Leading Automotive Supplier Meets Deadlines with ZW3D
With ZW3D software, the manufacturing process is a continuous flow from design through machining.
More Speed for the Automotive Market
Global competition has made speed to market a crucial factor in gaining market share. The worldwide automotive industry is a prime example. As manufacturers race to offer the newest car on the block, model turnover schedules have shrunk. That puts more pressure on automotive parts suppliers; even if a vehicle’s formal introduction is years away, prototype and early-production parts are needed long beforehand to fill the supply pipeline. To meet those deadlines, top suppliers seek out advanced manufacturing processes and technology.
Focused on the automotive industry, Grand Rapids Spring & Stamping, Inc. (GRS&S), Grand Rapids, Michigan, is an industry leader in the manufacture of custom stampings, value added assemblies, springs and slide-formed products. With six facilities in the U.S. and Mexico, GRS&S makes precision dies that form vehicle components such as attachment brackets and mounting mechanisms. Stamping equipment that employs the dies includes automatic presses of up to 1,000 lb. capacity with bed sizes as large as 72" x 168", providing the ability to handle work piece material up to 0.250" thick and 48" wide.
The company’s capabilities and reputation for quality make it uniquely competitive. For example in 2006, GRS&S was selected from several qualified tooling sources to produce the first sets of dies ever built in the United States for use in the North American assembly plants of Nissan U.S.A.
To meet the quality, volume, cost and lead-time challenges of automotive part supply, GRS&S employs a variety of innovative manufacturing processes. For example, the company developed and patented its own “Smart Tooling” system, in which diesets controlled by optical sensors adjust to prevent any deviations in stamped parts that might result from changes in stock thickness or tooling wear.
In addition to the quality and cost pressures of automotive parts supply, “timing is a big issue,” according to design manager Chris Bloss. Typical lead times average just eight weeks, and for a new part, that schedule includes design, build and trial runs. To maximize productivity and throughput, GRS&S continually fine-tunes its design and communication technologies as well as its manufacturing processes. A key element of those efforts was the company’s switch from the use of separate CAD and CAM software packages to the application of integrated CAD/CAM software from ZW3D Corp. The ZW3D package combines 3D solid/surface hybrid modeling and parametric design and drafting capabilities with an integrated CAM package that includes 2- through 5-axis milling. The end-to-end nature of the software facilitates communication between design and manufacturing personnel, and at the same time provides powerful capabilities in both CAD and CAM.
grss2With ZW3D software, the manufacturing process is a continuous flow from design through machining. At GRS&S, a customer’s CAD model of a part is first translated into an IGES file. That file is then perfected via ZW3D’s advanced healing capabilities. “When you're not dealing with native software to native software you have to translate, and there's always a chance that some of the CAD data might become corrupted,” Bloss said. “ZW3D healing takes care of a large percentage of any problems, and it also has a good variety of tools to fix everything else. To get the cleanest part possible, we use the tools to reconstruct faces or fix edges that might be open or corrupted. The cleaner the model is, the better it goes through the process.” The software’s hybrid modeling features are “quite handy” for cleaning up surfaces, he said, “A lot of software is very particular about what kind of file the solid model is, whereas with ZW3D, you can use quite a few different solid files.”
As received, customer’s part models are oriented as they will function in the vehicle. Bloss said, “We'll reposition the model in a more advantageous condition, then start designing a tool to produce the part. We basically reverse engineer it.” Die configuration is based on experience, “and sometimes we utilize a simulation software to find the best process for forming a part, whether it's in one hit or in a progressive series of different forms to get the shape,” Bloss said.
A typical GRS&S die is made up of 150-200 separate 3-D solid CAD elements. “Each component is drawn as a solid in ZW3D, then we assemble it virtually. We can view each component separately, or in the context of the entire tool,” Bloss said. After machining, the components are assembled and fastened to upper and lower plates to form a progressive die.
