Canadian Plastics

Welding a fine line: MPD Welding Ltd.

For a molder hoping to avoid production interruptions, the agony of a tiny mold defect is that it requires just as much time and expense for repair as does a larger defect. And with pressures from ris...

March 1, 2007   Canadian Plastics



For a molder hoping to avoid production interruptions, the agony of a tiny mold defect is that it requires just as much time and expense for repair as does a larger defect. And with pressures from rising material prices and from auto makers seeking to reduce costs, coupled with increasing competition from Asia, time and expense are two things in very short supply today.

This was the situation that MPD Welding Ltd., of Windsor, Ont., hoped to alleviate last year when it acquired a high-tech laser welder, manufactured by O.R. Lasertechnologie GmbH of Dieburg, Germany, in order to perform rapid repairs of small mold defects. “The laser welder makes a real difference in the amount of downtime we can save our customers,” MPD’s Joe Catalano said.

Laser welding has been used in Europe for almost ten years, and MPD’s U.S. parent company has been using a laser welder for several years also. MPD Welding, however, was the first shop in southwest Ontario to adapt the laser welding technology, Catalano said, although several other mold repair shops in the Windsor area have since followed suit.

Hand-fed and controlled with a foot pedal, the laser welder travels along three axes by use of a joystick. In addition, MPD has fitted the machine with a periscope attachment that enables deflection of the laser in order to weld on a vertical wall, as well as a second attachment that allows for welding in circular patterns.

Traditionally, Catalano said, mold repair was a lengthy and costly process. It could take almost a full working day to generate the 1,000 to 1,100 Fahrenheit (F) necessary to begin welding, followed by another two to three days for the mold to cool down before it could be returned to the customer for use in production.

In addition to being time-consuming, this conventional method had other drawbacks. “First, there was the risk that, by heating the mold to 1,000 F, the metal might move a little bit, which meant that you no longer had a matching cavity and core,” Catalano explained. “Also, welding on the mold would leave a visible discolouration against the original steel.”

With the laser welding, however, heat is only applied to the mold surface for approximately 7 milliseconds. Thus, the property of the steel is not affected, and there is no visible weld line generated. “We weld for a very short time and also get a perfect colour match,” Catalano said.

And although the fine, delicate work created by the laser welder can take longer to complete, the elimination of the pre-job and post-job time means that a repair that used to take days can now be done in a few hours, Catalano continued.

It didn’t take long for word of MPD’s laser welder to spread throughout the molding industry, according to Catalano. “We now have customers sending molds to us from as far away as Quebec,” he said. “No matter how high the shipping costs, they still save enough time to make it cost-effective.”

While ideal for small mold defects, the laser welder is not designed for large imperfections. And, at present, the technology has other shortcomings as well, MPD’s Ryan Bondar said. “The technology has come a long way in just a few years, but it’s still evolving, and there are still some areas of difficulty,” he explained. “For example, the machine operates on a specific axis, and if you can’t stay within that axis while welding then it won’t work.” In all, however, there has only been a handful of molds over the past year for which MPD was not able to use the laser welder, Bondar continued.

With 8 employees and 6,000 square feet of shop floor, MPD is not a large outfit, Catalano said, but the laser welder allows the company to achieve turnaround times for mold repairs that bigger companies would be hard pressed to match. “We have customers who come to us in the morning with molds to repair who require it back for the afternoon shift, and we can accommodate them,” he said. “The result is that we’re so busy we have had to adopt a first come, first served policy.”

Which, given today’s economic climate, is certainly not the worst problem for a repair shop to have.

MPD Welding Ltd. (Windsor, Ont.)

www.mpdweldingltd.com

877-253-9353


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