Heavy workpieces are not allowed to be directly placed on the surface of granite measuring plates without protective measures.Direct placement will cause irreversible damage to the precision reference surface and reduce the service life and measurement accuracy of the granite plate,and the specific hazards and standard operation specifications are as follows.
1.Hazards of directly putting heavy workpieces on granite surface
Collision pits and surface indentations
Heavy metal workpieces have large impact inertia.Dropping or placing them directly will form obvious sunken pits on the granite flat surface.These pits break the continuous flat benchmark,making the local flatness out of tolerance and unable to meet precision inspection standards.Even small pits will interfere with the reading of dial indicators,height gauges and other measuring tools.
Long-term compression deformation
If overweight workpieces are fixed on one position for a long time,the local stone body will bear concentrated static load.Even granite with good rigidity will produce slow micro-deformation under long-term unbalanced pressure,leading to permanent distortion of the whole plate’s flatness.
Scratches and embedded rust
The bottom of castings,forgings and heavy mechanical parts often carry sharp burrs,iron filings and oxide scales.Sliding heavy workpieces on the granite surface will draw dense deep scratches.Metal debris pressed into stone pores will oxidize into rust spots that are difficult to clean,further destroying the surface finish and precision.
Local stress concentration triggering internal cracks
Sudden heavy impact generates instantaneous stress inside the granite.Microcracks will appear at the impact position after repeated collisions.As temperature and vibration change,the cracks will expand gradually,and even cause partial collapse of the measuring plate in severe cases.
2.Standard correct placement methods for heavy workpieces
Lay soft buffer gaskets first
Before placing heavy workpieces,spread copper sheets,thick plastic pads or hard rubber blocks on the contact area between the workpiece and granite plate.The buffer layer disperses the pressure,buffers impact force,isolates sharp burrs and avoids direct metal-to-stone friction and collision.
Slow hoisting and gentle lowering
Use cranes,forklifts or manual hoist tools to lift heavy parts.Keep the workpiece parallel to the granite surface and lower it slowly from a height of less than 10 mm,strictly forbid free falling,throwing or sliding the workpiece on the plate.
Uniform distribution of bearing positions
Place support points of heavy workpieces at multiple scattered positions on the granite plate,avoid single-point concentrated load on the edge or thin area of the stone plate.Do not stack multiple heavy parts in the same small area for a long time.
Limit the maximum bearing weight
Each specification of granite measuring plate has a rated safe load.Workpieces exceeding the load limit cannot be placed on the plate for measurement.For ultra-heavy components,transfer measurement tasks to special heavy-load cast iron platforms.
3.Supplementary operation rules
After removing heavy workpieces each time,clean iron filings,oxide skin and cutting fluid left on the granite surface immediately.Check for new pits,scratches and rust spots;repair minor defects in a timely manner to prevent further expansion of damage.
Reference List
GB/T 7714 Format
Wang L.Load bearing specification and protection operation of granite precision measuring platform[J].Measuring Technology,2022,49(10):84-88.
MLA Format
Wang,Lei."Load Bearing Specification and Protection Operation of Granite Precision Measuring Platform."Measuring Technology,vol.49,no.10,2022,pp.84-88.
APA 7th Format
Wang,L.(2022).Load bearing specification and protection operation of granite precision measuring platform.Measuring Technology,49(10),84–88.
