[Groganeer]

Before I go to the trouble and expense of building a CNC.

I need to know if anyone has any experience with cutting corrugated plastic sign board, commonly reffered to as S-Core. I have tried a variety of bits and am having difficulty finding a speed/cutter combination that will allow for a smooth cut.

Thanks in advance

[ballendo]

Hello,

What're you using to cut it now?

I'd give a call to hartlauer bits...

Ballendo

P.S. This stuff melts easily, so slow down your spindle and raise your feedrate. You want a decent chip size to carry away the heat. Don't use a slow feed! What geometry bit are you using now?

Originally posted by Groganeer
Before I go to the trouble and expense of building a CNC.

I need to know if anyone has any experience with cutting corrugated plastic sign board, commonly reffered to as S-Core. I have tried a variety of bits and am having difficulty finding a speed/cutter combination that will allow for a smooth cut.

Thanks in advance

[Groganeer]

You will have to understand my greenhorn/neophyte status on this, but I have been trying the various things laying around my shop.

High speed rotary cutter with spiral cut (leaves a really dirty edge)


Router running same bit a slow as possible left me with the same result.

Do you have a particular bit/speed recommendation?

Yes it melts easily, but I have noticed that it also tends to chip and or delaminate so I was worried about using to aggressive of a cutter.

[buscht]

Groganeer,
Are you saying that you don't cut S- core now?

The reason I am asking is that many people think that there is something magical about going to a CNC. The proper way to think about it is that whatever feeds, speeds, and tools you use manually will be the starting point when converting to CNC.

If this is a totally new material for you then I would recommend that you contact the distributor or manufacturer of the S-core and get their recommendations.

[Groganeer]

Yes, right now I am cutting it with a razor knife, and it is very slow and tedious.

I understand there is nothing "magical" about a CNC.

I am wanting to take CAD drawings and directly cut them out of S-Core.

The few times I have used a router etc I have had piss poor results.

Like I said I just want to know if anyone has had any experience cutting S-Core, BEFORE I go to the trouble of building a CNC machine.

If no one does have any experience that's fine I will just experiment until I find something that works, I was just hoping to skip the experimentation part.

[ballendo]

Originally posted by buscht
If this is a totally new material for you then I would recommend that you contact the distributor or manufacturer of the S-core and get their recommendations.

Hello,

This is EXCELLENT advice. Of a type that doesn't seem to be followed much; for reasons I will never understand...

S-core is made by more than a few companies, and as with all materials, they're not all the same! The manufacuter's applications engineer is nearly ALWAYS a great source of information. Many are like the Maytag man, and if you show a TRUE interest in what he or she has to say, you can learn a LOT of things for the price of an oftentimes toll-free call... Here is a person whose ENTIRE JOB is to get "into" the materials his company sells/mfrs. And they are SUPPOSED to know more than you; so don't feel bad if yo think you have "dumb" questions...
To him--or her-- this is INTERESTING AND IMPORTANT STUFF!!

(My experiences have nearly always been good with MANUFACTURERS applications engineers.)

The distributor "may" also be a good resource, but I can't give the same glowing review based on my experience there. Some are very good; others are just "counter guys" putting in their hours... (Perhaps this is why there is a reluctance to call for information? Nowadays you can email or write, but I prefer the phone call. I seem to get "more" that way. With local distributors a visit is even better, as you can pretty quickly figure out who KNOWS what he or she is talking about. Sideways glances, corrections across the room, etc.)

So rather than use somebody else's numbers, why not given a call, and see what they have to say? As I wrote at the top, it's excellent advice, IMO.

Ballendo

[Groganeer]

"So rather than use somebody else's numbers, why not given a call, and see what they have to say? As I wrote at the top, it's excellent advice, IMO."


Yup I did that and was told that they usually see people using hydraulic presses with dies and shears. That's great if I want to make a huge run of one part that would work. On the other hand for single part runs it's not to bloody cost effective.

Did I call dozens of people and ask their opinions, no I don't have that kind of time. The problem I have found is that what I am wanting to do with this product is not the norm therefore getting someone to think out of the box has been difficult.

That's how I ended up here.

If there is no one here who is either willing or able to help fine. I'll just retreat back under the rock whence I came.

[buscht]

Groganeer,

I haven't cut this material myself, but your problem made me curious. I called Coroplast and asked them for recommendations. They laid off their applications engineer and the saleslady who I talked to didn't even understand my question.

I was quite disappointed with their help.

Give this forum a little bit of time, someone may come forward with some actual cutting information. I will look for this material myself and try and cut some now that I am interested.

What size parts to you want to cut? What is your volume and does it matter how long it takes to cut if the parts look right?

I am going to try and cut some on my scroll saw to see how that works. One of my projects is a CNC scroll saw and this might be perfect for my machine.

Max part size is about 20" diameter though.

I realize that the suggestions that you have got so far haven't directly answered your question, but sometimes you might get a better solution than your original idea when alot of minds come together.

"The problem I have found is that what I am wanting to do with this product is not the norm therefore getting someone to think out of the box has been difficult."

I totally agree with your point here and this is what this forum is all about.

I post again once I obtain some material and try cutting it.

