Coordinate measuring machine test standard apparatus and method

A coordinate measuring machine test standard apparatus, comprising:

• a rotary spindle having an upper phase plate, said phase plate having a circumference and an axis of rotation;
• a kinematic ball mount attached to said phase plate concentric with said axis of rotation of said phase plate;
• a angular locating groove comprising at least two locking cylinders mounted at said circumference of said phase plate;
• an arm assembly, said arm of said arm assembly having a first end and a second end, said first end having a small sphere attached thereto and said second end having a large sphere attached thereto, said large sphere mounted in said kinematic ball mount and said arm resting in said groove;
• means for securing said second sphere in said kinematic ball mount;
• and
• means for holding said arm in said groove.

A method of evaluating short periodic measuring performance evaluation of a coordinate measuring machine using a coordinate measuring machine test standard apparatus, comprising the steps of:

• measuring a small sphere at a first position;
• measuring the distance along an X-axis between said small sphere centerpoints at said first position and at a second position;
• measuring the distance along a Y-axis between said small sphere centerpoints at said first and second positions;
• measuring the diagonal distance in the X-Y plane of the coordinate measuring machine between said small sphere centerpoints said positions one and two;
• and
• measuring coordinate machine performance by measuring small sphere in space at position two.

A method of evaluating squareness of a coordinate measuring machine using a coordinate measuring machine test standard apparatus, comprising the steps of:

• a) evaluating the centerpoints of said small sphere and said large sphere in a first position, and identify a first line between said centerpoints;
• b) rotating said spindle 90 degrees to a second position, evaluate the centerpoints of said spheres and identify a second line through the said centerpoints at the second position;
• and
• c) calculating the angle between said first and second lines, wherein the difference between said calculated angle and the actual angle of the apparatus is defined as the coordinate measuring machine squareness error.

A method of checking the rotary axis of the coordinate measuring machine using a coordinate measuring machine test standard apparatus, comprising the steps of:

• a) placing said machine test standard onto said face plate of said machine test standard rotary axis;
• b) measuring a small sphere with said machine test standard;
• c) rotating said machine test standard by said rotary spindle 90 degrees clockwise;
• d) rotating said rotary axis 90 degrees counterclockwise where said small sphere is returned to its original location prior to rotation of said machine test standard;
• e) measuring said small sphere with said coordinate measuring machine wherein any difference in location of said small sphere is a result of coordinate measuring machine rotary axis error;
• and
• f) repeating steps (c) through (e) until said machine test standard has been checked 360 degrees.