laser cutting source

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bilinghm

Joined
Nov 10, 2005
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Does anyone know or use a laser cutting shop that understands knives? Having trouble finding someone willing to do small batches. help!
 
Contact Randy McDaniel. His website is http://www.drgnfly4g.com/ He's a blacksmith that offers laser cutting and design services and will do small batches. The folks who do his cutting don't stock knife steels, so you'd likely have to send them the material, but I asked him about this a while back and he said he could work out knife blank cutting.

-d
 
waterjets.org tosee truly amazing stuff that was done by 60000 psi water, with some abrasive added .

You should not have any taper in this thicknesses, not on a decent machine.
 
I am told by those that do laser cutting that laser cutting can cause 'heat affected zones' along the edge of the cut due to the temperatures involved. This, they say, can cause problems for subsequent opertions and can result in uncertain material condition within these zones. This is reportedly a relevant consideration for titanium and blade banks. How big of an issue this is, I don't know. It's obvious, however, that some of the big makers use Laser, at least for liners.

I've just had a pile of waterjet work done and have shopped (and continue to shop) for the best vendor for this process. I don't care what they say, waterjetting develops a taper. Even on a brand new machine when you cut a slot in .080 Ti with a .020 nozzle (for example), you can easily see the difference in the thickness of the cut comparing one side with the other. Some guys use a 'tilt-a-jet' feature and that seems to be beneficial, especially for really thick parts, but I'm told it can add a bit of imprecision of its own as it attempts to negotiate your pattern.

Waterjet is an "intermediate-precision" technology at the moment. To achieve the tollerances I'm requiring on an upcoming folder, we've decided to 'blank' parts by waterjet oversized (no holes), precision grind, then machine the exact profile and holes. It's not the cheapest way by a long shot, but we're getting the accuracy and perpendicularity.
 
Thanks to all for the excellent advice. My experience with waterjet was mixed. The service/turnaround time/cost were excellent. If I was making fixed blade knives, or even liner locks, waterjet would work fine. But I am making a lock back. The locking notch and tab must be very square and very high tolerance. The water cut pieces were less accurate than I can produce on my band saw.

On the question of heat related problems from laser cutting, does anyone have direct experience with this that they can share?
 
bilinghm said:
On the question of heat related problems from laser cutting, does anyone have direct experience with this that they can share?
Click to expand...

I can comment on that. I program and run a laser for a living. The heat affected zone can vary quite a bit based on the cut. I can cut with very little haz, but it will take longer. I can cut fast, but the haz will be bigger. Thickness, material type, machine settings, assist gas type, and a number of other variables affect it's outcome.

What tolerances are you looking for? (Plus or minus how many thousands of an inch?)

What thickness and steel type?

Jamie
 
I use laser cutting for my Limited Series folders.
The Damascus should be cut about 0.010" oversize to allow for cleanup.And it has to be annealed after cutting since the laser machine blasts compressed air (or nitrogen for titanium)at the point of cutting which leaves the edge very hard. This is why I don't get stainless steel laser cut.
The laser will not only cut the outline, but can spot cut the screw holes to 0.030", so that when you drill the holes to size everthing lines up beautifully. It also does the pierced cuts in my blades and scales.
The main disadvantages with laser cutting are:- slag from the molten metal, :-and hardening of the cut area.
Hope this helps. Regards,Don
www.Bellknives.com
 
I have been using Les and Mary from halpren Titanium they do a great job, just my 2 cents

sar
 
polarbearforge said:
I can comment on that. I program and run a laser for a living. The heat affected zone can vary quite a bit based on the cut. I can cut with very little haz, but it will take longer. I can cut fast, but the haz will be bigger. Thickness, material type, machine settings, assist gas type, and a number of other variables affect it's outcome.

What tolerances are you looking for? (Plus or minus how many thousands of an inch?)

What thickness and steel type?

Jamie
Click to expand...

The steel is S30V, 1/8" thick. The tolerance for the locking notch is very close, + - .002 is about it. Howerever, because the lock recess tapers, this isn't as hard as it might sound.
 
