DFM is to design parts, components and products with the goal of making manufacturing easier and cheaper without affecting its performance. It involves actions like simplifying, optimizing and refining the product design to achieve a better final product.

There are 5 layers to be examined during DFM:

1. Process: you need to choose the proper manufacturing process that aligns with the volumes being produced, the maturity of the design, the complexity of the part and other requirements like tolerances or materials
2. Design: the parts need to be designed according to the best practices and general design rules for the manufacturing process selected
3. Material: materials must be selected to comply with the required mechanical properties, chemical compatibility, flamability level, thermal properties...
4. Environment: the parts or the product and the product as a whole should be design in a way that it cwithstands the environment it will be subjected to
5. Regulatory: the product and its parts should comply with any industry, safety and quality standards

Design general rules per technology:

• Machined parts: tolerances, wall thickness, radiused internal corners (use standard radius), tool accessibility
  • Turning: relief for blind-holes, remove sharp edges from outer diameter, symmetrical axial slots
  • Milling: avoid deep narrow holes, avoid narrow regions in pockets, avoid/reduce angular faces with the base
  • Drilling: avoid small and deep holes, perpendicular external surface for entry and exit holes, avoid holes with flat bottom
• Sheetmetal: tolerances, bending, bend-to-bend and feature-to-bend distances, foldable design
• Plastic injection: tolerances, wall thickness, draft angles (avoid big faces parallel to unmolding direction), radiused edges, avoid/reduce undercuts, convert big solids into shells, add support ribs/gussets