February 2008 Edition

QUALITY CONTROL

Out With the Old, In With the New

An Alabama job shop increased its throughput by saying Auf Wiedersehen to its manual coordinate measuring machine

Avans Machine & Tool, Scottsboro, AL, needed an upgrade. Not happy with the speed or accuracy of its manual coordinate measuring machine – CMM – it looked for a machine and software package that could handle its output. A German import did the trick.

Avans is a family-owned, precision machine shop with 35 employees that specializes in CNC turning, four-axis milling, and 3D machining of parts and components for the aerospace, defense, automotive, medical, pharmaceutical, and textile industries. Short- or long-run parts are manufactured with delivery schedules ranging from immediate to long-term.

"As a precision machine shop, meeting our customers' needs is simple: be professional, be fast, be accurate, and be competitive," Lawrence Ariel, Avans quality manager, said.

"What we were finding, however, was that our manual CMMs had a negative impact on our ability to be fast. We knew that would cost the company new and existing business."

Ariel said he knew his company needed to improve its CMM capabilities. It was going to take a couple of direct computer controlled CMM machines with varying work envelopes and a common comprehensive software package on which technicians as well as machine operators could be easily trained.

After making some initial inquiries with CMM manufacturers, Keith Mills, president of Xspect Solutions, Wixom, MI, the North American representatives for Wenzel, GmbH, Germany, put Avans in contact with a number of nearby Alabama companies with Wenzel machines. Visits to those facilities to evaluate the Wenzel equipment and talk to the users followed.

"We were impressed with the robust construction of the equipment; in particular Wenzel's use of granite construction," Ariel said. "The users we talked to were pleased with the OpenDMIS software because of its broad capabilities and ease of use."

This software has full CAD capabilities allowing the CMM to be an integral part of the manufacturing process, permitting the generation of inspection programs before manufacturing is performed. Avans manufactures a range of aircraft and aerospace parts where CAD modeling capability is needed; with this feature, the operator just loads IGES files and checks them to the part.

"With this interface, we can quickly train unskilled operators to operate the machine," Ariel said.

With the QuickMeasure feature, operators can complete hands-free inspection from the PC. QuickMeasure uses the software's ability to determine the feature type under measurement. This allows rapid part inspection without the need to instruct the software what to inspect next. The part is probed and the software does the rest.

What Tipped the Scale

Being able to talk to current Wenzel customers sold Avans on the benefits and features of the equipment and the software.

"Xspect Solutions worked with us to determine the size machine we needed and then provided a cost that fit into our budget," Ariel said. "We settled on a Wenzel Smart and a Wenzel LH8.10.7 machine."

The Smart machine has a measuring range of 500mm × 450mm × 400mm and the LH 8.10.7, the larger of the two machines, has a measuring range of 800mm × 100mm × 700mm.

"A pre-programmed part can be checked two-thirds faster"

Each machine has thermal stability with dynamic performance, stiffness, and vibration dampening. Each machine is equipped with a standard Renishaw TP200 probing system and offers volumetric accuracy of 2.5 microns with a maximum 3D measuring speed of 700 mm/sec with maximum acceleration of 2,000mm/sec².

Other options that Avans requested included a probe change rack that could be mounted on the granite table, as well as an HT400RC wireless teach pedant, which eliminates the keyboard interaction associated with CMM teach pendants. Using a joystick, the operator has the capabilities needed: programmable fast and slow modes, function keys for probe index, go-to and point record, individual axis locks, and an emergency stop switch. It lets the operator walk around the machine without having to determine the orientation of the pendant control.

"Complex parts can be inspected in half the time, or less, than on our manual CMM, with better accuracy," Ariel said. "A pre-programmmed production part can be checked two-thirds faster than checking manually. This frees the operator for other duties," he said. Wenzel, GmbH.

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