Donald Bell said:
it has to be annealed after cutting since the laser machine blasts compressed air (or nitrogen for titanium)at the point of cutting which leaves the edge very hard. This is why I don't get stainless steel laser cut.

Well crap! I hadn't even considered the hardening of the edge where it is cut (and the holes as well). This is a potentially big problem with laser cutting. Annealing S30V will require a trip to the heat treater. Rats! Maybe it's possible to completely CNC mill the blades and lock bars, and water cut the rest. My current bandsaw method is just too time consuming.
Click to expand...
 
bilinghm said:
Donald Bell said:
Well crap! I hadn't even considered the hardening of the edge where it is cut (and the holes as well). This is a potentially big problem with laser cutting. Annealing S30V will require a trip to the heat treater. Rats! Maybe it's possible to completely CNC mill the blades and lock bars, and water cut the rest. My current bandsaw method is just too time consuming.
Click to expand...

You will probably find, as I did, that it's cheaper to waterjet your blades, etc. oversized (say .020) then CNC the blanks to size, since you're paying for time on either machine and waterjet should be cheaper (faster and no cutters to buy) than CNC for blanking operations. It also provides an opportunity to double-disc grind your parts to final dimension before going off to CNC. This way, you have an improved chance of getting your holes and edges square and perpendicular since the blanks will be precision-flattened before you hit the CNC.

Sometimes I wonder if the discussion about S30V sometimes chipping out, sometimes behaving well, sometimes chipping until resharpened, etc. has something to do with folks laser cutting that material, generating conditions along the edges that could explain some of the strange behavior.
Click to expand...
 
bilinghm said:
The steel is S30V, 1/8" thick. The tolerance for the locking notch is very close, + - .002 is about it. Howerever, because the lock recess tapers, this isn't as hard as it might sound.
Click to expand...

Actually, that is a bit more of a challenge for waterjet and laser. Their range is usually +- .004. A good machine and a good operator can definately hit closer though. Cutting it oversize and drilling out the holes is a good idea. For most of the stuff that I cut at work, hardening at the edges isn't an issue. I haven't cut S30V, so I'm not sure how much of a problem that would be.

Jamie
 
I just remembered, while training for the new machine, we did actually cut out a few liner lock knife blades. (I just found one). The haz is pretty much non existant on this one. There is one small dimple on one hole where it cut it's start point for the circle, but that's it. The finish wouldn't be a problem either. It'll be a little while before I can cut a test piece, but I'll cut one out for a lockback.

Jamie
 
bilinghm said:
The steel is S30V, 1/8" thick. The tolerance for the locking notch is very close, + - .002 is about it. Howerever, because the lock recess tapers, this isn't as hard as it might sound.
Click to expand...

Again, you're not going to get a satisfactory cut for a lock face with just waterjet or laser. You will have to do some machining/grinding.
I'm not sure which tolerance would be +/- .002, but if it's the slop in the notch, I would think that would be excessive. For this procedure, I think I'd leave the lockface oversized and build a fixture to grind/lap it to final fit. If you have a CNC machinist that will work with you, you could get them to dial in the relevant tolerance until it's just what you want. I suspect you'll be talking about +/- .0005.
 
JCaswell said:
Again, you're not going to get a satisfactory cut for a lock face with just waterjet or laser. You will have to do some machining/grinding.
I'm not sure which tolerance would be +/- .002, but if it's the slop in the notch, I would think that would be excessive. For this procedure, I think I'd leave the lockface oversized and build a fixture to grind/lap it to final fit. If you have a CNC machinist that will work with you, you could get them to dial in the relevant tolerance until it's just what you want. I suspect you'll be talking about +/- .0005.
Click to expand...

Because of the taper in the design of the locking tab, it moves deeper into the notch intil it locks up with zero slop. However, I believe that your analysis of the situation is exactly correct. I have decided to stick with water jet, cutting slightly oversize, and then taking the "critical fit" parts to final size in a filing fixture/jig. Actually, all of the local laser cutting sources aren't really intersted in my small quantities. My water jet guy is happy to work on small peojects. Thanks for your help.
 
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