You might have heard the term design for manufacturing, or one of its various other names as design for manufacturability or simply abbreviated DFM. The goal of DFM is to engineer and design a product that is easy to manufacture. The idea of designing a product to be simple to manufacture exists in almost every engineering discipline, but the application of the concept varies widely based on the manufacturing type and technology used.
Design for manufacturing is best utilized in the beginning stages of the product. The design phase, which should be at the beginning of the product lifecycle, offers the best chance to prevent many of the problems that can inhibit manufacturing. This phase also allows for the identification of materials to be used, tooling and secondary processes required, and the dimensional tolerances needed to meet the customer’s demand.
What Does Design for Manufacturing Involve?
Knowing that DFM stands for Design for Manufacturing (or Manufacturability) doesn’t always translate well into what it really involves. It’s not just one simple discussion over coffee. It’s a multi-step process to ensure that everything has been covered and thought of in the beginning. Some of the items that should be covered include:
- Create a DFMEA Process Sheet – A DFMEA process sheet does many things for your manufacturing operation. The first benefit is to list out every step in the manufacturing operation. The process of writing it down can reveal forgotten or discounted steps. At each step of the manufacturing process, you should look for ways to reduce the required number of items needed to complete the step. The second benefit of a DFMEA process sheet is to brainstorm every conceivable way that a mistake can be made in manufacturing. Your design should include error-proofing. The DFMEA sheet is most commonly organized in a matrix form with assembly errors listed by failure mode type, then ranked by projected severity, and their projected occurrence. The goal of the document is to indicate which assembly error would be most annoying or harmful to your end customer and where the design team should focus their effort to prevent issues in manufacturing.
- Use Datum Strategies & Features – One of your design team’s goals should be to ensure your product is easy to manufacture. If your manufacturing staff are second-guessing if they are assembling your products correctly, the design isn’t simplified enough. One way to take the guesswork out of manufacturing is to utilize a datum strategy to identify how an assembly comes together without an error. A datum scheme, for reference, pinpoints which feature of an assembly to connect first, second, third, and beyond. When it references manufacturing, a datum scheme may translate into hole sizes being round, oblong, or oversized based on their sequence in the process. The smallest round hole will dictate a primary assembly point, an oblong could be used a secondary point to limit rotation, and an oversized third hole just simply used for the connection of the parts. These holes are used typically to cause a misalignment when completed out of sequence. The final manufactured product shouldn’t operate if manufactured incorrectly, and it should clearly indicate a problem at or before the final inspection stage.
- Decide on Attachment Concepts – Datum strategies don’t have to involve fasteners. Datums allow for alignment of parts or components, and an opportunity to prevent errors. Some designs may require fasteners to be serviceable, or you may need them to meet durability criteria. If fasteners aren’t a requirement, DFM may dictate utilizing a simpler attachment option like heat staking or ultrasonic welding for permanent attachment.
- Use Standard Fasteners and Common Torque – If your design does require fasteners for attachment purposes, your design team should utilize standard fasteners and torques as best as possible. Complex designs may require multiple fasteners to be used with different torque requirements, and these differences can cause chaos in manufacturing. When multiple fasteners are needed, the simplest option is to use the same fastener to reduce confusion. If you need to use multiple fasteners of various sizes or materials, make the heads different in shape or size. If tool A needs to secure fastener A, make sure tool B doesn’t fit. The easiest way to ensure errors can be made is to make every tool fit every fastener at a workstation.
- Improve Manpower with Automation and JIT Options – Manufacturing personnel can be the most expensive variable cost of your business, so your design should incorporate options to adjust manpower as demand dictates. There may also be opportunities to add automation in place of human personnel to reduce cost at a certain volume threshold. Beyond manpower, adding Just-In-Time (JIT) sub-assemblies and kitting from different workstations may add efficiency to the overall product line.
Designing for Manufacturing (DFM) means you have thought about how to manufacture a product with minimal errors, make it so simple that anyone can do it, and reduce the operations, parts, fasteners, and labor needed to save costs where applicable. Some Computer Aided Design (CAD) software includes various built-in tools that can aid designers in prediction, and some of the know-how will come from experience. SEA-LECT Plastics has an elite staff of designers and manufacturing professionals that design and produce world-class products. We have the knowledge to make your design simple, cost-effective, and the turn-key assembly options to produce it in-house in Everett, Washington. If you have a new idea, call us (425) 339-0288 or email us at mattp@sealectplastics.mystagingwebsite.com. We can offer you advice on the best technology to use, the best materials to meet your product demands, and how to navigate through each development stage with ease.
Matthias Poischbeg was born and raised in Hamburg, Germany. Matt moved to Everett, Wash., after finishing his bachelor’s degree in business in 1995 to work for Sea-Dog Corporation, a manufacturer, and distributor of marine and rigging hardware established in 1923.
In 1999, Matt took over the reins at Sea-Lect Plastics Corporation, a sister company of Sea-Dog and a manufacturer of plastic injection molded products with an in-house tool & die shop. Matthias Poischbeg is also a contributor to Grit Daily.
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