Accuracy in Production Drawing on 30 years of design and manufacturing experience, Ansco (Cuyahoga Falls, OH) always turns a critical eye to the design and functionality of the parts it produces and actively seeks cost savings and efficiencies in its processes and finished products. It put this critical thinking to use when it was challenged with the machining of a cast iron housing that weighs approximately 750 pounds. This part was too large and cumbersome to be inspected by Ansco’s traditional bridge-type coordinate measuring machine (CMM). The cast iron housing had several large bored holes and ring grooves that had to be held to within a 0.001- inch tolerance. There also were several drilled and tapped holes for various bolts and fittings. Although the bores could easily be checked with dial bore gages, it was difficult to check the location and relation between features using conventional methods. The older technology could not accommodate the housing and all of its features, particularly with the features being on different sides. With an inspection requirement of 100% and full documentation on all 80 critical features, it was not practical to do a layout and check using conventional methods. These methods were not sufficient in terms of size, time or cost. PORTABLE CMM TO THE RESCUE After seeing an on-site demonstration of the Faro (Lake Mary, FL) Gage, Ansco could easily see that the gage was the only tool that could do and meet its needs. The Faro Gage is a portable CMM designed to enable machinists to speed through measurement challenges and produce the most accurate results. It allows measurements to be taken right on the shop floor, without the need for stopping production. The gage provides accuracy up to 0.0002 inch, and because it offers portability and quick setup, it reduces inspection time. Since the gage can automatically record measurements, inspection reports are easily generated. RETURN ON INVESTMENT A conventional layout and checkout would take more than an hour and a half using conventional technology. But with the Faro Gage, Ansco can set the part up on the table, check out all of the required features, and return it to the skid in less than 20 minutes. That is almost an 80% reduction of the standard work time, which equates to a real savings in time and productivity. Without this capability, Ansco would not be able to meet the delivery requirements for this project. “This project is now in its third year of production and we are still going strong,” said Wes Suladie, Ansco’s quality assurance manager. “We can honestly say that of all of the suppliers of machined components for the end product, Ansco was the only supplier that did not have one field reject. That’s because we were able to find the errors and correct them before they ever got to the customer and the Faro Gage was a big part of that success.” An Upgraded Inspection Process The pressure is on in the automotive industry to generate more and better dimensional data for designing and building the next generation of automobiles and trucks. The sheet metal team at Chrysler’s Advanced Metrology Group (Belvidere, IL) is responding to this challenge. New inspection procedures and software to manage them have dramatically improved the team’s productivity during the past two years. For example, during the first four months of 2009, the team delivered approximately 200 coordinate measuring machine (CMM) programs for evaluating new Chrysler truck and passenger car designs, including model launches scheduled for 2010 and 2011. Judging from the number of inspection programs that were written, sheet metal team leader Howard Casey believes his team was at least 40% more productive last year than they have been in previous years. As it becomes even more proficient with the new procedures and tools, he anticipates that its productivity could increase by as much as 60%. E-TOOL AND INSPECTION PLANS The new approach evolved rapidly between 2007 and 2009 when Chrysler was making its transition to CATIA v5. Since this upgrade would require substantial changes in the corporate design software anyway, it was a perfect opportunity to correct longstanding problems in the way design intent information is communicated to CMM programmers. Part designers need to communicate to the CMM programmers creating inspection routines which dimensions and tolerances to evaluate. There are many ways to do this, but each shares the same flaw: Designers may print out 2-D blueprints of the part, model and mark up the critical dimensions; they may jot down some notes in a text document or they may pass this information along via phone calls. In each case, the electronic link between manufacturing and the original design data is broken, and there is no assurance that the parameters used to inspect the parts are current. Chrysler knew there had to be a better way. So, as part of its upgrade to CATIA v5, it developed a module inside a software package called eTool that allows designers to embed their inspection plans in the CATIA file. This ensures that the link between design data and its inspection requirements is never broken. The inspection plans include datum definitions, feature measurement information and dimensional evaluation information. Chrysler’s next objective was to find software tools that would automatically transform these inspection plans into inspection programs for a range of CMMs used at several of its facilities. This would save a substantial amount of time and money. Hexagon’s software arm, Wilcox Associates (North Kingstown, RI), was already at work on this very problem. It was developing a new, standalone product, PC-DMIS Planner, which would let designers embed inspection plans inside its computer-aided design (CAD) data so that it could be used by inspection system programmers to create programs. The tool set Wilcox was developing within PC-DMIS Planner was very close to what Chrysler had envisioned to round out its eTool software. It included a plan importer, a probe path optimization module, an auto clearance move insertion tool, and a Change Manager for keeping the inspection plan and the part program in sync. During the next two years, Chrysler and Wilcox worked together to incorporate these tools into the Chrysler software while Wilcox worked independently to refine its own commercial product based on its experience with the Chrysler eTool system. CLEAR COMMUNICATION Both Chrysler’s eTool and the commercial version of PC-DMIS Planner close the loop between design and inspection by providing tool designers and inspectors with special tools that allow for the clear communication of design intent along with the verification and incorporation of changes that occur during the product development process. This is accomplished by automating previously informal lines of communication between design and inspection personnel to establish bidirectional data flow between a CAD model and its related inspection part programs. The design engineer can use PC-DMIS Planner to identify and embed information about critical characteristics in a planning file that is associated with the product’s CAD file. PC-DMIS Planner offers Direct CAD Interface to the CAD model in the original CAD database so updated planning files can be easily associated with updated CAD files. Bidirectional change management tools within PC-DMIS Planner allow the user to identify changes to an original part model or inspection plan, and provide fast and easy methods to update part programs based on the new information.
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