Constraint-Free Modeling Frees Up Fixture Designers23 Feb, 2011 By: Mike Paludan
Melling Tool implements Solid Edge with synchronous technology and cuts CAD time by half.
Melling Tool Company is a manufacturer of oil pumps and other power-train components. From nine facilities in North America, the company serves global automotive OEMs (original equipment manufacturers) as well as after-market suppliers through its engineering, product development, and distribution capabilities.
Melling product designers use NX from Siemens PLM Software, then pass NX data to fixture designers who use Siemens Solid Edge software to create the fixtures that hold parts during the manufacturing process. As Melling has expanded its product line in recent years, fixture designers Steve Trefry and Jason Mulcahy have been under pressure to get more done in less time.
"A typical manufacturing job requires three operations, so we need three fixtures per product," explained Trefry. "Designing them used to take us about four weeks [for all three]. When our company started diversifying with new products such as door closers, we had to find a way to work faster to keep up with the increased workload."
New Approach to Modeling
The fixture designers adopted Solid Edge with synchronous technology — even though neither of them really understood the potential benefits the technology offered. They knew what to expect with Solid Edge prior to the introduction of synchronous technology, but were pleasantly surprised when they learned how much time the new technology could save them.
Synchronous technology is a history-free, feature-based modeling approach that eliminates the need to constrain design elements by allowing direct modeling. Synchronous technology creates persistent features without the computational overhead needed to re-compute models from the construction history. Older parametric modeling technology serially applies rules to geometry, helping to automate planned change but not addressing unanticipated engineering changes.
During the transition to Solid Edge, Trefry actually didn't view constraints as a problem; he had used AutoCAD for years and was "used to all the constraints in traditional 3D modeling," he recounted. "I was actually a little leery of synchronous technology at first," Trefry added. He expected to simply keep modeling in the old way and not jump into synchronous technology. But when he tried the new software, Trefry realized measurable productivity increases.
Design in a Fraction of the Time
Trefry and Mulcahy use Solid Edge to design new fixtures and modify existing designs. With a large database of 2D AutoCAD drawings, the latter is something they do often.
"Synchronous technology has made a very big impact with all of our legacy fixture designs," explained Trefry. "A simple task such as moving holes in a fixture takes two minutes with synchronous technology versus 15 minutes with a traditional 3D CAD system."
Mulcahy agreed: "A ten-minute task in SolidWorks would literally just take a couple of clicks in Solid Edge with synchronous technology."
This oil pump fixture represents an example of synchronous technology capabilities. The complex part was originally designed in 2D AutoCAD, then brought into 3D Solid Edge in order to design this fixture. According to Melling designers, simple tasks such as moving holes in the fixture take two minutes with synchronous technology versus 15 minutes with a traditional 3D CAD system.
Since implementing synchronous technology, average fixture design time at Melling Tool has dropped from four weeks to two or two-and-a-half weeks. And because the design work consumes less of their time now, Trefry and Mulcahy are able to address other challenges. "I spend more time thinking about engineering than CAD, so I can consider more design iterations," said Mulcahy. "And we are able to do some engineering work that we didn't have time for in the past, such as specifying setups so the machinists don't have to guess," Trefry added.
From the perspective of accomplished users of traditional 3D modeling, Trefry and Mulcahy advocate synchronous technology for those upgrading from 2D to 3D. "Synchronous technology is more intuitive and easier to grasp," said Trefry. "Once I started using it, I never looked back."
For those already using 3D but in the traditional mode — even for those who are very good at doing so — the fixture designers at Melling Tool have the same recommendation. Said Trefry, "I don't know why anyone wouldn't use it. There's nothing to learn."
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