Page 40 - MetalForming December 2011

Tooling Technology
Welds
local customer Dayton Systems Group (DSG) with fresh carbide-insert stamp- ing tools for its customers in the can- making industry.
Entrepreneurial at Heart
Mourouzis launched Wicked Weld- ing in 2003 after having worked for sev- eral years in small injection-mold shops. He spent three of those years running CNC machines and doing assembly work, and the last two as an inhouse welder.
“While others around town can weld as well as I can,” he shares, “what I bring to the table is my knowledge of tool and die applications. I talk the toolmaker’s language and understand how tools work in the press, all of which impacts my ability to offer the right weld-repair solution for the job.”
Wicked Welding’s sweet spot is rela- tively small tooling—shoebox-sized work weighing a few hundred pounds or less. Mourouzis and the firm’s other two welders will use the micro-tig process when it can, but “trying to tig weld traditional tool steels cold is a recipe for disaster,” says Mourouzis. “Without proper preheat, cracking is inevitable, and that’s where laser weld- ing has proven to be a huge benefit. I can laser-weld without preheating (depending on the size of the repair area), filling small pits that affect the surface finish of the part or restoring worn or damaged cutting edges. Also, as stampers have moved away from stocking several replacement inserts, the value on our services has risen. We’re laser-welding to repair die inserts weekly for our customers.”
“Free-Moving” Laser Welding
Mourouzis launched his company as a provider of traditional tig and micro-tig welding services, and made his foray into laser welding in 2005 with the purchase of a small LaserStar 80-W manually operated machine. In 2008 he added a larger 100-W Rofin model, equipped with a three-axis joystick-con- trolled table and rotary fixture. Both machines run pulsed-YAG lasers and feature a stereomicroscope and cross-
hair for precision beam align-
ment. By year-end, Mourouzis should have a third laser-welding system inhouse, this one rated to 200 W.
Here’s how LaserStar describes what it calls the “free moving” process of using laser welding for mold and die repair:
“The laser generates a stationary infrared light pulse which is targeted through the microscope’s crosshair. The laser pulse can be controlled in size and intensity. Because the heat generated remains localized, opera- tors can handle or fixture items with their fingers, welding small areas with pinpoint accuracy without causing any harm to the operator’s fingers or hands. This free-moving concept enables users to eliminate costly fixturing devices.”
When we visited the welding shop, customer Jon Ledford, DSG manufac- turing manager, was there picking up some recently repaired tools. DSG sup- plies the can-making industry with production systems, sheet-feeding lines and tooling.
“Welding, for applications such as replacing carbide inserts on our tools, is part of our process, and Wicked Weld- ing is on our routers,” says Ledford. He showed us a few tools that Mourouzis works on regularly, which feature car- bide inserts. Says Mourouzis: “Of
To maintain these stamping tools for Dayton Systems Group, Mourouzis deposits tiny, precise laser welds to hold replaceable carbide inserts in place.
course, we don’t actually weld on the carbide. But we can make tiny laser welds to hold the inserts in place in the tools. The carbide inserts are light- ly pressed into place, then I push the weld beads right up against the car- bide. It’s a fine line—put too much heat on the carbide and it will crack, so I try to use the laser to dig into the base material (M4 tool steel) and shove it up against the carbide to lock it into place.”
Ledford explains that at one time, brazing was used to assemble the inserts into the tools. However, the process proved messy and slow, and it was difficult to remove the inserts when they needed to be replaced.
“I can tack an insert in place in about 2 min.,” says Mourouzis, “while brazing might take 15 min. or more.”
Hair-Thin Filler Wire
While micro-tig welding requires what most would call thin filler wire— down to 0.010-in. dia.—filler wire for laser welding is hair-thin, as delicate as 0.005-in. dia. M2 filler wire is a favorite of Mourouzis and his crew.
“It’s a fantastic all-purpose filler metal for A2 and D2, as well as M2,” he says. “It’s my go-to-rod unless a cus- tomer requests a direct match to the base metal. And we also burn a lot of
38 MetalForming/December 2011
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