[Momentz]

HI
i am in the picture framing business and i am wanting to build a mat cutter, i have already bought than plans for a joes 4x4 hybrid and in the process of building that, but i have been thing surely its not that hard to put a Tangential Knife on the z axis so it does 90deg cuts and 45deg cuts aswell, has anyone built one or does anyone know where you can buy just the cutter? i did a google search but with not much luck
thanks

[Momentz]

wow put of 161,616 members no one can answer my questions or there just not interested, i have only posted 6 threads and only one has a reply, i guess this forum isnt that great

[otto_pjm]

Perhaps the other 80 people who've looked at your post don't know what a tangential knife is either, I checked out your thread because I've never heard of it. Would it be like a drag cutter? If so maybe check the threads on vinyl sign cutting and the like. I wouldn't be so quick to blame the forums.

Good luck with the Joe's it's a great design, are you going to go with the R&P or Leadscrews? I'll look for your build on Joe's as well, try your question there as well if you haven't it tends to be very active.

Pete

[Momentz]

hi
i will be doing the R&P version it looks easier and people seem to upgrading to it, i havnt read anypost about people upgrading to the leadscrew

[gfc62]

I'm curious about adding a tangential knife to my Joes hybrid but haven't done anything about it.

Have you looked at this video?
[nomedia="http://www.youtube.com/watch?v=quagNm5HHOY"]YouTube- Tangential Knife[/nomedia]

Or read:
http://www.machsupport.com/forum/ind...?topic=13082.0

Looks like they used a stepper motor where the router would be on the Z axis. A knife holder on the stepper shaft rotates to stay on the cut line.

Hope this is of some small help. What's your user name on Joe's forum?

Gordon

[Momentz]

hi
my user name is the same here aswell "momentz". i have seen that video, whe i get my joes 4x4 complete i will buy an extra stepper motor and start trialing but that is a long time away. if you could come up with the design beofre i do that would be great and then you could tell me how to do it

[lovebugjunkie]

http://www.rockcliffmachine.com/prod...products_id=89

[gfc62]

http://www.rockcliffmachine.com/prod...products_id=89

That's a drag knife, not the tangential knife he's asking about.

[gfc62]

Maybe we can just get lovebugjunkie to do it for both of us ;^)

[fatal-exception]

It seems that there are a few companies out there that sell tangential cutting heads. AXYZ is one, there are others on google.

I see there's an easy way to get Mach3 to do the tangential control, just a single button on the settings screen and adding another motor to the ports and pins setup page.

I think I will take on the challenge of designing a cutting head. I'm thinking NEMA23 stepper motor coupled to the knife shaft with pulleys and a belt. A simple way to mount the knife, possibly some sort of collet system to allow different knives to be used?

Would it be beneficial to have the knife reciprocate up and down? I see that there are oscillating cutters and tangential cutters, but is there such a thing as an oscillating/tangential cutter?

Thanks,
Paul

[gfc62]

Have you seen this video as well?

http://www.youtube.com/v/anspATAZZQA

That looks like a simple design for a knifeholder. Just some aluminum bar stock and a clamping plate for the blade. I could cob that together on the mini mill and lathe.

I don't have any experience using a CNC cutter to cut mats, do you think the cut needs to be done in one pass or can it be done with multiple passes as you would with a router?

At what point does an oscillating knife become necessary? Is that only for cutting thicker or denser materials?

[gfc62]

It seems that there are a few companies out there that sell tangential cutting heads. AXYZ is one, there are others on google.

I'm guessing these are out of my budget, have you priced any?

I see there's an easy way to get Mach3 to do the tangential control, just a single button on the settings screen and adding another motor to the ports and pins setup page.

I think I will take on the challenge of designing a cutting head. I'm thinking NEMA23 stepper motor coupled to the knife shaft with pulleys and a belt.

Do you think the pulleys are needed for gear reduction? Or is that for some other purpose? I'd think a stepper motor of the size you're thinking would have enough torque as is.

