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Plastic Injection Molded Parts Quality Control 100% Inspection

ABERY, a professional plastic injection molding company with rich experience, attaches great importance to quality control for injection molds and plastic molded parts.

The characteristics of precision injection molding is: the size of the injection molded parts with high precision, small tolerance.

precision injection molding
precision injection molding

To achieve the requirements of precision injection conditions must be met:

(1) the mold material is better, rigid, cavity dimension precision and template between positioning accuracy is higher, lower surface roughness.

(2) to adopt precision plastic molding machine.

(3) to adopt precision molding process.

(4) to choose suitable for precision injection molding process of the material. Commonly used precision molding materials have several: POM, POM = CF (carbon fiber), PNM = GF (glass fiber), PA \ FRPA66 (enhanced PA), PC, etc.

Precision injection process can ensure the size ,that molding is the important way to control the shrinkage of injection molded parts, including: thermal contraction, disguised contraction of molded parts, orientation and compressed contraction and elastic recovery.

Common injection molding features not high than precision injection molding, the size of injection molded parts are typically can be assembled into standard, requirements for the appearance of the injection molded parts is relatively high, if necessary, may use the second processing (oil, for example) to improve the appearance of defects. Ordinary injection molding don’t need to use special precision injection molding machine, also do not need to specially designated materials, general common thermoplastics can be used to production. So ordinary injection molding technology is widely used in modern plastic industry.

Precision injection molding process

In the process of precision injection molding, the raw material is pre- loaded into the box.
Automatic feeding (in the form of particles) to the injection molding machine hopper.
Melt the raw material in the barrel and inject the mold under high pressure.
The molten polymer is allowed to cool and solidify, and is removed from the mold.
If necessary, used water to clean, dry with a hair dryer. Then they are shipped for packing inspection.

Medical supplies and equipment for precision semiconductors as well as data storage, consumer electronics, medical and automotive industries in the production of precision injection molding of other high precision plastic parts.

Various tonnage of automatic precision injection molding machine (from 80 to 650 tons), our products meet the customer’s strict size, functional and aesthetic requirements.
We also provide medical products, the formation of non dust production plant, clean the packaging of various products, molding parts without pollution risk.

SELECT A GOOD PRECISION INJECTION MOLDING MACHINE
To buy a high precision injection molding machine, the impact of injection molding machine selection factors include the following:
1 die size (length * width * height), weight, special design
2 kinds of plastics (pure or many kinds of plastics)
3 injection product size (L, W, H, thickness), weight and so on.
4 molding requirements: such as quality conditions, production speed, etc….
According to the above information, you can choose the machine that suits you.
First, select the type of product and plastic material
Second, the mold can be placed on the machine, to determine the size of the tie, the height of the mold, the minimum size of the mold is appropriate.
Third, you can take out the product.
Switch trip is more than two times the height of the opening and closing of the product.
The jet’s journey is enough to spray the product.
Fourth, the clamping tonnage is determined by the plastic materials and products.
Fifth, the weight of the injection depends on the weight of the product and the mold cavity.
Sixth. Injection speed: thin-walled products always require high injection speed.

Compared with the traditional technology, Cn-moulding has higher precision injection molding and more perfect performance, which is often supplied to electronic information engineering, medical devices, packeging, cars, machinery, hardware, apparatus，timepiece industry, weapons and aerospace, etc. Therefore, it will become a revolution between parts molding and processing.

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Problem About Molding Flash & Flashing

Flash can occur during injection filling or during the pack/hold stage, and it can occur any kind of conventional parts ,especially easy happen of thin-walled parts with high MFI material . Discovering in when flash occurs helps to be responsible for the problem simplification . A simple test is to bring the pressure to the minimum the machine allows, Limitations lie is the plastic pressure should be below 500 psi . The aim is to see the effect of just barely filling the cavity. First step is injection fills 92% to 99.9% of the part, but the cavity is full then stop there. At the minimal pressure level we can easy to inspect If there is flash happen on the short shot,then we should do is focus on parameters adjust during injection. If no flash happen after a short shot, then we should go to another way to adjust the transfer point to avoid over-filling the cavity.

molding flash

When designing your plastic parts, as far as possible to reduce the thin-walled section, resulting in a thicker wall section, the entire product into a uniform wall thickness of the parts.

The rapid change in wall thickness is the most common cause of flash, due to the production process of plastic materials under pressure, through the liquid state to fill the injection mold.

If the product design in the thick and thin wall thickness of the part is necessary to exist, the use of different injection point to help the flow of materials.It is very important to control the location of the gate, especially in the tight tolerances of the plastic parts.

Flash of an injection molded part can happen for several reasons – slight variations in the material, pressure, speed, injection mold process and/or problems with the tooling itself.

For example,The sprue bushing is one of the reasons that can not be ignored.Need to know is that nozzle contact forces can range from 5 to 15 tons.If the thermal expansion makes the critical distance sleeve “growth” out of the parting line, the nozzle contact force enough to move the mold side, resulting in flash generation not only mold precision will produce flash operation,The operation of the injection molding is the same as the source of the problem, the mold should take advantage of the length of the hot runner bushing inspection, into the standard of each production.

Through analyze every stag of the injection molding process at our company, and ensuring consistent stress free manufacturing of your custom plastic parts.Our process engines allow us to produce tight tolerances parts for all of our customer.

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