Using offline programming keeps that CMM on track.

Author:Boucher, Mark

With growing competition aboard, you must meet your goals of supplying a quality product and staying competitive by keeping costs down. In such a fast-paced environment, how do you increase throughput and maintain a quality-control system that ensures your parts are being measured accurately and meeting your customers expectations?

Coordinate measuring machines (CMMs) relieve some of the back-up that occurs in inspection, but they do little good when they have to be taken offline to program a new part. In some cases, a CMM could be offline for several days while programming a difficult part.

Offline programming is the key to keeping your CMM maintaining throughput. Offline programming provides a way to program parts without having a physical part in front of the operator. This means you can program a part days or weeks ahead of schedule.

Offline programming is done by using a CAD model. Whether you have a manual or a DCC CMM, a model can be used to generate a CMM program. A CAD model can be provided by the customer, or generated in your engineering department. This model provides all the math data needed to generate a CMM program. Nominal data used to create the model are used by the offline program to generate all the CMM moves and measurements. To further elaborate, the vectors used to drive a

DCC CMM come directly from the CAD model. This means the probe on your CMM will drive normal to the surface being measured and will eliminate any cosine error, ensuring that your measurement data are accurate.

In the past, CMM offline programs were expensive and out of the reach of many operations. With costs starting in the $15,000 range, it became hard to justify the return on investment. That has changed. For example, NewCastle Measurement's Offline is a CAD-based full-functioning soft ware program that costs much less - with software maintenance costs below $1,000.

It is important to make sure any offline package is compliant with the current DMIS standards. This ensures that the offline program will write the correct DMIS code for any CMM manufacture's software.

Moreover, all offline CMM programming software should have these basic tools:

Probe system: Building a probe representation is necessary to view just how your probe system will move around the part. With a built-in catalog of probes and styli building, the probe system has become simplified.

Probe orientations can be defined by the user or, in the case of NewCastle Offline, can be...

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