Product design – fit for purpose, on time and on budget

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It’s a fallacy that the only things blokes talk about in bars is football and cars.When John Tumelty pulls up a stool, a debate ensues about at what point in the development process can a product be considered ‘complete’
Despite all of the advances over the last few years, and probably thankfully, your CAD software doesn’t do the design for you. SolidWorks et al have certainly made the process of representing your thoughts easier but only you, the designer, really knows and understands the workings of the components that come together to create the finished product. A beautiful rendering of a bad design is nothing more than that; a bad design.

The rise and rise of additive prototyping technologies (FDM, SLS etc.) exhibits some parallels from a manufacturing viewpoint. Virtually any form can be created with additive rapid prototyping and in the same vein that the beautiful rendering of the poor design is meaningless; if your product can not be economically produced then we loop back to the crap design line. As these technologies move into the future it is possible to visualise a time when additive manufacturing becomes viable for volume production, however, today these technologies are residing firmly in the prototyping arena.

In the hotel bar after a long day at Euromold I was informed by a fairly high brow product designer that the design is completed at the point when it is aesthetically pleasing. We disagreed. Having done our bit to support a certain Dublin brewery’s income statement, we still disagreed; just a little bit louder. My argument is that a design is complete when the product is fit for purpose, market and manufacture – on budget. The counter argument I was hearing was that manufacturing engineers and marketers can define these details. I continued to disagree; if the design process is given up so early then the product will vary significantly from the designer’s intent. Is that what the product designer wants to transpire?

Our discussion then drifted onto how the mainstream CAD packages (just the tiniest glimpse into quite how riveting a social life I lead) have tried to assist the designer. Draft analysis for cast and moulded parts, split line definition, FEA for material analysis, built in flow simulations etc. We concluded this delightful break in the main debate of the evening with the theory that it should be almost impossible for the design to get past the CAD package without being fit for purpose and ready to manufacture.

Frustratingly we found ourselves starting to reach some common ground on the point at which a design can be said to be complete.

The design process should finish when a product is fit for purpose, market and manu-facture – on budget

Before the design is classed as finished the designer needs to recognise when to call upon others to input to the creative process. Use the manufacturing engineers, the marketers, the team. Expertise develops over time and as the level of detail and difficulty increases in any given subject the field and scope of this expertise inevitably narrows. The draft and split line analysis in SW doesn’t come with a built in master toolmaker to give you a little guidance, the flow simulations don’t give you a starting point of several thousand experiments feeding the first and most important input – where to start, a list of 100,000 different grades of material is a little daunting before you can run the FEA.


I guess what I am saying is that these features are tools; put them in the right hands and they are incredibly powerful.

The point is that the design process should finish when a product is fit for purpose, market and manufacture – on budget. The designer should see this process through to completion, but the designer should not be left to answer all the questions. Use the experts and lean on their experience. In the same way that the design process is not a series of algorithms and fully automated neither is the process that makes that part manufacturable.
The software today is staggeringly good, but it is still just a tool.

Note to self – get out less!

John Tumelty is managing drector of Proto Labs. He’s currently working hard on a new set of topics to discuss with strangers in bars.
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When can a product be considered complete?, asks John Tumelty

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