Cutting foam sheets... with a needle!

dkj4linux

Elite member
Hai-Lee,

I, too, am old and easily confused and/or put off by some of these outfits. But I will HEARTILY RECOMMEND the Estlcam software that has been recommended to you. Christian Knull, author of Estlcam, looks in on these forums occasionally and has been extremely helpful to us, especially MPCNC users... actually adding the MPCNC/Marlin "flavor" gcode into Estlcam and offering up timely advice/explanation to those having issues with it. As far as licensing, the software can be used indefinitely, with full functionality... but will impose an increasingly long "wait" (time delay) that will eventually, gently, encourage you to spend the $60 for a license. It is good, readily usable, software and I, for one, am deeply appreciative of Christian's efforts and happily paid for the license... long before the imposed wait was a bother to me. The MPCNC website also has some pretty straight-forward "how-to" pages for using Estlcam to generate our gcode... and bunches of us used this page to get started off on the right foot.

-- David
 
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jhitesma

Some guy in the desert
Mentor
IronKane runs down the process pretty well. The only things I really do differently are:

1) I keep the bevel marks, I just do them as a 0.5mm deep cut so they just barely mark the paper. That way they make nice guides for me when cutting my bevels. I've tried some of the 3d printed bevel cutters but find I still prefer to cut them freehand and the extra guidelines help.

2) I pretty much exclusively use the engraving tool for needle cutting FT Plans. It will auto detect completed paths just like the part tool will and I don't have to switch back and forth between two tools. But FT plans have so few complete paths I find I wind up doing most of them manually. Once you get into the groove they go really quick on most planes.

I was really skeptical of estlcam at first and wasn't big on the licensing. But I tried the demo...and before the timer got to the point it was annoying me I was sold on it and paid up. I've tried a number of other CAM options and none of them were as quick or easy for me. My only complaint about estlcam was I couldn't run it on my macbook - but once I figured out wine I was able to install it there as well...it's a little flaky under wine sometimes but fully usable, just the mouse sometimes acts a bit wonky.
 

ironkane

Member
IronKane runs down the process pretty well. The only things I really do differently are:

1) I keep the bevel marks, I just do them as a 0.5mm deep cut so they just barely mark the paper. That way they make nice guides for me when cutting my bevels. I've tried some of the 3d printed bevel cutters but find I still prefer to cut them freehand and the extra guidelines help.

2) I pretty much exclusively use the engraving tool for needle cutting FT Plans. It will auto detect completed paths just like the part tool will and I don't have to switch back and forth between two tools. But FT plans have so few complete paths I find I wind up doing most of them manually. Once you get into the groove they go really quick on most planes.

I was really skeptical of estlcam at first and wasn't big on the licensing. But I tried the demo...and before the timer got to the point it was annoying me I was sold on it and paid up. I've tried a number of other CAM options and none of them were as quick or easy for me. My only complaint about estlcam was I couldn't run it on my macbook - but once I figured out wine I was able to install it there as well...it's a little flaky under wine sometimes but fully usable, just the mouse sometimes acts a bit wonky.
Peel your bevel cut paper before cutting your bevel. I have a 3D printed bevel cutter that work great except in tight places. Then I finish with a razor.

Break your line intersections in Inkscape before opening the .svg in Estlcam. Then the only dot to dot's you'll have to do are score cuts and reference lines. Saves a ton of time, especially when you want to reuse the .svg.
 

ironkane

Member
Segue to Needle construction: A while back we were discussing needle length and how much should protrude from the MiG tip. I was making great cuts and then I decided to shorten up the needle so that it retracts completely into the tip. This was not a good idea. It's cutting pretty raggedly and the sheets are sticking to the foam waste board.

I believe the sticking is the hot-ish needle is pushing the paper on the bottom into the waste board and partially fusing.

The raggedness I attribute to taking longer to achieve the full vertical alignment because the needle isn't protruding from the tip to provide that counter to the bend from the elliptical motion. I had aprox .5" protruding at full extension.

That and the fact I'm currently using DTFB and not FliteTest WPFB which is vastly superior. Which I'm going to order as soon as I can make a new longer needle. Right after I find the my homemade coil winding tool. I really need to clean up my garage and workbench.
 

Jorge Pi

New member
Peel your bevel cut paper before cutting your bevel. I have a 3D printed bevel cutter that work great except in tight places. Then I finish with a razor.

