Forming Copper

[aepeszel]

Hello
Something simple today. On 3/16" Copper Alloy 110, what is the minimum bending radius?

apeszel@neuro-kinetics.com
or
apeszel@hotmail.com

 

[kenvlach]

Tubing? Pipe? Solid rod?
Wall thickness?
Annealed?
Hard drawn?
Hardness or strength?
Specifications?
Is a tubing or conduit bender being used?

Absent the above data, note that per ASTM B188, soft tubing should be able to be bent 180^o over a mandrel 6x the OD, while hard tubing should be capable of a 90^o bend over the same mandrel. Pipe and tube may be filled with sand, etc. before bending. Thus, a minimum radius of 1.125” is required for 3/16” OD tubing. [Pipe of nominal 3/16” size would require about 2.25”]

Hope this helps. If not, please describe material more fully.
Ken

 

[aepeszel]

My bad. It is sheet, 3/16 thick. Do not know if it is tempered. The Rockwell for it is 65-80 F Scale.

 

[kenvlach]

For C11000, this hardness corresponds to a cold worked H01 temper (1/4 hard), HRF range 60-84 --- ASTM B152. Maximum elongation is 35% vs. 50% for annealed.

I’m not expert at forming sheet metal, but from data for forming aluminum alloy of 35% elongation, it appears: If forming is done in a brake press with lubricated male and female dies, a 90^o bend with 0^o inside radius can be achieved. However, without dies, e.g., by bending over an edge, the material will stretch and thin, and cracks will appear in the outside surface.

For the latter, unconstrained case, I estimate a minimum inside radius of at least 5/8” is necessary to avoid elongation greater than 35% for the outside surface of the copper sheet.

Anyone with experience: please feel free to comment.