Machining automation: Beginning Anew
- May 28, 2018
Toronto die manufacturer sets aside a 50-year legacy to make a fresh start
by Kip Hanson | photos by Ron Ng
With more than 50 years in business, 140 employees, a 12,500 sq m (135,000 sq ft) production facility, and a customer list that includes major automakers on multiple continents, calling Exco Engineering anything but successful would be grossly incorrect. But when plant manager Richard Dunn took a long, unbiased look at how he and his team were producing high pressure die cast tooling, he realized there must be a better way.
The longest mile
“None of our Skoda or PBR boring mills have a tool changer, so our spindle uptime was maybe 40 per cent, with another 40 per cent or so spent on handling the tools–taking the cutter out, replacing inserts, putting on an extension, making a test cut, and so on,” he says.
Machine downtime was bad enough, but then Dunn analyzed the different machining steps and found that each block of steel traveled roughly one mile through ten different departments before completion. That meant using a crane to lift it, move it to the next area, and set it back down at least 18 times. “Once we’d actually mapped everything out, we just shook our heads and said, ‘No, this is ridiculous.’”
Nor was Exco alone. The team traveled to several tool shops in Japan, where they found that, even though their peers there had invested in the latest and greatest equipment, had in fact built entire plants from scratch, the end result was little different than that achieved by Exco.
“All they did was perfect the old process,” says Dunn. “They took the traditional, department-based manufacturing methodology, improved every part of it, added a bunch of robots to move things around, and then turned out the lights. These were very impressive shops, but they missed one very important thing: combining more operations into a single handling.”
Leapfrogging the competition
Exco builds big moulds. A typical one might be the size of an eight-person hot tub and weigh more than 45,000 kg (100,000 lb). Your car’s engine block may have been cast using one of Exco’s tools, as well as its transmission housing, the differential, the sub frame wheels and instrument panel.
Each mould is filled with bolt-in machined inserts that create the die cast part’s complex geometry. Running through and around these inserts as well as the mould body itself are hundreds of internal cooling channels that must be gundrilled, often to depth-to-diameter ratios of 80x or more. To condense most of this work into one operation would require a machine tool larger and far more capable than anything on Exco’s production floor.
Exco defined its machine requirements: a 10,000 rpm spindle. HSK 100 tooling. Through-the-tool coolant with 100 bar (1500 psi) pressure. In-process probing and tool measurement. High feedrate accuracy for fine finishing work with the rigidity and power for heavy roughing. At least 1200 mm (48 in.) of axis travel. After reviewing “all of the top brands from Japan and Europe,” Exco chose a Mazak Integrex e-1600V and two e-1250V five axis machining centres, each equipped with a pallet changer.
There was one problem, however. None of the machines they looked at had enough tool stations. “The biggest tool changer we could find had 350 tools and we needed two to three times that,” Dunn explains. “We also wanted the ability to share tools between machines. That’s what led us to the idea of building our own tool storage system.”
Enter the hive
Working closely with Oregon-based Predator Software, Exco designed and built its own “tool hive” able to store 4,000 toolholders and service all three machines. A Fanuc R-2000 robot rides a 30-meter long (100 ft) rail, plucking tools from the hive and carrying them to the tool carousel of whichever Mazak calls for them, each of which carries 120 tools.
“I can’t say whether it’s the largest tool system in the world, but it’s certainly the largest that we’re aware of,” says Mazak Canada general manager Ray Buxton.
The idea, says Dunn, was that the next 100 tools needed for the job are always in the machine. “When a tool has reached its end of life, the robot takes it to a central location for changing. Everything is tracked using read/write Balluff RFID chips. That information is shared between the robot, the machine controller, and a central database. We know where every tool is at any given time, how much life it has, what job it’s working on...everything.”
As if that weren’t enough change for a company that had been building moulds in much the same manner for the past five decades, Exco decided to leverage the Mazak’s hard milling capabilities and switched the majority of its moulds to H13 steel, pre-hardened to 44 Rockwell. This eliminates the traditional process of rough machining in the soft state, then finishing after heat treatment. The result is less handling, less warpage and chance of scrap, and far less hassle.
This move led to even more change: entirely new cutting tools. Exco reached out to its long-time partner Iscar Tools Inc. Canada for a complete makeover of its existing tool lineup, and soon took delivery of Helido high feed cutters, Dove-IQ face mills, Sumocham and Tri-Deep indexable drills, the last of which had to be modified with carbide guide pads to support the tool through the intersecting cross-holes present on most of Exco’s workpieces.
“The Mazak five axis machines, the fully automated cell, and the use of high performance tooling from Iscar resulted in higher productivity, allowing Exco to reduce lead times to their customers,” says Iscar area sales manager Nikhil Antani. “This investment has given them an edge over their competition.”
Beyond the bottom line
That last part is an understatement. Dunn readily admits that Exco is enjoying additional business that would have been impossible to win without the new equipment. Instead of ten setups per job there’s now often just one. Lead times have dropped from upwards of 16 weeks to “less than three” in some cases. And spindle uptime now measures in the 90s, much of it unattended.
The result is better cash flow, lower work-in-process, improved part quality and profitability, and far greater flexibility. In fact, Dunn is so pleased with the system that he plans to spend the rest of 2018 fine tuning it before taking the next step: doubling the size of the tool hive to 8000 tools and adding three more Mazaks.
“It’s always been a profitable company,” he says. “We could have upgraded our old boring mills to current models and kept doing things the way we’ve always done it. It would have been easier. But we voted to start with a clean slate. The programming, the tooling, the machines and even the process itself...nothing is carried forward from our old system. We asked ourselves, ‘how would we do this if we were going to build a brand new shop? What would we do?’ This is what we came up with. Our intent was to leapfrog any competition, and I think we’ve done exactly that.” SMT