Cutting Vulcanized Rubber

[andyb]

Has anyone tried to cut vulcanized rubber on their machine? I have a customer that is asking me to cut some 4'x8'x3/4" sheets. They tried to cut it with a panel saw and it was burning it. The smell lingers and is not a pleasant smell.

Andy B.

[Brady Watson]

You'll want to avoid using any type of rotary cutter. You want to use some type of drag knife. I don't know off the top of my head what max cut depth is on the ones currently available, but that would be the way to go. If none of them cut a full 3/4, it may be possible to scribe as deep as you can with the knife, then finish out the cuts by hand - not ideal, but it may be the only choice unless you want to make your own knife that can go deep enough. Keep in mind, the higher the durometer, the tougher it is going to be to get through.

Maybe one of the knife guys can chime in and offer their perspective.

-B

[jerry_stanek]

I cut some horse mats on mine. I used an up cut bit and took multiple cuts.

[steve_g]

I used to pocket Hockey pucks to hold circuitry for a military application... That density of rubber machines very nice.

SG

[dana_swift]

I have not tried rubber, but something that is worth a try, put it in the deep freeze so it gets really hard. Then put it on the table and try cutting it then. Dont give it time to thaw out tho! The up spiral bit sound like the way to go, but my experience is ZERO. Just how I would try doing it..

I will be curious to know if this method works..

D

[andyb]

Thanks for the info.

Brady, the customer is cutting it with a razor knife right now. He is trying to get away from that.

Jerry, this material is used in barns also but that is not the use from this application. I may try it.

Dana, that would be interesting but the material is in 48"x96" sheets. I would need an industrial freezer. ;)

Andy B.

[cnc_works]

I did try to cut some rubber for gasketing purposes. Tried sandwiching it between two pieces of ply, tried gluing it to ply, and, yes, I did try freezing it. I was not successful with any of these methods using a rotary bit. Ended up cutting templates and slicing it, which worked, but wasn't efficient enough.

[gerryv]

Or, you could take Dana's advise and just move to Michigan or Ontario this week and set it outside overnight!

[andyb]

Gerald,
Let me thanks about that.... NO. It's 49 degrees here in NE Georgia right now. That is cold enough for me thanks you. :) Spent a winter in Chicago in 1979 on the Great Lakes Navy base. That was enough northern winter for me.

Andy B.

[Steve M]

Water jet.

[donek]

Thanks for the info.

Brady, the customer is cutting it with a razor knife right now. He is trying to get away from that.

Jerry, this material is used in barns also but that is not the use from this application. I may try it.

Dana, that would be interesting but the material is in 48"x96" sheets. I would need an industrial freezer. ;)

Andy B.

Sounds like an application for our drag knife. There is not enough depth with a standard blade, but someone with a dremel tool could easily make it happen by cutting a custom blade. We have been experimenting a bit with non standard blade shapes in the D2 in order to alter the cut characteristics. Utility knife blades are quite easy to cut with a dremel and cut off wheel. If you have a sample of the material, I'd be happy to do some test cutting if you need a proof of concept. My only real concern lies in the depth and the force required to pull a blade through 3/4in thick material.

[rb99]

What about putting it on 1"-2" foam and using one of those jigsaw type cutters?

Something like this: http://www.youtube.com/watch?v=NVQW-xYwIVk

What shapes are you cutting? The Donek drag knife would be great if it worked: http://www.youtube.com/watch?v=P8jbtRTV6uw

Or this one: http://www.youtube.com/watch?v=gXWa1UCKtMk

[Brady Watson]

Unfortunately 'vulcanized rubber' gives next to no valuable information. What durometer is it? If it is Shore A90 or higher - you can cut it with the router. If it is lower than that, you need another means, like a drag knife. 18,000-24,000 RPM just isn't high enough to overcome the bit grabbing the material and yanking out chunks. If you had a 400,000 RPM spindle with enough torque to swing a 1/4" bit, then it would be no problem...A dentil drill doesn't have enough cookies.

-B

[John David]

I agree water jet is fast and clean

[Brady Watson]

I agree water jet is fast and clean

Ya...but I think the OP was looking to make the $$$ himself with his Bot, not farm it out to a WJ shop.

-B

[shilala]

The guys at work cut it on our shear in the tinshop. On the job, they'd roll it up and cut it with a bandsaw. This was papermill belt material, lots of nylon fiber sandwiched between two surfaces of rubber. Relatively soft stuff, maybe like a four wheeler tire.
I'm coming up with nothing so far as the bot goes, but I'd probably try coming at it with a side-cutting bit rather than ramping down into it. Leave a skin and finish up with a razor knife.
No idea why I think that'd work, it's just something I'd try.

