Machine Tool Installation, Levelling and Geometric Accuracy Testing
What this domain tests
Foundation and foundation-bolt practice, levelling with precision levels, checking straightness, squareness and run-out, and acceptance tests to ISO 230-1.
Core rules
- Sequence: prepare foundation, position machine on packing/shim plates, grout bolts, rough level, finish level after grout cures, then check geometry.
- Level sensitivity is quoted in mm/m. A 0.02 mm/m level reading 3 divisions over a 400 mm span means 0.02 × 3 = 0.06 mm per metre, so over 0.4 m the error is 0.024 mm.
- Bed twist is checked at several points along the bed; shim the low corner to remove twist before checking any other geometry.
- Straightness of a bed or table is checked with a dial indicator on a saddle or a straightedge and feeler; squareness with a try square and dial indicator or a precision square.
- Spindle tests: run-out at the bore and at the face of the spindle nose, using a test mandrel and dial indicator, and checking axial float and taper contact by blue marking.
- Anti-vibration pads isolate the machine but do not replace correct grouting and levelling.
Worked example
A precision level of 0.02 mm/m shows 3 divisions out of level across a 400 mm bed span. Deviation = 0.02 × 3 × (400/1000) = 0.024 mm. Place a 0.024 mm shim under the low end, re-check, and repeat until the bubble is within one division.
Traps that cost marks
- Checking geometry before the bed is free of twist.
- Forgetting to convert the level reading for the actual span length.
- Reading the level with the machine still on temporary packing or before grout has cured.
- Taking spindle run-out readings at only one angular position.