1. Gas-assisted injection molding (GAIM)
Forming principle:
Gas-assisted molding (GAIM) refers to the injection of high-pressure inert gas when the plastic is properly filled into the cavity (90%~99%), the gas pushes the molten plastic to continue filling the cavity, and the gas pressure is used to replace the plastic pressure holding process An emerging injection molding technology.
Features:
Reduce residual stress and reduce warpage problems;
Eliminate dent marks;
Reduce clamping force;
Reduce the length of the runner;
Save material
Shorten the production cycle time;
Extend mold life;
Reduce mechanical loss of injection molding machine;
Applied to finished products with large thickness changes.
GAIM can be used to produce tubular and rod-shaped products, plate-shaped products, and complex products with uneven thickness.
2. Water-assisted injection molding (WAIM)
Forming principle:
Water-assisted injection molding (WAIM) is an auxiliary injection molding technology developed on the basis of GAIM, and its principle and process are similar to GAIM. WAIM uses water instead of GAIM's N2 as a medium for emptying, penetrating the melt and transferring pressure.
Features: Compared with GAIM, WAIM has many advantages
The thermal conductivity and heat capacity of water are much larger than N2, so the product cooling time is short, which can shorten the molding cycle;
Water is cheaper than N2 and can be recycled;
Water is incompressible, the finger effect is not easy to appear, and the wall thickness of the product is relatively uniform;
Gas is easy to penetrate or dissolve into the melt to make the inner wall of the product rough, and to generate bubbles on the inner wall, while water is not easy to penetrate or dissolve into the melt, so products with smooth inner walls can be produced.
3. Precision injection
Forming principle:
Precision injection molding refers to a type of injection molding technology that can mold products with high requirements for intrinsic quality, dimensional accuracy and surface quality. The dimensional accuracy of the plastic products produced can reach 0.01mm or less, usually between 0.01mm and 0.001mm.
Features:
The dimensional accuracy of the parts is high, and the tolerance range is small, that is, there are high-precision dimensional limits. The dimensional deviation of precision plastic parts will be within 0.03mm, and some even as small as micrometers. The inspection tool depends on the projector.
High product repeatability
It is mainly manifested in the small deviation of the weight of the part, which is usually below 0.7%.
The material of the mold is good, the rigidity is sufficient, the dimensional accuracy of the cavity, the smoothness and the positioning accuracy between the templates are high
Using precision injection machine equipment
Using precision injection molding process
Precisely control mold temperature, molding cycle, part weight, molding production process.
Applicable precision injection molding materials PPS, PPA, LCP, PC, PMMA, PA, POM, PBT, engineering materials with glass fiber or carbon fiber, etc.
Precision injection molding is widely used in computers, mobile phones, optical discs, and other microelectronics products that require high internal quality uniformity, external dimensional accuracy and surface quality of injection molded products.
4. Micro injection molding
Forming principle:
Because of the small size of plastic parts in micro-injection molding, the small fluctuations of process parameters have a significant impact on the dimensional accuracy of the product. Therefore, the control accuracy of process parameters such as measurement, temperature and pressure is very high. The measurement accuracy must be accurate to milligrams, the barrel and nozzle temperature control accuracy must reach ±0.5℃, and the mold temperature control accuracy must reach ±0.2℃.
Features:
Simple molding process
Stable quality of plastic parts
high productivity
Low manufacturing cost
Easy to realize batch and automated production
Micro-plastic parts produced by micro-injection molding methods are increasingly popular in the fields of micro-pumps, valves, micro-optical devices, microbial medical devices, and micro-electronic products.
5. Micro-hole injection
Forming principle:
Microcellular injection molding machine has one more gas injection system than ordinary injection molding machine. The foaming agent is injected into the plastic melt through the gas injection system and forms a homogeneous solution with the melt under high pressure. After the gas-dissolved polymer melt is injected into the mold, due to the sudden pressure drop, the gas quickly escapes from the melt to form a bubble core, which grows to form micropores, and the microporous plastic is obtained after shaping.
Features:
Using thermoplastic material as the matrix, the middle layer of the product is densely covered with closed micropores with sizes ranging from ten to tens of microns.
Micro-foam injection molding technology breaks through many limitations of traditional injection molding. On the basis of basically ensuring product performance, it can significantly reduce the weight and molding cycle, greatly reduce the clamping force of the machine, and has small internal stress and warpage. High straightness, no shrinkage, stable size, large forming window, etc.
Micro-hole injection molding has unique advantages compared with conventional injection molding, especially in the production of high-precision and more expensive products, and has become an important direction of injection molding technology development in recent years.
6. Vibration injection
Forming principle:
Vibration injection molding is an injection molding technology that improves the mechanical properties of the product by superimposing the vibration field during the melt injection process to control the polymer condensed state structure.
Features:
After introducing the vibration force field in the injection molding process, the impact strength and tensile strength of the product increase, and the molding shrinkage rate decreases. The screw of the electromagnetic dynamic injection molding machine can axially pulsate under the action of the electromagnetic winding, so that the melt pressure in the barrel and the mold cavity changes periodically. This pressure pulsation can homogenize the melt temperature and structure, and reduce the melt. Viscosity and elasticity.
7. In-mold decoration injection
Forming principle:
The decorative pattern and functional pattern are printed on the film by a high-precision printing machine, and the foil is fed into a special molding mold through a high-precision foil feeding device for precise positioning, and the high temperature and high pressure of the plastic raw material are injected. .Transcribing the pattern on the foil film to the surface of the plastic product is a technology that can realize the integral molding of the decorative pattern and the plastic.
Features:
The surface of the finished product can be solid color, it can also have a metal appearance or wood grain effect, and it can also be printed with graphic symbols. The surface of the finished product is not only bright in color, delicate and beautiful, but also corrosion-resistant, abrasion-resistant and scratch-resistant. IMD can replace the traditional painting, printing, chrome plating and other processes used after the product is demolded.
In-mold decoration injection molding can be used to produce automotive interior and exterior parts, panels and displays of electronic and electrical products.
8. Co-injection
Forming principle:
Co-injection is a technology in which at least two injection molding machines inject different materials into the same mold. The two-color injection molding is actually an insert molding process of in-mold assembly or in-mold welding. It first injects a part of the product; after cooling and solidification, it switches the core or cavity, and then injects the remaining part, which is embedded with the first part; after cooling and solidification, products with two different colors are obtained.
Features:
Co-injection can give products a variety of colors, such as two-color or multi-color injection molding; or give products a variety of characteristics, such as soft and hard co-injection molding; or reduce product costs, such as sandwich injection molding.
9. Injection CAE
principle:
Injection CAE technology is based on the basic theories of plastic processing rheology and heat transfer, using computer technology to establish a mathematical model of the flow and heat transfer of plastic melt in the mold cavity, to achieve dynamic simulation analysis of the molding process, and to optimize the mold Provide basis for product design and optimization of molding process plan.
Features:
Injection CAE can quantitatively and dynamically display the speed, pressure, temperature, shear rate, shear stress distribution and orientation state of the filler when the melt flows in the gating system and cavity, and can predict the location and size of weld marks and air pockets. Predict the shrinkage rate, warpage deformation degree and structural stress distribution of plastic parts, so as to judge whether the given mold, product design plan and molding process plan are reasonable.
The combination of injection molding CAE and engineering optimization methods such as extension correlation, artificial neural network, ant colony algorithm and expert system can be used for the optimization of mold, product design and molding process parameters.
