The design of plastic parts is part of the foundation of injection mold making. It affects both the initial investment and the profitability in the long term for each new product. This is why it is so important in the early part of the design takes two important factors into consideration:
- The thickness of the part and the injection mold
- The undercuts required by the injection mold
These two aspects are critical to the initial success of a product and the long-term production of the product.
The Part Thickness
The thickness of a part plays a vital role in how well the final product will function. If a part is too think, it will not fit properly within the final product. If the walls of the part are uneven lengths, it can cause problems with shrinking, sinking, and bubbles within the part walls during the injection process.
This is one reason why many companies are coring out the parts of their products. Coring out is when the walls include notches or slots in them. This ensures that the part cools to fit the desired length and width without many of the structural issues that a solid part can have. Also called ribs, this method of part production provides more structural integrity to the part. Another benefit is the reduced cost to make the part as less material is needed to complete it, as well as less time.
To properly core out a part, you have to determine the length and direction of each rib so that it enhances the strength of the part. It should allow the part to bend without breaking
The Product Undercuts
Undercuts to a part are the additions to a product that allow for movement or part to be added. The following are the most common types of undercuts:
- Protrusions
- Holes
- Indentations
- Slots
- Spirals
Injection mold making frequently requires one or more of these in a final product, which can noticeably increase the cost. It also increases the time required to design and produce the product. With the right kind of design, you may be able to minimize the number of undercuts required in a part. Before committing to an undercut, it is best that you look into smart designs that will minimize the use of them.
Topics: Injection Mold Design