injection mold design in china

Injection mold design in china.

Our injection molding design process is simple, 4 steps process, that start with :

1: Analysing the 3d cad file of the plastic parts.

Our mold design process starts with studying the 3d cad file plastic part and the material requirements of the parts. We check on our major design guides, see the 5 main design rules for injection molding plastic parts, for example on using the right draft angles on the surfaces of the component and a wall thickness analysis, if walls are too thick  sink marks will occur.

In addition to the 3D cad design , desired order quantities of the parts are important, as-well as the finishing requirements and the tolerances of the part. Usually when a part is required in an assembly, tolerances are more important than when the product is used in an environment without other parts or stand-alone…

Additionally we can execute Mold-flow analysis, to check different gate types and locations, as-well to determine the general mold flow in the component

2: Determining the right mold steel.

Mold steel this is a major factor that determines the final mold costs. In China there are tons of steel types , so as a non-expert it is hard to choose the right mold steel type. The right mold steel depends mainly on the choosen plastic parts material, the part/mold structure and the total desired quantities to name a few factors..

The harder the mold steel the better it is its resistance against temperature and mold wear, and the more injection shots you can make. So the quantity of the total injection shots must be know in order to have a basic idea of the tool steel to be used: 1000 shots per year makes a mayor difference compared to 10 million shots per year. If you only need 1000 pc of your product. One can think of the cheaper tool steel with a less wear resistance , and less hard, such as  aluminium steel. So for low-volume projects with easy to inject materials such as ABS or PP aluminium tooling is a great choice. also aluminium tooling can be made rather fast compared to Hardened tool steel. And aluminium tool steel has low cycle times.

If you have quantities of 1000-100.000 P15 or p20 toolsteel can be chosen.

Hardened molds

When using  a hardened mold make sure in the 3d cad model of both the part and the mold design all edges are rounded.

So when you, as a customer, have anticipated how many parts you will need to sell and have choosen the right material we can choose the right mold steel for you , for the right budget.

chosing the righ mold steel requires experts

3: choosing the right mold structure.

When our injection molding company starts designing a mold the parting line will be determined firstly. The parting line can be defined as : the line where the core touches the mold cavity..

Secondly,  to make a two , three plate mold structure or any other, more exotic structure will be made. Mold structure and number of plates depend on  the part’s structure and the way of ejecting the part out of the mold.

2 plate mold example

part complexity determines the mold structure

How many cavities will be used or is a family mold worth while?

If the desired number of shots are high , eg 10000 a week, multi cavity molds must be manufactured.

Deciding what kind of gate to use.

Other mold structure issues: venting and cooling

Cooling system: The cooling system used to cool the plastic after injection can also affect the mold structure. The cooling rate and the placement of cooling channels within the mold can impact the final shape and dimensions of the product


4: Quality control of the mold assembly.

Once your mold is designed ,  we will execute a general quality control of the mold design using a mold review form. This form is a structured approach that covers all the aspects that we have mentioned here above. Usually a senior designer, injection molder and part designer will execute such a quality control of the mold drawings.

The goal of this list is to avoid design mistakes by reviewing by third persons. Main overall goal is of this QC process is first of all to get the best parts and to keep a short time to market.