I. Preliminary Steps: Visual Inspection Quick Screening with Simple Tools (Defects must be aed)
- Check for Abnormal Appearance
If any of the following occur, precision is essentially lost:
Obvious cracks, hidden cracks, chipped corners, or missing pieces
Local ons, depressions, or impact marks
Severe scratches or deep grooves on the working surface
Large-scale discoloration, yellowing, or blackening (caused ong-term oil seepage leading to uneven stress)
Stone fragmentation or shedding near leveling support points - Tactile Inspection
The working surface feels uneven or has a steppedn
A distinct grainy or burr-like feel when fingers are drawn across it
Originally smooth precision surfaces become sticky, rough, or gritty - Preliminary Judgment with Simple LevelStraightedge
Using a high-precision straightedge feeler gauge:
The straightedge is pressed against the base; if light transmission is obvious, gaps are large and unevnserting the feeler gauge into the gap yields a value exceeding the equipment’s allowable tolerance
→ Indicates that flatness is no longer up to standard.
II. Precision Inspection: Verification of Compliance with Standards (Most Reliable)
- Flatness Inspection
Common Tools:
Electronic level / Optical comparator level
Laser flatness instrument
Marble straighdge feeler gauge
Judgment Criteria (Referencing Common Precision Equipment Requirements):
Ordinary equipment base: Flatness approx. 0.02~0.05 mmsion machine tool / measuring equipment base: 0.01~0.02 mm/m
Ultra-precision platform: ≤0.005 mm/m
After Inspectiasured value > Drawing / Equipment Requirement Tolerance → Precision is unqualified
Large fluctuations in data from multiple retests → Base is subject to abnormal stress or deformation - Pendicularity and Parallelism Inspection
Tools:
Right angle square
مقياس التداخل الليزري
Dial indicator / Micrometer indicator
Judgment:
Perpendicularity between the base and matg surfaces (e.g., guides, columns) exceeds tolerance
Parallelism of support surfaces on both sides is inconsistent
→ Directly affects equipment operating precision and is deemed unq. - Dynamic Stability Judgment (During Operation)
Observe while the equipment is running:
Significant changes in precision readings before and after startup
Obvious drift in flatness / level values afteus operation for several hours
Precision fluctuations exceed standards during cutting or under load
Indicates that granite base stress has not been fully released or support is inadequate, failing to meet usage ndards.
III. Inferring Base Precision from Equipment Processing / Measurement Results
This is the most practical method for on-site judgment:
Unstable dimensions and poor consistency of processed wores
Workpiece flatness or parallelism exceeds tolerance, and spindle / tool issues are ruled out
Reduced repeatability of coordinate measuring machine and large R value
Abnormal vibratiooises during equipment operation
If other component issues are ruled out, it is basically due to unqualified base precision.
IV. Simple Summary: When to Determine “Precision Does Not Meetandards”
Any one of the following conditions warrants a determination:
Presence of cracks, hidden cracks, or severe impact damage
Measured values for flatness / perpendicularity / parallelism exceed drawin tolerances
Large data drift and poor repeatability in multiple retests
Equipment processing / measurement precision remains unqualified, and other component causes are ruled out
Unable to achieve requirevelness and geometric precision even after leveling.
