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Easy Volumetric Compensation

Fagor Automation's Volumetric Compensation feature is designed to ensure accuracy by correcting typical geometric errors, making sure that more products end up in the hands of the customer and not the scrap pile.

"Previously, Volumetric Compensation, in most cases, was only applied on large high-performance machine tools due to the high cost of the equipment necessary to gather the data points, as well as the lengthy time it takes to complete the procedure," said a company spokesperson. "Despite the costs, there is still quite a lot of demand for less expensive machines to obtain the type of accuracy and repeatability that only Volumetric Compensation can give. Therefore, as requested by our customers, Fagor Automation has developed a new feature we call 'Easy Volumetric.'"

Volumetric Compensation-What It Is

"Applications requiring acute accuracy-not just on individual applications, but also in uniformed applications that tie together, as frequently seen in the aerospace market-have become commonplace," said the spokesperson. "For over 30 years, traditionally offered linear compensation tables have been the final solution for providing machine tool accuracy. However, to comply with global accuracy standards, as frequently required within the aerospace industry, these conventional compensation tools are insufficient considering they do not take into account the machine's kinematics and other factors related to the mechanical and electrical relationship between the multiple combinations of axes of motion."

Primary causes of the lack of machine tool accuracy and precision derive from geometric machine errors that can arise during manufacturing and assembly and also in production machine wear and abuse, which can cause premature deformations of the machine.

The Volumetric Compensation feature corrects these geometric errors, thus improving machine tool repeatability and accuracy. The volume to be compensated is defined by a cloud of points, in each of which the error to be corrected is measured. This error is recorded in a file that is then uploaded to the CNC. Therefore, the conventional compensation tools must be complemented with more advanced tools that adapt to the different designs of the machine and their specific kinematic.

"Volumetric Compensation can be an expensive feature that requires expensive hardware-as well as valuable time-to gather all compensation data points and then apply to the CNC," said the spokesperson. "This expense is well accepted for large high-performance machine tools, but is much more difficult to justify for small to mid-size machine tools. Hence, in conjunction with our customer's request, this is why Fagor has developed Easy Volumetric that simplifies the process, thus making it not just an acceptable process, but desirable for all machines."

"Easy Volumetric Compensation limits the points to just 25 per axis, thus is much faster to calibrate the points and integrate to the CNC," said the spokesperson. "It improves accuracy dramatically, yet is fast and easy to integrate. This is a groundbreaking development for small machines."

Both the Fagor 8065 and 8070 CNC platforms allow for both complex medium/large machine Volumetric Compensation or the Easy Volumetric compensation. Traditional ball screw and backlash compensation can still be utilized, but is not necessary since Volumetric compensates for these errors as well. However, operators can still utilize these tables and the CNC will automatically integrate them into the compensation matrix.

Easy (basic) volumetric compensation overview:

  • The volume to be compensated is defined by up to 25 points on each axis
  • This compensation corrects translation errors
  • The compensation tables are generated by the calibration application; they are not editable from the CNC
  • The OEM must define all the compensation data (axes that move, axes to be compensated, position and the size of the volume to be compensated, etc.) in the machine parameters and select the file containing the compensation data
  • The basic compensation is the fastest to calibrate, but it can be less precise than the others (it corrects fewer error components).

Medium/large machine volumetric compensation overview:

  • Volume compensation up to 10 cu. m (medium) or more than 10 cu. m (large).
  • This compensation corrects the 21 geometric error components (translation, rotation and squaring).
  • The compensation tables are generated by the calibration application; they are not editable from the CNC.
  • The OEM only needs to define the axes to be compensated in the machine parameters and select the file containing the calibration data. The rest of the data (axes that move, error to be compensated, etc.) are implicit in the file.
  • Medium and large compensations are more precise than basic compensation, but they are slower to calibrate.

For more information contact:

Fagor Automation - USA

2250 Estes Avenue

Elk Grove Village, IL 60007


Todd Drane

Fagor Automation

800-423-2467 ext. 303


Bob Miceli (CNC)

Fagor East Coast Operations

800-423-2467 ext. 301

Joel Kasnik (DRO & Feedback Products)

Fagor Southeast Operations

800-423-2467 ext. 302


Wayne Nelson

Fagor East Coast Operations

800-423-2467 ext. 301


Art Gugulski (CNC)

800-423-2467 ext. 431

Alex Escamilla (DRO & Feedback Products)

800-423-2467 ext. 436


Mike Pitts (CNC)

800-423-2467 ext. 106

Humberto Gomez (DRO & Feedback Products)

800-423-2467 ext. 107

Dan Chovan (Imports & Distributor Relations)

847-981-1500 ext. 250

Service Line

847-981-1500 ext. 750

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