Taking Lean to a New Level Within Hardinge Inc.
Hardinge, Inc., has been providing the industry with machine tools (turning, milling, grinding) and workolding solutions for more than a century. But look at the company closely, and
you’ll see supplier/customer relationships just about everywhere between groups and divisions under the corporate umbrella. Nowhere is this more evident today than in the Workholding Group.
ELMIRA, NY — Bill Clark, manufacturing superintendent for Workholding at Hardinge, says that they produce such a large number and variety of parts — families, sizes, shapes, materials, volumes, and applications — that over the years his Group has become the beta site for any number of new machines from other Hardinge divisions. “Which is really the way we like it,” he says. “We provide feedback to the Company and at the same time we see if this new machine can provide us with an advantage or process improvement over the way we currently do things here. That’s how we got the new Hardinge QUEST® LMC 42 (lean manufacturing cell). We were considered for a beta site for this machine while it was still in development. Now here it is in a four-machine cell, taking our lean initiatives through cellular manufacturing to higher levels.”
Clark says they’ve been trying to bring cellular manufacturing into the Group since 1990, and over time they’ve been successful — to the point that 80 percent of standard product is produced via cellular manufacturing in the Workholding Group. “So cellular manufacturing isn’t really all that new to us,” Clark says, “but we continue to add product and develop our expertise and become more effective. What we were looking for was a new approach to help us continue to get our process lead times down so we can supply our customers with standard products, like the bushings we’re currently running. These are products we keep on the shelf for immediate customer delivery. Before we turned to cellular manufacturing, we had lead times of 24 weeks to replace stock on the shelves, which was unacceptable and placing the Group at a competitive disadvantage. Now, with this particular cell in which the QUEST LMC is a part of, we’re actually replacing product on a 15 to 20 day cycle. Which allows us to supply parts to our customers faster than our competitors — which is not just a goal but a necessity.”
One thing you’ve got to remember is that we’re hole makers,” Clark says. “What we sell are hole sizes of different diameters, different wall thicknesses and confi gurations. These bushings start as bar stock and through drilling, boring, reaming and so on, we reduce the stock by 80 percent. So our challenge is to make sure the right styles and sizes of bushings are always on the shelf and ready to ship.
The families of bushings are huge in number and variation, and in many cases are used up very quickly by our customers. Some of their applications put these bushings through some very tough machining challenges.”
The parts moving through the QUEST LMC beta site cell are HD-style bushings, which are hardened and precision ground inside and out. The hardness and resiliency manufactured into Hardinge bushings make them the longest lasting and most accurate in the industry. There are three styles: the HDB (split), the HDC (slotted solid) and HDZ (slotted, solid pre-set), with more than 500 different variations or part numbers in the HD family.
“Before today’s cell, we had two Hardinge lathes facing one another with a Fanuc robot between,” Clark says. “The bar loader would load bar stock into the fi rst lathe where the first end would be machined; then the robot would remove the part and insert it into the second lathe which would machine the other end of the part. The robot would then pick the part and put it in a basket. You can imagine the challenge of perfectly timing two lathes and a robot.”
What the dual lathe and robot setup did for the production of these bushings was that it freed up the operator’s hands — i.e., operators were able to do other things as long as the lathe and robot arrangement worked as planned. Plus, it reduced cost — but changeover was time consuming, Clark says.
“When putting the lathe/robot arrangement in operation, we realized the immense number of tools required to get the high volume of small lots and part families to meet customer requirements,” says Craig Carpenter, programmer. “Back in 1994 and 1995, we went all over the world trying to fi nd a lathe with a tool changer that could do this kind of work, and we found one in Germany, but it was very expensive and complicated. Our biggest concern was having enough tools on the machine.”
Another option to make these bushings was a Hardinge QUEST® TwinTurn® Multitasking Turning Center. Carpenter says that the TwinTurn would have been a viable option, but he would have been limited to fi ve drills on sub spindle operations, which require a lot of boring between each drill size.
“It would have been more diffi cult, more chip problems,” Carpenter says, “and we could not fi t all those the required tools on the QUEST TT machine. This would have resulted in longer setup time with greater potential for tool interference and crashes. The QUEST LMC offers increased tool capacity over the QUEST TT machine, that is ideal for the types of parts that we make in this Group. The QUEST LMC supports bar work up to 1.625” (42mm), which works just fine for these bushings.”
Other observations Carpenter makes include cycle time, which he says has fallen by about 30 percent over the robotic/lathe arrangement and a setup time reduction of about 66 percent.
“On the previous arrangement,” he says, “we didn’t have a Y-axis capability, which is very important for doing milling operations. This machine does have Y-axis milling tools right in the turret, and for every job we run, there is no tool setup involved. The programming takes care of calling up the correct tool. There was one job on the old process (with the robot and two lathes) that took close to four hours to set up. Now, we’re down to half an hour or less on that part. With some parts there are more savings than others, but on average for every job that required an hour or more in setup, we’re now doing in 30 minutes or less. And that’s pretty signifi cant when you consider the variety and volumes of these bushings.”
The QUEST LMC 42:
Breaking with tradition According to Pete Lewis, machine operator, “the QUEST LMC features four metalcutting zones that provide fl exible processing capacity for a variety of applications from lot sizes of one to volume production capability. Parts are machined in a single setup.”
