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Helen Cast
11-10-2008, 2:02 PM
What kind of laser would you need to cut this stainless pendant? I know my 30 watt Co2 won't do it. Is this done with a Yag setup or a high wattage unit (Kern...)?

For short runs, it would seem farming out the job is the way to go. For mega production can anyone ballpark a price for an appropriate laser.

The stainless is app 3/32" thick.

Thanks for any info!

Helen

Neal Schlee
11-10-2008, 2:53 PM
Contact Kern Lasers they have a metal cutting setup. Also might be able to get you in contact with one of their customers that does job shop work.

Neal

Dave Johnson29
11-10-2008, 5:05 PM
What kind of laser would you need to cut this stainless pendant?



Hi Helen,

A 3000+ Watt CO2 or Nd-Yag, but you would be talking big bucks, 6 figures.

Unless you are talking of say half a million of the critters, then farm them out.

Word of warning from personal experience. Stainless does not cut clean unless there is an abundance of power and good gas assist, preferably Nitrogen.

Several years back I got a 1000 parts cut from 1/16" stianless by a company in Phoneix and they were terrible as it was approaching the limit of the laser. I then dealt with a company in Bakersfield, MetalTek I think it was and they tumble deburred everything before shipping.

If you farm them out, get say 10 or so samples of the parts cut before OK-ing the run. Make sure what you eventually get is what they sent as samples.

Kenneth Hertzog
11-10-2008, 5:13 PM
Helen
If I were to do those items I would use a small cnc milling machine.
I've cut stainless its a little slower but the cut is clean.

ken

Gary Hair
11-10-2008, 5:56 PM
I have a local shop that uses a 2,000 watt laser with nitrogen and they have done stainless up to 1/8" thick. There a always a few with a little glitch where they punch through but most of them are virtually perfect.

Gary

Jack Harper
11-10-2008, 6:21 PM
Look for a local waterjet shop. They can do them easily and stack the sheets for faster/cheaper cutting up 4"-6" thick at a time if needed.

Bruce Volden
11-10-2008, 6:39 PM
Look for a local waterjet shop. They can do them easily and stack the sheets for faster/cheaper cutting up 4"-6" thick at a time if needed.


Hands down - Water Jet - much better and faster than laser. Plus it's a one stop process (no de-burring, tumbling...)

Hey, I just hit 500 messages!! Yipppeee!!!

Bruce

Frank Corker
11-10-2008, 6:51 PM
Yep, Bruce is right, the toy that I want, by far the most impressive piece of kit that can be bought. Best finish is going to be with the waterjet. IMHO (which I am entitled to have). I am hoping that if he should ever decide croak he is going to will it to me.

Dave Johnson29
11-10-2008, 9:20 PM
I have a local shop that uses a 2,000 watt laser with nitrogen and they have done stainless up to 1/8" thick. There a always a few with a little glitch where they punch through but most of them are virtually perfect.


Gary, I suspect the 2000W is exactly what I am talking about. I will never get stainless laser cut again unless I am sure the power is way mor4 than suggested.

When I am paying 5 bucks a piece I do not want "virtually perfect." :):) I want all perfect.

The guys are correct that a water jet is better but they were charging almost 3-times more per piece than laser.

I did get some EDM and they were good finish and a reasonable price just slower delivery.

Dave Johnson29
11-10-2008, 9:24 PM
If I were to do those items I would use a small cnc milling machine.
I've cut stainless its a little slower but the cut is clean.


Hi Kenneth,

A CNC would be very slow as you would need to use tiny cutters to get into some of those sharp corners. I actually have a bunch of CNC metalworking machines that I take jobbing work for, but I would not be lining up to do those parts.

Ignoring the sharp corners for a moment, the single biggest problem with CNC machining is holding the parts and they would be a bear to do.

Jack Harper
11-10-2008, 10:35 PM
Yep, Bruce is right, the toy that I want, by far the most impressive piece of kit that can be bought. Best finish is going to be with the waterjet. IMHO (which I am entitled to have). I am hoping that if he should ever decide croak he is going to will it to me.

