Negative effects to laser cutting blanks?

[Nsled]

Has anyone had experience with laser cutting knife blanks and the effect the laser has on the edge?

I'm considering having a few cut out to play with and laser is considerable cheaper and more common the waterjet.

 

[Mikel_24]

I don't know how clean of a cut you are going to get but if you are going to clean them with a belt grinder anyways, I wouldn't worry about burnt steel if that's what worries you.

 

[kuraki]

Depends on the laser, the operator, and the steel alloy and thickness. With a nice laser running nitrogen assist gas and properly tweaked parameters, you'll get maybe a .005" thick heat affected zone on the edges with a very easily cleaned surface. With oxygen and less than ideal cutting conditions, you'll get a scaly edge with a greater depth of HAZ and probably a bunch of dross. If you're cutting an air hardening steel like Elmax or A2, that HAZ will be quite hard as well.

Most laser houses don't know or care to know how to cut knives. They're cutting steel as quickly as they can to be formed in a brake press or stamping die or welded into a fabrication. So most, even if they take your work, won't take the time to tweak parameters to make the nice kind of cuts you're going to want. I recommend using a shop that does knife work for that reason.

I do it all the time myself.

 

[TRfromMT]

I work for a manufacturing shop and we use a laser all the time, every day. We are near Golden, Colorado, and have made blanks for a well known knife company, including the trademark round hole, several years ago.

All of what kuraki says is true. We do not make knife blanks any more.

It just isn't the best process for it. We cannot process a small batch of blades. Buying a whole sheet of steel is kind of a special order. Small time makers buy small bars and we cannot process them on a laser designed to take a whole sheet.

The quality of the edge and how deep the hardened layer goes was never a concern.

 

[Leading Edge Fab]

We are putting a 5 Kw fiber laser on line this coming week. The laser manufacturer has already developed cutting conditions for the common PM steels and is on our control. The conditions were developed by the OM for a well know production knife manufacturer who is running the same set up. The testing we've done so far looks very promising. We intend to shift a lot of what we do with our waterjet onto the laser.

 

[dirc]

We are putting a 5 Kw fiber laser on line this coming week. The laser manufacturer has already developed cutting conditions for the common PM steels and is on our control. The conditions were developed by the OM for a well know production knife manufacturer who is running the same set up. The testing we've done so far looks very promising. We intend to shift a lot of what we do with our waterjet onto the laser.

Just curious, how much of a cost savings do you expect going from waterjet to this 5kw laser? Or, is it just a case of too much hassle with water + powder/sand/etc (or does it use aluminum oxide?)

 

[Leading Edge Fab]

Just curious, how much of a cost savings do you expect going from waterjet to this 5kw laser? Or, is it just a case of too much hassle with water + powder/sand/etc (or does it use aluminum oxide?)

Waterjet has higher operating costs and is definitely more hassle. Laser is higher capital expense and less operating cost. Prices will depend on the amount of set up and machine run time it takes to process an order, there are a lot of variables doing custom work.

 

[kuraki]

Waterjet has higher operating costs and is definitely more hassle. Laser is higher capital expense and less operating cost. Prices will depend on the amount of set up and machine run time it takes to process an order, there are a lot of variables doing custom work.

Are you doing anything special for workholding? I keep thinking about making a special flask for holding bar material or the like, but generally just end up tack welding smaller pieces to a piece of 1/2" plate so they don't float around on the slats.

 

[Leading Edge Fab]

Are you doing anything special for workholding? I keep thinking about making a special flask for holding bar material or the like, but generally just end up tack welding smaller pieces to a piece of 1/2" plate so they don't float around on the slats.

We have a couple pneumatic clamps on tee slot rails that was an option when I orders the machine. I ran our first job today and they work like a champ. I'll probably add a couple more sets so we can set up multipul sheets.