Surface plates are flat and plane surface used as a horizontal reference space for dimensional measurement, it’s a base for inspection, toolmaking, gauging, spotting, marking, and layout. They can be made from granite, metal, cast iron, or glass.
Serving as the benchmark for all measurements, surface plates play a pivotal role in quality checking and control. This surface is extremely flat that comes in Grade-00 to Grade-3 flatness accuracy substandard. Machine shops, all types of precise manufacturing, defense, automotive, and aerospace manufacturers require tight tolerances for machine shop tools and surface plates are widely used to assess out of accuracy or warped areas on manufactured parts.
As far as use is concerned, surface plates must be calibrated on a regular basis, at least once to twice a year, but most efficiently and for long-lasting use, it is to be calibrated every six months. Problems usually occur in certain areas having frequent use, so frequent calibration will make sure of chipping, warping, or wear has not observed. An uneven surface will impact the efficient functionality of the whole plate causing errors in measurements and the passing of checked defected parts.
Material Properties of Surface Plate :
To make an ideal surface plate, the material must have the following requirements.
- Must have a high degree of rigidity
- Resistance to the wear and corrosion
- Free from warping that is from being Twisted
Materials used to make Surface Plates
- Cast Iron (C.I)
Cast Iron Surface plate / C. I Surface Plates
Cast Iron is the most commonly used material in manufacturing, machine shops, and shop floor as it provides the best surface plates over the other materials. and hard annealed in order to relieve internal stresses. The surface plates are made up of Cast Iron (C.I) are duly provided heat treatment for relieving internal stresses. The top surface of the surface plate is manufactured as absolute flat. The backside of the surface plates is having cored and ribbed structure to increase the structural rigidity to withstand the heavy loads.
Granite Surface Plates
Granite surface plates are best known due to their rustless properties. Granite surface plates remain unaffected by the change in temperature and Heat as well so hence it can maintain the flatness for a longer period of time. The hardness of the granite surface plates is more than the C. I Surface Plates.
Glass Surface Plates
Apparently, surface plates can also be made up of Glass. The main reasons to make the surface plates from the glass are due to the following reasons.
- Less Weight
- Free from corrosion and burrs
- Achieve high accuracy and it can maintain for longer life
But they need to be handled carefully they can be broken. Ceramic Surface plates are slowly replacing the glass.
Precautions while using the Surface Plates :
- The flatness accuracy of the surface plate must be checked on a regular basis to make sure the surface is in an ideal condition
- The top surface must be properly cleaned before use in order to avoid dust and other polluted particles.
- Must be covered with the rexine or wooden cover when they are not in use
- Make sure to use every nook and corner of the plate so that the plate must be used in a uniform manner.
- The top surface of the plate should always be coated with corrosion resistive elements such as Oil or Grease after use
What are the important applications of Surface Plates?
A surface plate provides a precisely accurate plain surface that is wear-resistant, and in the case of the granite surface, it has a very low thermal coefficient of expansion, so this helps its flatness resilience against temperature excursions. Heights may be measured and surfaces marked accurately.