Who's croaking?

Stephen Beckham
11-10-2008, 10:53 PM
Are you sure those aren't die-punched? Something that thin could be punched by the thousands with a punching machine. Some machine shops might be able to do it for you quickly with the right equipment. I'm sure they'll charge you the die fee - quite hefty last time I checked.

Helen Cast
11-10-2008, 11:28 PM
The cutout is quite smooth, no burr or file marks so I did not think die cutting was used.

Water jet appears to be a viable solution. Can anybody share info regarding cost comparison between WJ and laser cutting. I am certain that farming the job(s) out is the way to go since the investment in WJ equipment is not presently in the budget.

Any details about WJ cutting that you may have learned the hard way is much appreciated. I'm still busy soaking up all the great laser info on the CREEK and would rather not start from scratch with WJ concepts.

Many thanks to you all on this incredible forum!

Helen

Scott Challoner
11-11-2008, 12:06 AM
Could those be done with a CNC plasma cutter? Like a Torchmate or PlasmaCam? Those systems seem pretty reasonable.

Derek Kern
11-11-2008, 9:59 AM
Helen-

Just a word of advice when looking for this system. Not only should you be concerned about the cost of the equipment itself, but the cost to run it(electricity, other consumables), maintenance costs, setup costs, etc.

Depending on how many pieces of stainless you need cut in a year will probably determine if you job it out or purchase a piece of machinery to cut them yourselves.

If you are strictly cutting stainless of that thickness and you are not engraving, etching, or cutting other materials then a waterjet or plasma cutter may be the way to go. A plasma might not give you the detail that you wanted in the photo I seen. But I am not certain so I would check it out.

Good Luck!

Jack Harper
11-11-2008, 12:14 PM
Helen,

If you can post a vector drawing to scale for the piece, I will run it through my waterjet software and let you know the time it would take to cut. From there you can shop it to your local waterjet shops and see who can do the best deal. I must caution one thing though, not all waterjets are made equally. You can still get a bad out of spec cut from a waterjet operator. You will want to specify your tolerance requirements. I run +/- .002 but you will probably want to spec +/- .010 to get cheaper/more bids. You can find some shops listed by state on waterjets dot org.

Kevin Groenke
11-11-2008, 8:01 PM
Hi Helen,

We have had a number of small and mid-sized laser cutting and fabrication projects done by Twin City Metalfab. They've been great to work with and have turned parts around very quickly at what seems to me very reasonable cost.

The have 4-6 4000 watt MAZAK lasers and a couple shops full of punch presses, die presses, etc...

Twin City Metalfab
1319 Pierce Butler Rte
Saint Paul, MN , 55104-1453
Phone: 651-646-9401
FAX: 651-646-0940


We've also used Ameristar which I see also has waterjet in house.
http://www.ameristarlaser.com/

Kevin Groenke
University of Minnesota
College of Design

Bill Cunningham
11-11-2008, 9:45 PM
My local water jet guy charges $150.00 per hour.. I would imagine you could cut quite few of those in a hour..

Helen Cast
11-12-2008, 12:40 AM
Jack,
Would you be gracious enough to run this quickie sample through your WJ software? A tolerance of +/- .010 is fine and the stainless is .09375 thick. How much deformation might there be on a piece this size? What size sheet will your OMAX handle?


Thanks for the offer!

Helen

Frank Corker
11-12-2008, 8:01 AM
Hey Jack, I've just looked at the specs for your Omax 80160 waterjet, my goodness that is a collosal machine!

Jack Harper
11-12-2008, 1:03 PM
Jack,
Would you be gracious enough to run this quickie sample through your WJ software? A tolerance of +/- .010 is fine and the stainless is .09375 thick. How much deformation might there be on a piece this size? What size sheet will your OMAX handle?


Thanks for the offer!

