Machine Tool Foundation vs. Steel Plate/Epoxy

[DrDarrell]

I need to relocate some Machine Tools, some of which have foundations (3-4ft Re-enforced Concrete).

One of our sister companies placed a Steel Plate and Epoxy beneath one of their Machine Tools in lieu of the manufacturers recommended foundation. They Claim that this has worked quite well. So the same has been recommended to me for my machine tools.

Does anyone have familiarity with this application? Is there a standard formula for this application?

FYI, I have two VTL's and an HMC which I need to address. Also, the new location has a Railroad running next to the building.

Thanks,
Darrell

 

[BillPSU]

It all depends on what you are trying to achieve for tolerances and the length of the parts you are making. The longer the part the more bending of the ways will impact the tolerance. Your train will cause movement of the machine unless there is bedrock around your plant.
I have seen a train 1/8 of a mile away send an electronic level from stop to stop in North Dakato but bedrock is 12,000 feet down up there.

The manufacturer have reasons for the foundations and if you don't follow them then don't expect the machine supplier to guarantee you performance.

 

[gerhardl]

Hi DrDarrell, thanks to this link :

http://www.acronymfinder.com/HMC.html

I think you are talking about a Vertical Turret Lathe and a Horizontal Machining Center.

In itself this gives us no certain data, only an indication that tooling operations, eg. machines, must be stable and not transfer movements or shakes to the tools or working pieces above certain, not given, limits during the tooling process.

Let us presume that the original concrete foundation represents a stable platform, solid enough to bear all feet of the machine. Some of the feet might be firm anchored others might under circumstances also be able to move a bit according to temerature differences, allternatively all firm or all moveable.

Epoxy (plates)in connection with feet and plates would have two purposes: to some degree even out the load and give sliding/movements possible if machine moves according to temperature.

Two points must be taken care of: weight on plastic material always well under flowing limit for the material to avoid any deformation over time. Epoxy might not be the best material. PTFE or PU alternatives? (No expert on this)

Secondly the steel plates must be stable enogh not to deform because of weight and loads transferred during process, and not to contribute with extra forces with shrinking or incrasing in length because of temperature.

What worries me most is the nearby train. Shakings could perhaps be measured before moving, and machine supplier (original or similar) cpuld parhaps advice on what shakings (G's?) are acceptable under operational conditions. Marine or military specialist could perhaps advice?

If G-forces (shakings or even 'standing waves' inforcing) are to be avoided, one way to prevent would perhaps be to build a 'sand pillow' and place a free-standing concrete foundation on this. Earthquake specialists or building fundamentation specialists to advice?

If the machines are lightweight and precision requirements and repetition accuracy are on the not too stringnent side, it is easier to say a plain yes to alternative steelplate foundamentation. Nevertheless the steelplates itself must be solidly anchored to the ground and sliding on temperature movements allowed.