Lasers, HAZ and hardening.... post laser reaming?

[InspirationTool]

I have a question about lasers and the heat affected zone.

How hard does the metal get? I need to cut some 1/4" to 1/2" plate and will need to ream the holes to tolerance afterwards. If it's too hard to ream I will have to specify waterjet instead.

Thanks!

-Jeff

[mxtras]

I have had no problems in the past. I would not recommend using a brand new reamer but I was able to ream 16x 1/2" holes in .25" plate that were laser cut without an issue. I c'cunk by hand first then floated the part (not in a vise, not clamped to the table - chocked against a post) to let the reamer remain on center - the tolerance was not super tight and the fit was acceptable.

I have also tapped lasered holes in 3/8 plate without issues. If the laser guy gets the set up right, the edge quality is very acceptable and the HAZ is not really all that great. If they penetrate on the diameter you will have a problem, but if they penetrate somewhere in the middle and iterpolate to the diam you will end up with a relatively smooth hole. If you are handing them the data, do this for your holes.

No problems reaming or tapping due to hardness, though. I have not dealt with anything thicker than 3/8" from a laser, though.

Scott

[pauluk]

Jeff, You don’t say what sort of steel you are having cut, if it is a low or medium carbon steel you should have no problems. However if it is high carbon, say gauge plate then the cut edges will be glass hard. I had some curved links cut from gauge plate, and the only way to finish them was to grind them. The hard area is only a few thou thick, like case hardening, but it will defeat HSS tooling.

[InspirationTool]

Ooooooooooohhhhhhhhh..... that makes perfect sense now.... It will get hard if it is heat hardenable!

I love it when the should-be-obvious finally becomes obvious!

Thanks guys!

-Jeff

[mxtras]

Originally Posted by pauluk ..... However if it is high carbon, say gauge plate then the cut edges will be glass hard....

Good point! Thanks for bringing it to our attention.

Scott