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Cutting foam sheets... with a needle!

All right, not having a 3D printer, where can I get the components for the needle cutter head printed? I looked at the wood needle cutter head, and I have the tools to make one, I just didn't see a pattern.
 
All right, not having a 3D printer, where can I get the components for the needle cutter head printed? I looked at the wood needle cutter head, and I have the tools to make one, I just didn't see a pattern.
Does your area have maker spaces? Some of them have 3D printers. Also check with your local library.
 
synjin,

There are no patterns, to my knowledge, for the needle-cutter... other than a few 3d-printed ones, such as Jhitesma's Improved Needle Cutter out on Thingiverse.

The needle cutter is strictly a DIY project. Your post indicates you are a "Compulsive DIYer"... so this should be right up your alley. This thread is teeming with scores of needle-cutter builds and, even without patterns, there's plenty of information sprinkled throughout to, hopefully, give you a few rough dimensions and a sense of direction.

I know this is a long thread but it is worth the read... or at least a scan. Look back at post #1952... my first needle cutters were re-purposed CPU fans, then brushed DC motors on wooden platforms, and brushless motor setups on mouse-traps, laser-cut plywood, 3d printed, etc. There have been metal ones, wooden ones, plastic ones... and cutters built with a combination of materials. The idea is to use whatever materials and components you might have on hand, or are readily available to you, and that you are comfortable working with... using whatever tools and abilities you have.

I'm really not trying to discourage you. I am trying to let you know that this is a very straight-forward build, using common everyday materials, and is well within the capabilities of almost anyone who's a little bit "handy". And this forum is full of friendly folks who have built and use them... and are ready, willing, and able to help you build your own.

So, join in and tell us a little about yourself and your foam-cutting plans... and give us an idea of what you'd like your needle-cutter to look like. We're here to help.

Welcome to the party!

-- David
 
Adjusting the SCALE value in the LinuxCNC configuration file does indeed allow for "fine tuning" each axis...

My X and Y values for SCALE, in the <config>.ini file, were initially set at 80... and the units are "steps/mm".

So, commanding a G0 move for a specific distance and measuring the actual distance moved should yield an adjustment factor for the current SCALE value... i.e.

( commanded / actual ) * current SCALE​

gives a new SCALE value to be put into the <config>.ini file. Specifically,

I sent "G0 X900" and X moved just 898.5 mm, therefore the new SCALE is (900/898.5) * 80... or 80.134.

I sent "G0 Y300" and Y moved just 299 mm, therefore the new SCALE is (300/299) * 80... or 80.268.

With these adjustments, both X and Y now move the commanded distance.

-- David
 
Looks like you're having fun David. This is something that I've been interested in doing for a while.
I think you're biggest hurdle is going to be when you have to flip the DTFB over after marking/decorating one side to do your cuts on the opposite side. Mostly when your art intersects with cut lines and you don't want it to fall a little short.

Have you considered using a laser set low enough to mark but not burn enough to melt the foam or compromise the structural integrity of the paper? I was thinking it'd be faster to draw the lines and some shading and just fill in the color by hand like a DTFB coloring book.
 
All right, not having a 3D printer, where can I get the components for the needle cutter head printed? I looked at the wood needle cutter head, and I have the tools to make one, I just didn't see a pattern.
What David said. Basically, it's a L shaped bracket with a motor on one wall and a guide on the other to constrain the elliptically rotating needle. Wood is perfectly acceptable. Acrylic from Tap Plastics is fairly cheap. If you have a MPCNC, download the file and try your library or local secondary schools to 3D print. Look at my cutter on page whatever. It's about as simple as I could make it and could have done it with scrap wood.
 
Looks like you're having fun David. This is something that I've been interested in doing for a while.
I think you're biggest hurdle is going to be when you have to flip the DTFB over after marking/decorating one side to do your cuts on the opposite side. Mostly when your art intersects with cut lines and you don't want it to fall a little short.

Have you considered using a laser set low enough to mark but not burn enough to melt the foam or compromise the structural integrity of the paper? I was thinking it'd be faster to draw the lines and some shading and just fill in the color by hand like a DTFB coloring book.
It has been fun and a bit different... coming full-circle with LinuxCNC, messing with a little electronics, and thinking about cutting foam again. But this is starting to get out of my area of expertise/interest and I'm personally not going to go too much further with this. I'm totally out of the "build/fly/crash/repeat" game now... and was never one for finishing/decorating my planes anyway. So I'll leave it to folks with more ability and a greater interest in building and decorating their planes to carry on with development along these lines. Our machines are capable of a lot of really neat stuff now... and the remaining issues IMO are primarily operating procedures (registration, flipping, tool changes, etc...) and software (for generating CNC-friendly artwork). A laser offers many advantages over pens/markers, of course, but I've built enough laser machines now my curiosity is satisfied and I can see pretty much what I want/need to see using pen and paper. -- David
 
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David,

Compulsive DIYer, yes. Simply yes. CDIYS (Compulsive Do it Yourself Syndrome) is, I think, a genetic disorder (though I hate to blame my wonderful parents). I may even have materials for projects squirreled away in at least three states...thousands of miles apart. But, I digress.