Break your line intersections in Inkscape before opening the .svg in Estlcam. Then the only dot to dot's you'll have to do are score cuts and reference lines. Saves a ton of time, especially when you want to reuse the .svg.

Which 3D printed bevel cutter are you using?
 

billr

New member
Hi guys. After scratch building a few FT planes, I decided I wanted to use a CNC machine to cut the foam. I saw moebeast's "Foam Ripper" article and was about to build that when I discovered the Low Rider 2 on the V1 Engineering site. I had a 1 meter length of 20x40 openbeam v-rail laying around, so I decided to use that instead of EMT. I removed the Z axis from the end plates of the Low Rider 2 and put a simple Z elevator on the gantry. It's working extremely well and I wanted to give a big "Thank You" to all who have pioneered this needle cutter. I have read all of this thread (much of it twice) and found it to be a great resource.

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dkj4linux

Elite member
Hi guys. After scratch building a few FT planes, I decided I wanted to use a CNC machine to cut the foam. I saw moebeast's "Foam Ripper" article and was about to build that when I discovered the Low Rider 2 on the V1 Engineering site. I had a 1 meter length of 20x40 openbeam v-rail laying around, so I decided to use that instead of EMT. I removed the Z axis from the end plates of the Low Rider 2 and put a simple Z elevator on the gantry. It's working extremely well and I wanted to give a big "Thank You" to all who have pioneered this needle cutter. I have read all of this thread (much of it twice) and found it to be a great resource.

View attachment 115176

Billr,

Thanks for the kind words of appreciation... this is a good bunch of folks. Welcome to the party!

You've really got an interesting machine there... and we really, really need to see more ;) I'm just now putting the finishing touches on my own copy of Moebeast's Foam Ripper... so it will be good to compare machines since neither of them use the Z-lift of the LR2. I'm not terribly happy with the Z-axis on my machine at the moment... with the very modest travel I've accidently jammed it a couple of times (and threaded rod gives it quite a bit of torque) to where I'm not really sure it's "right in the head" anymore. And I've relocated it to another room and haven't got it all hooked back up (I have family in right now...) so can't really check it out yet.

Anyway, we're thrilled you are here. Please tell us more about your machine and foam-cutting activities. Have you done your vacuum pad yet? And... congrats and well done!

-- David
 

Jorge Pi

New member
https://www.thingiverse.com/thing:1358344
I wish he had a version that was only as wide as necessary for those tight spaces. I can do it with a razor (after removing the bevel strip of paper), but I cuss a lot when I dip too far down and cut through the hinge side.

Thank you, I’m actually using the same, but I scaled it up a little to handle the double bevel without marking the Foamboard. I wish I had Josh’s steady hand, but this solution works great for me.
 

billr

New member
Billr,

Thanks for the kind words of appreciation... this is a good bunch of folks. Welcome to the party!

You've really got an interesting machine there... and we really, really need to see more ;) I'm just now putting the finishing touches on my own copy of Moebeast's Foam Ripper... so it will be good to compare machines since neither of them use the Z-lift of the LR2. I'm not terribly happy with the Z-axis on my machine at the moment... with the very modest travel I've accidently jammed it a couple of times (and threaded rod gives it quite a bit of torque) to where I'm not really sure it's "right in the head" anymore. And I've relocated it to another room and haven't got it all hooked back up (I have family in right now...) so can't really check it out yet.

Anyway, we're thrilled you are here. Please tell us more about your machine and foam-cutting activities. Have you done your vacuum pad yet? And... congrats and well done!

-- David

Hi David,

I have it modeled in onshape. You can see it here: https://bit.ly/2O0NHo6
I just finished the vacuum pad. It seems to be holding down well. I haven't cut any foam with the vacuum yet.

--Bill
 

billr

New member
I first used a standard flywheel with the bearing on the outside and the needle wrapped around the bearing. It was difficult to get a groove in the bearing. After a few tries, I got it to work and the needle stayed on. I decided to try the bearing pressed in to the flywheel and I think it is a simpler design. That's what I have on the motor now. I haven't cut much foam with it yet. That screw sticking out the other end is the counter balance. By having it mounted radially, it is easy to balance by just tuning the screw. I static balanced it using a prop balancer and later fine tuned it on the machine.
 

