DFM Tenet 1: What is Design For Manufacturability? Creating a design that is extremely simple and cheap to make.
80% of the costs incurred throughout the life of a project happens during production, which is the last phase. However, those costs are dictated by the design concept, engineering, manufacturability, and planning during the first 20% of the project (first phase).
DFM Tenet 2: It can be perceived as a bias to CNC machining, but the truth applies to all manufacturing processes and their respective DFM (Design for Manufacturability) best practices. Be careful how you use 3D CAD software and 3D Printing.
Why? These tools allow us to design and build anything imaginable, whether its manufacturable or not, and that’s dangerous.
Designs can travel far down the road of product development creating a situation where there is too much risk in function, performance, and time to improve it for manufacturability. Hence, designs are uber expensive or impossible to make.
Be very aware of this dilemma while ensuring that every feature is manufacturable in at least one of the Top 3 manufacturing processes. CNC machining, plastic injection molding, or die-cast. There are always exceptions, but this rule of thumb can save a design from ruining a project later when it comes time to produce in volume.
We want to leverage the power of CAD software and 3D printing to flush through design concepts at a record pace and while doing it, make sure ALL the features are manufacturable in volume too.
DFM Tenet 3: Counter-Intuitively, do not design solely for the end process upfront. It creates chaos. DFM (Design For Manufacturability) is also dependent upon which phase of the project you are in. For example, the statistical probability of your initial design hitting production is very, very low. If the end process is plastic injection molding and you embrace DFM to design your part 100% for injection molding, you will have designed yourself into an expensive manufacturing corner.
I’ve made the mistake many times designing plastic injection molded parts, that were easy to 3D print to prove the concept, but then a nightmare to be CNC machined when it came time for true mechanical testing with production materials. It’s common to switch from 3D printing to CNC machining when functional performance testing is needed and cosmetic finishes for demos.
They don’t teach it in engineering school, lock these axioms deep in your subconscious. The personal win isn’t all about manufacturable designs. The personal win is, you elevate your effectiveness, you save your employer tens of thousands of dollars, you save your company time, and if you track the dollar signs and share them with your superiors? Salary increases, vacations, and other privileges are now on the negotiating table. All because you adopted the 3 Tenets of DFM.