Clamping System Allows One Machine To Do It All

One setup on one machining center does it all – high speed, 5-axis roughing, facemilling, and tapping operations to create the intricate 3D features of a custom mold cavity, reducing production by 50%.

Previously, the mold's upper and lower surfaces were machined on a vertical machining center, then moved to an HMC for machining on the other four sides.

The improved approach using the vertical machining center alone is possible due to Kurt's VB 5X100 Schenke 5.1 clamping system. The device allows continuous 5-axis cutting motion of complex pockets, sculptured and contoured surfaces, and intricate 3D features with repeatable precision in a single setup.

Omnitool, Inc. of Minneapolis, MN, a high-precision manufacturer specializing in designing and building large thermoform molds and match metal trim dies, utilizes the Kurt clamping system.

"For our 5-axis machining operations, the Kurt 5-axis Schenke clamping system is ideal," reports Dave Korton, Omnitool foreman. "It frees up a horizontal machining center for other jobs. And it allows us to really run the job fast on the vertical machining center at 270ipm. The Kurt system allows us to fully utilize the 5-axis capabilities of our machines, non-stop. There's no other clamping device out there that can handle this kind of 5-axis work."

Ominitool, founded in 1976, has a long history of utilizing the latest machining technologies to achieve maximum productivity while delivering top quality results.

A key factor in Omnitool's precision machine work is part runs, which vary from just one part to a high of 200 parts. These relatively short runs mean setups are frequent, time-consuming, and with machining centers idled between jobs. Anything that can be done to reduce setups and increase machine utilization is a constant target for improvement.

"Workholding is almost as important as the machining center," Korton says. "It can make a critical difference from one job to the next. The workholding has to suit the job, as well as the machining center that's doing the work. Our programmer, Mike Beckman, discovered the 5-axis Schenke system on the Kurt website. We tried it, bought it, and it paid for itself on the first two jobs."

Initially used on an Okuma MU 400AV, the VB 5X100 Schenke 5.1 clamping system matches up with its simultaneous 5-axis capabilities. The Okuma features a fixed spindle and trunnion table for optimum versatility and performance.

Omnitool set up the Okuma with the VB 5X100 Schenke 5.1 clamping system to machine a 6061 aluminum part. Calling for 120 finished pieces, the job was run at a machine speed of 9,000rpm, with roughing and face milling operations done at 270ipm. This job, according to Korton, was one of several that the new clamping system was used for, replacing more restrictive conventional vises. That's because the VB 5X100 Schenke 5.1 is adjustable to handle any desired clamping width, so it is limited only by the size of the Okuma machine table.

Actual clamping width for this VB 5X100 Schenke 5.1 system is 0.0787" to 9.291" (2mm to 236mm) that can be extended with optional spindle screws, a clamping depth of 0.315" (8mm), height above the machine table of 6.889" (175mm), and extended height options to 7.874" (200mm) and 8.858" (225mm).

The system is designed to easily mount on standard T-slot tables, location grid machine tables, or custom fixtures. For Omnitool, it sets up like a standard vise on the Okuma trunnion table in about the same amount of time – less than two hours – taking into account tweaking the setup and part program to avoid false starts and scrapped parts. The success with Omnitool's application is the total elimination of a second setup and machining operation.

Clamping Rigidity

"We ran the machine at 9,000rpm with very aggressive rouging and finishing cuts at 270ipm. We experienced no tool chatter, nor any misalignment problems," Korton says. "Everything about the setup was rock solid." The reason for this rigidity is that the clamping system's design eliminates jaw deflection and/or part misalignment during high-speed operations. By locating the tension spindle directly under the workpiece, the clamping system's jaws do not flare out under tension and the machine table does not distort like conventional workholding. Also, the system handles a full range of workpiece configurations with equal rigidity including blank, machined, round and irregular shapes with repeatable accuracy.

Kurt 5-axis Schenke clamping system provides rigidity and machine spindle access to all sides of a workpiece.