Connecting CAD And Measurement

When it comes to creating an NC program for machining, the value of using a CAD model is evident. As long as a readable CAD model exists, a CAM system using this model will likely be able to generate tool paths more quickly and effectively than manual programming could. For some complex parts, creating tool paths without an electronic model simply isn't an option.

But when it comes to inspection devices such as CMMs, manual programming is an option. In fact, because serviceable measurement programs can be created from 2D drawings alone, many shops assume that this is the natural, preferable way for the programming to be done. Perhaps that's unfortunate.

A not-uncommon procedure goes like this: While a CAD file allows CAM software to create the machining tool paths, that same CAD model is used to create 2D drawings to convey inspection-related information. From these hard-copy drawings, a technician develops an inspection program by thinking through moves for one measured feature at a time. The work is likely to proceed at a "measured" pace. The procedure also introduces opportunities for error.

If the approach is less than ideal, however, that's not necessarily the fault of the shop. Either the designer or the inspection programmer may lack the tools necessary to knit their two disciplines together.

Wilcox Associates is trying to provide these tools. Part of Hexagon Metrology, the software developer in North Kingstown, Rhode Island, makes programming tools for inspection devices, and also makes tools for analyzing and reporting on inspection findings. Two new products from the company, "IP Planner" and "IP Measure," address the needs of design and inspection in the attempt to achieve a more paperless process.

Both of these disciplines play a role. Design is addressed by IP Planner, which resides in the user's CAD software. This product allows the designer to flag features for inspection after attaching geometric dimensioning and tolerancing (GD&T) information to them. IP Measure then interprets this information, automatically creating the inspection program for the user's intended device. The designer does not even have to have a complete understanding of this inspection device in order to use it in this way.

The two new software modules comprise an interconnected suite. Inspection often fails to benefit from this kind of interconnection, says Wilcox director of business development Steve Logee, noting that the chief competitors to these products tend to be the stitched-together systems and sets of procedures that manufacturers themselves develop internally.

At least one of these complementary products does bring benefits by itself, he says. IP Measure not only generates an inspection routine, but it also tries to optimize the routine to save time and machine motion. A shop's existing measurement routines can even be read into the software to receive this benefit. Thus the software fills a niche that is similar to what CAM does for machine tools. It generates a measurement program quickly and effectively, and it also raises the level of programming complexity that can easily be put to use.