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9 Factors Affecting Injection Mold Quality

There are many factors affecting injection mold quality from all kind of aspects of raw materials, mold design, injection molding process and so on.
1. Mold steel
Steel is the decisive factor affecting injection mold quality, so selecting reasonable steel is very important. The criteria for selecting steel are followings:
(1) Plastic parts requirements
Different plastic parts should use different steels, such as plastic part requiring high polishing and corrosion resistance, etc. 
(2) Price
Not the more expensive, the better. Considering the cost factor of injection mold, select the mold steel corresponding to the mold service life to prevent unnecessary waste. The service life of general P20 mold steel is about 300,000 times, 2738 mold steel can be 500,000 times, H13/2344 mold steel is usually more than 80-100 million times. So the mold steel can be selected according to specific situation.
(3) Surface processing
Surface of injection mold is also very important. Nit riding can enhance the surface hardness of mold steel, and it can also increase injection mold service life. Electroplating can modify the performance of mold steel. For some plastic parts requiring high brightness and corrosion resistant, electroplating can be used to enhance and improve the performance of mold steel.
How to choose plastic injection mold steel?
Mold steel
2. Structure design of injection mold
The mature mold structure not only takes into account the characteristics of plastic parts, such as shortening rate, molding temperature and elastic tensile deformation coefficient, etc., but also takes into consideration the cooling water runner, the speed of mold opening and closing and so on. Reasonable mold structure can be useful to increase mold service life and ensure the smooth production of mold, improve efficiency, and reduce costs.
Prepare information for injection mold design
Mold structure
3. Mold machining
The organization of mold process is particularly important. Reasonable process organization can speed up the production cycle, shorten the processing time, and save cost. And more importantly, accurate and reasonable processing can ensure the stability and extended life of the mold during the production process. Some mistakes in processing will lead to mold welding, no matter how good the welding is, it is a loss to the mold. Other poor processing may affect the mold movement, reduce the mold service life, resulting in the mold in the production process cracking or even breaking.

4. Standard parts
Although standard parts are not directly involved in the forming, controls the operation of the entire mold. Good standard parts should be wear-resistant, hard enough, high precision, and not easy to deform. The standard parts of different brands have great difference on price, so don't just want to consider how to reduce mold price, maybe the price is reduced will cause the reduction of mold quality.

5. Collision 
It depends on the experience of mold fitter. It seems to be simple work, but in fact it is the most technical work. The flat mold is the most simple, it only require that there is no flashing on the parting surface. The mold such as car accessories mold is very troublesome. Not only the parting surface is irregular, but often contains multiple sliders and ejector blocks. Through collision, it can also improve and perfect other problems of injection mold, so it is a comprehensive operation. 

6. Polishing
The polishing of injection mold is the final step in mold making. Polishing is directly reflected on the plastic part. Polishing can also help and compensate for the movement of the mold, especially for demolding. Often some molds are not smooth because the resistance is too large, the demolding is difficult, and even ejected mark, ejected crack and so on.

7. Mold assembly
Mold assembly is the same as machine assembly. Every installation step of component and screw can't make mistakes. Otherwise, it will cause serious problem. It might cause product defects, even affect the production. So the work of mold assembly must be very careful. In the assembly process, it is especially important to clean the mold. Iron filings in the water runner and screw hole must be blow off.Injection mold tooling engineer

8. Hot runner and cold runner
This actually has the least impact on the quality of injection mold. Because that the hot runners are generally use in branded by customers, especially some big customers. Well-known foreign brands do a good job in quality and after-sales service, so there is generally no problem in quality. Hot runner injection molds in China have great difference on quality. In order to save cost and gain advantages on price, some small sized injection molding companies use some unreliable heating and conduction accessories. The primary problem of cold runners is how to ensure the balance of injection molding, gate size, and injection pressure and so on.

9. Cooling waterway
Cooling is very important to injection mold. Because of the increase in plastic prices and labor costs, when mass production, every seconds injection molding cycle saving of will bring great profits. However, if the speed of production is raised, the mold temperature will be also raised. If this situation can't be effectively controlled, the molding of plastic part won’t be successful due to the overheating mold, and even causes the mold deformation. Therefore, excellent waterway design is particularly important, including the arrangement density, diameter, and connection between the waterways.
The choice of a good plastic injection mold factory is half the success.

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