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Laser Cutting of Polycarbonate

05/18/2012 10:14 PM

Recently I went to a service provider who normally provide laser cutting service for acrylic, I requested for cutting Polycarbonate material. She adamantly refused, saying that laser cutting cannot be used for PC, it will only burn the material up, unlike laser cutting of acrylic .

Is it true? Is there other way to laser cutting PC? I need precision cut.

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#1

Re: Laser Cutting of Polycarbonate

05/18/2012 11:13 PM

Laser cutting polycarbonate tends to make a mess on the cut edge. You can also ruin the lens on the laser if you're not careful. That's probably why your provider won't do it. We use a water jet for cutting polycarbonate. Works well but the cut edge will not be clear and you should not expect accuracy tighter than .005in. Hope this helps.

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#2
In reply to #1

Re: Laser Cutting of Polycarbonate

05/18/2012 11:24 PM

Useful info, much appreciate it. Thx

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#12
In reply to #2

Re: Laser Cutting of Polycarbonate

05/21/2012 10:50 AM

ESAB makes water jet cutting system which is suitable for almost any material.

Details from the Esab are as below:

The most versatile process for shape cutting

  • Highest precision cutting on virtually any material
  • Can be combined with plasma or oxy-fuel on the same part
  • Most versatile cutting process

Water Jet cutting uses an ultra-high pressure stream of water to carry an abrasive grit. The abrasive does the cutting through a mechanical sawing action, leaving a smooth, precision cut surface.

Waterjet is the most versatile process, because it is able to cut almost any type of material. Limitations include materials that are highly brittle, such as tempered glass and some ceramics.

Water jet is a very precise cutting process. It has a narrow kerf width, allowing fine contours to be cut, and producing high tolerance parts. However, it is a very slow, expensive process when compared to plasma on most metals.

That is why ESAB offers the patented combination of waterjet and plasma on the same machine. This option allows you to take advantage of the accuracy of water jet where you need precision, and also benefit from the speed and low cost of plasma where high precision isn't necessary. The effect is to produce the parts you need for substantially lower cost, in substantially less time.

Waterjet Process Basics

The water jet cutting process starts with an intensifier pump, which creates the ultra-high pressure (over 50,000 psi) water pressure required for cutting hard materials.

The Intensifier pump uses a hydraulic pressure over water system. A large horsepower motor drives a hydraulic pump, creating hydraulic pressure which powers a piston in a cylinder. The hydraulic pressure is amplified by the ratio of the larger hydraulic cylinder pushing a smaller piston into a cylinder filled with water, thus creating the ultra-high water pressure.

The pressurized water is delivered to a cutting head by either high pressure tubing or hose. At the cutting head, the high pressure water is applied to an orifice with a typical diameter ranging from 0.005" to 0.020". This orifice is made in a diamond or sapphire, to resist abrasion of the high pressure water. The orifice defines and creates the water stream which cuts through the material.

After the water stream exits the orifice, an abrasive can be added to the water stream, to allow it to cut hard materials. When cutting hard materials, including steel, stainless steel, aluminum, stone, wood, plastic, glass, etc., it is the abrasive that does the actual cutting using a mechanical sawing type action.

The abrasive is usually crushed garnet, the same type of material often used as the abrasive on sand paper. Some special applications utilize other abrasive types.

When cutting soft materials, such as rubber, leather, cloth, paper, cardboard, insulation, foam, etc., the high pressure water stream does the cutting, and no abrasive is used.

ESAB manufactures CNC water jet cutting machines for large and small cutting applications, and can customize a machine to fit your exact needs.

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#13
In reply to #12

Re: Laser Cutting of Polycarbonate

05/21/2012 7:47 PM

Good info.

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#3

Re: Laser Cutting of Polycarbonate

05/18/2012 11:34 PM
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#4

Re: Laser Cutting of Polycarbonate

05/18/2012 11:50 PM

"Is there other way to laser cutting PC? I need precision cut."

Water Jet or CNC router/mill.

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#5

Re: Laser Cutting of Polycarbonate

05/19/2012 10:02 AM

Why did you not believe your "service provider"?????

What do you mean by precision cut?

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#6
In reply to #5

Re: Laser Cutting of Polycarbonate

05/20/2012 12:32 AM

I never entirely believe my "service providers" either. Unless they can explain the technical details of it, it is usually an excuse.

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#7
In reply to #6

Re: Laser Cutting of Polycarbonate

05/20/2012 12:10 PM

How many service providers do you know that will turn down work if they can do it. I think the service provider is far more competent than the OP.

The OP has no knowledge or experience that would qualify him to judge the competence of his supplier. He comes here for "technical" advice on many subjects that he should already know.

I could be an incompetent idiot for all anybody knows, so could the rest of us here.

If forced to choose between believing my supplier and this forum, I'd go with the supplier.

There are some very intelligent people here, to be sure. But there is no penalty for us if we give a wrong answer. The supplier will lose business if they are wrong.

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#8

Re: Laser Cutting of Polycarbonate

05/20/2012 12:12 PM

Terra man gave you the best answer, water jet cutting is the best bet!

Spencer.

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#9
In reply to #8

Re: Laser Cutting of Polycarbonate

05/20/2012 12:47 PM

We don't know what the OP is cutting. If it's flat, thin sheet then water jet will be OK.

Thicker materials will have a wedge effect as the jet expands as it gets further from the nozzle.

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#10
In reply to #9

Re: Laser Cutting of Polycarbonate

05/21/2012 12:47 AM

Now, I consider this info of yours useful (thanks !) and I would certainly not dismiss it as mere anectodal only.

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#11
In reply to #10

Re: Laser Cutting of Polycarbonate

05/21/2012 8:45 AM

Bravo88, the wedge effect or taper your "friend" Lyn is talking about is mostly caused by cutting speed. It's not only due to the thickness of the part. It can be very pronounced even in thin material if you cut too fast. It's always a compromise between precision and efficiency.

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#14
In reply to #11

Re: Laser Cutting of Polycarbonate

05/30/2012 3:24 AM

TerraMan,

I recently had to cut 3/4 Acrylic and it had to be .0001 water-tight fitting pieces for a camera housing... But we didn't want to glue it all up and then have to make another so we just wanted one that looked really slick. We used water jet and to get the edges dead-square, the CNC WJ guys used a "creeping up on it" method that I didn't understand until I watched. Like Lyn mentioned, the first pass had a lot of cone defect at the bottom. So they made the first and second passes "close" to the actual edge. Then, on the last pass, the only cutting that occured was very similar to using a profile following bit on a router. Only one edge of the jet did any cutting. It was more like "sanding" the edge. The pieces fit so tight they held air pressure overnight with very little pressure drop. We did a very tiny bit of acetone polish and it looked like polished glass. I've loved WJ ever since.

Yes, it took a lot more machine time, but it was a lot faster than any other process and we had been turned down for laser on polycarb many times before also.

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