Never mind downstream lean processes, the most sure-fire way of eliminating product cost before it arises is to take time to carefully consider the best way to manufacture or assemble a part before you begin. The die is cast at the point of ‘final design freeze’, and it is that die that sets overall cost, lead-time, supply chain, product robustness, logistics, serviceability, reliability and time-to-market.

Even the most honed of lean processes can only go so far, so looking upstream to the design phase is the single biggest opportunity to control these variables. However, all too many design departments are overly keen to play safe with established processes and when faced with commercial pressures will simply default to familiar ways of producing a new component or assembly.

This is where Design for Manufacture and Assembly (DFMA) comes in. DFMA exercises play a key role in helping stakeholders to work together, early in the development process, to outline needs and wants and explore strategies of how to achieve them all (or at least achieve the optimum compromise). Design for Manufacture (DFM) and Design for Assembly (DFA) were traditionally considered as two separate disciplines, but are now increasingly combined to good effect. We’ve put together a useful factsheet to introduce you to the topic.

A DFMA exercise generally involves methodically working through the following tasks in this sequence, with all the relevant individuals around the table:

1. Reduce the total number of parts – This can slash overheads such as stock, space, inspection and related admin and transaction costs.
2. Consider ‘modular’ designs – This reduces handling, purchasing and inspections while maintaining familiarity in assembly and maintenance / service.
3. Use standard parts – Well chosen, off-the-shelf, readily available parts can reduce stock and inspection, as well as cutting lead-times.
4. Make parts multi-functional and or multi-use – Imaginative use of one or more components for more than one function across product ranges can achieve major cost reductions.
5. Avoid over spec-ing – Analyse tolerances and surface finishes of all kinds, which are often overlooked and meet a default specification that can be unnecessarily expensive.
6. Consider any fastening methods – Fastening one part to another can be expensive; alternative approaches and new technologies can often provide economical and efficient solutions.
7. Consider the handling difficulty of parts – Avoid heavy, sharp, fragile or tiny parts which make handling time-consuming, costly and risky.
8. Avoid parts which need tricky holding or manipulation for further assembly – Use parts which are self-locating and don’t require humans to hold them carefully in place. This will reduce assembly time and skill requirements.