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END USER: Helac Corp., (800) 327-2589, www.helac.com. CHALLENGE: Reduce maintenance and programming time on a large vertical turning center. SOLUTION: Retrofit the VTC with a new CNC and AC digital-axis servodrives and servomotors. SOLUTION PROVIDER: MAG IAS LLC, (859) 534-4600, www.mag-ias.com
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Relying on a workhorse machine tool with a CNC that functions more like a wounded pony is not a plan for optimal production. Helac Corp., Enumclaw, Wash., dealt with that scenario on its 1998 Giddings & Lewis-brand vertical turning center from MAG IAS LLC, Erlanger, Ky. “It never did work right,” said Jerry Gilara, director of continuous improvement, about the factory-installed CNC. “It was a beast for us and the only weird one we had in the shop.” He noted that, for example, the control had to be programmed using a radius instead of a diameter.
In addition, the machine had DC axis servodrives and servomotors, which are more maintenance intensive and harder to get parts for than AC ones. “The VTC is a rock-solid, very capable machine, but its older CNC and DC drives/motors were an Achilles’ heel,” Gilara said.
Helac’s main product line is helical hydraulic rotary actuators, which translate linear piston movement into rotary motion and produce high torque with high load-bearing capacity. They are used as positioning and steering components for mobile construction, agricultural and marine equipment.
According to Gilara, a significant percentage of the company’s parts, which typically weigh 60 to 500 lbs., are machined on the 36 ", fixed-height, 2-axis VTC. For example, the machine roughs drawn-over-mandrel, tube-shaped actuator housings, utilizing a 3-pallet pool of queued work to maintain production during the machine shop’s 80-plus-hour workweek.
The tube-style parts have welded steel flanges on each end and some have off-center plates on the sides. “We mount these on an angle plate that has half-rounds to locate off the tube OD,” Gilara said. “We bore the part completely in one shot from the top, with tolerances of 0.001 ". Then we face two parallel surfaces so everything is concentric. We do all the machining from one end, using a 250-lb. boring bar with a CAT 60 taper.”
Being able to handle heavy tools with long reaches in an automatic toolchanger was one of the main reasons Helac purchased the VTC, Gilara noted. “We wanted to be able to do everything from one side instead of flipping the part.”
He added that the shop has an older CNC lathe that once machined the parts the VTC produces and serves as a slower, backup machine. “Another reason I bought this machine is because I got tired of that backup machine,” Gilara said. “When our primary machine is down, we’re quite unhappy.”
Rather than investing in a new machine tool, Helac decided to have the VTC retrofitted, including installation of a new Fanuc 0iTD CNC, AC spindle and AC digital-axis servodrives and servomotors. The shop requested quotes from a number of retrofitters and decided to go with the company that built the machine even though the other quotes were considerably less. “I did not want to have some dirt-cheap deal and try to make it work and have the machine sit there for 2 months,” Gilara said.
All images courtesy of Helac
Helac’s MAG VTC—which the machine builder retrofitted with a new CNC, AC spindle and AC servodrives and servomotors—performs heavy metal removal (top) on tube-shaped housings for helical hydraulic rotary actuators (bottom).
The retrofit also included a health check of the machine tool to ensure its accuracy.
MAG uses pre-engineered, modular retrofit packages with prebuilt panels. The modular approach allows retrofitting just the CNC or the CNC, drives and motors at different times, if needed, to accommodate tight budgets.
“We did it during our slower season, and we struggled while it was down,” Gilara said. “The VTC is a prime piece of equipment for us.”
Although Helac is not standardized on Fanuc controls, the similarity of the 0iTD CNC to others in the shop enables quicker programming and easier training. “Operators familiar with other machines in our plant can migrate to this machine with less training,” Gilara said. “You almost had to talk to that special control, bring it a cup of coffee and pat it on the butt to make sure it worked OK. Now we don’t have to do that.”
Related Glossary Terms
- angle plate
angle plate
Solid adjustable or nonadjustable plate that holds work at a precise angle to the spindle during machining. Also used for inspection.
- automatic toolchanger
automatic toolchanger
Mechanism typically included in a machining center that, on the appropriate command, removes one cutting tool from the spindle nose and replaces it with another. The changer restores the used tool to the magazine and selects and withdraws the next desired tool from the storage magazine. The changer is controlled by a set of prerecorded/predetermined instructions associated with the part(s) to be produced.
- boring
boring
Enlarging a hole that already has been drilled or cored. Generally, it is an operation of truing the previously drilled hole with a single-point, lathe-type tool. Boring is essentially internal turning, in that usually a single-point cutting tool forms the internal shape. Some tools are available with two cutting edges to balance cutting forces.
- boring bar
boring bar
Essentially a cantilever beam that holds one or more cutting tools in position during a boring operation. Can be held stationary and moved axially while the workpiece revolves around it, or revolved and moved axially while the workpiece is held stationary, or a combination of these actions. Installed on milling, drilling and boring machines, as well as lathes and machining centers.
- computer numerical control ( CNC)
computer numerical control ( CNC)
Microprocessor-based controller dedicated to a machine tool that permits the creation or modification of parts. Programmed numerical control activates the machine’s servos and spindle drives and controls the various machining operations. See DNC, direct numerical control; NC, numerical control.
- lathe
lathe
Turning machine capable of sawing, milling, grinding, gear-cutting, drilling, reaming, boring, threading, facing, chamfering, grooving, knurling, spinning, parting, necking, taper-cutting, and cam- and eccentric-cutting, as well as step- and straight-turning. Comes in a variety of forms, ranging from manual to semiautomatic to fully automatic, with major types being engine lathes, turning and contouring lathes, turret lathes and numerical-control lathes. The engine lathe consists of a headstock and spindle, tailstock, bed, carriage (complete with apron) and cross slides. Features include gear- (speed) and feed-selector levers, toolpost, compound rest, lead screw and reversing lead screw, threading dial and rapid-traverse lever. Special lathe types include through-the-spindle, camshaft and crankshaft, brake drum and rotor, spinning and gun-barrel machines. Toolroom and bench lathes are used for precision work; the former for tool-and-die work and similar tasks, the latter for small workpieces (instruments, watches), normally without a power feed. Models are typically designated according to their “swing,” or the largest-diameter workpiece that can be rotated; bed length, or the distance between centers; and horsepower generated. See turning machine.
- outer diameter ( OD)
outer diameter ( OD)
Dimension that defines the exterior diameter of a cylindrical or round part. See ID, inner diameter.
- parallel
parallel
Strip or block of precision-ground stock used to elevate a workpiece, while keeping it parallel to the worktable, to prevent cutter/table contact.
- toolchanger
toolchanger
Carriage or drum attached to a machining center that holds tools until needed; when a tool is needed, the toolchanger inserts the tool into the machine spindle. See automatic toolchanger.
- turning
turning
Workpiece is held in a chuck, mounted on a face plate or secured between centers and rotated while a cutting tool, normally a single-point tool, is fed into it along its periphery or across its end or face. Takes the form of straight turning (cutting along the periphery of the workpiece); taper turning (creating a taper); step turning (turning different-size diameters on the same work); chamfering (beveling an edge or shoulder); facing (cutting on an end); turning threads (usually external but can be internal); roughing (high-volume metal removal); and finishing (final light cuts). Performed on lathes, turning centers, chucking machines, automatic screw machines and similar machines.
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