For global automakers, the ideal is to design a vehicle once and then produce nearly identical versions of it in all global markets. Key suppliers know how to support those goals, offering digital quality control technologies that ensure a widget produced in Bangkok is the same as one from Detroit.
However, there’s one key sector that continues to use old, analog technology instead of the digital CAD systems that guarantee consistency in multiple manufacturing sites – texture contractors that add faux-leather and other aesthetic treatments to plastic parts. And as producers step up the use of lightweight plastics to lower vehicle weights, getting consistent results using analog processes will become increasingly difficult.
“Most of the other suppliers are already digital. We’ve got to go
that way,” says Don Melonio, vice president of Custom Etch Inc., a
texturing company in New Castle, Pennsylvania. “With laser technology,
we can do this. The lasers can be anywhere in the world. Any
automotive supplier that masters a pattern, they can say, ‘This is our
spec’ and send out a digital file. And they should get consistent
results, anywhere in the world.”
Lincolnshire, Illinois-GF Machining Solutions makes a range of laser products designed to etch patterns into the tool steel used in injection molds. Custom Etch is the first U.S. customer to buy the company’s largest machine from that line, the Laser 4000 5Ax, a 5-axis machine that gives Melonio’s shop the ability to bid for large automotive interior components such as complete dashboards.
Melonio says laser etching is a more accurate process than the photochemical systems used for the vast majority of automotive texturing. Under the old process, texture houses would get a 1ft x 1ft pattern master, typically a wax copy of the surface the customer wanted on its plastics.
Texture producers would effectively copy the pattern and apply that design to the surface of the steel injection molding tools used for the plastic. Acid would etch away negative portions of the pattern, leaving the positive areas higher – the thin standing veins left behind in that process became the valleys in the faux-leather patterns, while the etched-away low parts became the pillowy top surface.
The consistency problems come from the fact that photochemical transfer is a manual, two-dimensional process, but plastic parts tend to be three-dimensional. Melonio explains that wrapping the texture map around corners and curves requires a lot of custom overlays, and each shop is going to do those differently.
“You can have one guy in one shop do a great job, and the surface is going to look consistent every time,” Melonio says. “But it’s going to look different from how the guy does the same part for a car at a different plant. Or if someone doesn’t do a great job, you’re going to notice all kinds of flaws.”
Lasers that etch a digitally approved texture directly onto to the tool steel, Melonio states, have an easier time with edges and corners because CAD software can create the 3D images needed. Having that three-dimensional image eliminates the complex overlay system that can create the biggest inconsistencies between part textures from different suppliers.
Laser etching advantages
In addition to repeatability and greater design freedom, switching to laser etching from photochemical processes can solve several automotive texturing problems.
Tool assembly – Injection-molding tools can be very large, so it’s common to disassemble the systems and ship individual parts for texturing after the tools have been approved for production. After texturing, the tool must be reassembled and tested again for quality. The individually etched pieces must be carefully lined up to avoid continuity breaks between veins in faux-leather surfaces.
With large laser equipment, companies can etch texture treatments into the tool without disassembling it, removing several rework steps, lowering shipping costs, and removing potential continuity errors.
Tool safety – Theoretically, tool steel used for injection molding is identical from supplier to supplier. P20 is P20, regardless of who manufactures it. But impurities can work their way into molds, and those problems aren’t always obvious. Custom Etch Inc. Vice President Don Melonio says on occasion, a tool will pass rigorous part-creation testing and be approved for texturing. At that point, the acids used to create the surface treatment can uncover any inconsistencies in the metal.
“The acid can react to high sulfur content in steel. We call it a streaking flaw. Sometimes you can start to see the grain of the metal in the etch,” Melonio says. Lasers, on the other hand, don’t react to subtle material changes. If the tool is strong enough to pass production testing, laser texturing won’t change that, he adds.
Gisbert Ledvon, director of business development for GF Machining Solutions, says German automakers have led the adoption of lasers as a way of replacing photochemical texture etching.
“At BMW, the i3 electric car uses lots of textured molds to get a leather-like look in its plastics,” Ledvon says. “The carmakers want to differentiate themselves from each other, and a lot of that effort is coming from interiors – using interior materials that look better or feel softer to the touch.”