Primarily, I’d like to accurately cut those cool patterns I keep finding for RC aircraft. Secondary, I’d like to cut parts for miniature architecture (at some point I’ll probably get back to miniature war gaming). It takes too long to cut pieces compared to putting together...stuff. So, that’s the objective. If I can cut foam board and, hopefully, cardboard I’ll be a happy camper (chipboard would be a bonus). If I can replicate the work, I’ll be even happier.

I suppose I have folks I can go to for 3D printing (though I’d love to know where that metal flywheel I saw on the thread came from). In any case, I’ll get the main body of the MPCNC together, then worry about the the cutting head (the printed parts should be here tomorrow).

I plan to control it with a Raspberry Pi 3 B+ and CNC Hat. Why? ‘Cause I had the RPi and saw there was a hat (which is currently sitting in the box with the RPi). If I could figure out how to convert .SVG files to GCode on the Pi I could do everything on the Pi (Theoretically. LibreDraw can save as .SVG files.).

There is all this stuff I have. I love it when I can make something useful out of the stuff I have (or can easily get a hold of).

I’m testing the limits. Being a nubbie to CNC I don’t know all of what can and can’t be done. But, being afflicted with CDIYS I’m going to find out.

Drew
 
Welcome, Drew! Thanks for coming back :)

It sounds as though you're wanting to take almost the same path I did... and this thread pretty well chronicles my trip.

First, RC aircraft... initially I introduced the needle cutter out on the RCPowers forum... which, sadly, no longer exists. I chose that venue because the needle cutter and their "score, cut, and fold" technology seemed a great "marriage" that yielded some really nice looking planes.
Shortly thereafter, I introduced it to the FliteTest and RCGroups forums... and ultimately the FT forum is the one that really generated interest and took off. My very first post in this thread shows a couple of those RCPowers planes (F-117 and Mig-29)... along with a scaled-down FT Old Fogey, a T-rex for the grandson, examples of the DTFB cut quality, and the MPCNC I was using at the time. So, the CNC machine doesn't care whether the parts it's producing are RC planes, dinosaurs, or architectural pieces... I think we've got you're covered.

Early on, I also used the needle-cutter to cut 3mm cardboard. Check out post #907... the stegasaurus on the placemat was needle-cut. But cutting cardboard was a torture-test of sorts... it readily cut through in a single pass but an Xacto blade had to be used in places on the bottom-side to fully extract the parts. I've intended for a long time to revisit those efforts... possibly making multiple passes can improve the result.

In that same post #907, you'll see a tiny triceratops laser-cut from cereal-box cardboard (chipboard?). Shaky as I am, I put only the head together -- using tweezers to pick up and place the parts -- but I was impressed with the precision I could now get. Miniatures are not my thing but the laser is the way to go for that kind of stuff.

So, there you have it. Unless you have a 40+ watt CO2 laser -- and I don't -- papered foam is IMHO best cut with a needle-cutter... inexpensive, great detail, straight-sided cuts (no under-cutting), little/no debris generated, etc. With cardboard and chipboard, larger pieces can be needle-cut somewhat successfully but a laser is IMHO far preferable, especially for miniatures. Even a modest diode laser is a great addition to the arsenal... with patience, it can cut many materials -- sadly, not white DTFB -- but it also engraves many materials beautifully.

Finally, MPCNC is a great choice for those first steps into the world of CNC... relatively inexpensive, flexible sizing/tooling, fun and incredibly educational to build, etc. In short, it is a DIYer's dream and pretty much why this thread is so eclectic... without the flexibility MPCNC affords, much, if not most, of this stuff I would have never attempted.

There's so much more to talk about but we can save that for later. Virtually everything you mentioned can be, and has been, done... much of it routinely. And, one of the greatest attributes of automation, the time spent preparing the work for machine operations, is recouped in spades when you start making copies.

Again, welcome to the party, Drew.

-- David
 
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David,

Compulsive DIYer, yes. Simply yes. CDIYS (Compulsive Do it Yourself Syndrome) is, I think, a genetic disorder (though I hate to blame my wonderful parents). I may even have materials for projects squirreled away in at least three states...thousands of miles apart. But, I digress.

Primarily, I’d like to accurately cut those cool patterns I keep finding for RC aircraft. Secondary, I’d like to cut parts for miniature architecture (at some point I’ll probably get back to miniature war gaming). It takes too long to cut pieces compared to putting together...stuff. So, that’s the objective. If I can cut foam board and, hopefully, cardboard I’ll be a happy camper (chipboard would be a bonus). If I can replicate the work, I’ll be even happier.

