Identifying Manufacturing Processes for Low-Volume Production
Product design and manufacture are intertwined. Although there’s little evidence supporting the adage that 80% of product cost is dictated by design, this fits with our intuitive sense of how things are made. Adding more features, tighter tolerances, and specific finishes always has implications for the complexity, and hence cost, of manufacturing.
What’s more, processes yielding the lowest piece cost need high volumes to amortize the steep cost of tooling. (In general this applies to net-shape processes like molding and casting.)
But when demand for a new product is unknown, a commitment to expensive tooling bills is seldom forthcoming. For these reasons, different production methods are used in the early days of a product launch than those that will be employed as volumes grow.
Transitioning into low-volume production must be handled with great care. Inevitably, changes will be identified and made, usually to save money. But it’s essential that their impact on product performance also be considered. The people involved at the start understand the reasons behind the design and manufacturing decisions and are best placed to steer the production launch. This is why it’s so beneficial to have the same team stay with a project from prototyping all the way through to production.
Where Knowledge About Prototyping and Low-Volume Production Lives
Prototypes are tools for learning, and that includes determining optimal manufacturing methods. Making and assembling parts always reveals challenges that weren’t foreseen during design. No matter how powerful the design tools, nothing provides insights into how product and manufacturing processes should be modified like a physical prototype.
Inevitably, despite the best intentions, only a portion of what’s learned about the manufacture of a product is ever documented. Much of the knowledge essential for problem-free prototyping and low-volume production remains with the people involved in the process.
Few organizations have the luxury of an in-house prototype manufacturing capability, which mean that a lot of this accrued knowledge will be found with an out-of-house prototyping specialist. Such a company will have an extensive range of rapid prototyping capabilities — not just additive manufacturing systems but a wide range of flexible equipment (usually CNC), backed up by a full complement of CAD technology.
However, unless they are also intimately acquainted with both prototyping and low-volume production methods, they will be unable to help with the scaling-up of production quantities. The problems they’ll face will be twofold. First, lacking familiarity with low-volume production methods, their input into product design will be limited. Second, prototype production methods will be selected with little or no regard for either the final or interim processes. As a result, prototype parts may have a different look, feel and function than eventual production parts.
Perhaps most important, though, is the fact that whatever was learned during the prototyping process will be lost as a new partner is brought in to handle low-volume production. Higher production costs and reduced functionality are likely to result.