Slide 19 of 24
Combine Differing Grades of Material Roughly in Order of Hardness -
- By depositing hard material first, the material can be machined (roughened) for good bonding with softer materials. This process issue relates directly back to design considerations:
A difficult part to create is a soft urethane cylinder with a small hard urethane cylinder in its center. Ideally, the hard plastic would be deposited and machined first but depending on the dimensions this part may be difficult to fixture (if the height was significantly greater than its diameter). Although the part could be created with holes sunk into the substrate, the part has clearly not been designed for manufacturability.
Bond Surfaces Should be Freshly Machined
- Ideally, the process step immediately before a deposition layer should be a machining step freshly cutting surfaces to be bonded.