curvature tolerance for rolled strip

[airborne12]

Hi
I need a steel strip (St52) (thickness10mm, height 60mm)to use as a guide rail for a curved door. The strip is 2.5m long, and has two radii. First part radius: 3.5m, 2nd part radius: 0.35m).
I am thinking of making this rail by rolling the strip. What tolerances can be met with the rolling process? How accurate is the transition from the one radius to the other?

THanks
jasper

 

[MintJulep]

If you are willing to throw away enough parts, any specified tolerance can be met by any process.

 

[diamondjim]

I would think that tolerance would not even
be critical once you have it close to the
shape you need. I assume when you fasten
it, it will take the necessary shape.
I used to have cage segments bent radially
and felt it was more important to control
the length of the curvature rather than
the bend radii.

 

[airborne12]

Thanks,
PRoblem is that i have to have two guide rails with the same curvature. Guidance should be accurate (around +/-2mm) so the two rolled strips should be of the same curvature.

Btw: how about the transition from the large radius to the small radius? is this possible?

 

[MintJulep]

Could you roll a double-wide strip and cut it in half afterwards? This would give you the same curve on both.

Your potential suppliers are your best source of info.

 

[TheTick]

Start wi a tight tolerance and send it out for quote. See what the vendors say. Chances are different vendors have different capabilities.

 

[BillPSU]

Rolling in general is not a very accurate process. You are dealing with springback of the material, changes in thickness in the material affect the bending, changes in material hardness/strength also affect the bending and scale and coating can affect the forming.

My solution would be to make a support gusset with your intended contour and weld your rail to the support gusset applying heat and clamping loads to make the rail conform to your gusset. The gusset should me accurate if you have it laser cut.