Design for Manufacturability (DFM) is the proactive process of designing a part to meet the specifications of the chosen manufacturing process used to produce that part. No longer can a product engineer design a part for fit and function only. Product Engineers are also expected to understand the manufacturing process and incorporate those parameters into their design to ensure good part production.
Ignoring design for manufacturability can have disastrous consequences. By the time a product concept gets through the design phase and into the testing/prototyping phase, up to 80% of the budget for that product has been committed. The material costs have been identified, the tooling costs are known and any assembly costs are also worked into the budget by then. And once it has been committed, it is very expensive to turn back to change the design.

For example, consider the Rule of 10. At each subsequent phase of the development process, it will cost up to 10 times more to find and repair a defect in the design. What this means is that any error or defect will exponentially add cost the further down the road it gets made apparent.
So, if your product costs $Y at the design phase, it will cost 10 x Y to repair any defects at the testing/prototyping phase or 100 x Y at the production phase.
It adds up quickly. One mistake in the concept or design phase can ruin a product launch.
This is why Designing for Manufacturing is so important.
Designing for Manufacturability has been proven to save time and money through the product development cycle; in some cases, by up to half. Incorporating manufacturability techniques of your chosen manufacturing method early in the design stage will also minimize the need for revisions and can make the process many times faster than an I designed it, you build it, approach. 
So, understanding the benefits, limitations and techniques of your manufacturing process and knowing how to design for it is the first step toward a great product.
But that’s not all. Because the Concept to Design phase is so critical to a successful product launch, we’ve identified some other tips to get the most out of your development cycle.

  • Gather a comprehensive enough team to be able to identify product design shortcomings and to anticipate changes to the design from the customer or a senior member of your team.
  • Be sure to completely understand the customer or end user’s needs for the product to eliminate costly changes further in the development cycle.
  • Simplify your concept as much as possible to optimize the design and the manufacturability.
  • It is generally not a good idea to design mirror images of the same part to accommodate right and left handed users. Instead, design something more universal. It will save you time and money from having to develop two different parts when one will suffice.
  • Design symmetrical parts which will not require orientation during assembly.

Fortunately, we have created The Smart Guide to Designing for Manufacturability to help guide you through some of the pitfalls associated with a poorly designed injection molding or CNC machined part. It will cover the basics of the injection molding process, the best practices to use when designing a part and will also include some of the features you can incorporate to save you time and money.