Increasingly, builders are responding to customer demands for part-processing fl exibility and reduced part handling by designing machine tools capable of performing numerous operations within a single platform. The QUEST LMC is no exception and leads the way in the Group’s applications. It is built to be a self-contained manufacturing cell that uses four distinct manufacturing zones to perform a variety of metalcutting operations. It’s a “clean slate” design that takes proven component elements from conventional machine tools and confi gures them to enable complete part processing in a single handling.
“Selecting a desired tool matrix allows us to run, in a single setup, a one-piece order or families of bushings from barstock or slugs,” Lewis says. “For our applications, the QUEST LMC concept applies principles of lean manufacturing — reduced operating expenses, reduced change-over time, reduced human intervention and waste — to maximize fl exibility and throughput, thereby promoting the effi cient manufacture of what’s needed when it’s needed. The QUEST LMC is designed to give us the flexibility to confi gure the machine to accommodate multiple operations within a single platform.”
A close look at the QUEST LMC’s zones
The QUEST LMC is comprised of four manufacturing zones within the working envelope of the machine tool. “Zone 1,” says Lewis, “includes a fi xed headstock, supporting bar work up to 1.625” in diameter with collets. For turning blanks, the spindle accommodates workpieces up to 4” (101.6mm) in diameter with a step-jaw chuck. The headstock is paired with a 16-station VDI 25-mm vertical turret top plate that allows live tooling on all stations. The spindle has C-axis contouring as a standard feature, and the turret can be optionally equipped with Y-axis capability.
“The Zone 2 chucking spindle can be used for primary or secondary operations. When used for primary operation, its three-axis (X, Y, Z) movement can be used for a variety of operations. Custom automation was integrated to pick off the part from the sub-spindle and drop it into a conveyor for added effi ciency. For secondary operations, this spindle has suffi cient travel to pick off a workpiece from the Zone 1 spindle for backworking operations. In the Zone 2 workholding function, this spindle uses a B-42 stationary dead-length collet with a gripping capacity of 1.625” (42mm). Machining with the three-axis spindle takes place in Zone 3 and Zone 4.
“The three-axis unit in Zone 2 spindle can be used as a sub-spindle for secondary backworking of Zone 1 work or as a machining unit for work being processed in Zones 3 and 4,” Lewis continues. “The spindle speed range is 60 rpm to 6,000 rpm, and it is powered by a 10-hp motor.”
Zone 3 is designed specifi cally for fl exibility and ease of confi guration. It can be equipped with a turret, a high-density gang tool plate, or the blank mounting surface can be used
for a component customized to an application. “The turret top plate used in this zone,” says Lewis, “is the same confi guration as the turret used in Zone 1 and can accommodate
a range of turning, milling and drilling tools. Like the Zone 1 turret, live tooling is available on all stations.
“In Zone 4,” Lewis concludes, “KM-40 quick-change modular tooling is loaded and unloaded by an automatic toolchanger arm that services either a static tool station or
optional live spindle from a 24-tool capacity carousel. The static tool station is used for conventional turning, drilling and boring operations. The live tooling option can do these
traditional operations as well as milling.”
The QUEST LMC uses the GE Fanuc 31i CNC control that features a touch screen PCbased front end.
Macros speed setup, increase productivity
“Progressively, machine tool design is migrating from specialized function to more fl exible operations in the form of combining traditional stand-alone machining modules into a single machine platform,” says Craig Carpenter. “For our applications, the benefits are reduced manufacturing costs and better throughput. Advances in the programmability and functionality of the QUEST LMC are putting us into a better competitive position.”
Carpenter notes that they’re using macro programming on the QUEST LMC. “So, if Pete was to run a 0.500” diameter hole size, we have variables in his control — variable 500 to 999. He’ll set variable 502 to equal the 0.005” .500 and the variable for the drill diameter will be a 438 drill, and the program will take the information that Pete types in and pull the correct drill off the carousel or the correct center drill or boring bar, and the machine will make the part. So, the program is capable of making hundreds of parts in different sizes. The operator just types in the
information for the size that he needs, and that’s it.”
Bill Clark: “We use a lot of macro programming here for our parts, and it’s like I told you up front we’re hole makers. We use macro programming to make it very convenient for our operators to change from one hole size to another. He puts the one program in and can run the entire family of parts — which certainly beats downloading 500 programs off the network, assuming the computer is free.”
A second QUEST LMC?
Clark isn’t reluctant to say that he already has Hardinge looking into building a second QUEST LMC for the Workholding Group — even though the fi rst is running just fi ne and not fully
loaded. But that’s the point: The fi rst QUEST LMC will continue to be loaded, and there are other parts — families of very small bushings as well as some other parts that could be considered for this machine.
“As superintendent,” Clark says, “my biggest fear was that I would have unpredictable downtime, because the QUEST LMC was a new machine. But I’m to a point now that I’m comfortable enough to put the two lathes and the robot in new production in the factory. We really haven’t experienced any downtime. We were up and running in no time considering the complexity of this machine. I defi nitely see room for one or two more back here in the Workholding Group.”