[myxpykalix]

In your description you say they cut it with a panel saw. That says to me that they were making just straight cuts. Why not take it to a metal shop that has a metal press (The thing that looks like a guillotine) and have them cut it with that? If it can cut a piece of steel, i'd imagine rubber would be a no brainer for them:confused:

[shilala]

In your description you say they cut it with a panel saw. That says to me that they were making just straight cuts. Why not take it to a metal shop that has a metal press (The thing that looks like a guillotine) and have them cut it with that? If it can cut a piece of steel, i'd imagine rubber would be a no brainer for them:confused:
That's a Shear, brother. There's all different kinds. Some just cut thin stuff, some can cut plate steel and expanded metal like it's butter. The thickest stock I ever saw cut was 1/2" plate. That machine was supposed to cut up to 1" material. I'd like to watch that!!! :)

[steve_g]

High dollar plate shears have adjustments for blade clearance ... Every material and thickness has a clearance setting that's ideal for it. Any steel fabricator I worked for wouldn't shear a mystery material that they didn't know the correct setting for... I vote for the water jet!

SG

[kubotaman]

If the material I am thinking of , used for horse stalls, it as a cord that is running thru it. My opinion only would be that a Bot could not successfully cut it without some problems making it non productive. Seems to me the heat made by cutting with a rotary bit would really give you some problems! Just my opinion.

[pyrodenis]

I have bought strips of rubber, that are cut from a sheet. They used a tool with a spinning disc that had well polished sides and a knife edge. Think of a spinning pizza cutter.
Brady's drag knife approach makes sense. Spraying with a lubricant would help.
Freezing it would allow a rotary cutter to work. And, thinking of someone other than myself running from large freezer to bot with a large, brittle sheet of rubber; well, that would make me feel better about some of my antics over the years.
But, if you're tempted to freeze, here's my 2 cents worth: get a metal channel to lay over the cut. fill it with dry ice, move it over to next location, while cutting the first.

[jerry_stanek]

I have bought strips of rubber, that are cut from a sheet. They used a tool with a spinning disc that had well polished sides and a knife edge. Think of a spinning pizza cutter.
Brady's drag knife approach makes sense. Spraying with a lubricant would help.
Freezing it would allow a rotary cutter to work. And, thinking of someone other than myself running from large freezer to bot with a large, brittle sheet of rubber; well, that would make me feel better about some of my antics over the years.
But, if you're tempted to freeze, here's my 2 cents worth: get a metal channel to lay over the cut. fill it with dry ice, move it over to next location, while cutting the first.


What you are describing is a carpet cutter

[Brady Watson]

Speaking of rotary knife cutters...If you add a stepper (same channel as Indexer for instance) you can cobble together a rotary cutter using the utility in ShopBot Labs (http://www.shopbottools.com/LabFiles/RotaryCutter.htm) - From what I've heard, it works really well.

-B

[gerryv]

Don't know if it will help but I did my garage floor with stable mats and used a <$100 Porter Cable orbital jigsaw to cut them. The orbital feature made a very big difference. Then again, I was only doing under a dozen mats.

[knight_toolworks]

I made a drag knife that could do 1/2" cardboard. but anything more it took two passes. rubber would be more work. but get rubber wet and it cuts far easier.

[andyb]

Thanks for all the info guys. I'll look into the drag knife but I have a feeling a jigsaw or something that the customer can do himself is going to be the answer.

Andy B.

[shilala]

Would a laser work?
I've never had any exposure to laser machining at all, and have no clue what they do and don't do, or even how they do it. I'd think "burn and smoke", but I'd think that of everything they do, so I just wanted to throw it out there and see what you guys say.

[donek]

As I understand it lasers can be sensitive to certain types of smoke, so it may be an issue.

Rubber properties do change a bit with temp, but as we all know our tires don't get hard and crack, even at 30 below. It's doubtful that even those temps would make the material machinable.

I'm not an expert in rubber, but any rubber operations I have seen done, have been done with a knife blade or ruled die. Even drilling is done with a special hollow drill that is sharpened like a knife.

[twelchPTM]

When I need to cut rubber I use a scalloped band saw blade or a v-tooth for the harder stuff. If your cutting a lot the smell is almost inevitable. I roll my band saw out to my paint booth and kick on the fans.