Material Selection and Processing for Injection Moulds

About seventy-five percent of the work that is involved in the plastic molding processes is known to be injecting molding processes. The success of this process relies on the work that has been done on the design and functionality of the mold and also on the material that has been used in making the mold. But adopting the right material for the making of the mold goes a long way in making sure the mold is strong, accurate and efficient as far the molding process is concerned specifically when mass production modes of operations are employed. In the present work, we discuss the material selection and processing for injection molds and HSM, a dominant player in injection molding industry, is taken as a case study.

Need of Material Selection for Injection Moulds

Mould life, use, cost efficiency, replacement all are affected by the material that has been used in the injection mold making. The molds used are always subjected to use extreme temperatures, pressures and friction and it is obvious that some materials have to be chosen that can take such abusive conditions. These are some of the considerations that should be taken into account when material selection is in perspective. 

1. Strength and Wear: Due to the number of injection cycles that are performed, it is not unusual for Moulds to experience repeated usage which results in a certain amount of wear. This is the reason why materials with high hardness and wear resistance, such as tool steels, are used for the molds which have to be very durable.

2. Thermal Conductivity: One of the most important requirements for producing the desired cycle times and achieving uniform cooling is the efficiency of heat transfer. There is a reduction of cycle time and such materials are good quality finished products as they conduct heat well. Engineers regularly use thermal energy which helps them efficiently finish their tasks. 

Corrosion Resistance: Due to moisture and chemicals, Moulds are bound to come into contact with corrosion. Therefore, parts that are complex and made with high precision should be crafted with materials that have high corrosion resistance. 

Main Materials Used In Injection Moulds

1. Tool Steel: Injection moulds are made up of tool steels like P20, H13, S7 and others due to their relatively higher ability to retain hardness, and their wear and temperature resistances. This is why HSM often makes use of these high performing steels which assist in the tool birthing highly durable molds in the injection molding sector. 

2. Stainless Steel: Moulds made out of stainless steel are usable in sectors such as medical and food industry, where there is a lot of hygiene and resistance to harsher environments is needed, since this material is tough and does not easily corrode. 

3. Aluminium: Injection moulds made out of aluminum are not as tough but are sometimes adopted out especially in low production volume injection molds as aluminum provides good thermal conductivity for shorter cycle times and allows better machinability than steel.

HSM’s Material Selection Strategy

HSM as one of the leading injection molding companies, knows that the right material has to be chosen for each particular application. Their extensive experienced engineers take into account different aspects like the kind of the material that is going to be injected, the intricacy level of the Mold design or the size of the market target for the proposed materials.

HSM, however, uses a general practice of employing high grade steel H13 type of tool for larger more complex molds that would require high wear and temperature resistant properties. For those applications where such properties are not sufficiently high, they may suggest the use of stainless steel, or provide special coatings to the mold that would effectively protect it against chemicals and moisture. Furthermore, HSM employs the latest technologies in production in order to have a controlled and sustainable processing treatment adding to the quality of the molds and there life expectency.

Mould Reprocessing and Ecology

After the optimal material is chosen, the mold is then subject to very accurate operations of making and finishing molds such as milling, grinding and polishing so as to conform to the required geometry. As HSM has advanced technology, the company also focuses on improving the conditions of each mold which will enhance the strength and durability of each mold due to wearing out.