To the naked eye, two plastic parts may look similar, but they may have been made from two different molds that did not require the same amount of financial investment.
What are the factors influencing the price of a plastic injection mold and how to choose the most appropriate solution for your project? We can explain and advise you:
Technical characteristics of the plastic injection tooling
Steel and a mold’s components are the main factors influencing the price of a plastic injection mold.
The steel’s hardness and characteristics are selected according to the number of parts to be produced and the specificities of the injected part. Imported steel and the harden steel are the most expensive. For the same steel grade, several price ranges are possible.
Other supplies such as standard elements are similar to the choice of steel. Many possibilities exist on the market.
At Unimold, we assessed and selected suppliers that have a wide range of choices available covering all our customers’ requirements. We can thus recommend the best value for your money based on the specific requirements of the plastic injection mold project.
Injection type by cold runner or hot runner
Cold runner injection is the most economical solution, but this leads to a loss of material.
For hot runner injection we call on a hot runner provider. Such device can affect the price of the plastic injection molds by up to 100%.
Based on our experience, we rely on several different suppliers. The final decision is taken in conjunction with the customer. This can influence not only the cost of a part, but also the maintenance of the production plant’s.
The part's finishing is another factor not to be neglected
The least expensive is a rough machining finish, i.e. there is no post-processing after the machining operation. The surfaces will have traces of milling or erosion that will be visible on the injection part.
To eliminate such traces, polishing, often manually done, must be applied. The simplest form of polishing is known as: “Cloth polish”, which removes all tooling traces. There is an entire range of polishing up to mirror polishing, rendering the steel shiny. The produced part is either bright or transparent depending on the color of the material.
Other post machining processes are also possible such as chemical texture. These operations are carried out by specialised texturing companies. The price varies enormously depending on the supplier and the texture references. We work with several texturing companies that have a very wide array of processing possibilities.
The geometry of the part
A part’s shape greatly influences the price of a plastic injection mold.
Generally, it is not possible to change the size of a part because it corresponds to a specific function. On the other hand, the presence of undercutting can weigh heavily on the tooling’s cost. This requires installing sliders, lifters, or more complex mechanics with pre-opening movement. There are several ways to remove or simplify these undercut shapes. As each case is different, our design office will be able to recommend simplifications applicable to your requirements.
Dimensional tolerance is also a factor in the cost of a mold. The smaller the tolerance, the more precise the machining must be. Machines with high dimensional precision will have to be used, requiring a higher hourly cost.