials are heated and melted in a flowing state, driven by the screw or piston of the injection machine, through the nozzle and the pouring system of the mold into the mold cavity, hardening and shaping in the mold cavity. Factors that affect the quality of injection molding: injection pressure, injection molding time, injection temperature.
Process features:
merit:
1, short molding cycle, high production efficiency, easy to achieve automation
2. It can form plastic parts with complex shapes, precise dimensions, and metal or non-metal inserts
3. Stable product quality
4. Wide range of adaptation
shortcoming:
1. The price of injection molding equipment is high
2. The injection mold structure is complex
3, high production costs, long production cycle, not suitable for single pieces of small batch plastic parts production
apply:
In industrial products, injection molding products are: kitchen supplies (garbage cans, bowls, buckets, pots, tableware and various containers), electrical equipment shells (hair dryers, vacuum cleaners, food mixers, etc.), toys and games, various products of the automotive industry, parts of many other products, etc.
(2) Insert injection molding
Insert injection molding: insertmolding refers to the molding method of injecting resin into the mold after loading pre-prepared foreign material inserts, and the molten material is bonded and cured with the inserts to make an integrated product.
1. The pre-molding combination of multiple inserts makes the post-engineering of the product unit combination more reasonable.
2. The combination of the formability and bendability of the resin and the rigidity, strength and heat resistance of the metal can be made into a complex and exquisite metal plastic integration product.
3, especially the use of resin insulation and metal conductivity of the combination, the molding products can meet the basic functions of electrical products.
4. For rigid molded products and curved elastic molded products on the rubber sealing gasket plate, after the integrated product is made by injection molding on the substrate, the complex operation of arranging the sealing ring can be eliminated, making the automatic combination of the post-process easier.
(3) Two-color injection molding
Two-color injection molding: refers to the molding method of injecting two different colors of plastic into the same mold. It can make the plastic appear in two different colors, and can make the plastic parts present a regular pattern or irregular moiré pattern to improve the use and aesthetics of the plastic parts.
1, the core material can use low viscosity materials to reduce the injection pressure.
2, from the consideration of environmental protection, the core material can use recycled secondary materials.
3, according to different use characteristics, such as thick finished leather material using soft material, core material using hard material or core material can use foam plastic to reduce weight.
4, can use lower quality core materials to reduce costs.
5, the leather material or core material can be used expensive and has special surface properties, such as anti-electromagnetic wave interference, high conductivity and other materials to increase product performance.
6. Proper cortex and core material combination can reduce the residual stress of the molded product, increase the mechanical strength or surface properties of the product.
(4) Micro-foam injection molding process
Micro foam injection molding process: is an innovative precision injection molding technology, which relies on the expansion of pores to fill the product, and completes the molding of the part at a low and average pressure. The microporous foaming molding process can be divided into three stages: first, the supercritical fluid (carbon dioxide or nitrogen) is dissolved into the hot melt adhesive to form a single-phase sol; then the mold cavity with low temperature and pressure is shot through the switching nozzle, and a large number of bubble nuclei are formed in the product due to the instability of the molecules caused by the decrease in temperature and pressure, and these bubble nuclei gradually grow to form tiny holes.
1. Precision injection molding;
2. It breaks through many limitations of traditional injection molding, which can significantly reduce the weight of the parts and shorten the molding cycle;
3. Greatly improve the warpage deformation and dimensional stability of the parts.
Automotive dashboards, door panels, air conditioning ducts, etc
(5) Nano Injection Molding (NMT)
NMT (NanoMolding Technology): Is a combination of metal and plastic nanotechnology, the metal surface after nano-treatment, the plastic is directly injected into the metal surface, so that the metal and plastic can be formed as one. Nanoforming technology is divided into two types of processes according to the position of the plastic:
1. Plastic is integrally molded for non-appearance surfaces
2. Plastic is the integral molding of the appearance surface
1, the product has a metallic appearance texture,
2. The design of the product mechanism parts is simplified, so that the product is lighter, thinner, shorter, smaller, and more cost-effective than the CNC processing method.
3. Reduce production costs and high bonding strength, and greatly reduce the use rate of related consumables
Applicable metal and resin materials:
1, aluminum, magnesium, copper, stainless steel, titanium, iron, galvanized sheet, brass;
2. The adaptability of aluminum alloy is strong, including 1000 to 7000 series;
3. Resin includes PPS, PBT, PA6, PA66, PPA;
4. PPS has a particularly strong adhesion strength (3000N/c㎡).
Mobile phone case, laptop case, etc
Second, blow molding
Blow molding: it is a method of extruding the molten thermoplastic raw materials extruded from the extruder, clamping into the mold, and then blowing air into the raw materials, and the molten raw materials expand under the action of air pressure, adhere to the wall of the mold cavity, and finally cool and solidify into the desired product shape. Blow molding is divided into two types: film blow molding and hollow blow molding:
1. Film blow molding
Film blow molding is to extrude the molten plastic from the circular gap of the extruder head mold in a cylindrical thin tube, and at the same time blow compressed air into the inner cavity of the thin tube from the center hole of the head, blow the thin tube into a larger diameter tubular film (commonly known as bubble tube), cool and roll it.
2. Hollow blow molding
Hollow blow molding is a secondary molding technology that inflates the rubber-like billet closed in the mold cavity with the help of gas pressure into a hollow product, which is a method of producing hollow plastic products. The manufacturing methods of hollow blow molding according to the blank are different, including extrusion blow molding, injection blow molding, and stretch blow molding.
1) Extrusion blow molding: Extrusion blow molding is to extrude the tubular blank with an extruder, clamp it in the mold cavity and seal the bottom while it is hot, and then inject compressed air into the inner cavity of the pipe blank to blow the molding.
2) Injection blow molding: The type blank used is obtained by injection molding. The blank remains on the core mold of the mold, and after the mold is closed with the blow molding mold, compressed air is introduced from the core mold, and the blank is inflated, cooled, and the product is obtained after demoulding.
The product wall thickness is uniform, the weight tolerance is small, the post-processing is small, and the waste corner is small; it is suitable for the production of small fine products with large batches.
3) Stretch blow molding: the blank that has been heated to the stretching temperature is placed in the blow molding mold, the longitudinal stretch is carried out with the stretching rod, and the compressed air is blown in for lateral stretching and expansion, so as to obtain the method of obtaining the product.
1. Film blow molding is mainly used for the manufacture of plastic thin molds;
2. Hollow blow molding is mainly used to make hollow plastic products (bottles, packaging barrels, watering cans, fuel tanks, cans, toys, etc.).
Third, extrusion molding (profile)
Extrusion: Also known as extrusion molding, it is mainly suitable for the molding of thermoplastics, and is also suitable for the molding of some thermosets with good fluidity and reinforced plastics. The molding process is to use a rotating screw to extrude the heated and molten thermoplastic raw material from the machine head with the desired cross-section shape, and then set by the stylizer, and then through the cooler to make it cold and hard cured, becoming the product of the required cross-section.
1. Low equipment cost;
2. Simple operation, easy process control, easy to achieve continuous automated production;
3, high production efficiency, product quality is uniform, dense;
4. By changing the head die, various cross-sectional shapes of products or semi-finished products can be formed.
In the field of product design, extrusion molding has strong applicability. The types of extruded products are pipes, films, rods, monofilaments, flat belts, nets, hollow containers, windows, door frames, plates, cable cladding, monofilaments and other profiles.