Show Notes for Manufacturing Podcast

Podcast Topic:  Manufacturing Questions Answered
Date:  Thursday, June 10, 2010
Guest:  Brent Erickson

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Brent, the first question is; what are the advantages of waterjet versus laser cutting?

One advantage of waterjet cutting over laser cutting is there's no heat affected zones. A lot of times, this can make parts hard to work with, with secondary operations.

What are the advantages of the laser over waterjet cutting?

Lasers cut a lot faster, typically. Usually they're more economical and they hold a tighter tolerance. At the same time, with waterjet you can cut basically any material. With the laser you can be limited to stainless steels, carbon steels and aluminum.

And thin ones at that?

Not necessarily thin, we can do some plate, up to 3/16" thick for aluminum, 1/2" thick for stainless steel, and about 1" thick for carbon steel.

That answers the next question of how thick can laser cut?

Yeah, that's about the limits that we have.

So what's the best tool to cut teflon?

Teflon is typically used for either washers or small gaskets, or wearplates. Something like that is usually a water-only application, we run that on the waterjet with no abrasive mixed in. It's a real fine stream of water, about .006" in diameter, it's a real precise cut.

And why is that a benefit to cut this material without abrasive?

It just gives you a cleaner cut and allows us to hold better tolerances.

Is it possible to bend armor plate?

Yes, we do form armor plate. We do it on our largest press brake, it's a 352 ton brake with a 12 foot bed.

And that will get the job done.

Yeah.

How thick can a waterjet cut?

Usually about 12" is as thick as you want to go with the waterjet.

So, a lot thicker than laser.

Yeah, a lot thicker.

What's the best cutting method to cut bronze?

Here, we would do it on either on the waterjet or one of the milling centers, depending on what the part looks like.

How about perforated sheet metal? How would you form that?

Again, that would go on one of the press brakes. We do have three brakes here, so we do have some options with which equipment we would use.

Now one of the other questions that was brought up, is which is less expensive (because people are always looking for the cost-effective option.) Is it going to be waterjet cutting or laser cutting?

Typically it's going to be laser cutting. Again, the system is just more automated than the waterjet and the cutting speeds are a lot faster. Then again, you are limited to which materials you can use.

Does the abrasive have anything to do with it, is that a larger cost for the waterjet versus the laser, since laser doesn't use abrasive?

That is a big part of the cost of waterjet, there's a lot of consumables in the process that dictates the cost of it.

Another question we had was, if waterjet will warp a steel plate when it cuts.

Yes and no. The waterjet itself is not going to, due to any heat it adds. But at the same time, when you cut materials (especially steel) just the cutting process kinda relieves some of that natural stress within the plate. Sometimes that will have a tendency to warp, you're not going to see it as bad as you would on a flame cut part or a plasma cut part, but it can still warp.

Is it common to warp?

It depends on the type or the thickness of the plate and the type of the material. Typically A36, Grade 50, anything like that; that's under 3 or 4" - it's pretty good. Once you start getting to the thicker materials, or some of the higher tensile strengths is when you're going to start seeing some warpage.

When people say "Rockwell" or refer to a "Rockwell" what are they referring to?

Rockwell refers to a scale commonly used to note the hardness of a given material.

What is the difference between laser and waterjet cutting tolerances?

Laser can hold a tighter tolerance, typically on thinner materials; anything 1/8" or thinner we can hold +/- .003", once you start getting up to 3/8" or 1/2", we want to have a little more, maybe +/-.001".

On the waterjet, we can typically do +/- .005". If it's a real small feature, we can tighten that up some, but it's going to be on a case by case basis. Generally the tolerances on the laser are a little bit tighter and a little easier to  control.

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