How to improve the service life of injection mold


Injection molds are an important part of many manufacturing processes, and it is important to take steps to ensure that they last as long as possible. In this blog post, we will discuss several ways to improve injection mold life.

First of all, it is important to keep the molds clean and free of debris. This will help reduce the wear and tear on the mold and increase its service life. Second, it should be inspected regularly for damage or defects and repaired as soon as possible. Third, ensure that the temperature of the injected material is within the specified range. Fourthly, the mold design should also maintain the thermal balance of the mold. Through the reasonable design of the gating system, temperature regulation system and exhaust system, the mold hot crack tendency can be reduced, the service life of the mold can be improved. Finally, use appropriate lubricants, if necessary, to reduce friction between the mold and the material being injected. By following these tips, you can improve the mold quality and extend the life of your injection molds and improve your manufacturing process overall.

Extending the Life and Enhancing the Performance of Plastic Injection Molds

1. Tell me the meaning of injection mold life?

Injection Mould tool life is defined as the molding process in which molds can be produced. The number of manufacturing cycles before a mold fails should include life of the molds. Mold service life can last about 300 cycles. When a new mold has been created, a new one must be replaced. Molding firms also offer service on lifetime mold if necessary. The Moulds are able to be used for a lifetime. It also requires work and care. Steel Mold Life Warranty P 20 covers 400,000 mold cycles. The life of the H3 molded Moulds can be estimated to take up to 100,000 molds. When buying molds, you should be confident that you choose the best manufacturer. They offer you excellent equipment.

2. Failure form and injection mold life

Plastic injection molding process is the plastic raw material in the injection machine barrel by the heater heating and friction shear heat effect of plasticization, in the injection machine plunger or screw propulsion, with a certain temperature, pressure and speed through the injection machine nozzle into the mold cavity, after holding pressure, cooling and shaping after opening the mold and get plastic products. In the molding process, the mold has to withstand the pressure when the mold is closed, the pressure of the plastic melt in the cavity and the tensile force when the mold is opened, among which the pressure of the plastic melt on the cavity is the most important. At the same time, the mold has to work under certain temperature conditions, the mold temperature is cyclically changing, the injection requires high mold temperature, and the mold temperature is low when the plastic products are demolded. Under such working conditions, the main working parts of the mold are susceptible to excessive deformation and hot and cold fatigue rupture by temperature and pressure.

When the mold breaks or the shape, dimensional accuracy and surface quality of plastic parts cannot reach the requirements due to excessive wear of the mold, and the overflow of material is serious, and the mold cannot be repaired, the mold fails. Production Cycle Time It is common that faster, high-speed production can cause the mold to fail early. Normal failure means that the die can not continue to serve due to slow plastic deformation, uniform wear, or fatigue fracture after mass production. What is Injection Mold Life? Mold life refers to the number of parts that can be manufactured on the premise of ensuring quality. What mold life exactly means is how many parts are guaranteed by the factory to produce off of a given tool. Mold failure is divided into abnormal failure and normal failure.

3.How can I improve my cycle time in injection moulding?

Cycle time of a part in injection molding process is very important as the rate of production and the quality of the parts produced depend on it, whereas the cycle time of a part can be reduced by reducing the cooling time which can only be achieved by the uniform temperature distribution in the mold.

Factors affecting the life of the injection mold and the basic way to improve the service life

3.1 Plastic raw material selection

The temperature and pressure required for molding different plastic varieties are different, and the working conditions are different and have different effects on the service life of the molds. Different plastic components also have an impact on the wear and tear of the mold. For example, when molding reinforced plastics with inorganic fiber materials as fillers, the wear and tear of the mold is relatively large. The process of molding PVC plastic will release HCL gas, which will easily corrode the surface of the mold. Therefore, under the premise of meeting the use of performance and product quality, we generally have to choose plastic raw materials with good process performance to mold the molded products. This is conducive to both the molding of products and the improvement of mold life.

3.2 Keep the injection mold clean and free of debris

Contamination from dirt, dust and other debris can cause damage to the mold. Clean the molds regularly with a soft cloth or brush to avoid the build-up of residue that can lead to corrosion.


3.3 Check the damage or wear of the mold

Regularly check for wear and tear. Wear is a common occurrence in the injection molding process and should be monitored closely for rust, abrasion, damage and other signs of deterioration. Wear of the mold is usually caused by friction between its parts. It is important to regularly check the parts for signs of wear and take corrective action if necessary. Ensure that all parts are properly tightened, lubricated and aligned prior to use.


3.4 Monitor the temperature.

Temperature plays a huge role in the life of an injection mold, as heat can make it brittle and even crack over time. Therefore, be sure to keep a close eye on the temperature inside the machine so you can adjust accordingly if necessary.  Mold watering is a critical component to increased mold life: Watering is an important part of extending mold life. Increased mold temperatures adversely affect mold life. Mold temperatures should be limited to minimum requirements to achieve acceptable part aesthetics. 

