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Top 10 Factors Affecting the Quality of Injection Molds

Released on Jun. 16, 2022

Injection Mold


Mold manufacturing is a complex process, from design, processing, assembly, commissioning, and other steps, to the final real use, in the whole life cycle, there are 10 main factors that affect the quality of the mold as follows.


1. Mold steel

Steel is the decisive factor of mold quality, and choosing reasonable steel is the most important. The criteria for choosing steel are


①The requirements of injection materials

different plastics to use different steel, such as the requirements of high polish, corrosion resistance, etc..



steel properties can be good, not the more expensive the better; taking into account the cost factors of the mold, mold steel should be used and mold life corresponding to the material, to avoid unnecessary waste; general P20 material life of about 300,000; 2738 material in 500,000 no problem, H13/2344 usually in 800,000-1,000,000 or more, can be selected according to the situation.


③Surface treatment

The surface treatment of the mold is also very important. Nitriding can enhance the surface hardness of the steel and effectively extend the life of the mold; electroplating can effectively modify the mold steel, and for some plastic parts that need high brightness and corrosion resistance can use electroplating to enhance and improve the performance of the steel.


2. Structure design

Mature mold structure not only takes into account the product material properties, shrinkage rate, molding temperature, elastic tensile deformation coefficient, etc. but also takes into account the cooling water circuit, the speed of opening and closing the mold, etc. Reasonable mold structure can effectively extend the mold life and ensure the smooth production of the mold, improve efficiency and reduce costs.


3. Mould processing

The arrangement of the molding process is especially important. A reasonable process arrangement can speed up the production cycle, shorten the processing time and effectively save cost. And more importantly, accurate and reasonable processing can ensure stability and extend the life of the mold in the production process.

Some processing errors will lead to mold welding, no matter how good the welding is, it is a loss to the mold; in addition, poor processing may also affect the mold action, reduce the mold life, leading to mold in the production process of pulling crack or even broken.


4. Standard parts

Although standard parts are not directly involved in molding, they control the operation of the whole mold. Good standard parts should be able to be wear-resistant, hard enough, high precision, and should not be deformed.


5. clash (flying mold)

The clash depends on the experience of mold clampers, which seems to be a simple job but the most technical work. Complex mold mainly depends on this kung fu. Flat mold is the most simple, fractal surface as long as there is no flying edge break difference basic on OK.

Like auto parts mold is very troublesome, not only the fractal surface is more irregular, and often includes more than one slider, top block. At the same time through the clash can also improve and perfect other problems of the mold, so it is a comprehensive work.

Injection Mold

6. polishing/skin pattern

The polishing of the mold is the last part of the manufacturing of the mold. Polishing reflects directly on the plastic part, so it is a most face-saving job. Polishing can also help and complement the mold action, especially very meaningful for mold release. Often some mold production is not smooth is because the polishing is not in place, too much resistance, difficult to take off the mold, and even top white, top crack, etc.


7. mold assembly

The mold assembly is like assembling a machine, each part, each screw can not be wrong, otherwise, the consequences will be quite serious, the light will lead to product defects, affecting production, the heavy will completely damage the mold, resulting in scrap. So the assembly work must be very careful. The assembly process especially to pay attention to the clean work of the mold, especially the waterway, screw holes, must be blown clean inside the iron chips.


8. hot runner or cold runner

This actually has the least impact on the quality of the mold, because the hot runner is generally the brand specified by the customer, especially some large customers. Foreign well-known brands whether in the quality or after-sales service are very in place, so the quality of the general will not have problems.

Just some of the domestic hot runner is a big difference in quality. Individual small enterprises in order to save costs, to fight for price advantages, with some unreliable heating and conduction accessories, it is easy to have problems. The main problem of the cold runners is how to ensure the balance of injection, gate size, injection pressure and so on.


9. cooling water channel

Anyone who has experience in molds knows how important cooling is to a mold. Due to the increase of price and labor wage, when mass production of products, the profit brought by not reducing one second of injection cycle is unimaginable.

But speeding up the production cycle at the same time will be the rise of mold temperature, if not effectively controlled, it will make the mold too hot to mold, or even lead to mold deformation failure scrap. So the excellent water circuit design is especially important, including the density of water circuit arrangement, diameter, the link between each other, and so on.


10. Mold maintenance

Mold maintenance is mainly the maintenance and repair in the production process. Mold is just like a car, if it is not used for a long time and not maintained, it may lead to the scrapping of the mold. Therefore, every time after using the mold, we should carry out comprehensive maintenance, especially the rust prevention of the molding part and the rust prevention of the main action parts.


Because the mold has to receive water during the production process, there may be sleep on the mold during the installation or disassembly process, so make sure the mold is dry, and then brush a layer of oil to protect it.


Hebei Fine Art Co., Ltd.

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