Replacing the analog system with lasers won’t happen immediately. GF Machining Solutions has only sold a handful of its largest machines, so a limited number of suppliers in Europe, Asia, and North America can offer the service.
Melonio says he talks to laser texturing companies in Germany and Asia regularly, and they have agreed to bid on some work together so a global producer can send the same CAD files to three different suppliers on three different continents, yet still expect to get identical work.
He adds that the biggest barriers to wider adoption by the industry are the high costs of laser equipment compared to photochemical etching systems, and the amount of expertise needed to run the lasers. On the other hand, the laser systems can run 24/7, require fewer man-hours, and can be automated with pallet changers to keep them operating constantly.
“We’ve gotten to the point where we can bid about the same price for laser or chemical,” Melonio says. “Laser’s a lot less labor intensive, but the equipment is much more expensive, so we can make that about a wash. For the customers, we think there’s a big savings, not so much in money but in time at the end of the process.”
Texture etching comes late in the production prove-out process – after automakers have already approved injection molding tools – so any problems in texturing can be expensive as they can delay product launches. Sometimes, texture companies can quickly resolve an unacceptable finish. But in worst-case scenarios, they have to scour the surface of the molding tool clean and start over.
“All of those problems add delays. Some of these guys build weeks or months into the end of the process to account for all of that rework. We can eliminate most, if not all, of those problems,” Melonio says.
Managing file sizes
One of the biggest challenges that Custom Etch faced when it bought its first laser-texturing equipment several years ago was machine speed, says Don Melonio, vice president. Massive, three-dimensional images that his staff had created resulted in extensive processing time for the machine’s software.
“When we started, we’d see a black area on the design, but the machine saw that as 1 million black dots. The laser would take every single one of those pixels and turn that into a bit of information. Every one of those bits became a head movement on the laser,” Melonio explains.
When engineers realized that they were sending too much data to the
lasers, they were able to work out much more efficient file sizes.
Now, digital artists at the company consolidate all of the black areas
of image files, creating far fewer data points. Cycle times fell by
Laser 4000 5Ax specs
- X, Y, Z travel: 157.48" x 118.11" x 59.05"
- X, Y, Z axes speed: 1,181.1ipm x 1,181ipm x 787.4ipm
- Max. weight on table: 39,683 lb
- Working height over floor: 5.9"
- Max. workpiece dimensions: 98.42" x 59.05" x 35.43"
- Machine dimensions: 334.64" x 350.39" x 206.69"
While global repeatability is a big draw for laser texturing, the ability to create more complex, three-dimensional shapes is another draw to the technology. Texture specialists tend to work with a very small amount of space, rarely more than a few millimeters from the top to the bottom of the etch. Melonio says photochemical processes get very binary under those limitations – the surface is either raised or lowered. Acid can’t cut away by degrees.
Custom etch recently textured the injection mold for an engine cover used by Volkswagen in the United States. Showing off the cover, Melonio states, “You have a three-dimensional geometric design, wrapping through a radii, stretching with perfect continuity around edges, without being broken or changed. That wouldn’t be possible with anything other than lasers.”
Ledvon adds that one of GF Machining Solutions’ Asian customers has used the laser etching systems to carve dragon images with company logos into surface textures. As automakers adopt the technology, car buyers can expect the same innovation in interiors that Melonio’s biggest customers – plastic beverage bottle producers – have enjoyed for more than a decade. The average 20oz. soft drink bottle used to feature straight-sided, blank surfaces. Now, the vast majority feature complex textures and designs, often incorporating company logos, video game characters, or movie titles.
“This is where you can really see the benefits of technology,” Melonio says.
Because of his customer base and equipment, Melonio adds that he’s very excited about the lightweighting trend sweeping the automotive industry. Plastics are very light, so the desire to lower vehicle weights creates more opportunities for his company to add treatments to surfaces that once would have been metal. And with several automakers replacing steel with aluminum in cars and trucks, plastic is looking more attractive to his beverage customers.
“I love what Ford’s doing with aluminum,” making the body of the 2015 F-150 out of the lightweight metal, Melonio says with a laugh. “The more they demand aluminum, the higher the cost for the beverage guys, and they won’t sell Pepsi in a can anymore. They’ll have to sell it in a plastic bottle. I’d love that.”
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