Helen

Helen,

The part on a machine like mine running at 55KSI and a Tilt-A-Jet-Head would take 1.722 minutes per part of 18.3748 cutting inches, without stacking the material. If you were to do high volumes of the part and stacked the material to maximize the efficiency, you could stack 4 sheets and bring your cutting time down to 1.5297 minutes per part.

As for deformation, there should not be any as the waterjet process does not heat or bend the part.

Things to consider when designing something to be cut on the waterjet are kerf and edge quality. On most waterjets you have a kerf of .030 (I can go down to .020 with a mini-jet nozzle), this means that the tightest inside radius will be equal to the kerf size. Naturally, the out side radius can be as sharp as needed. As for edge quality, the speed effects the smoothness of the edge along with the mesh of the garnet used in the stream. 80 mesh is standard, but you can go down to about 150 if you want to get a smoother edge. To better understand this, think sandpaper. All of theses variables adjust time and therefor cost. You will want to get all these details nailed down with the company you select.

I hope I have helped more than confuse.

Jack Harper
11-12-2008, 1:09 PM
Hey Jack, I've just looked at the specs for your Omax 80160 waterjet, my goodness that is a collosal machine!

Yep, she's a big one. In fact that model is the largest production waterjet manufactured. You can get bigger if you do a custom order for big bucks.

I took the same approach with my waterjet as I did with my laser, I wanted to stay in the large format and or high volume side of the businesses to avoid competition with the broader market. In fact when someone comes in and asks for a single picture to be engraved on a small piece, I just refer them to there local laser company or yellow pages.

Frank Corker
11-12-2008, 1:20 PM
Yep, she's a big one. In fact that model is the largest production waterjet manufactured. You can get bigger if you do a custom order for big bucks.

Okay, might have to re think my shipping estimates to get it here. You mentioned big bucks for a custom order, I suspect it's big bucks regardles. Still very jealous (did I actually type that in?). Seeing as you are the man 'in the know', what is the smallest machine and would you know the maker? (Thinking on my feet here Jack... lotto night tonight you know)

Jack Harper
11-12-2008, 3:12 PM
The smallest one I know of is from the same manufacturer, Omax, They have one that has a cutting area of just 24"x24". Unfortunately, the cost is still quite high. The problem is, no matter what size bed you buy, you still need the pump, control system, cutting head and software. This is the biggest part of the expense. It is sort of like buying a 200W laser, the bed size does not change the cost to much as the laser is the main expense. If you are serious, I would recommend trying to find a used one locally. A small new one will still set you back over $100K. Of course, if you think about it, how cheap can any machine be that uses diamonds as a disposable wear part?

Helen Cast
11-12-2008, 4:32 PM
Jack,

Excellent information! It works out to a conservative $4 per piece (@ Bill's WJ pricing) plus material and shipping costs.

I suppose an entry level WJ is still not cost effective for me if 4-5 bucks gets me finished parts. Still, the technology is remarkable and if you can suggest a LOW end, small run unit to take a look at, I would check it out.

Many thanks for running the file and sharing the information. Quite a timesaver.

Regards,
Helen

Frank Corker
11-12-2008, 6:17 PM
If you are serious, I would recommend .....


I'd really really love one but I'm sorry Jack, I'm still a dreamer, I had a dream...... (now I'm sure I've heard that somewhere else).

Richard Rumancik
11-12-2008, 9:56 PM
Helen, I'll throw out another option. Photo etching. I thought of this originally but felt it might be too expensive for your budget requirements. But if you are willing to pay a couple dollars or more per part it may be viable.

Normally, you would not photo etch .094" stainless as it is often considered a bit too thick for the process. But if you were okay with say 2mm (.078") I know some fabricators will process stainless that thick.

What you need is vector artwork. The only tooling they need to make is a film.

One advantage is that in some designs you could add some "relief" ie. decoration to the surface. For example, look at these bookmarks:

http://www.decorativeetching.com/bookmarks.php

I don't know if this particular company does 2mm stainless, but if you were interested you could find a few companies, ask a few questions, and see if anyone is interested in tackling this for you and determine the cost.