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Twin Customized Kurt Vises Mounted Vertically and Back to Back on HMC's Reduce Setups to Under 10 Minutes

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Photos One and Two Caption: Two customized Kurt XL vises (left) are mounted back-to-back and vertically. The setup eliminates the need for a tombstone, provides center-of-gravity machining with vibration-free rigidity. Mark Schroeder (left) and Scott Ness (right) of Haberman Machine report major productivity increases using the new setup by eliminating a much slower process in vertical machining centers.

Twin Customized Kurt Vises Mounted Vertically
And Back-To-Back On Horizontal Machining Centers
Reduce Setups To Under 10 Minutes -- Workholding Facilitates Centering Large, Heavy Workpieces Over The Machine
Pallet At Haberman Machine

Minneapolis, Minnesota: Twin customized Kurt Vises mounted vertically and back-to-back on horizontal machining centers at Haberman Machine accurately center two heavy workpieces over the machine pallet for extra rigidity while facilitating aggressive metal removal.

The new workholding setup replaced a much slower setup process on vertical machining centers where parts were clamped lying down. In the new setup, the matched Kurt vises both have huge 21 inch jaw openings for clamping vertically steel workblanks weighing well over 100 lbs. Important also, the workholding setup is designed for use on two different size machine pallets, thus giving Haberman Machine maximum flexibility to machine a wider range of large parts, required by NessTech Concrete Molds, Inc. for mold components. By reducing setup time, throughput is increased providing a good example of how important, well-designed flexible workholding is to get the most productivity out of expensive machining centers. (Photos One And Two)

Being able to center and clamp the large workpieces vertically and with rigidity is key to high metal removal rates so that the machine spindle can effortlessly hog out large amounts of material at the center of gravity.

With over 60 successful years in the precision machining business, Haberman Machine, Inc. (ISO 9001-2000 registered Oakdale, MN based company) knows the importance of innovative workholding and makes use of it to increase productivity. It uses dozens of pre-set tower and vise fixtures for quick setups on repeat projects instead of more costly dedicated fixtures. Its work covers the complete spectrum of parts, materials and customers, from tiny medical devices to large defense components. All require precision machining with relatively short run quantities, frequent setups and the clever use of modular workholding.

The components at issue here are machined out of 8620 steel alloy and are used in a patented mold system designed by NessTech Concrete Molds, Inc. and built by Haberman Machine. The mold system utilizes different size plates which are movable with a gear drive assembly to produce different size architectural wall, paver stones and retaining wall blocks. These precision machined mold components are large and heavy with the 30 inch x 40 inch workblanks often weighing well over 100 lbs. Machining these components requires robust workholding to align and rigidly hold the workpieces. Because of their size and weight, operators are challenged to position and clamp these mold components in the machine. Workholding that makes this job easier and faster is a welcome addition by the machine operator. (Photo Three)

“Standard vises mou nted on a tombstone really didn’t work for this type of machining application,” reported Scott Ness, of Haberman Machine, Inc. “Machining these parts laying down in a vertical machining center required too much setup time. We were limited with the area we could machine with each setup. We needed a setup that could accommodate machining these long parts in a vertical position (Z axis) with enough clearance for machining on both sides (XY axis). We needed workholding that was flexible for use on two different machines and was relatively easy for operators to handle. We’ve been a Kurt workholding user for over 25 years so we checked with Mike Granlund of Kurt’s Custom Engineered Workholding department to see what ideas they had.”

Custom Vise Setup Provides The Flexible Solution For Mounting
On Two Different Size Horizontal Machining Centers

The vises Granlund recommended were two Kurt 8 inch wide, extra long, pull type, single station vises (8XLPTLSS back-to-back). (Photo Four And Illustration One). The reason for this approach is that the setup is flexible providing the part capacity and rigidity needed plus it’s an easier and less expensive solution compared to a custom fixture. In addition to a huge 21 inch jaw capacity, what’s unique about these vises is that they’re designed to mount without disassembly or modification to two different horizontal machining centers with different size pallets (Mori Seiki MH63 – 630 mm pallet and Niigata SPN 50-HO – 500 mm pallet).

