Page 19 - MetalForming December 2019
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 CMMs in stamping environments, Met- alForming offers the expertise of Alex Green, 3D manufacturing Alabama/ Mississippi account manager at Faro (, a provider of quality- assurance solutions.
Evolution of CMMs
Introduced in the 1960s, fixed-loca- tion CMMs offered a way to capture complex geometries at high accuracy via a measurement bed, probe, com- puter and software to operate the probe. Limiting measurements: the range of the probe on the bed, and the probes ability to move only in three axes.
Growing from the need for more measuring and data-gathering flexi- bility, portable CMM arms entered the manufacturing arena, providing more portability and flexibility than a fixed CMM. These portable measurement arms determine and record the location of a probe in 3D space―calculating the exact position of the probe at each point through embedded encoders on each axis (or joint) in the arm, as explained by Faro officials―and report the results through software. The avail- able software not only converts from various formats to enable compatibility with other CMM software employed by a manufacturer, but can even break down components into subsections for more effective inspection of indi- vidual features.
Typically offering working volumes of 4 to 12 ft. with radial reach from 2 to 6 ft., these arms primarily come in six- or seven-axis configurations depending on need. Fixed CMMs offer extreme precision, beyond that of portable CMM arms, but the two sys- tems often are employed together to cover both rapid inspection and/or reverse engineering across a manufac- turing location, and ultra-precise, extensive quality checks.
Speed Essential on the Shop Floor
Production volume, a major benefit of metal stamping, enables efficient production that delivers parts in a short
Users of portable CMM arms can refine measurement data to report only tolerance- critical information deemed essential for quality and production personnel, or customers.
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time frame as compared to other processes. The ability to provide quality measurements inline or close to the production process enhances that ben- efit, making portable CMM arms ideal in stamping operations, according to Green.
“A portable CMM arm can be taken to the line or nearby to scan a part every minute or two as a check to see if something is wrong,” he explains, noting that an automotive A-frame pil- lar can be scanned in about 1 minute, with perhaps another minute for data to run through the automated inspec- tion program, yielding a 100-percent
inspected part with statistical process control for every feature and every data point. “If so, the part can get a closer look at the fixed CMM. With the arm, instead of blocking and fixturing the part for a fixed-CMM scan, a user just sets it on a flat and stable surface for scanning in a fraction of the amount of time and pick up any sur- face deviations.”
With scanning via portable CMM arms yielding so much data, users can refine that data to report only toler- ance-critical information or other data deemed essential for quality and pro- duction personnel, or customers.
 Advantages of Portable-Arm CMMs
• Measure full parts, including those with complex geometries
• Measure on-demand, without needing to program a specific routine first
• Operate in a variety of environments, unlike a traditional CMM that requires a
temperature-controlled room
• Transport the arm to where the part is made rather than bringing each part to a
special room
• Perform a full digital analysis and review the data at any time
• Produce inspection reports for documentation and sharing
• Use for die maintenance
• Reverse engineer for part-design changes and replacement of worn or broken
machine parts
• Assure accurate positioning of fixtures • Gain hand-tool versatility

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