Flatness measurement
Flatness measurement
(OP)
I am looking for a way to measure steel plates flatness. The plate is 3'X 5' and is approximately 2 inches thick. I believe that the plate is slightly concave on one side. Is there any instrument I can use to get an exact meamsurement? I have already used a a straight edge.





RE: Flatness measurement
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Flatness measurement
A straight edge is usually close enough for most purposes. Right off you can check the standard under which the plate was ordered and see what is allowed dimension wise.
You can get very accurate measurements though it its usually less expensive to have the plate finished or purchased to the desired dimensions.
Come back with a little more information as to the results you are expecting.
RE: Flatness measurement
They work by first leveling the level then aiming at a white faced venier scale at different points on the plate. In your case I would probably do readings in a grid pattern then calculate the slope and surface contour.
These instruments are tricky to level the first few times but you should get plenty of practice after everyone and their brother kicks the tripod while trying to look thru it.
I am going to assume this plate is evenly supported.
Barry1961
RE: Flatness measurement
RE: Flatness measurement
You can order plate to half tolerence. A good plate roll man/person(PC) can make it flatter.
RE: Flatness measurement
deanc is right. I could also imagine that the pyramid builders would do it exactly the same way. ASTM A6 has permissible plate waviness tolerance for structural grade plate. ASTM A20 has tolerances for pressure vessel grade steels.
Steve Braune
Tank Industry Consultants
www.tankindustry.com
RE: Flatness measurement
RE: Flatness measurement
Find a local Blanchard grinding job shop and have them sweep the part for you until you develop in-house inspection capabilities. (Assuming they check flatness...)
RE: Flatness measurement
Application:
http://www.damalini.com/pages/en/flatness_eng.htm
Product:
http://www.reliabilitydirect.com/alignmentproducts/DAM-D525.htm
http://www.reliabilitydirect.com/alignmentproducts/DAM-D22.htm