But if you combined these two fundamentally different CMMs, how wide could your measuring envelope become? 

That is the concept behind a new market approach taken by metrology specialist Avid Quality Group Inc., Windsor, Ontario, Avid Quality Group Inc. Avid employs both the Laser Tracker and FaroArm CMMs from FARO Technologies, Lake Mary, FL to measure almost any physical object, to almost any degree of detail required.

"Our ambition was to have no limit to what we could measure for our customers," says Angela Snary, one of the operating partners of Avid.

Avid's core activity is with automotive suppliers to the Big Three. Avid's customers include tool and die makers, stamping companies, and forge shops that supply the automotive OEMs. Avid performs inspections, dimensional verifications, repeatability studies, and reverse engineering for production lines, fixture setups, and a wide array of forming tools.

For objects that are several feet at their greatest dimension, they use the FaroArm Platinum model with an  accuracy of 0.0005 in. This is an articulating-type CMM that takes measurements with a true 6? of freedom. The internally counter-balanced Arm enables operators to move it around frame posts, down into mold cavities, and over obstructions such as bosses or standoffs to reach desired points. When an operator touches or drags the Arm's hard probe along the surface to be measured, the coordinates are simultaneously registered on a laptop computer, either as a sequence of discrete points or as a stream of points. A digital image of the object is created in the CAD-friendly software.

For large objects outside the FaroArm's working envelope-such as a machine frame or an entire automotive production line-Avid employs the FARO Laser Tracker. The Tracker can be positioned well back from the equipment-within a range of 230 ft. and still record data. By bouncing a laser beam off a moving target reflector, an operator captures position points in the software. The Tracker follows the target, storing data points as the target is moved, thus creating an overall digital image of the hardware.

Both CMMs are portable and can be set up in remote locations to measure equipment or product that would be difficult or expensive to move.

"This is a great advantage for us and a wonderful benefit to our customers," explains Snary. "We bring high-precision measurement right to the shop floor. Nothing is disturbed. No machine setups or tooling is altered, and in most cases the data can be acquired in a few minutes to an hour. This way, a mold or motor does not have to be decommissioned and transported somewhere else to be measured." One such example was a pair of 12 ft. steel gear discs that were 1.5 in. thick; moving these to a metrology center would have been difficult and expensive. Much of Avid's business comes from tool and die makers in the region who need to verify that the shape of a forming tool falls within design tolerances. Employing a verification technique that has become the standard in aircraft building and model making, an Avid operator traces the pertinent surfaces with the FaroArm and creates a digital image of them in the software. The operator can increase or decrease the rate of data collection as needed. Where tight turns or complex 3-D shapes are being recorded, data density is increased so that the surface is captured with a high degree of fidelity. On areas that are flat or those that change slowly, data density is reduced. Once the capture is complete, the recreated surface is digitally superimposed on the original design image, in the software. This CAD-to-part analysis enables the user to see instantly where the surface varies from design specifications-and by how much. This procedure almost completely eliminates the trial-and-error method formerly used for qualifying first-article parts.

Reverse engineering is another service that Avid provides. Because the Arm captures surface detail quickly, Avid technicians use it to reverse engineer numerous complex parts.

"We often do this for tool and die makers in this area," explained Snary. "They call us to remake a section of tooling for which they have no CAD documentation. With the FaroArm, we can get into tight spaces and recover excellent detail."

Then, with the file that was made from the original part, the user can machine a duplicate of the tool. Avid   also applies their CMMs together. In circumstances where a large production process must be verified down to the smallest dimension, Avid uses the Laser Tracker and the FaroArm together to capture both macro and micro dimensions.

This article was supplied by FARO Technologies, Lake Mary, FL.

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