In high-precision motion, "Straightness" of a single rail is only half the battle. When building an XY or XYZ gantry system using TOCO TGB or TGH modules, the most difficult parameter to master is Orthogonality—ensuring that the X-axis and Y-axis are perfectly perpendicular (90.000-degree to one another.

1. The Cost of "Squareness" Errors

If your axes are off by even 0.01-degree, a square programmed to be 500mm x 500 mm will actually be a parallelogram. In CNC cutting, PCB assembly, or pick-and-place automation, this leads to components that don't fit and holes that don't align.

2. The Master-Slave Alignment Method

When installing parallel TOCO rails, we recommend the Master-Slave approach:

• The Master Rail: This is the primary reference. It is bolted down and aligned to a precision-ground reference edge or laser line.

• The Slave Rail: This rail is left slightly loose. The carriage is moved to the far end of the stroke to "find" the natural parallel position before final torquing. This prevents binding and ensures smooth travel across the entire stroke.

3. Verification with Laser Metrology

To verify Article #81-level precision, engineers use laser interferometers. By measuring the diagonal distance of a large rectangular move and comparing it to the theoretical hypotenuse  , we can detect angular errors as small as ±2 arc-seconds.