more parts per load,” said Rob Kornfeld, president of Hi-Tech Furnace Systems Inc. (Shelby Township, MI). Then there are times when the work zone can be utilized beyond what the manufacturer specifies. For example, an individual furnace can be resurveyed to verify that there is a larger work zone with uniform temperature within specification. Or there are certain types of parts that don’t require the precision heating obtained within the manufac- turer’s specified work zone. If the parts can tolerate a wider temperature range and still meet their design purpose, then a larger fixture holding more parts can be designed, recognizing that some of the processed parts will be outside the manufacturer’s specified work zone. Alternatively, there is the option of layering the parts. Instead of laying the parts out on a single level, a custom- ized solution can be designed with multiple levels of the precise height needed to allow even heating of the parts, while utilizing the full height of the work zone.
Hitchiner is an investment casting company that manufactures parts for the commercial, automotive, aerospace and defense industries. It uses an Ipsen vacuum furnace with a 48 × 48 × 72" (1220 × 1220 × 1830-mm) work zone for solution annealing of turbine blades at 2250° F. A few years ago, it decided to go with a custom fixture from Hi-Tech Furnace Systems. “I was familiar with the low lifespan of alloy fixturing at those kinds of tem- peratures,” Hutchinson said. “I studied switching to graphite and it seemed an ideal material to use.” One of his company’s managers had experience with Hi-Tech’s cus- tomized fixtures and recommended that Hutchinson contact Kornfeld to look into a custom fixture. Hi-Tech
Furnace designed a stackable graphite fixture that would hold 200 pieces per level. The fixture had five levels with 4" (101.6-mm) spaces in between, allowing 1000 blades to be processed at a time.