This article is a brief guide to improving the turnaround of both the mechanical design and sourcing of prototypes parts during the early stage of a product or technology development program. The process is mapped and priorities explained to reduce risk and improve overall project timelines.
Regardless of the complexity of a product development there will be something new which carries risk. Project timelines are often stretched and discoveries, by their nature, are not planned. Delays in the infancy of any project can cast a big shadow in more ways than one on a project.
Identify the risks
Once an idea needs developing identifying the risks should be the first detailed. Start a design failure mode and effect analysis (DFMEA). This document will evolve though the project. For most of us it may be difficult to leave a document incomplete, but it’s necessary to reap the benefits. Leaving the DFMEA too late, to show final due diligence and complete the design documentation, will not reveal the risks. Identify any
concerns and rate them by a relative severity then perceived occurrence. Multiplying the ratings together will give a Risk Priority Number (RPN) to rank the concerns by.
For each identified risk, starting with the highest risk priority number, where possible design a test piece. These simple pieces should be as simple as possible to make, and test rapidly. In parallel the design of the final assembly should be started. It is natural for every engineer to resist or delay progressing a final design until the majority of concerns have been addressed, as the final design could change drastically as a result. It is important to accept that this work is carried out at risk. There will be changes to the design but a large proportion of the work will stand and reduce the overall time to complete. Development engineering is a high performance activity and not always and efficient one. Where speed is important there will be some waste in engineering time and materials.
Sourcing low volume parts on a fast turnaround is challenging. If parts can be tested with rapid prototypes then parts could be available next day. Online rapid machined or moulded services are readily available between next day and one week. If the part materials, finishes or tolerances are specific then stick to local workshops. A small workshop with a few experienced employees are more likely to produce quality parts on a fast turnaround. Local enough to be able to discuss the parts, drop material off and collect the finished parts. Often these workshops do not have an online presence, but operate word of mouth, so ask everyone you meet and keep a contacts book. Always state the urgency and offer to drop off the material, pay overtime, and have a taxi waiting to pick up the parts. This way the quote given will be targeting a short lead time. Expect to pay a premium for the parts.
As results impact the design, both test assemblies and the final assembly design, update the FMEA and tackle the next highest RPN. Keep focusing on the highest risk concerns and do not get bogged down reducing one concern to the lowest perceivable score.
For an observer looking in, the constant change in focus and rework of the final assembly may seem chaotic, but using the DFMEA and workflow is a clear way to communicate the projects risks and progress to the team. The process can rapidly reduce the chances of an unplanned discovery delaying the project but also focuses the team on the critical few.