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END USER: LMC Industries Inc., (636) 282-8080, www.lmcindustries.com. CHALLENGE: Heat treat tooling components in-house to reduce costs and turnaround times. SOLUTION: A dual-chamber heat-treatment furnace. SOLUTION PROVIDER: Lucifer Furnaces Inc., (800) 378-0095, www.luciferfurnances.com
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Outsourcing heat treatment of parts can be costly and require lengthy turnaround times—which are especially problematic in emergency and weekend situations. Therefore, LMC Industries Inc. recently added a dual-chamber furnace for heat treating tool steels to its cadre of equipment. LMC, Arnold, Mo., is a metal stamping and plastic injection-molding company that serves the automotive industry.
According to Toolroom Manager Max Vogl, LMC wanted a furnace for its tooling facility, which supports its stamping and molding operations, to reign in the cost of outsourcing heat treatment and improve heat-treatment turnaround time.
After searching the Web and talking to various furnace manufacturers, LMC determined the Model HL82-H24 from Lucifer Furnaces Inc., Warrington, Pa., was the best fit as far as versatility and price. In addition, both a tool shop and steel supplier highly recommended the furnace.
Courtesy of LMC Industries
LMC’s dual-chamber heat-treatment furnace from Lucifer Furnaces has a high-temperature upper chamber and a lower tempering chamber.
“We needed a furnace that heats up high enough to handle all our tool steels, including powder metals such as CPM (Crucible Particle Metal),” Vogl said. “Regular tool steel requires a temperature around 1,800° F whereas CPM requires temperatures in the 2,150° F to 2,200° F range.”
The furnace has 5 " of multilayered firebrick and mineral wool block insulation for energy efficiency and to maintain a low outer shell temperature. The upper chamber measures 9 "×12 "×24 " and heats to 2,300° F. The lower tempering chamber has the same dimensions, is built with 4.5 " of insulating firebrick and mineral wool block and heats to 1,200° F. Both chambers are controlled by Honeywell UDC 2500 microprocessor-based, proportioning temperature controllers, with a separate high-limit controller on the upper chamber.
The dual-chamber design saves time. “With one chamber, there is a lot of waiting,” Vogl said. “You have to heat treat the part, wait until the chamber cools down, and then put the same part in the chamber but at a lower temperature. With two chambers, you can go right from one chamber to the other. While the tempering chamber is being used, you can put more pieces in the first one.”
Vogl also appreciates that the Model HL82-H24 is compact and easy to operate. “It took us only about 3 or 4 days of heat treating various parts to figure out how to make them come out right,” he said.
LMC plans to use the furnace to remove the 0.003 "- to 0.005 "-deep, white cast layer wire EDMing creates by tempering its punches and die sections. “We are still working out how to use the furnace to remove the white layer,” he said.
Tempering also removes the stresses and relieves high hardness on the surface edge, Vogl noted, adding that punches can break if stresses aren’t relieved. “When stamping, you are punching steel against steel, which starts to put stresses in the punches and die sections,” he continued. “So after every one, two or three cycles—we haven’t decided yet what that number needs to be—before we sharpen our punches and die sections, we want to put them in the lower chamber just below the tempering stage. That should relieve the stresses.”
Otherwise, Vogl noted, LMC experiences premature chipping on those punches and die sections. Those sections either have to be sharpened more frequently or scrapped.
Overall, LMC is satisfied with the Lucifer furnace and would recommend it to any company in the same type of business.
Vogl also noted that “since we bought the furnace, we haven’t sent one piece out to be heat treated. One furnace takes care of all our needs. In the future, I’m sure there will be times the pieces are bigger than our furnace can handle, but, for now, it services our needs.”
Related Glossary Terms
- hardness
hardness
Hardness is a measure of the resistance of a material to surface indentation or abrasion. There is no absolute scale for hardness. In order to express hardness quantitatively, each type of test has its own scale, which defines hardness. Indentation hardness obtained through static methods is measured by Brinell, Rockwell, Vickers and Knoop tests. Hardness without indentation is measured by a dynamic method, known as the Scleroscope test.
- lapping compound( powder)
lapping compound( powder)
Light, abrasive material used for finishing a surface.
- tempering
tempering
1. In heat-treatment, reheating hardened steel or hardened cast iron to a given temperature below the eutectoid temperature to decrease hardness and increase toughness. The process also is sometimes applied to normalized steel. 2. In nonferrous alloys and in some ferrous alloys (steels that cannot be hardened by heat-treatment), the hardness and strength produced by mechanical or thermal treatment, or both, and characterized by a certain structure, mechanical properties or reduction in area during cold working.
- tool steels
tool steels
Group of alloy steels which, after proper heat treatment, provide the combination of properties required for cutting tool and die applications. The American Iron and Steel Institute divides tool steels into six major categories: water hardening, shock resisting, cold work, hot work, special purpose and high speed.
- web
web
On a rotating tool, the portion of the tool body that joins the lands. Web is thicker at the shank end, relative to the point end, providing maximum torsional strength.
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