Designing For Moldability & Manufacturability

Designing For Moldability & Manufacturability

What’s The Difference Between Moldability and Manufacturability?

Though subtle, the differences between moldability and manufacturability can have an impact when designing parts for the plastic injection molding process. In this post we will explain the differences and provide resources for following injection molding best practices.

What is Moldability?

moldabilityMoldability refers to how well the mold of your part will conform to being injected with molten plastic. Once your mold has been created from your design, a good injection molding process needs to account for how well plastic can fill that mold cavity.  From material selection to mold complexity, there are many factors that will determine whether the part you designed is capable of accepting this process.  Certain features in your part design like undercuts and threading, can be tricky to mold correctly and consistently.   These can cause problems like knit lines, warp and flash.

Designing for Manufacturability

Designing for Manufacturability

Designing for Manufacturability

Some things to consider moving forward toward manufacturing is the time and effort put into designing your part for manufacturability. As your project makes its way through the progression of its development, your original model may need to be altered to fit the manufacturing process.
As we have shown, each process has different accuracy and resolution attributes. They also have inherent design limitations.
In other words, designing for one is different than designing for another. Therefore, the design considerations you need to make at the start of your project will impact the costs associated with production.

Additive Manufacturing

When designing a part destined to be additively manufactured, it is important to understand that some design features may need to be altered for production.
Some things to consider for designing for additive manufacturing…

  • Larger parts outside the space limitations of your chosen process can be broken up into smaller pieces and assembled later.
  • Avoiding sharp edges in your AM design can improve accuracy.
  • Be aware of overhang – geometric angles larger than 45 degrees will require supports which could limit the complexity.
  • Thicker walls and hollowed interiors can reduce print time (SLA parts will need drain holes incorporated on all hollowed-out features).

Subtractive Manufacturing

CNC machining is an option for prototypes as well. The benefits include being able to achieve tight tolerances and creating objects out of the exact production material needed, both metal and plastic. However, if production of more than 50 parts is required, it can become costly in both time and money.

  • You have a wide selection of engineered grade materials for more accurate strength, flexibility, chemical resistance or other critical characteristics
  • If outsourcing your CNC project, 5-axis capabilities are capable of producing more complex designs
  • Part features can be as thin as 0.020 in.
  • Internal Threads can be achieved.

Injection Molding

Injection Molding is usually the preferred method for producing production parts. And because injection molding is economical in as few as 50 parts, it could be wise to design directly for the injection molding process if a production run is already in the budget.
With that in mind, we’ve produced a helpful guide to help you learn a little more about what it takes to design a part for the injection molding process.