Quality Applications

Mitutoyo Quick Vision Measuring Machine Benefits Highly accurate 3-D measurements Automatically retains results High-precision lens with 380,000- pixel camera www.mitutoyo.com/emtech.html

Quick Vision Improves Inspection Method

Work faster, work smarter: That's what Emtech, a Minnesota-based electronics component manufacturer, did for its inspection operation. To measure more than 50 different machined and injection-molded electronics components, Emtech switched from semiautomatic contact measuring to the Quick Vision (QV) Measuring Machine from Mitutoyo America Corp. based in Aurora, Illinois. By implementing the automated vision measuring machine, Emtech improved its inspection throughput by a 10-to-1 ratio.

 The Mitutoyo QV Measuring Machine performs noncontact dimensional measuring plus automatic referencing of hole tolerances for position call-outs. With Emtech's switch to this new system, the company has eliminated undesirable contact probing and an unreliable manual step. Moreover, inspection time dropped from 90 minutes to nine minutes per component.

 As a rule, a shorter inspection cycle time enables a manufacturer to detect defects early, increase inspection frequency and quickly implement production adjustments. In Emtech's case, the tenfold reduction in inspection cycle time, plus accurate three-dimensional measurement, has cut the incidence of discrepant parts by more than 50 percent.

 For example, Emtech's inspection of a 100-hole connector housing originally presented itself as a somewhat cumbersome feat. The engineering-grade plastic pin connector ranges from 0.5 in. to 2 in. (length) and from to 0.25 in. to 0.75 in. (width), depending on the model. The hole diameter is 0.025 in. and has a depth of 0.025 in. The part has 100 holes laid out in symmetric rows 0.100 in. apart left to right and 0.100 in. apart top to bottom. The rows are staggered by 0.050 in.

 The company requires Z-axis call-outs and X- and Y-axis dimensions of the connector housing, as well as of most of the other electronic components. Uniformity of the entire Z-axis has to be precisely accurate to ensure proper matching with the connector pins.

 Using the former mechanical probe,  entry and fit through the entire hole depth was problematic and involved several steps. Besides being slow, this process lent itself to measurement and transcription errors. "It was difficult and time-consuming to inspect the connector housings with the earlier CMM because of the narrow 0.025 in. hole diameters," recalls Emtech Operations Manager Linda Peterson.

 With the Mitutoyo QV, Emtech operators simply set up the fixture to hold the    part and select the part program, performing both measurements with a single setup. Once activated, the QV's opto-electronic system focuses on the component, measures the specified dimensions in all three axes and retains the results automatically so that they can be printed out as needed.

 "Now, the Mitutoyo QV enables us to measure one hole in half the time," says Peterson. "It takes nine minutes to inspect the same part with one setup. We expected a significant improvement from the speed of the QV, but we had some additional pleasant surprises."

 The pleasant surprises are Emtech's ability to reliably verify tight hole tolerances of ±0.003 in. in one inspection pass. In addition, the company can supply the QV's reports to customers who request them, thereby eliminating the need for an extra inspection.

 Generating the report is quite easy. Emtech relates the housing's geometric dimensioning and tolerancing call-out to two or more axes or datums logged in the QV computer. Once verified, the actual measurements are transferred directly onto a pre-programmed inspection report and can be printed out with the simple touch of a button.

 Emtech's Quick Vision is the standard model Barracuda, QVB 202, with an 8 in./s (200 mm/s) drive speed. It's a benchtop system with a compact footprint and a high U1 accuracy of (4+5L/1000) µm. Mitutoyo opto-electronic technology--a high-precision objective lens and 380,000-pixel CCD camera--allows 3-D vision measurement of very narrow, minute or complex workpiece images. The QV also features Mitutoyo's patented Triangular Pattern Focus, which projects a triangular pattern onto the inspection surface and then targets these patterns for focusing.

 Besides having solved the fit and measuring problems, Emtech has eliminated component contamination and damage, which sometimes occur with mechanical probes. With the implementation of the vision system, there's no longer a risk of damage to interior walls or introduction of unwanted foreign particles.

 Overall, Emtech has gained a competitive edge with the QV's accuracy and documentation capabilities. Some customers can forego their internal inspection and proceed from "dock-to-stock" on arrival of Emtech's connector housing and documents.

 Peterson reports that the company is currently training their machinists to use the Mitutoyo QV immediately so that the parts they machine can be inspected right on the production floor, enabling Emtech to save more time and money and continue their course in the pursuit of excellence.