Laser cutting?!
Laser cutting?!
(OP)
Hi,
When you cut 0.063" AL or just any aluminium sheet using a laser cutter, what are the adverse effects? - I noticed very rough outline finishes, but I've also seen very smooth ones from a different supplier on the same product. Just curious to know why?
Does the laser produce sheets which have smaller dimension than what it was programmed or a larger dim?
Example: If I have to program a 3mm hole with a laser cutter what could potentially be the end result? - 2.9mm or 3.1mm (Do not worry about what my drawing tolerances say, I want to know what a laser can do?)
If possible please give me an reasonable explanation.
Thanks,
V.
When you cut 0.063" AL or just any aluminium sheet using a laser cutter, what are the adverse effects? - I noticed very rough outline finishes, but I've also seen very smooth ones from a different supplier on the same product. Just curious to know why?
Does the laser produce sheets which have smaller dimension than what it was programmed or a larger dim?
Example: If I have to program a 3mm hole with a laser cutter what could potentially be the end result? - 2.9mm or 3.1mm (Do not worry about what my drawing tolerances say, I want to know what a laser can do?)
If possible please give me an reasonable explanation.
Thanks,
V.





RE: Laser cutting?!
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RE: Laser cutting?!
As a point of reference, the kerf for a laser cutter than can handle stainless steel sheet is somewhere between .007" and .025", depending on the thickness of the sheet and hence the beam power. If you call the cutting outfit and tell them the material and thickness you want to cut, they can decide which photon cannon to use and tell you how wide the kerf will be. This is only of interest if you are making some kinds of self-conjugate parts, but they can be helpful if you are nice and ask intelligent questions.
The typical cut finish, under magnification, looks like the cut was made by plunging a row of holes with a tiny drill, which is sort of how the process actually works. In stainless, it leaves a HAZ that 'welds funny', about .005" thick and slightly blue under magnification. I'm not sure what the HAZ looks like in aluminum; I'd guess an edge burr sort of like you get by cutting aluminum with a MIG welder, but on a smaller scale.
The edge finish of waterjet cut metal is generally a little better than lasercut, but the waterjet parts arrive covered with fine abrasive sand, unless you pay someone to wash them. Lasercut parts have always arrived clean for me, but I don't know if they come out of the machine clean or not.
Mike Halloran
Pembroke Pines, FL, USA
RE: Laser cutting?!
Tell the subcontractor you need a better finish, if they can't do it, find another subcontractor.
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RE: Laser cutting?!
A small diameter laser beam leaves a smoother finish probably.
The molten metal may react with the air or gas.
There is a heat effected zone. We use the "rule of thumb" figure of 0.010".
This is pretty mcuh the same as the o.oo5" given above with extra room.
Thomas J. Walz
Carbide Processors, Inc.
www.carbideprocessors.com
Good engineering starts with a Grainger Catalog.
RE: Laser cutting?!
Is this possible what I said happens with 0.063" and 0.090" Alu?
RE: Laser cutting?!
Is it specified in your contract? The contract probably should specify that the drawing dimensions are to the cut edges. If the drawing is actually the intended toolpath, i.e. no offset is to be applied, the contract should say so.
Did someone add an offset in your drawing already?
You need to talk to the technical people at the cutter.
Do not delegate it.
You may have to go in person to straighten it out.
Mike Halloran
Pembroke Pines, FL, USA
RE: Laser cutting?!
Never underestimate the stupidity of people. You may be surprised
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RE: Laser cutting?!
Thomas J. Walz
Carbide Processors, Inc.
www.carbideprocessors.com
Good engineering starts with a Grainger Catalog.
RE: Laser cutting?!
http://www.youtube.com/watch?v=35nVJrJsUFc
Thomas J. Walz
Carbide Processors, Inc.
www.carbideprocessors.com
Good engineering starts with a Grainger Catalog.
RE: Laser cutting?!
Aluminum has always been unfriendly to lasers - reflective to the beam, and it sucks up power.
It also expands a lot as it changes temperature - so depending on the precision needed, the amount of cutting on a piece, etc - the material could be growing during the process - resulting in features that aren't within tolerance.
Make sure you specify edge finish and dimensional tolerance - if they don't meet the drawing, send them back!
jay
Jay Maechtlen
http://www.laserpubs.com/techcomm
RE: Laser cutting?!
Thanks all.
RE: Laser cutting?!
But getting good results requires some experience and knowhow.
If they can't show decent samples in the material you need done, then a different vendor or different process may be advisable.
fwiw, CNC turrets can do amazing work!
Jay Maechtlen
http://www.laserpubs.com/techcomm
RE: Laser cutting?!
But anyhow, when I have a hole that I need to hold to a tight tolerance, I have them laser cut a smaller diameter and drill it out using that location, then perhaps reaming it.