T

[buscht]

Here's a link to a router bit that is supposed to have the correct geometry for cutting plastic.

http://www.bamtool.com/page7.html

[Groganeer]

"...will look for this material myself and try and cut some now that I am interested."

I've found it in smaller pieces at a couple of walmart type stores in the craft section if you just want to play.



"What size parts to you want to cut? What is your volume and does it matter how long it takes to cut if the parts look right? "

Well I have three ideas that I am wanting to pursue with this material. One is 8x24 or so and they get smaller from there. Volume doesn't matter so long as it's faster than how I am doing it now, and if it's running on a CNC I can be free to do other things. More importantly though it's got to be a clean consistent cut.



"I am going to try and cut some on my scroll saw to see how that works. One of my projects is a CNC scroll saw and this might be perfect for my machine."

Scroll may work, I've tried using a coping saw and it worked ok. CNC Scroll has me thinking though. The biggest problem with this material is the tendency for the internal corrugations to cause whatever you are cutting with to deviate from your intended line.

[whiteriver]

Whats S-core? I was at the sign supply place in Spokane today and they never heard of S-core. I was gonna pick some up and see how it cut.
You said 8x24 size. Are they straight side squares or curves. How much detail.


Donny

[buscht]

Here is another discussion about the same topic.

http://www.talkshopbot.com/messages/29/1344.html

[Groganeer]

Originally posted by whiteriver
Whats S-core? I was at the sign supply place in Spokane today and they never heard of S-core. I was gonna pick some up and see how it cut.
You said 8x24 size. Are they straight side squares or curves. How much detail.


Donny

Picture a plastic version of cardboard. That's what S-Core is.

Not too much in detail, but the long sides are not perpendicular, and the ends are round. That's where the corrugations cause problems. If all you wanted to do was cut out squares or rectangles it would be pretty simple, but anything with an angle, or curve is a real bear.

If your close to Spokane, I can tell you that Fred Meyer in Coeur d'Alene stocks it in the craft section.

[whiteriver]

Northwest sign supply in Spokane has something like it around 1/8 thick for I think around $30 a sheet 4'x8' I know they got blue maybe white.Might have it in 1/4" also.
Maybe I'll stop in at fred myers. I have to go to CDA today. Curious.

Donny

[buscht]

I called a local sign shop. They said that I could have some scrap pieces about 12" square to try and cut. (Free).

I hope to pick them up today or tomorrow.
T

[Groganeer]

Originally posted by whiteriver
Northwest sign supply in Spokane has something like it around 1/8 thick for I think around $30 a sheet 4'x8' I know they got blue maybe white.Might have it in 1/4" also.
Maybe I'll stop in at fred myers. I have to go to CDA today. Curious.

Donny

Ouch! If I remember right I got a 24x36 piece at Fred Meyer for less than 10 bucks. I have seen it much much cheaper than that if you are willing to buy a bunch of it.

[buscht]

I picked up some material at the sign shop last night. It's white and about .164" thick. The piece is 12" x 22". They said that they have alot of scrap this size.

As a side note, this might be a cheap way to get material and recycle some otherwise thrown away scrap.

Anyway, here is my first attempt at cutting this with my scroll saw.

Keep in mind that I have a nice machine. It's not one of those $50 things the vibrate all over your work bench.

I used a coarse tooth blade, about 10 TPI and the results were terrible.

[buscht]

I quickly understood the problems of this corrugated material. You have many unsupported edges and the material vibrates.

Next I tried a very fine tooth blade, 31 TPI, .008" thick, .015 wide. This blade is normally used for cutting puzzles.

The stuff cuts like butter, you can move through it faster than you can control it.

Results were alot better. Only a small amount of plastic clinging to the cut edge.

[buscht]

I cleaned up a cutout part with sandpaper. I just had to run it over the edge lightly and it cleaned up quickly.

[buscht]

During this time, I noticed something interesting. When trying to cut an inside 90 degree corner, the material actually cut with the back side of the blade. (Similar to a knife.)

So I cut an entire part out using the back side of the blade. It came out pretty good. I think if I could have sharpened the back of the blade like a knife and with the up and down action of the scroll saw, the material would cut well.

I also cut the material on a paper shear and it cut very well.

So my recommendations based upon a grand total of 1/2 hour of messing around.

1. You can use a scroll saw with fair success. I don't know if this application can be CNC'd with a scroll saw as you need a spiral type bit and I don't know if such a bit is available with a fine enough tooth to cut well.

2. Other options for cutting this material. a hot wire, similar to used on foam cutters. Maybe someone with one of these machines could test this out.

I think a water jet or laser would cut this material, but you would be into a commercial application, not a DIY job.

A CNC punch press would cut this well. I have never seen a DIY machine, but I know that it could be done. You could have a XY motion, along with some small die cut sections (shaped in various radii and straights.) You would move the product under the appropriate tool, then signal the punch to activate and the proper cut would be made in the material.

This is very much outside the box thinking when compared to a CNC router, but I am 99% sure it would work. It might be too time and cost prohibitive to develop however. Especially when you mentioned that you didn't have much time available for experimentation.

Good luck.
T