Prior to using ZW3D, Bloss said, “We weren't utilizing 100 percent solid tools. We are now, not just in our design process but in our entire build process. It makes things go a lot smoother.” He pointed out that use of solid models facilitates communication amongst design and manufacturing personnel because a solid “is virtually complete. With 2-D renderings, a lot is left up to the imagination of the designer and his ability to communicate that block within a couple of views. With a solid, anyone is able to go in and rotate that block 180˚ and get every single vantage point.”
Bloss noted that use of 100-percent solids requires much more memory than 2-D rendering, and that the resulting file sizes are quite large; a typical complete die model can be 200 MB. Processing speed isn't compromised by the large file size, however, because the ZW3D software loads into memory only the display data for an object activated for editing. “When we are working on just one component, the software will just make that single component accessible, then push everything else in the background, so the memory isn't used up by doing any computations on those other components,” Bloss said.
Bloss also pointed out that a 3-D solid design by nature takes longer to create than a 2-D rendering. “By the same token, you're actually saving time in the long run because you are putting in more information,” he said, “The model requires less people and less time for interpretation. For every hour we are spending designing, we are gaining two hours at the end of the process.”
As a vehicle’s design evolves, dies require updates and modifications. “We call those engineering changes,” Bloss said, “they happen more often than not…it’s a bit of an ongoing struggle!” He said the software simplifies updating the parts of the tool that are changed. “The ZW3D structure has helped us a lot because we are able to use the parametric qualities and change things as we need to,” he said, “I've set up a lot of expression functions using variables, so we just plug in a variable and ZW3D will redraw the component. That's helped us quite a bit in trying to whittle down the time it takes. And, as much as possible, we will plug in pre-made components, so we are not drawing everything from scratch.”
Bloss said GRS&S’s “vast library” of designs created in the CAD software it used previously is easily translated into ZW3D via a compatible format such as IGES.
The company currently has eight seats of ZW3D, including six in design and two in manufacturing. The software’s end-to-end nature speeds communication between design and manufacturing functions. “We design as a solid the whole way through, and our CNC department is now able to pull directly from the ZW3D file, versus making a translation,” Bloss said.
Handling the transition from the previously used CAM software to full end-to-end use of ZW3D CAM capabilities is John Zawacki, a designer who formerly led the CNC and wire EDM operations at GRS&S. “We machine to extremely tight tolerances,” he said, adding that the shop cuts tool steels such as D2 and A2 for the dies, as well as 4140 for pads, using a mix of carbide insertable, solid carbide, and HSS tools.
Manufacturing the dies presents the acute challenge of making low volume, high precision parts quickly. “Speed definitely is an issue,” Zawacki said, “we have a very short lead time to build our dies.”
grss2Moreover, production volumes are in the single digits. Each die is basically a one-off project featuring one or two unique details. “We don’t do a lot of duplicate work.” Zawacki said. Therefore, the shop doesn’t have the luxury of trial and error and must get the program right the first time. “I like the libraries and feature recognition,” Zawacki said, noting that the software’s surfacing programming is very powerful as well.
The end-to-end nature of ZW3D software provides safeguards that can be valuable when dealing with the pressures of short lead times. Because the machining program is linked to the part model, “It won't let you drill a hole too big; you can’t program a 5/16" drill for a 1/4" hole. If it's not designed that way, it's not going to be programmed that way,” Zawacki said.
When the program is complete, Zawacki finds the verification capabilities of ZW3D software essential. “The verifying is very nice. We write the program and then we can simulate it right there in the CAM software to see if there are any issues, and see how it is going to look,” he said.
Small volume and short lead times also make it difficult to optimize machining parameters. “If we were to do duplicates, it would be easier to tweak the program,” Zawacki said. He noted that ZW3D features such as feed rate controls can help optimize cuts in corners or in roughing. Regarding the path from design to manufacturing, he said, “Our goal is to have a completely seamless translation,” he said.
GRS&S continually seeks ways to improve its competitiveness and satisfy its customers in the demanding automotive industry. Beyond the application of advanced manufacturing equipment, that improvement is “basically a communication process,” according to Chris Bloss. The end-to-end capabilities and power of software from ZW3D Corp. help smooth and speed communication and thereby give Grand Rapids Spring & Stamping a sharper competitive edge.