How much is the tool going to cost relative to the part costs and volumes? As previously stated, hard tooling has the lowest per-piece cost at very high volumes, but at low volumes, CNC machining may be a better choice. However, these trends are changing even during the writing of this book. Soft tooling is becoming cheaper and easier to source, so it may soon be the case that soft tooling is advisable even for relatively low volumes.

How many more design changes and what kinds of design changes do you expect? If the design changes are only going to be cosmetic, then starting the hard tooling first may be the right choice. If the teams are iterating on the design but need parts that behave like final parts, CNC machining might be the right starting point. The ultimate volumes may be very high, but if there is a risk that the tool will need to be scrapped, it might be worth building soft tooling until the design is stabilized.

What fixtures and jigs are going to help with assembly? The best-designed product won’t need any fixtures or jigs; however, design for assembly (DFA) can’t always remove all difficult assembly steps. If teams can think through the assembly fixtures and jigs ahead of time, parts can be designed to either avoid the need for fixtures or with features that make the design and use of fixtures and jigs more manageable. Based on analyzing the assembly process, teams should propose where fixtures and jigs may be needed. The assembly factory can provide input into these issues.

Where and how are parts and assemblies likely to get damaged in transit? Totes can be expensive and can have a long lead time. Teams need to think through how the material will be transported.