Revo(TM) Achieving Great Reductions in CMM Scanning Time for Early Adopters
Revolutionary ultra-high-speed scanning technology meets manufacturer needs for both faster throughput and more data points
November 2007 - Renishaw's revolutionary, ultra-high-speed scanning system for coordinate measuring machines is achieving tremendous productivity gains with early adopters. World-class manufacturers have retrofitted existing CMMs with the new Renscan5(TM) system and infinite positioning REVO(TM) head. They've applied the system to speeding inspection on some of their more complex and time-consuming parts
Following are results that they've realized, compared to previous practice:
o Jet engine blisk - 922% throughput improvement. The Inspection sequence comprised 9 section scans of the airfoil profile, 8 longitudinal scans of the blade, 2 scans of the root profile and 1 scan of the annulus profile.
Conventional 3 - axis scanning 10 mm/s - 46 minutes (1 blade).
REVO(TM) scanning 500 mm/s - 4 min. 30 sec. (1 blade)
o Automotive cylinder head - 680% throughput improvement. The inspection sequence comprised 12 valve seats and 3 circular scans in each of 12 valve guide bores.
3-axis axis scanning 15 mm/s - 29 min. 13 sec.
REVO(TM) scanning 400 mm/s for - 3 min. 42 sec.
valve seats 50 mm/s for valve guide bores
o Automatic transmission valve body - 155% throughput improvement. The inspection sequence comprised twelve 6mm-diameter holes, six 5mm-diameter holes, 25 points on the gasket face, 45 spool bores, 3 shot scan on the gasket face and 6 points on the spool face profiles.
Three axis scanning 15 mm/s - 18 min. 5 sec.
REVO(TM) scanning 500 mm/s - 7 min. 5 sec.
"These developments are revolutionizing measurement throughput," states Denis Zayia, Renishaw's CMM product manager. "Besides major reductions in cycle times, Renscan5 and REVO make it possible to obtain far greater data point coverage. REVO's low-mass, low-inertia design allows ultra-high-speed data capture - up to 4000 points a second compared to 200-300 data points for conventional scanning."
The agility and point-taking productivity of the Renscan5/REVO dynamic measurement system is stimulating the creativity of metrology professionals, says Zayia. Helical scanning, for example, can greatly speed the measurement of bores, while generating thousands of data points to determine roundness, concentricity or taper. In comparative testing, he notes, Renscan5 reduced form measurement scanning of a cylinder bore from 90 seconds to just 2.5, enabling all cylinders of a V-8 engine block to be scanned in less time than a single cylinder by conventional methods.
A leading automobile manufacturer, he notes, is applying the system's massive data capture capabilities to measure engines for wear analysis and deviations of the cylindricity of each cylinder in its spatial orientation. Wear is portrayed in visual graphics similar to a thermal scan.
"Faster inspection is especially vital on large, complex, high-value parts with many critical features," notes Zayia. "CMM inspection can be a major bottleneck to efforts to speed throughput and gain Lean efficiencies. Form measurement of complex parts and critical geometries for functional fits can demand many thousands of data points. Needing to produce and document parts to ever-higher precision, ever-tighter tolerances, manufacturers are looking to CMM speed for a solution."
As a practical matter, conventional three-axis CMMs scan at rates of 5 to 15 mm/sec in order to hold accuracy, notes Zayia. This is to avoid high acc/dec rates and rapid axis changes that can induce inertia errors, causing deterioration in measurement accuracy. "CMM inspection has been stuck in that time warp for over two decades," he says.
Created under Renishaw's longest and largest development program, Renscan5 blows away the speed limits, he says. The Renscan5 enabling technology encompasses a range of breakthrough 5-axis scanning products that measure at up to 500 mm and 4000 data points per second, while virtually eliminating the measurement errors normally associated with existing three-axis scanning systems.
A 3-D measuring device in its own right, the REVO head features two rotary axes- one in vertical plane, one in horizontal - to give infinite rotation and positioning capability, notes Zayia. The REVO measuring head performs synchronized Y and Z axis motion to quickly follow changes in part geometry during inspection routines, he stresses, avoiding the dynamic errors caused when moving the larger mass of a CMM structure. Where X axis motion is required for the probing routine, he says, Renscan5 moves the CMM at a constant velocity along a constant vector as measurements are being taken, removing the acceleration/deceleration inertia errors incurred in conventional scanning.
Jeff Seliga
Renishaw Inc
5277 Trillium Blvd.
Hoffman Estates,
IL 60192
Tel: 847.286.9953
Fax: 847.286.9974
jeffrey.seliga@renishaw.com
or
Roger Rude
Kemble & Rude Communications, Inc.
4242 Airport Rd.
Cincinnati
OH 45226
Tel: 513.871.4042
Fax: 513.871.4895
rrude@kemblerude.com
