If you have ever looked into injection molding of plastic parts, your first question may be why are injection molds so expensive? Injection molds can easily be the most pricey part of a project and can add significantly to the cost of running small parts.
The main factors that affect the cost of an injection mold are the mold material, the size and complexity of the part, the materials used, and the number of parts produced.
What is injection molding?
Injection molding is the process of heating a plastic pellet to its melting point and injecting it into a cavity (mold). As the plastic cools, it hardens into the shape of the cavity to form the part.
Why are injection molds so expensive?
- Design Cost
Injection molding includes high-precision molds whose design is time-consuming and labor-intensive. After having the 3D structure data of the product, it still needs to be fully analyzed, sub-molded, and split 2D parts drawing.
The choice of mold material has a great impact on the cost. Injection molds are subjected to thousands of pounds of pressure per cycle. Therefore, the mold must be made of a very strong material that can withstand repeated use without deformation.
The most common choice for injection molds is steel, and the grade of steel depends on the number of parts to be produced and the material to be injected into the mold.
Because of the very tight tolerances of the parts, the cavities of the mold must be virtually wear-free. They must not be deformed or dented.
To avoid any distortion and ensure minimal mold wear and hardness, pre-hardened tool steels are the best choice for molds. Steel and other metals are popular for a variety of reasons, such as heat, friction, hot and cold changes, stress and fatigue.
The choice of tooling material depends on the number of parts to be produced. The higher the number of parts, the more the quality required. In that manufacturers must have to use the better and more expensive grade of steel.
There is a wide range of steels available for dies and molds, and the properties, i.e. advantages, disadvantages, and prices, of steels from different countries vary greatly. Note that different prices of steel have different ways of heat treatment.
The cost of the raw material is only one factor because the cost of processing and finishing steel will depend on the characteristics of the chosen material.
Size of the part
The bigger the size of the product, the larger the tooling required, and the more steel used for the tooling material, the more expensive the process will be.
The complexity of the part
Another factor that determines the cost of an injection mold is the complexity of the part to be produced. The more complex your part is, the more complicated and expensive the mold will be.
And once made, the mold is very difficult and in many cases impossible to modify, making it challenging for you to change the design.
The number of sets of molds to be made depends on the sample. Sometimes a plastic part with a very simple structure needs two sets of injection molds, or even three sets of injection molds to be processed.
- The quality requirements of the parts.
If the quality requirements of the parts are high, then both the mold material and quality costs will be increased accordingly. The service life length requirement will also affect the cost of the mold.
- Other factors
- Power cost.
There are other factors in the cost of injection molding that fall into categories typical of all manufacturing industries, such as maintenance and utilities. For example, the entire process of plastic injection molding consumes a significant amount of electricity. Machines are constantly running, and each time a machine runs a cycle, this adds up to high power expenses.
- Labor Costs
Injection mold manufacturing takes a long time and to reach it, some plastic mold manufacturers have made this aspect of the mold very fine. The dedicated follow-up strives to get customer satisfaction; hence more time and more employees are required to carry out the process.
- The impact of the choice of processing technology on the cost of the mold
The accuracy of EDM, wire cutting, and fine engraving directly affects the speed of processing. The higher the accuracy, the longer the production cycle, and the higher the processing cost, including the surface polishing of the mold.
ZHXTOYS is a very strong manufacturer of injection molding products. It has its mold factory, where they can easily produce a variety of different specifications of mold products, including strollers, children’s toilets, and children’s plastic products including strollers, children’s bidets, children’s bathtubs, children’s luggage, chairs, stationery boxes, pet supplies, daily necessities and so on.
The quality of the products has won a good reputation in the industry, and the quotation for the injection mold given by the manufacturer is reasonable, making it a very cost-effective manufacturer.