I suppose I have folks I can go to for 3D printing (though I’d love to know where that metal flywheel I saw on the thread came from). In any case, I’ll get the main body of the MPCNC together, then worry about the the cutting head (the printed parts should be here tomorrow).

I plan to control it with a Raspberry Pi 3 B+ and CNC Hat. Why? ‘Cause I had the RPi and saw there was a hat (which is currently sitting in the box with the RPi). If I could figure out how to convert .SVG files to GCode on the Pi I could do everything on the Pi (Theoretically. LibreDraw can save as .SVG files.).

There is all this stuff I have. I love it when I can make something useful out of the stuff I have (or can easily get a hold of).

I’m testing the limits. Being a nubbie to CNC I don’t know all of what can and can’t be done. But, being afflicted with CDIYS I’m going to find out.

Drew
Drew,

If you are looking to build one of these let me know... I have a couple sets of the 3d printed sets done and will offer to someone who is willing to build one. I tinker with stuff & needed something to test my new 3d printer out on.. if interested drop me a msg. These are printed per Jhitesma's post & are very nicely designed.

Bob
 
Would you all say that a conical tipped needled is the best? Any other style would rip and or hang the needle up when moving in certain directions. With that being said would a long tapered point be best or a short tapered tip be best? I would assume with a long taper you'd need a slightly deeper cut stroke. Suggestions welcomed.
 

rockyboy

Skill Collector
Mentor
Would you all say that a conical tipped needled is the best? Any other style would rip and or hang the needle up when moving in certain directions. With that being said would a long tapered point be best or a short tapered tip be best? I would assume with a long taper you'd need a slightly deeper cut stroke. Suggestions welcomed.
I did a short conical tip - put the dremel in a vice and spun the needle up against the cutting wheel - and I've cut about 25 to 30 sheets without any problems or need to replace the needle yet. On through cuts, the needle goes about 1 to 2 mm into the foam spoil board.
 
From post #904, Joachim wrote...
===============
...
3) --> I tested a real sharp needle (pinpoint, like pencill) and an extrem blunt one (flat...like the bigger ones for punching holes in metal sheets) ---> after cutting some longer rows in Depron, both needle tips are looking nearly the same ( a rounded tip, not sharp and not blunt)

After all, the needle with the sharp tips is working "nicer"

This is the tips after needling the small Shockflyer and some aditional test rows

The pinpoint tip is gone...but it is still working fine

Joachim
=================

A short conical point is what I recommend and try to put on my needle.

-- David
 
I've made a little progress on my needle cutter.

Here is a couple shots of my setup and my homebuilt CNC router I'll be attaching it to.
How does the wire mount to the flywheel. It looks as if you just let it slip over the bearing and is not mounted.. how does it not fly off from vibration or movement? The photos are not big enough for me to see what's going on.
 
How does the wire mount to the flywheel. It looks as if you just let it slip over the bearing and is not mounted.. how does it not fly off from vibration or movement? The photos are not big enough for me to see what's going on.
Tingler,

I'm not trying to be mean or flippant but I admit I chuckled when I read this -- please forgive me. Quoting post #20 on the first page of a thread with 2400+ posts and 120+ pages, and then noting the photos were too small to get enough detail to see what's going on... my first suggestion is to keep reading ;)

Just six posts later, I detailed, with pictures, the very thing you've asked. I know this thread is a lengthy/difficult read and specific information can be hard to find -- and I apologize for that -- but I personally think it's a better thing to have *too much* information than *too little*.

There are numerous ways to attach the needle to the bearing...

Early on, I was grinding a very shallow groove in the outer race of the bearing... and under-sized loops formed on the end of the needle were opened slightly to slip over the bearing and into the groove, and they were held there by their own spring pressure. It actually works quite well but grooving the bearing race proved problematic for a number of people. MikeJM, who you quoted, successfully used this method... and this is the procedure I detailed in post #26.

Another DIYer destroyed a couple of bearings while trying to groove them, so he simply slipped the loops on the bearing and applied a small dab of super-glue. He then ran that needle for over a year and cut many planes.

Another machined a flywheel and embedded the entire bearing in a pocket... a crankpin/post extended from the center of the bearing and the needle was affixed. This is actually the way I would recommend if you print or machine a flywheel for needle cutter use.

Needle "keepers" have been printed which friction-fit over the outer bearing race... and the needle fab is a simple 90 degree bend, captured in the keeper. Some have made this work... others haven't.

I know it can be frustrating to find specific information buried in this thread but scores of needle cutter builds are presented -- along with many other tips and fab ideas -- so it can be very worthwhile to at least scan through the thread. Google and the forum search tools are also your friends... use them.

Best, tell us a bit about yourself and your foam-cutting plans and then ask specific questions relative to your planned build... there are many friendly and helpful folks here and they are more than willing, and able, to help.

-- David
 
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