Do-It-Yourself Laser Calibration Pays Off

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A s a Code-One Flight Item Vendor for over 40 years and an approved source for fracture-critical, Level 1/Sub-Safe and high-strength steel components, Scotts Valley, CA’s Tapemation Machining, Inc. relies on laser calibration for ensuring the accuracy of its machining processes. But calibrating 5-axis machine tools and CMM is a difficult and expensive process, especially when the cost of machine downtime and outside services are considered. "We were unable to find an outside service with the experience to calibrate many of our 5-axis machine tools and rotary tables,” reports Tapemation president Bruce Erickson. “Finally we purchased our own laser calibration equipment. We were able to realize pay back in two years." Large Components Because it makes large precision-machined components for the aerospace, defense, medical, scientific, electronic, marine and petroleum industries, which require tight toler- ances, laser calibration is somewhat of a competitive advantage for Tapemation. In its 50,000-sq-ft facility equipped with 22 major machines, including 5-axis Anayak, Mazak, SNK, Rambaudi and LeBlond-Makino machining centers, Tapemation boasts an internal quality control system that meets or exceeds MIL-I-45208A. "Calibration isn't mandated by our suppliers,” says Erickson, “it's mandated by the type of work we do. We don't include laser calibration as a part of our regular main- tenance plan, except for our CMM. We calibrate the CMM at least once a year for ISO 2000 and 45208 inspection pro- cedures. We calibrate the machine tools to ensure accuracy, so if we get a part that we have to hold flatness or position over a distance, we know the machine is capable." Laser Calibration System An Optodyne MCV 4000 laser calibration system was purchased with a dual beam laser head, dual channel processor and squareness optics for running linear, angular (pitch, yaw, straightness, flatness) and squareness calibration. Optional accessories were purchased for calibrating tilting spindles and rotary motion for calibrating 5-axis machine tools. In addition to machine tools, the MCV 4000 is used for calibrating Tapemation's Brown & Sharpe MDL 3000 Validator CMM with travels of 132" X, 47" Y and 78" Z. Most of the components machined at Tapemation are close tolerance, for example, ± 0.001" over a 40 inch diam- eter or ±0.005" flatness over a 10-foot-long part. Erickson: "Our QA manager, formerly a machinist, runs the calibration. Because we do 5-axis and rotary table cal- ibration, his training required about a week to be proficient. Still, that's not bad when you consider the high cost when a machine is down waiting for an outside service to show up. Now we can schedule calibration when it's convenient to our schedule." Easy Setup Based on Optodyne's patented Laser Doppler Displacement Meter (LDDM) technology, the MCV 4000 reflects a modulated laser beam off of a movable target. The beam is detected and processed for displacement infor- mation used by the control to determine position. Expensive precision and special optics are not required and rotary tables are calibrated without the use of an indexing table. Because there are only two components to align, setups are very quick. The laser requires only a small per- centage of the return beam, and a retro-reflector. Both components are machine mounted, which eliminates the need for a tripod and removing covers or dismantling the machine to run calibration. Do-It-Yourself Laser Calibration Pays Off A Code-One Flight Item Vendor Takes Laser Calibration In House. 46 CNC WEST/December 2003 • January 2004 Data collection during calibration of Tapemations’s large Brown and Sharpe MDL 3000 Validator CMM. The MCV 4000 laser head is shown at the left-rear corner of the CMM table- top. Laptop stores data. Calibration Case Study—

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