Mold Maintenance & Repair

OCT 2013

Mold Maintenance & Repair

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F e at U R e ent. The pulse is in contrast to a continuous arc used in Tig welding processes. The pulses are short bursts of energy high enough to actually melt both the base metal and the fller rod; yet residual heat is quickly dissipated in the base metal. it doesn't take much of a Tig weld to make a workpiece too hot to handle, laser, plasma and pulsed Tig result in a workpiece that is basically at ambient temperature when fnished. several of these options have been described as "easy to learn," which is not to say that they are child's play. in contrast to the dexterity, technique and experience required to perform delicate work with a conventional Tig, the more expensive options provide increased machine control of the welding process, and due to the micro size, the mishaps are likely to be less disastrous. From the Field The editors of MoldMaking Technology reached out to a handful of moldmakers and molders to learn about their mold repair and welding experiences. scott Phipps, President of united Tool and Mold (uTM; easley, s.c.) shares his thoughts on how laser welding is a tool, not a cure-all or magic eraser. "You still need to have a skilled employee with signifcant Tig welding experience that understands parent materials, rods, size of rods, and welding applications in general. laser welding is good for small edges, small build up, small pits, and hard Photo courtesy of R&D/Leverage. BEFORE rePAir AFTER rePAir Part: 20-ounce base cup received from customer damaged. Process: clean, weld damaged surfaces, CNC and manual machining to bring part back to print specification, polish and engrave. 18 Mold Maintenance & Repair to get to areas. We have employed laser welding in grained areas and high polish fnishes due to having very minimal heat afected zones and you do not afect the surrounding areas. special attention is needed to ensure that you are laying beads or build up so as to not have a chipping issue. laser welding is especially nice with copper nickel alloys and aluminum small touch up areas. skill levels on a laser welder can be increased at a faster pace than that of traditional welding applications. This is due, in part, to the simplicity of the machines versus the skill levels needed with the Tig welding applications." over at Thogus (Avon lake, ohio), micro welding experts sean Murphy and John lauer explain that in-house micro welding capabilities save them time and money from not having to outsource mold repair jobs—such as tiny core pins cracking. They get results within hours rather than waiting days for the new core pins to come back from an outside source. Micro welding allows them to build up small edges, grind down smaller areas, polish and put them back in the tool, so they can go back into production much faster than those without this technology. Adam nelson, laser business Manager for r&d/leverage (lee's summit, Mo.) explains how choosing the proper welding technique is essential. "We at r&d/leverage use fve-axis 100 Watt nd:YAg lasers, primarily. choosing the proper welding technique is key. You have to balance speed, efciency and precision. Tig can handle a large area for more bulk welding, but laser welding does not leave a HAZ (Heat Afected Zone) on the part. This allows us to laser weld a tool and machine it with much greater ease compared to a tradition Tig weld where you will fnd surface hardening due to the HAZ. We also fnd the laser weld can be applied in a more precise manner, making the post processing (whether it is milling, laser engraving or

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