Injection moulding is popular manufacturing method because of its high-speed production capability. Performance of plastic part is limited by its properties which is not as strong as metal. A well-designed plastic parts means that it was taken through many steps to solidify the mold you wish to create. It’s hard to change the specs and variables of a plastic part towards the end of the plastic part design process.Not only will you have to reassemble machine parts and measurements, it will be more time consuming and will cost more to fix the issues after production.Making changes during the design stage is relatively inexpensive. With today’s CAD software, being able to visualize, test, and change designs has never been easier.
These are just a few of the questions that should be asked during the plastic part design process.
- The Cost of Change
- A well designed plastic part has many variables that need to be taken into account.
- How will the mold come together?
- Can the part be ejected from the injection mold?(If the tools and machine aren’t sized correctly, it may be hard to eject the mold.)
- Are the walls too thick or too thin?(If the wall selections are too thin, it may break off in the tool and not fill correctly. Too thick of wall sections will take longer to cool and solidify before ejecting the mold, resulting in warped or cracked products.)
An improper design technique, if carried all the way to production, can have a negative result on the overall quality or appearance of the injection molded piece. The cost to fix issues observed after production are not only expensive but also time consuming.
It is important however to look beyond just the question “Can this part be injection molded successfully?” While this is an important aspect of the design, we must also be mindful of manufacturing costs. Because the tooling cost is closely related to the product design, it is crucial to have an understanding of the mold making process even during the design stages. Plastic part design can greatly vary the overall costs and in some cases out-price the project. Implementing cost saving design features while maintaining design intent, or just optimizing the design for injection molding will save you money and make for a more robust design. Jingwei industry has served the injection molding industry for over 20 years and has a team dedicated to providing you with the most cost effective solutions for design and manufacturing.
Design points before production:
Select the proper material for the building tools. The coefficient of thermal expansion must be taken into consideration; large differences in material and size can damage and uneven the components.
Be sure the runner system is balanced. Unbalanced runner systems can cause filling disturbances and inefficient tool running.
Choosing a gate design is similar to having a balanced runner system. The gate is the area where the polymer transits from the runner to the part. If this is wrong, the gate could cause restrictions, incorrect polymer flow, turbulence, or other defective filling issues.