Jerry Karp, president of CNC shop Ran-Shel Inc., invested in new technology to increase capacity to meet customer demand. The Sterling Hts., Michigan, shop began in 1956 when Karp’s father, a lathe operator, began making tooling blanks for Detroit area companies. In 1980, he landed a volume order from General Motors and invested in his first NC lathe. Since then, the company’s focus has been CNC turning and milling parts for heavy truck and other automotive customers. Today, products they make include transmission gear blanks, engine pulleys, bearing adjustment rings, and chassis and suspension brackets.
“We do both low- and high-volume production runs, but when one of our major customers substantially increased their order volume for a truck differential part, I knew we’d have to increase capacity,” Karp says. “However, it was clear that just adding another machine tool wasn’t the best answer. We needed to analyze the way we were making the parts and come up with a more efficient process. That’s when we turned to our long-time Okuma dealer, Gosiger, for advice.”
In Ran-Shel’s former process, the machine operator loaded D5506 ductile castings weighing 35 lb to 45 lb into a single-spindle, Okuma L470 Captain turning center for one operation. Then the casting had to be moved to an Okuma vertical machining center for drilling, and moved again to an Okuma single-spindle vertical lathe for final turning. The part loading and unloading added cost to the process, misspent the operator’s time, and created excessive heavy lifting. With the new order, production volume increased to more than 440 parts each day, so the company needed a better solution.
Although Ran-Shel had overhead gantry systems for many years to move heavy parts, they weren’t practical for this situation. Instead, Gosiger Automation designed a work cell using a floor-mounted robot for loading and unloading. The initial plan was for the robot to service the existing V40 RM vertical lathe as it performs one operation. However, based on the anticipated increase in production volume and the desire to reduce cycle time, Gosiger proposed adding a new machine tool to the cell to perform a second operation. Both machines would be served by the same robot. Karp studied both proposals and decided on the second approach.
Integrating operations
Gosiger positioned a Fanuc R-1000iA/80F 6-axis industrial robot between the new Okuma LU4000 EX 4-axis horizontal lathe with live milling and the existing V40 RM vertical lathe. An inbound belt conveyor carries the raw castings to the Fanuc robot, which receives an M180 signal from the machine tool so it positions itself to the inbound conveyor. The robot picks a rough, radially oriented part from the inbound conveyor; repositions to a static part turnover device; turns the part 180°; repositions to a static vision camera that determines its current radial orientation; and loads the part into the LU4000 EX horizontal lathe. When the operation is complete, the robot unloads the part, turns it over, and places it on the outbound conveyor to move to the drilling operation. From the drilling station, the part travels on another inbound conveyor to the robot. Again, the robot receives an M180 signal, loads the part, unloads it when the operation is complete, and places the finished part on an outbound conveyor.
Ran-Shel has not yet integrated the drilling operation into the cell, which will make producing this part completely automated. However, Gosiger Automation designed the system so that the function can be incorporated later, when the V40 RM is replaced with an Okuma model that will enable the new machine to complete both operations.
“If we hadn’t added this new work cell, we could not have met the increased production demands with one operator,” Karp says. “Not only can the operator manage the entire work cell production, he has more time to devote to quality assurance and other activities. The cell also frees him from a lot of heavy lifting, so it’s a major ergonomic improvement.”
Ran-Shel Inc.
Okuma America Corp.
IMTS 2016 Booth #S-8500
Gosiger Automation
IMTS 2016 Booth #S-9266
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