Using Tolerance Analysis Software to Explore Manufacturing Alternatives

[Tmetcalf]

Vestas Wind Systems A/S, the world’s largest producer and manufacturer of wind turbines, used Excel to run tolerance analyses combined with some trial and error on the prototypes for a new design. During one final test before shipping the first unit to the field they realized that the spinner at the center of the blades was colliding with the fixed nacelle. The required gap in the design wasn’t there in the actual assembly. What would they do? What would be most effective in terms of cost and time? Would they change the design - an engineering change could cost 5000€ just for the paperwork? Before understanding the cause of the problem one consideration was making adjustments at the time of final assembly in the field. Before changing anything, though, they used CETOL integrated within Creo to understand the true cause of the problem and explore better alternatives for resolution. Attendees learned how Vestas explored both manufacturing and design alternatives to enable them to solve their hub and nacelle issue. Attendees also heard how to apply the same methodology in their design process by incorporating tolerance analysis tools, such as CETOL 6σ.

[dschenken]

They probably would have noticed when the blades didn't fit in the holes, but not before the unit was a few hundred feet in the air.

I've encountered similar problems before, where making a part more manufacturable left it harder to assemble correctly. One project I was on chose lengthy slotted holes to make up for low quality positioning of weld studs, but then, as here, used the slots not to make up for the misplaced weld studs but to add additional misplacement of the components. This could have been avoided by adding assembly dimensions or just a fixture for locating the studs, but no one cared to inspect items installed with a wrench.