This page contains a Flash digital edition of a book.
Measurement in Aerospace


machine tool. “When you have to probe, you are losing production time, so if you probe, you want to do it as quickly as possible,” said Jon Kulikowski, of Blum LMT (Erlanger, KY). To satisfy the need for both speed and accuracy, he pointed to their TC model probes, and to their TC64-Digilog analog touch probe for in-process workpiece inspection for special applications. “The Digilog probe is a combination of a digital touch trigger probe and analog probe,” he said. It collects data at a speed of 2 m/min and with a repeat- ability of 0.4 µm (two sigma), according to data from the company. Measurement data is communicated via Blum’s BRC wireless radio transmission technology. The advantage of the combined probe is in scanning bores or shafts for true roundness, scanning surface contours for deviations from a master part or generally scanning for flatness.


The SPRINT analog scanning sensor comes with its own software package designed for turbine blades.


Kulikowski describes an ideal scenario is to use the probe in comparative measurements. “A master part is scanned ahead of time, those measurements are stored, and then during production, a comparative measurement can be made to know whether the part is within its tolerances before it is removed from its fixturing,” he said. An application where the TC64-Digilog has been found to be particularly useful is in precision gear grinding, turbine blades, and blisks. “It is ideal for the low-volume, very-high-value parts one often finds in aerospace,” he explained.


Inspection as a Bottleneck


“The bottleneck in production flow today is inspection,” said Danny Shacham, chief technology officer for Nextec Laser Metrology LLC (Eastlake, OH). After reviewing exist-


72 ManufacturingEngineeringMedia.com | February 2014


ing touch probes, Nextec felt something better was needed. Its solution was to develop a unique laser probe to replace traditional probes used on CMMs. Nextec also understood that a fundamental problem with lasers as metrology instru- ments is their sensitivity to optical properties of the part. Color, reflectivity, material, surface finish, and viewing angle all can adversely affect the accuracy of simple laser measurements. Enter the WIZprobe, which combines a laser with im- age processing, performing what Shacham calls an infinite number of triangulations simultaneously through a toroidal lens. “The lens looks like a bagel,” he explained. The probe is adaptive, so it modulates both the laser power and the sensitivity of the CCD camera, performing self-calibration on- the-fly in response to changing conditions during the scanning process. Advertised key benefits include measuring highly shiny surfaces, soft material, edges, and sharp angles among others. He describes the output as similar to that of a touch probe, a single, highly accurate point, in contrast to scanning technologies that produce a cloud of thousands to millions of points within seconds, often with embedded noise. It collects data at 50 points per second to an accuracy of 2 µm at two sigma (described as a best-fit accuracy over 100 points). Combining their probe on a CMM chassis with special pur- pose software tailored for jet-engine turbine blades resulted in the WIZblade inspection system. The software automatically compares actual measurements to part CAD data for easy reporting, with special emphasis on important turbine blade features. Why? “The leading edge of the blade is critical to the fuel-efficiency of the engine,” he said. Engine efficiencies are becoming ever more critical, since companies he serves, like Rolls-Royce or Pratt & Whitney actually have to commit to a stated engine efficiency—or pay penalties if their engines do not meet agreed-to fuel consumption targets. “Using that data to create cross sections or make scan processes gives all the data the inspector needs.”


Automation Plus Scanning Equals Speed


Johan Gout, director of operations for Capture3D (Costa Mesa, CA) reports that automating inspections of jet engine components ranging from turbine blades to fan casings is also growing. “The great news is that noncontact scanning and automation are viewed more favorably now,” he said. “Engine manufacturers realize that the speed of noncontact scanning systems lets them determine issues faster. That is a great advantage to them.”


Photo courtesy Renishaw


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124