Laser Scanning for Improved Prototyping
When you’re doing production prototype work for Jaguar Land Rover (JLR), you’ve (1) got to be good and (2) you’ve got to be able to prove it. Which is what Redditch, U.K.-based Birmingham Prototypes discovered when it began to supply JLR with stampings and brackets a few years back.
According to Mick Adams, managing director of Birmingham Prototypes, JLR wanted both first article inspection and production part approval process (PPAP) documentation. Detail on component accuracy and repeatability required was much more than had been the case with other customers.
Doing the tasks with a manual CMM and Microsoft Office applications was taking a considerable amount of time, as much as a day for a single report.
Clearly, something had to be done, so they installed a ceramic bridge CMM, a model LK V 15.10.8, from Nikon Metrology (nikonmetrology.com). The unit is equipped with an LC15Dx laser scanner, which is the default tool for measuring the components. When there are tight tolerances—or sometimes when doing initial part setup on the CMM—a touch probe is selected from the stylus changer on the CMM with a Renishaw Inc. PH10M motorized indexing head. While most of the drawing tolerances on the stampings are fairly open—±0.25 mm on surfaces and ±1 mm on trim edges—hole positions are measured to within tens of microns, which is readily accommodated by the LK CMM.
The machine uses multi-sensor CAMIO V8 software, which produces DMIS programs for both laser scanning and touch probing. Nikon Metrology Focus 10 software manages the point clouds acquired during laser scanning—and know that a prototype aluminum engine bay mounting plate for a Jaguar car is on the order of seven- to eight-million points, so there is a considerable amount of managing. The Focus 10 software allows comparison of the CAD model and the part as produced (and scanned). There are color maps with annotations generated of the comparison.
To bring in work that it had outsourced, in 2015 Birmingham Prototypes added a five-axis laser profiling machine from Trumpf Inc. (trumpf-laser.com) to its shop floor. Noted Adams, “Practically every job that comes off the machine is a unique prototype that needs to be inspected, a job that was previously done by the laser cutting contractors.”
So Adams said that they decided to acquire a portable CMM arm, a Nikon MCAx, to handle the parts from the laser cutter. This unit is a 7-axis counterbalanced arm with continuous rotation; it offers a four-meter diameter measuring envelope. It is usually used with a digital laser scanner; a touch trigger probe can be used should additional accuracy be required. The arm is equipped with absolute encoders to assure precision.
Beyond measuring, Birmingham Prototypes is using the laser scanner to generate CAD models of parts that have no drawings or digital files. This is then used to create STL files. These files are used by the company’s Dimension 1200 es 3D printer from Stratasys Inc. (stratasys.com).
There are also four CNC machining centers from Hurco Companies, Inc. (hurco.com) at the facility that are used to manufacture both prototype tooling as well as low-volume production components. The Nikon Metrology CMMs are used to check these components, as well.
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