GMT CAST IRON SURFACE PLATES
GMT Cast Iron Surface plates are manufactured to three grades : Grade-0, I & II
GMT Cast Iron Surface Plates are the result of years experience as a manufacturer both in foundry technology and metrology. These plates are of close-grained cast iron. They are amply ribbed to minimize deflection under load. The composition of the metal, the depth and cross-section of the ribs and the thickness of the plate are designed to conform to the deflection limits specified in IS-2285-2003. GMT Surface plates are manufactured to three grades namely Grade-0, Grade-I & Grade-II, as per the standard stated above. They can be made to other standards on request.
Grade-I & Grade-II plates are artificially seasoned. They are hand scraped to achieve maximum local deviation from flatness as per standard at any point on the working surface.
A special scraping technique is used to achieve a uniform distribution of load bearing point and oil pockets. An average of 15-20% load bearing points after finish scraping is standard. This finish scraping technique ensures that the area of the load bearing points increases after the initial dulling of the high points. This guarantees a long working life, at the required accuracies. Grade-II plates are accurately machined to get the requisite flatness.
Plates of sizes 1000 x 630 mm and smaller, are provided with handle. A wooden cover is provided to protect the working surfaces.
Fabricated heavy angle iron stands, with required leveling screws, are offered for all plates to provide convenient working height. Cast iron column floor stands each with a leveling screw and nut are also offered as an option as : A set of 5 & 3 for leveling and 2 for support for sizes upto 2000 x 1000mm plate and a set of 7 & 5 for leveling and two for support, for sizes above 2000 x 1000 mm.
To meet special requirements we offer on request custom size cast iron surface plates above 4000×1200 mm as a joint surface plate, with fabricated heavy angle iron stands and bed plates with special cast iron floor stands.
PRECISION CAST IRON SURFACE PLATES – SPECIFICATIONS
Maximum deviation from flatness over the entire area expressed in Microns as per IS 2285 – 2003