This large AFP gantry machine exploits volumetric compensation techniques to achieve extreme accuracies.

CNC Machine Services

Are you making critical parts? Is your large CNC machine making good parts? Is it as accurate as its specifications claim? Would your business benefit if your machines were more accurate? Consider the value of periodic accuracy checks and machine compensation where those checks show it would be beneficial.

What is machine compensation?

All CNC machines are built “less than perfect” when it comes to accuracy. Especially with larger machines, the best approach is to build a very rigid machine that is highly repeatable. A machine that is repeatable drives to the same commanded position each time to within a very small number – less than a few ten-thousands of an inch even for extremely large machines. When a machine is highly repeatable it is possible to measure and characterize its imperfections (error mapping) and then adjust for them. This is called compensation. The result can be a machine that is superbly accurate.

Machine compensation equipment

With over 35 laser trackers in our stable as well as line lasers and other specialty tools we have the equipment and experience to check or improve your CNC machine accuracy. As well as conventional SMRs, for example, we use Hexagon Metrology's SuperCateye, API's Active Target or Hexagon Metrology's Active Reflector to simplify measuring throughout the volumes of very large CNC machines.

Hexagon Metrology Super CatEye is an effective tool for large machine compensation.
An Active Target speeds up volumetric measurements of very large machine tools.

If you are interesting in machine compensation and related topics here are a few white papers which may be of interest:

Bed setting - Bed alignment

Large CNC machines typically ride on bearing rails or ways which need to be straight and level to within tight tolerances. Very large machines are built on foundations which essentially become part of the machine. When the foundations shift or move it may be necessary to adjust level (we have seen foundations change shape from curing in the first two years, from earthquakes and from nearby excavation). We have set straight and level precision beds up to 175m long. We can set or check yours too!

  • Precision leveling with AT40X, AT930 laser trackers or DN03 Digital Optical level
  • Precision straightening with laser trackers, Renishaw XL-80 line laser and microscope enhanced tightlines
This spar assembly tool foundation cracked during an earthquake and one end dropped several tens of thousands of an inch.

CNC Machine Compensation or Calibration

  • Machine tool error mapping with laser tracker
  • Single axis compensations with laser tracker or Renishaw XL-80 line laser
A380 machine beds were over 172m long, and were set straight and level by èèɫ who designed these machines.

Foundation Reference System (FRS) installation

Do you machine parts which require inspection by laser tracker? Sometimes setup or measurement of such parts can be simplified by a permanent reference system around your CNC machine. Called a “control network” or FRS, it can allow you to “shoot in” from one side of the part and tie that to measurements done from the other side of the part, as well as tell you where the part is relative to your machine axes of motion.

We offer:

  • High quality, hardened, stainless steel FRS monuments
  • FRS monument installation
  • FRS monument valuation with USMN
Single Station FRS Measurement


  • ISO 9001+AS9100 aerospace standard Registered
  • Nadcap accredited:
  • AC7130A — Measurement & Inspection (M&I)
  • AC7130/1A — M&I — Coordinate Measuring Machines (CMM)
  • AC7130/2 — M&I — Laser Tracker
  • AC7130/3 — M&I — Articulating Arm
  • Experienced metrology technicians
  • Experienced degreed engineers available
  • Metrology lead with MA in Quality Management
  • CMS Level 1 certified 3D metrologist on staff

Metrology Software

  • Polyworks
  • Spatial Analyzer
  • Verisurf
  • Operation Commander (Task Execution Software)