4 Ways to Improve CMM Productivity

Expanding the role of coordinate measuring machines to save overall production time

Five-axis measuring machine

Five-axis technology allows rapid touch-trigger measurement by using “head touches,” a process in which measurement points are taken by moving only the head, rather than the entire CMM structure. Photo courtesy of Renishaw Canada.

Metrology touches many areas of a manufacturing business, but at the end of the day, it’s about producing good parts as quickly as possible.

Technology developments in recent years have enabled a coordinate measuring machine (CMM) to tackle tasks that other, additional machines previously handled. Keeping the machine measuring parts eliminates bottlenecks and increases the number of parts that can be measured in a given day.

Also, because CMMs can now perform multiple measuring tasks, labor costs are reduced.

Here is a look at some of the latest trends.

1. Program Offline

Offline CMM programming was developed, in part, to help maximize the ROI of the measuring machine by keeping it running as much as possible and therefore increasing throughput.

Preparing measurement programs before the part has even been machined eliminates the need for the CMM operator to sit in front of a real CMM to do the programming work. The major benefits of offline programming are that it reduces the time needed to get a new part up and running on the measuring machine and it reduces the time that the machine has to be taken out of production.

While it typically is faster to get a parts measured when the program is created first with offline programming, a small amount of time is required to upload the offline program and perhaps make small adjustments.

“Offline programming has been a major part of manufacturing for many years,” said Rob Johnston, Carl Zeiss product manager for Elliott-Matsuura Canada. “Recently QA departments have adopted this thinking for their CMM programming with great success. If you are creating the measuring program at the machine, you are not maximizing its potential.”

2. Use the Head

New 5-axis head technology allows rapid touch-trigger measurement by using “head touches,” a process in which measurement points are taken by moving only the head, rather than the entire CMM structure.

“[This technology] minimizes CMM motion, therefore reducing dynamic CMM errors, and its rapid head touches mean measurement points are taken much faster using only the rotary motion of the head. The result is improved accuracy and repeatability and significantly improved inspection throughput, with parts measured up to three times faster than current with touch-trigger systems,” explained Brian Gow, Renishaw’s CMM marketing manager.

Mitutoya measuring machine

Technology now exists that allows surface roughness analysis to be performed on the CMM. This eliminates the need for workpiece changeover to a second measurement device, combining dimensional evaluation and surface finish analysis in a single program. Photo courtesy of Mitutoyo Canada.

Unlike conventional touch-trigger measurement methods, which rely on increasing the speed of the CMM’s three axes to measure quickly, new head and probing technology requires only head motion to accomplish the measurement goals.

3. Add Functionality

Touch-trigger, scanning, laser, and vision probes are all common on CMMs today. What is new, however, is technology that enables a surface quality assessment to be performed on these devices as well.

This technology that allows surface roughness analysis to be performed on the CMM eliminates the need for workpiece changeover to a second measurement device, combining dimensional evaluation and surface finish analysis in a single program. An articulating probe head is needed to allow access to features requiring rotation for surface roughness measurement.

While this technology does not necessarily reduce programming time or actual measuring time, it does eliminate the time it takes to move the part from one machine to another.

“By adding the ability to perform another measuring function to a CMM, you reduce the number of machines and operators it takes to gather the data you require,” said Peter Detmers, vice president of sales for Mitutoyo Canada. “Now a single program is created, and a single report generated. This streamlined operation helps manufacturers both gather and disseminate their data.”

4. Advanced Software

Metrology departments can be busy places with many jobs needing processed at one time. When rush jobs enter the system, it can be important to be able to run them as quickly as possible. New CMM software enables the CMM to pause mid-part, run a new program on the rushed part, and then resume the first program.

It’s something that has gotten the attention of many QA departments.

“Our customers tell us that this feature alone can save them hours and hours of measuring time in a month,” said Johnston.