Pick and Place Machine Vision Calibration for Fine Pitch Components
Fine pitch machine vision calibration requires quartz grid targets, telecentric optics, and closed-loop thermal drift compensation to hold 5 µm accuracy.
Mechanical Spindle Runout
Rotational Error
Deviation of the axis of rotation of a high speed drilling or routing spindle from its true theoretical axis causes dimensional inaccuracy during printed circuit board fabrication. This rotational error, known as mechanical spindle runout, includes both radial and axial displacement of the spindle shaft during operation. It directly limits the minimum hole size and spacing that a fabricator can reliably achieve on high density boards.
Defect Propagation
During drilling operations, the wobble of the drill bit enlarges the drilled hole and causes it to deviate from its intended center. This mechanical spindle runout increases drill bit wear and leads to premature breakage of expensive micro-drills. The resulting larger hole size can damage adjacent copper traces, while the offset position misaligns the hole with internal copper pads.
In routing operations, it creates rough, inaccurate board edges and causes excessive mechanical vibration. This vibration degrades the mechanical life of the machine bearings and assembly tooling over time, which increases the total cost of production.
Measurement Validation
Laser dial indicators or capacitive non-contact sensors measure the offset of the spindle at various rotational speeds to verify its performance. This testing must be performed at full operating speed to capture dynamic runout effects that do not appear at rest. It ensures that the fabricator maintains the tight tolerances needed for advanced packaging.
Regular spindle maintenance keeps this error within acceptable limits.