THE NEW APPROACH TO FORGING
Forging die production has traditionally been a time-consuming, multiprocess operation.TRW, a global supplier of suspension products to the OEM and aftermarket automotive industry, is redefining that tradition with the aid of Makino’s high speed, high definition approach to die machining.
Nearly two years ago, the Linkage & Suspension Division of St. Catherine’s, Ontario-based TRW becamethe first die manufacturer in North America to implement a forging die machining work cell.Since implementing this innovative process, TRW has realized the benefits ofadvanced die machining and is taking it a step further.
Training Impacts the Process
When implementing the forging cell,TRW knew training and support from Makino would be essential.
"We were the first to use this technology in this application and also had new CAM software to implement, so we knew there would be a higher than usual learning curve," says Rob D’Addazio, TRW’s manager of manufacturing services. "Makino was essential in helping us through the learning curve, providing extensive support on the machining process and the selection of CAM software."
Initially, Makino took several of TRW’s tool makers through technology transfer. This exhaustive training program ensures the toolmakers understand the machine, the process and the intricacies of how each piece works together. These TRW employees are now training the remaining staff, each one receiving a thorough training program.
The New Approach in Action
Before TRW began manufacturing dies, D’Addazio and his staff questioned whether the faster cycle times Makino predicted were possible. "At first, no one at TRW thought these machines could machine a cavity in such a short time. Makino proved us wrong."
Using a Makino MC108 with a Jet 50 spindle cutting 300 inches per minute at 15,000 rpm, milling cycle time shrank 33 percent. Part of this reduction can be attributed to the advanced work cell design which supports a continuous flow of tooling.
Dramatic lead time reduction begins before machining starts — with setup. The forging die machining work cell setup requires only one operator to monitor the work cell’s four MC108s and the material handling system. A supervisor loads all schedule requirements into the distribution manager and one operator is able to quickly load and unload the 750 pound die blocks in under a few minutes. The work cell’s advanced design will not permit the wrong die block to be loaded onto the wrong fixture.
Once loaded onto the material handling system, the work cell’s shuttle does all loading and unloading of the blocks with the machines. The shuttle knows whether each die block must be transferred from the pallet to an open machine or left in the queue to wait for the next open machine. Since all shuttle loading mechanisms are internal, scheduling can be predetermined, freeing up the operator.
On a vertical machine, squaring and shimming a workpiece can be a long and laborious process - as much as six to eight hours for a large die. Meanwhile, the machining center sits idle. In fact, the lost productivity can be multiplied several times over in traditional mold processing.
"We eliminated these time consuming processes," says D’Addazio. "Makino’s process allows us to go from a die drawing to CNC to milling. From a design to finished product we shortened lead time by 30 percent."
This can be attributed to the machines’ ability to cut and rough out to true geometry. Rough machining eliminates the need for intermediate operations that are typically done on different machines, which would require separate setup and downtime.
Making The Machines Even Faster
TRW initially realized a need for this innovative die machining process to achieve the manufacturing flexibility necessary to respond to its customer base with just-in-time delivery of product — worldwide. Now well beyond implementation, TRW is taking forging standards to new levels as they improve the process.
"We spend more time programming than machining," says D’Addazio. "That’s the key to reducing machining cycles."
"TRW works closely with Camax, our CAM software provider, to realize many of the programming enhancements," says Bob Chausse, a TRW CNC programmer. A learning partnership has been developed between the two companies allowing Camax to develop enhancements using TRW’s input. "Optimizing technical support creates enhancements," says Chausse. "After the initial implementation, enhancements are easy, leveraging the existing program rather than starting from scratch."
TRW and Camax work together to leverage the cell’s existing strengths like the MC108s’ control systems with Makino’s Super Geometric Intelligence (SGI) servo control software. SGI fine tunes each machine’s response and accuracy during high speed moves. It has the capability to "look ahead" by approximately 120 blocks so the machine can maximize tool life. This ability to perform real-time adjustments to machine dynamics, such as servo error and inertia, also maintains toolpath accuracy on curves and contours.
"These enhancements permit extremely fine picks and high feedrates in machining cavities to very high definition in optimum cycle times," notes Chausse. "Finishes and features can be achieved in machining hard materials, formerly possible only through EDMing or benching, to simplify and shorten the forging die manufacturing process."
Realizing Superior Results
Through TRW’s relentless pursuit of process improvement, productivity has actually been increased from the initial 40 percent realized when the cell was installed two years ago. "This process has given us better quality tooling at an overall lower cost than with conventional die-build methods," says D’Addazio.
However, in addition to the more obvious improvements in quality, cost, throughput and lead time, D’Addazio points out that the process has impacted other areas of TRW.
"We’ve got faster delivery: from product launch to production tooling," says D’Addazio. With the flexibility to quickly react to changes and modifications to tooling dies, engineering has been empowered to improve parts and modify parts to meet customers’ needs — all without impacting production. "We’ve had to expand our production to meet the higher throughput levels," says D’Addazio. "Since we can deliver tooling much more quickly now, we’re having problems keeping up."
These impressive results and increased product demand are keeping TRW’s Linkage and Suspension Division hard at work. However, they will continue to enhance their machining center and forging die process, to the benefit of TRW and, most importantly, to their customers.