The inspection surface plats are basic datum for precision inspection in production department or measure department; the lineation surface plates are used for basic datum of lineation and marking.
Although they are all basic datum, they are different in processing, flat precision and functions.
The surface of the precision inspection cast iron surface plate need to be ground and scraped, any others need to be ground and scraped or finish-milled and polishing or finish-milling is ok for the lineation surface plates.
The inspection surface plates play an important role in checking the workpieces’ linearity and other measuring as auxiliary checking tools. The lineation surface plates act as basic datum in lineation work.
Many factors, for example, temperature, humidity, vibration, etc., will affect the flatness precision of the cast iron surface plates in some extent, so it’s very important to control the environmental aspects. But in order to get the higher precision in the daily using, you should pay more attention to the maintenance and proper use. The improper use will lead to an error measuring result. The insufficient maintenance will lower the surface precision. Even worse, the quality of the inspected products will be affected accordingly. Thus, we need to follow the below items when using and maintaining the cast iron surface plates.
1) Before the inspection, to be sure the surface precision is in the acceptable range. And check the surface of the cast iron surface plate to see whether there is any corrosion, abrasion, scratch, dusty, and the like. It’s very important of using the soft cloth or dust-free paper to wipe the surface. One more, the surface plate should be placed in proper position, overlap each other is not allowed.
2) When measuring, the cast iron surface plate should be properly contacted with the workpiece. Protect the cast iron surface; do not use your hands to touch the measuring surface. In the process of measuring, the force must be proper, too large will lead to an error measuring result, and the cast iron surface will be damaged also. Measuring the special shaped workpieces is allowed, but you need to follow the relevant steps.
3) After finishing your inspection, the first step you should to do is cleaning the surface plate; then coating it with anti-rust oil, placing it into the cabinet. Dismantling, debugging, revising and assembly should be carried out by the professional staff. Check the performance of the stored cast iron surface plate and verify whether the surface plate is qualified, make the record accordingly.
There are five identification items together about the surface plates: the appearance and surface quality, roughness of working surface and sides, included angle of sides, contact point of scraping surface plates and the flatness of working surface.
The cast iron surface plates can regain the precision grade though re-scraped after little wear and tear,
The cast iron surface plates can check the planeness by coloring method; it is accurate, intuitive and convenient. It is very easy and smoothly to push the gauge stand or workpieces on their surface, we can get the accurate result and it is very convenient for us to test.
The quality of the cast iron raw material and heat-treatment influence the capacity of cast iron surface plate greatly. The working surface couldn’t keep their shape if the innerstress exists; the precision grade could not be sure because of wear and tear; or we couldn’t get a minimum roughness because it’s hard to scrape and grind. So when you choose the cast iron surface plates, please pay more attention to the cast iron raw materials and how to clear the residual innerstress.
The granite surface plates are high accuracy and easy maintenance, for the following reasons:
①Uniformity in Hardness
②Easy To Clean
⑤Accurate Under Load Conditions
⑨Low maintenance cost
The disadvantages are not withstanding impact and beating, high humidity brings about granite deformation, and the hygroscopicity is 1%.