Rapid Prototyping: Bridging the Gap Between How Sheet Metal Parts Are Designed in CAD vs. How They are Manufactured on the Metal Shop-floor

Author Dan Harkins

One of the main advantages of working with Prototek is our experienced manufacturing engineers evaluate your CAD files for manufacturability the moment we receive them. On-line, computer automated quoting engines are not adept at recognizing all the variables inherent to sheet metal fabrication. A perfect design in CAD does not always translate over to perfect fabrication on the shop-floor. As a result, many engineers using these quick, real-time quoting websites end up receiving parts quite different than what they expected.

Here are a few tips that can help you minimize mistakes and ECO’s. Prototek’s 30+ years of rapid prototyping not only helps you get the right parts the first time, we help you design for manufacturability to make the transition from prototype to mass production as seamless as possible. Contact us today for a complete design guide or email us at fastquote@prototek.com and start your project today.

  • Hole diameters and locations: hole diameter should be greater than sheet thickness when possible. Never put holes too close to the edges or too close to bends. Holes that are too close to the edge can undermine the strength of the piece while those placed too close to the bend can be deformed out of tolerance during the bending process.
  • Tolerances: design parts with enough overlap so that hardware fit and mating can line up correctly. Especially if there is a secondary process such as painting or powder coating as that small amount of thickness may make all the difference in the final product. Parts with the same tolerance may look good in the model but in reality, if they end up at different ends of the spectrum, they may not join correctly or even at all.
  • Hardware and material compatibility: here is a great chart on fastener compatibility https://www.engineersedge.com/hardware/fastener_material_galvanic_13354.htm
  • Grain direction: sheet metal has a natural grain and how a part is fabricated in relation to the grain will affect strength as well as appearance. Always specify grain direction in drawings when using sheet metal.
  • Finish: Prototek offers a wide selection of finishing options including powder coating, anodizing, painting, chromating, etc. Specifying “no finish” or better yet the manufacturer and part number not only saves time it assures that you’ll get the exact finish and color you want.