Bal-tec™ Home Articulating Arm Measuring Machine Calibration
There are several good, but elaborate and expensive methods of calibrating an Articulating Arm Coordinate Measuring machine. There are also several elaborate and expensive methods that don’t work at all, and they do not meet any part of the A.S.M.E. B89.4.22-2004 specifications. The Ball Bar method of calibrating articulating Arm Coordinate Measuring Machines is the device specified by this A.S.M.E. spec; and it is neither elaborate, nor is it expensive.
The authoritative definition of how these machines should be calibrated is the ASME-B89.4.22-2004 specification for calibration of Articulating Arm Measuring Machines. The high force that is typically applied to a Ball Bar by any of the hand held probes will cause some small bending errors when it is applied to the side of the Ball Bar sphere. For this reason, the greatest accuracy will be achieved when contacting the Ball Bar Sphere on or near the very end.
It has often been found that errors that were being attributed to the measuring machine were actually caused by probing errors that were due to the difficulty of measuring the one inch ( 25.4 mm ) diameter sphere of the Ball Bar with another much smaller diameter spherical probe. A good method to eliminate this probing problem is to use a special probe that consists of a three ball kinematic couple. This three ball kinematic probe will automatically self align itself with the center of the Ball Bar sphere within micro inch accuracy.
In order to match the probe mounting method of your particular machine with our three ball probe without question, we ask you to supply a sample probe tip when ordering our three ball kinematic probe. There have been so many different probes built over the years, that this is a necessary precaution.