3.5 Reasonable mold design

The cavity and core are the main molding parts of the molded plastic accessories, the outer surface of the molded plastic components and the inner surface of the molded plastic products. Different structural forms of cavities and cores, their strength and stiffness, as well as the repair and replacement of vulnerable parts is different. Therefore, from the perspective of mold life, the use of strength and stiffness is better and easy to repair the structure of the form can extend the life of the mold. In the design of small and medium-sized injection molds, the determination of cavity wall thickness focuses on the strength conditions, and the determination of cavity wall thickness of large molds should be strictly calculated and calibrated according to the stiffness conditions to prevent excessive deformation during the working process. Complex cavities and cores can be used in combination or paneling structure, paneling combination structure to be reasonable, avoid sharp angles, adapt to the heat treatment process, to prevent stress concentration and cracking. Slender cores are designed to be inserted, which is also easy to replace. The strength of the insert and the reliability of the placement should not be neglected in the design. In addition to molding parts, other structural parts in the mold should have sufficient strength and stiffness to withstand the work of mold opening, clamping force, injection pressure and thermal stress, so as not to produce large deformation.

The structure and precision of the guiding device directly affects the mold fit of core and cavity, the accuracy of the molded part and the mold life, so it is necessary to choose the proper guiding form and guiding precision. In precision injection mold, in order to ensure the accuracy of the mold and the fixed mold, the tapered precision positioning mechanism or the cylindrical guide pin positioning mechanism can be designed to be used with the guide mechanism. If the injection mold launch mechanism is stuck in the work, it will easily cause damage to the mold and affect the service life of the mold. Therefore, the design of the push-out mechanism should not only have sufficient rigidity and strength to overcome the resistance of mold release, but also work reliably and flexibly. Push out parts should be easy to manufacture and easy to replace. The setting of push-out guide can improve the smoothness of the movement of the push-out mechanism. The mold structure design should also pay attention to maintain the thermal balance of the mold, through the reasonable design of the pouring system, temperature regulation system and exhaust system, to reduce the mold thermal cracking tendency, improve the purpose of mold life.


3.6 Regular lubrication of moving parts

Lubrication is critical for injection molds because it reduces friction between the mold and the plastic. Applying proper lubrication to areas such as the slides and pins of the injection mold helps prevent unnecessary wear and, if done properly, can greatly extend its life. Without lubrication, wear and tear on the mold surface can occur quickly, resulting in a shorter life.

A protective coating can not only make tooling materials harder, but also shield against corrosion and rust. This in turn decreases the yield loss and downtime due to worn valve gates or other mold components.


3.7 When not in use, place it in a dry environment

Another key step in preserving the life of your molds is proper storage. It is important to keep them in a cool, dry place, away from extreme temperatures. Extreme temperatures or cold can cause warping and corrosion of metal parts, reducing the life of your molds. Keep away from direct sunlight and other heat sources. Heat can cause the plastic materials used in injection molds to soften and deform, leading to problems with their performance.


3.8 Mold material and heat treatment

Injection mold cavities are generally complex, with high requirements for precision and surface roughness, and the choice of mold materials can affect mold quality and service life. The choice of mold material should not only meet the customer's requirements for product quality, but also consider the cost of the material and the strength in the set cycle. The selection should meet the requirements of certain working conditions such as wear resistance, toughness, high temperature resistance, hot and cold fatigue resistance and corrosion resistance. The manufacture of molds generally goes through forging, cutting, heat treatment and other processes.

In order to ensure the manufacturing quality of the mold, reduce production costs, the material should have good malleability, machinability, hardenability, hardenability and grindability; should also have a small oxidation, decarburization sensitivity and quenching deformation cracking tendency. The use of both excellent mechanical properties, but also has good processability of plastic mold steel, not only can greatly improve the molding quality of plastic parts, but also can greatly improve the service life of the mold.


3.9 Mold processing and surface finishing

During the mold making process, the method and accuracy adopted for mold machining and surface finishing have a direct influence on the quality and service life of the mold. When the cutting process of the mold is not proper, the sharp corner or rounded corner radius caused is too small, which will easily lead to serious stress concentration when the mold is working. After quenching and tempering, molds are generally subject to grinding processing to reduce the surface roughness value. 

The influence of factors such as too large speed, too fine grinding wheel grit or poor cooling conditions in the grinding process will cause local overheating on the surface of the mold, resulting in local microstructure changes or causing surface softening and hardness drop, which will lead to a lower service life of the mold. Therefore, the cutting process of the mold should strictly ensure the radius of the rounded corners and the smooth connection between straight and rounded arcs at the size transition. In order to prevent grinding overheating and grinding cracks, measures such as appropriate reduction of grinding feed and selection of coarse-grained grinding wheels with strong cutting force or poorly bonded grinding wheels can be taken. 

In order to ensure the machining accuracy of the parts in the mold, high precision machining methods such as EDM, wire cutting, CNC machining should be reasonably selected in the mold manufacturing to improve the mold manufacturing quality and service life. For the injection mold, due to the requirements of the surface quality of the plastic parts and corrosion resistance and the need for mold release, the smoothness of the mold surface requirements is very high, while mold wear, bonding is occurring on the surface of the parts, fatigue, fracture is often from the surface, mold surface quality has a direct impact on the quality of plastic molding and mold life.

But in fact, due to the existence of processing traces, the surface oxidation and decarburization during heat treatment is inevitable, and the surface performance of the mold is worse than the substrate. The use of surface strengthening treatment can effectively improve the mold cavity surface hardness, wear resistance and resistance to high temperature oxidation and lubrication performance, thus improving the mold life.

4. Conclusion

There are many factors that affect the life of an injection mold, and comprehensive measures must be taken to improve the life of an injection mold. At the same time injection molds are an important part of many manufacturing processes and steps must be taken to ensure they have the longest possible service life. By following the tips in this article, you can keep your injection molds in good condition and improve their performance. Have any questions about how to care for your injection mold? Contact us today for more information.