A simple way to mount the knife, possibly some sort of collet system to allow different knives to be used?

Are we talking about xacto type blades here? Or something different?

Would it be beneficial to have the knife reciprocate up and down? I see that there are oscillating cutters and tangential cutters, but is there such a thing as an oscillating/tangential cutter?

I'm pretty sure all oscillating cutters are tangential.

Would you try to oscillate the entire motor/knifeholder assembly? Or just the knife?

Thanks,
Paul

[fatal-exception]

Yes, that one looks pretty simple.

I'm not sure if using more than one z pass is common. You certainly wouldn't want the material moving between the passes, which I think could happen pretty easily.

I'm not sure how cutting with the blade on a 45deg would work. Wouldn't Mach3 have to drive the blade in on a 45deg angle? I suppose if you used a ramp angle with a lead in it would probably be OK.

I think the oscillating knife is used on drag type cutters to go through thicker materials. Anyways, it wouldn't be hard to design oscillation into the tangential head, just not sure if it's needed or not.

[fatal-exception]

I havent priced any, but I agree, they look expensive. Plus, what type of control are they? Can they just plug into a BOB? Doubt it...

I would put in gear reduction for more torque and finer resolution. Just my preference. I'm sure that you could just modify a stepper motor shaft to hold a knife if you wanted to keep it that simple.

The commercial blades have a round shank, they look pretty heavy duty. For what I want to cut, xacto blades would be good enough...probably.

I would oscillate just the knife shaft with a little DC motor on a cam.

[Momentz]

here is a link to a computerized mat cutter and shows close up of the end

http://www.wizardint.com/product_details.cfm?pid=9

it just looks like they have a stepper motor inside the black case with a neat little case that you slot blades into, and the blades go in at a 45deg angle,

so maybe a stepper motor with a collet on the end that you can put a blade holder onto, one that is machined to hold a striaght up and down blade(90deg) and another holder that you could put a blade in on a 45deg so it cuts mat boards using exato blades,

i have access to computerized mat cutting software, which i can source for free if any of you guys want to play around with it, i wonder if you could use that to control the machine as it would generate all the gcode for all the lead ins/outs and they use dxf files from memory.

picture framing matboards are only 2mm thick. but some framers put a 2mm matt board on top of a 5mm foam board and will cut both at the same time, the.

this is all very exciting having a few peoples input now, and maybe we can get something designed that nobody else has DIY'ed yet

[Momentz]

as an add on to my previous post a few hours ago, i recieved a call from AXYZ after sending them an email, they sell the cutters by themselves without the controller boxes, so just the cutter is $16,000aus YIKES!!! i could build 8 joes 4x4 hybrids for that much, so that is outta the question. but i asked him if it was just a case with a stepper motor inside and the blade mounts to that and he said "basicly" but just kept saying its all about the controller box that controls the cutter...he called it a w axis? i thought it it was an A axis, i thought it started at X then Y,Z and back to A etc etc

[Benonymous]

$16K huh, so there's still some money to be made in the CNC machinery game!

The problem is that the average owner/operator of CNC machinery really only knows what the supplier has told them or put in the manual. The fact that the cutting head is nothing more than a clamp and a stepper motor isn't important as the owners of these machines probably wouldn't dream of tackling a build on a part like this. I wonder how much the "control box" is??
Sounds like the problem can be handled on the forum though, especially if someone is prepared to prototype it.

[Momentz]

hes ringing me back on monday so i will ask him then how much the controller box is.

[P.Passuello]

For what it's worth, I do know there is a special mat cutting router bit made for cutting mats. That would be the easiest solution for cutting mats as nothing special would be needed other than the bit.
The problem is I can't remember who it was that sold them and you had to buy 10 at a time. If I remember I will let you know or someone here may know.

Cheers
Peter

[fatal-exception]

16k? That's ludicrous. They obviously don't price if for what it's worth, rather for what the returns over a period of time should be.

Well, my budget is about $200 for everything so we will see what happens.

Paul