Charles, I don't really think that it was overdesigned because of lack of understanding about the forces, but much more because of a fairly good understanding about the variability of the materials involved. We have had very excellent engineers for a long time, but inconsistent materials.
it seems to me, WilliamK, that your point about "not understanding the forces involved" is right on target. I could be wrong about this, but I think that design engineers often don't have a good grasp on the forces, which is why, many years ago, pretty much everything was overdesigned. The problem today is that our technology allows us to come too close to the edge, and when we don't appropriately understand those forces, we unintentionally go over the edge.
A bit of other consideration does not stand out in this discussion, which is the design for usability part, and the consideration that just possibly some of these items may need to be adjusted or even repaired. A whole lot of DFM seems to have resulted in products that could not possibly be adjusted, cleaned, or ever serviced. So those wonderful snap togather tabs that will shatter two months later if they are deflected enough to relaese are not such a good thing if you ever want to sell another unit to anybody whom I advise. Or those products with the very thin walls of brittle plastic, and those stress concentrating profiles. Of course it is a great design that puts all of the intermediate gear shafts into one molded part that includes the case, but when they break because the change to a injection molded all in one plastic integrated assembly did not account for the reality that plastic shafts are not as strong or durable as the steel ones that they replaced. The problem arises when redesigners don't understand the product that they ar5e redesigning, nor have any clue about the forces involved.
If this product truly provides real-time moldability feedback during design creation (without significant sacrifice to CAD geometry speed or performance) then it is a really nice break-through. It would be interesting to see if there is a slight performance penalty on very complex parts with a large number of features.
Excellent article. Design for manufacturability has always been important, so it's great to see advanced software tools that are helping to make this process more streamlined. Completely agree that simulation is also an area that is growing in importance and is really an important part of the next step in manufacturing/design advances.
An interesting article providing insight and solutions for a longtime problem not just in design/manufacturing but in many practices where creative vision and technical practicality must meet somewhere in the middle. With a background covering software design, I wrote a lot about the issue between developers of code and designers of user interfaces and how they sometimes clashed. This relationship between designers and manufacturers seems similar. Thanks for the informative and insightful read.
From design feasibility, to development, to production, having the right information to make good decisions can ultimately keep a product from failing validation. The key is highly focused information that doesn’t come from conventional, statistics-based tests but from accelerated stress testing.
There’s a good chance that a few of the things mentioned here won't fully come to fruition in 2015 but rather much later down the line. However, as Malcolm X once said, "The future belongs to those who prepare for it today."
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