Engineer Bill Davis was surprised recently to learn that one of his engineering firm's customers who used 2D CAD redrew every part in the machine shop before building it, adding time and cost to the product-development process. "They had run into several instances where the geometry was out of scale," says Davis, of Impact Engineering Inc. The machine shop just didn't trust the models.
It's not often that you hear the mushy word "trust" in engineering, but Davis believes it's a key part of avoiding hidden costs in the design process. And, he says, it only comes about when a company installs a "best practices" regimen that dictates how you create geometry for your products, where the fillets and chamfers go, and where you put tolerances. "You have to be disciplined," he says, if you expect others to believe in and be able to use your models.
"With software, it's still garbage in, garbage out," says Chris Hayes, of engineering services firm Roush Industries. "If you constrain the model wrong, use bad loads, or use the wrong units in FEA, for example, you'll get bad results."
Lesson One in avoiding extra costs with software: Establish ground rules for how every engineer in the company will design models in your chosen software, and stick with those rules.
Lesson Two: Remember that the software is only a tool, a means to an end, not the end in itself.
Borg Warner Automotive engineer Paris Altidis believes some engineers forget that principle. "Some people get so revved up about making the model look good, they forget about making it optimal," Altidis says. Avoiding that trap, he asserts, comes down to exercising good engineering judgment.
And that also applies to your choice of software. Lesson Three: Make sure you're using the right software for your needs.
PTC's Tom Shoemaker says with 3D CAD, you can use the same model in many downstream applications, such as simulation, saving time and money.
But there are no free lunches in engineering, says Wayne Biery, manager of engineering design at Victaulic Inc. "Be sure you have the right hardware for the software, and factor in administrative costs," he cautions. That may seem elementary, but it can escape the person enamored with the bevy of features a new software release might offer. Likewise, a software sales person may be so enthusiastic about the features he forgets to talk about hardware needs, or at least downplays them. And it's not just the hardware that can trip you up: You may need additional enabling software too.
"For example," Biery says, "with product data management software you may need special server software to run it, and you might not find that out until after you bought the PDM system." That actually happened to him.
Another hidden cost is administrative. If you have a lot of software, you may need an administrator to configure it for you and provide regular support. "If you use other engineers to do the configuring and administrating, you're taking them away from their primary job, and then you have the costs of finding another way to get their work done," Biery asserts.
Even upgrading to software with important new features that your present software lacks can include hidden costs. First, says Biery, the features and functionality may be built into the software in a way that favors the software developer's vision of the ideal design process. "If it's not the way you do things, you'll have to either change your ways or customize the software," he says. And, says Ansys's Barry Christianson, remember translations and training. Both can present an unexpected expense. The solution: Having all data in one tool like Workbench eases both costs, he says.
Machining Costs: Designing parts that require excessive material removal causes long run times, tool wear, and chip-removal issues. Instead, fabricate the part as two or more simple parts with surfaces joined to form a subassembly, as this example shows.