Photo Four And Illustration One Caption: 21 inch jaw capacity handles large parts while the pull type, Anglock clamping feature insures high precision and repeatability.

To accomplish this, the two Kurt vises are bolted (6 half inch Allen nuts) and doweled back-to-back. All sides of these vises are machined accurate to 0.001 inch (a standard Kurt feature) so they align when mounted back-to-back. Bolted together, the two vises are mounted on a 500 mm base plate which then mounts to the 500 mm machine pallet. A 630 mm subplate allows mounting directly to the 500 mm base plate which can then be mounted to the second machining center. A 2.250 inch high riser is also used in the setup to achieve the desired spindle clearance for both machine setups. The subplate, baseplate and riser are sized and machined for this application at less than a fourth of the cost of a tombstone.

Vises Incorporate Kurt Anglock Feature And Pull-Type Clamping Design

The Xtra Long, Pull Type Kurt vises used in this application are the ultimate in heavy duty workholding. They are made of the 80,000-PSI ductile iron to provide stability so possible chatter or vibration is eliminated from the machining process. Delivering up to 12,000 lbs precision clamping force, Kurt’s Anglock vise design actually helps to automatically position the workpiece in the vise jaws. As clamping force is applied, the mold workblank is pushed down and onto the vise base, which also aligns it accurately. The Anglock design also resists any tendency for part lift during machining operations. This pull-type clamping design insures high precision and repeatability. (Illustration Two With Callouts)

Illustration Two Caption: Kurt Anglock design helps prevent part lift. Pulling action reduces jaw deflection and provides all directional alignment.

Photo Five Caption: The Kurt vise setup is operator friendly, easy to use and maximizes the output potential of the Mori Seiki MH63 machining center.

“The machine operator uses an overhead crane to lower the workblank into the vise clamping area,” reports Ness. “ Once moved into the open jaws, the vise is clamped manually. With this setup, there are no machining clearance issues as there would be using a tombstone set up. This new setup consumes a lot less time than the way we were doing it before.” (Photo Five)

Workholding Complements And Helps Maximize Machining Center’s Capabilities

The day this writer visited, the new Kurt workholding setup was operating on the Mori Seiki MH63 horizontal machining center (X=39.40 Y=33.50 Z=36.20 and 50 taper spindle). Heavy duty 3 inch face mill cutters were running at 1000 rpm and were hogging out material at 50 inch/minute. Later in the machining sequence, roughing and small grooving was done at between 5000/6000 rpm. The part was completed in about 2 hours with tolerances on machined surfaces to .0005 inch.

“This is a really a great workholding setup,” reports Ness. “We’ve eliminated the need for a tombstone which saves us $5000 to $8000 and we’re not sacrificing clamping rigidity. The fact that we can center workpieces and take advantage of gravity in the setup really prevents vibration and tool chatter when making the most aggressive cuts. Our operators like it because it’s easier to set up and there are no machining clearance issues. We’re getting top machine speeds, great finishes and no scrapped parts, thanks again to Kurt for the workholding solution.”

For more information about Haberman Machine capabilities, visit www.habermanmachine.com Or call 651-777-4511. Email: scottn@habermanmachine.com or write to Haberman Machine, 6290 Highway 36 Boulevard North, St. Paul, Minnesota 55128-1408. Fax: 651-777-4014.

For more information about Mori Seiki machining centers, visit www.moriseiki.com or call 1-847-593-5400.

For more information about Niigata machining centers, visit www.snkamerica.com or call1-847-364-0801.

For more information about Kurt Workholding, visit www.kurtworkholding.com Or call in USA and Canada, 1-877-226-7823. Outside USA and Canada, call 1-763-574-8309. Email: workholding@kurt.com Write to Kurt Manufacturing Company, Industrial Products Division, 9445 East River Road NW, Minneapolis, Minnesota 55433. In USA, Fax 1-877-226-7828. Outside USA, Fax 1-763-574-8313.

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