shaping the future of metrology - Brown & Sharpe

More documents

Recommendations

Info

ing in pop-up menus.The beginning programmer does not have to memorize codes, and programming a part is up to ten times faster. 3.Working at the CMM in teach-andlearn, any part of any program can be freely edited without having to run the program from the beginning.This is an enormous time-saver. 4.To measure a complete part or assembly, any number of points and features may be selected for measurement, once the part program has been written, so that one program substitutes for many. 5. Once programs are available, it only takes operators a few hours to learn how to measure parts using the graphicscoupled 28 mfg. Shaping the Future of Metrology measurement software. By the middle of June, Luu felt that his department was ready for the crunch. It came about six weeks later. Lots On The Table A hydroformed front engine cradle, radiator supports, control arms, lots of smaller parts and assemblies—these and more were beginning to test Deco’s measurement capacity by late in the summer. The system held up well because during the start-up phase Deco engineers had learned how to appropriately balance the work load between its smaller and slower old CMM and its large new high-throughput TYPHOON. Many of the new parts, especially the hydroformed ones, pressed or exceeded the work envelope of the older machine. These parts can weigh up to 45 pounds and they are typically loaded onto holding fixtures that weigh up to 600 or 700 pounds.To measure critical part features it would take an hour or more just to load the fixture on the CMM. Then it would have to be removed again to make room for other measurement tasks. (left) TYPHOON’s large cross section permits the inspection of large assemblies, often in the same position as the assembly occupies in the finished product. (right) PC-DMIS for WINDOWS software is helping Deco engineers set up welding cells. Data gathering takes only a few minutes, and the information is used to adjust the welding process. The table of the TYPHOON is spacious enough to hold two large fixtures, and its low table (two feet) is at an ideal height for setting up large parts. Now, fixturing a large part, booting up the program and measuring critical features only take 10 or 15 minutes for the complete job. In October, Deco was busy qualifying large parts for new products for Chrysler and Ford.The two fixtures (4.5 x 4.5 ft. and 4 x 6 ft.) stayed on the TYPHOON full-time. The Ford launch went into high gear and Deco was shipping 50 to 60 pieces a day, each with accompanying measurement data. Chrysler was approaching full production, and a couple of smaller start-ups were underway.The TYPHOON was operating three shifts, 24 hours a day.The older machine was used for small assemblies and laying out indi- The table of the TYPHOON is spacious enough to hold two large fixtures. vidual components, as many as 10 to 15 for the larger assemblies. Everyday Workhorse During the next 12 months there will be other start-up situations, but none approaching the magnitude of these. Even so, Browning does not anticipate the workload on the TYPHOON decreasing sig- nificantly.There is always something else to do. For example, the CMM and graphics-coupled software have proven to be invaluable tools for setting up the welding cells downstream from the hydroforming system. “These are fairly large assemblies held to very tight tolerances so the weld cells need a lot of adjustment and tweaking,” Browning said. “Frequently an engineer will ask for an impromptu measurement of specific points. In the past we would have to request the XYZ coordinates from our CAD department.That would take hours or days. Now we can walk over to Luu, show him the points we want on the screen, and we have our data in minutes.” Browning added that the same flexibility is allowing Deco to respond immediately to requests for part data from customers. “If they are calling about a problem at an assembly plant, they are having the problem right now and they don’t want to wait a week or a day—they want answers back within the hour.With this software we can usually do that.” Browning concluded, “Without our new CMM and graphics-coupled software we certainly would have been forced to have other people lay out our parts for us.We are much happier being in control of our own destiny.” o Circle 708 on the READER SERVICE CARD mfg. The Brown & Sharpe Publication of Precision Manufacturing 29
Tech Tip easurement of a threaded hole on a coordinate measuring machine has traditionally been performed using several methods. For users of software such as MicroMeasure ® IV, TUTOR for WINDOWS and PC-DMIS for WINDOWS , the easiest choice is to simply ignore the thread and measure the hole as a circular feature. Another option is the use of flex plugs. QUINDOS ® M users have the ability to evaluate the entire thread by calculating features such as pitch, lead, and thread profile. This Tech Tip will focus on the majority of CMM users who do not have access to high level evaluation tools, and are only interested in thread location. The method discussed is that of “walking” the probe along the thread pitch. Ignoring the thread pitch has obvious accuracy problems, but may be acceptable if the positional tolerance is fairly open. The use of flex plugs, while being accurate, requires the operator to insert these plugs into all threaded holes before the part is inspected. Walking the probe along the thread pitch is more accurate than ignoring the thread, but requires no additional operator intervention. Measuring a Threaded Hole the Easy Way by Greg Privette Applications Engineer Brown & Sharpe A cross section of a threaded hole, and the corresponding point locations. In performing the calculations to determine how to adjust the depth, the thread pitch and number of points are the only parameters needed. A 20 pitch thread using four points is used for an example: A 20 pitch thread has 20 threads per inch, or .05 (1/20) inches per thread. Therefore, to measure one revolution on the thread, the probe must be dropped .0125 (.05/4) inches per point. Remember, these points must be equally spaced for this to be valid. Following is a generic subroutine for MicroMeasure IV that measures a threaded hole in the XY reference plane. THREAD =SUBROUTINE/START; !$1 = NAME OF NEW CIRCLE !$2 = LOCATION IN X DIR. !$3 = LOCATION IN Y DIR. !$4 = LOCATION IN Z DIR. !$5 = DIAMETER !$6 = THREAD PITCH (ENGLISH) !THIS SUB ALWAYS USES FOUR HITS MOVE/TO;$2,$3,$4+.5 WALK = 1/($6 *4) $1 =GEOM/CIR;XYPL MEASURE/;$2-$5/2,$3,$4,-1,0,0,0 MEASURE/;$2,$3+$5/2,$4-WALK,0,1,0,0 MEASURE/;$2+$5/2,$3,$4-2*WALK,-1,0,0,0 MEASURE/;$2,$3-$5/2,$4-3*WALK,0,-1,0,0 DONE/; MOVE/TO;$2,$3,$4+.5 SUBROUTINE/END; Circle 710 on the READER SERVICE CARD mfg. The Brown & Sharpe Publication of Precision Manufacturing 31
Page 1 and 2: mfg The Brown & Sharpe Publication
Page 3 and 4: Marietta, Georgia The World’s Lar
Page 5 and 6: Moscow, Russia Thirst Quenching Fir
Page 7 and 8: Guelph, Ontario Gantry CMM Cuts Ins
Page 9 and 10: Industry News Brown & Sharpe is hav
Page 11 and 12: environment in some other type of s
Page 13 and 14: Cumbernauld, Scotland Brown & Sharp
Page 15 and 16: AEC cont. from page 23 said, “plu
Page 17: Rexdale, Ontario Deco Automotive St
Page 21 and 22: probing speed, probing method (sing
Page 23 and 24: Multifunction CMM systems speed up
Page 25: Product Profile The Brown & Sharpe

shaping the future of metrology - Brown & Sharpe

Create successful ePaper yourself

Delete template?

Save as template?