dkj4linux

Elite member
I do like your flywheel, Bill. I don't know whether you've seen it or not... but I drew the same conclusions when I finally got around to addressing my printed flywheel recently for the Foam Ripper. I wanted the flywheel to completely enclose the bearing, with just a free-wheeling center shaft to affix the needle to (a feature of Shurakair's great cutter way back in post #71) , and I wanted it to be easier to balance... using the motor bell itself, if possible, as the "flywheel" (ala Steve "ironkane"s larger diameter motor with needle attached to motor bell), and a simple radial counter-weight. The result was this "slip-on" flywheel that shortens the entire assembly, uses less hardware, makes for a more compact cutter, and reduces the amount of "flailing mass" cantilevered out on the end of the motor shaft. It was pretty easy to get smooth operation up in the 9k - 10k rpm range... quite difficult to achieve with the old design. It's a very quick and easy "build"... though it does require careful measurement of the motor bell dimensions and a pretty "dialed-in" 3d printer. It has performed well so far, cutting the first few sheets... only time will tell over the long term. ;)

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jhitesma

Some guy in the desert
Mentor
Segue to Needle construction: A while back we were discussing needle length and how much should protrude from the MiG tip. I was making great cuts and then I decided to shorten up the needle so that it retracts completely into the tip. This was not a good idea. It's cutting pretty raggedly and the sheets are sticking to the foam waste board.

I believe the sticking is the hot-ish needle is pushing the paper on the bottom into the waste board and partially fusing.

The raggedness I attribute to taking longer to achieve the full vertical alignment because the needle isn't protruding from the tip to provide that counter to the bend from the elliptical motion. I had aprox .5" protruding at full extension.

That and the fact I'm currently using DTFB and not FliteTest WPFB which is vastly superior. Which I'm going to order as soon as I can make a new longer needle. Right after I find the my homemade coil winding tool. I really need to clean up my garage and workbench.

I find this very interesting - because I had the exact opposite experience. I started with my needle long and had the same problems with ragged cuts and the DTFB fusing to the waste board from heat.

When I trimmed my needle back so it fully retracted at the top of the stroke both issues went away.

That was back before I got my tach though and was using a crankshaft style needle mount so I still had issues with needles going flying. Once I solved that issue and switched to a bearing/flywheel setup for the needle mount I haven't gone back to a longer needle since I get such good results.

I have noticed a difference with the vacuum table. Without it parts stay "attached" more after cutting but with the vacuum table parts practically fall out...except sometimes they stay stuck to the waste board but don't appear to be melted (the needle and guide are both still cool enough to touch comfortably.) I actually experimented doing the same cut back to back with and without the vacuum and confirmed that for whatever reason the vacuum seems to make the difference. All I can speculate is that the vacuum is strong enough to pull part of the frayed paper from the cut down into the waste board...and that holding the work flatter causes the cleaner cuts that let parts fall out on their own more.
 

lukejackson

New member
really nice work! im currently pondering building a v1 engineering lowrider CNC with a foamcutter attachment.
Do you guys know of any other DIY CNC bases or have experience with the lowrider? (i know dkj4linux uses the MPCNC which is similar to the lowrider)

has anyone ever tried freehanding with the foamcutter attachment? ie using it instead of a knife?
 

ironkane

Member
really nice work! im currently pondering building a v1 engineering lowrider CNC with a foamcutter attachment.
Do you guys know of any other DIY CNC bases or have experience with the lowrider? (i know dkj4linux uses the MPCNC which is similar to the lowrider)

has anyone ever tried freehanding with the foamcutter attachment? ie using it instead of a knife?
I've used my CNC with the needle cutter like bandsaw. But I was just checking the cut.
 

Michael9865

Elite member
Segue to Needle construction: A while back we were discussing needle length and how much should protrude from the MiG tip. I was making great cuts and then I decided to shorten up the needle so that it retracts completely into the tip. This was not a good idea. It's cutting pretty raggedly and the sheets are sticking to the foam waste board.

I believe the sticking is the hot-ish needle is pushing the paper on the bottom into the waste board and partially fusing.

The raggedness I attribute to taking longer to achieve the full vertical alignment because the needle isn't protruding from the tip to provide that counter to the bend from the elliptical motion. I had aprox .5" protruding at full extension.

That and the fact I'm currently using DTFB and not FliteTest WPFB which is vastly superior. Which I'm going to order as soon as I can make a new longer needle. Right after I find the my homemade coil winding tool. I really need to clean up my garage and workbench.

Are you using a cotton wad and some light oil?