Cutting foam sheets... with a needle!

[CMS_1961]

From David

"With the popularity of Edward Chew's ERC TimSav foam cutter machine growing rapidly... his needle cutter remix/design IMO might be the most likely candidate for a new "standard" cutter. He's borrowed from proven designs, documented it extremely well in both written form and video, used parts that are readily available online, and the number of cutters being built and the planes now being cut serves as evidence that it works quite well. "


David,

As always, IMO your level of design and workmanship is excellent!! Nice job adapting this over for the MPCNC. Thanks for all you do here in the forum!!

Chalie

 

[lostphoenix]

This is my needle cutter it designed like others an adapted to be used with a Emax 2215/09 motor. I also use different guide bearing. Anyway just thought I see what I am using. Happy building.

Do you have a link to your models?

Overall, I'm super impressed with everyone's modeling/design skills. It seems like there's a ton of good options out there. I can't wait to get one of them working

 

[jhitesma]

I'm still torn about whether I like Edwards "flat pack" design or not. I see obvious advantages for him with how he's turning it into a commercial product. Manufacturing and shipping will be much easier. But for people building their own I kind of prefer a less-assembly required one part print since there's less to go wrong.

I'm honestly not a fan of 3d printing flat parts - in my experience they're far more likely to have warping issues which can lead to assembly issues. I've actually considered taking edwards design and re-assembling it in CAD before converting to STL so it can be printed as one piece. But my attention has been focused elsewhere lately...and with my CO2 laser hopefully being moved into a permanent home soon I'm also kind of tempted to try cutting one of edwards machines that way. (I even have 2 spare steppers on hand and a spare GRBL shield like he uses...all I really need is some belt, pulleys, and extrusions) The main reason I haven't is with my CO2 laser taking up my entire dining room table I don't really have anywhere I could even use the TimSav if I built one as my floors are all carpet or uneven tile that would be no good to work on. So...just one more reason I need to stay focused on getting the CO2 moved out of the dining room and into my back room ASAP (That table is also where I build planes so getting it cleared off again will let me finally finish a pile of planes I've cut but have yet to assemble!)

 

[dkj4linux]

Thank you, Chalie, for the kind words.

I've printed all the parts for Edward's machine and haven't seen any warping of parts at all... even with the larger endplates. Of course, I've got a decent printer and settings that have always worked well for me... but with the actual cutter parts, they are so small I really don't think warping will be that much of a problem. I've also considered building as a one-piece design... in that Tinkercad screenshot all the gray parts are grouped and the MPCNC backplate could certainly be added... and then the whole thing exported as one piece. But, so far, the parts have fit so nice and snug and square, you'd almost think CA wouldn't be necessary at all. Simply drizzling a little thin CA on the joints, as he shows in his assembly video, seemed to work well on the first cutter I did for the TimSav machine.

I'm not a fan of working on the floor either... it's gotten way too difficult for me to get up and down. I'm mulling whether to attach it to an MDF base and maybe even use it in a near-vertical orientation... somewhat like Tom McGuire's foam cutter machine that I've often thought I'd like build and modernize. That could be done pretty easily by adding a "real" but limited-motion Z-axis (not gravity dependent) and capturing the "landing gear" out on the end of the X-axis (should be Y... I like my long axis to be X ) extrusion in a track of some kind. I've also considered going straight to laser with Edward's machine... but since it's still on my [rented] floor, I don't want to run the risk of engraving something that can't be mopped up

 

[Keno]

Do you have a link to your models?

Overall, I'm super impressed with everyone's modeling/design skills. It seems like there's a ton of good options out there. I can't wait to get one of them working

STL's are now on my above post.

 

[Wildthing]

Thank you, Chalie, for the kind words.

I've printed all the parts for Edward's machine and haven't seen any warping of parts at all... even with the larger endplates. Of course, I've got a decent printer and settings that have always worked well for me... but with the actual cutter parts, they are so small I really don't think warping will be that much of a problem. I've also considered building as a one-piece design... in that Tinkercad screenshot all the gray parts are grouped and the MPCNC backplate could certainly be added... and then the whole thing exported as one piece. But, so far, the parts have fit so nice and snug and square, you'd almost think CA wouldn't be necessary at all. Simply drizzling a little thin CA on the joints, as he shows in his assembly video, seemed to work well on the first cutter I did for the TimSav machine.

I'm not a fan of working on the floor either... it's gotten way too difficult for me to get up and down. I'm mulling whether to attach it to an MDF base and maybe even use it in a near-vertical orientation... somewhat like Tom McGuire's foam cutter machine that I've often thought I'd like build and modernize. That could be done pretty easily by adding a "real" but limited-motion Z-axis (not gravity dependent) and capturing the "landing gear" out on the end of the X-axis (should be Y... I like my long axis to be X ) extrusion in a track of some kind. I've also considered going straight to laser with Edward's machine... but since it's still on my [rented] floor, I don't want to run the risk of engraving something that can't be mopped up

Vertical wall mounted cutter ???????? Huge space saver . Still could use the vacuum plate to hold it in place.

 

[dkj4linux]

Vertical wall mounted cutter ???????? Huge space saver . Still could use the vacuum plate to hold it in place.

Tom McGuire (aka "atomicwire") was my inspiration... and note the date (Aug 13, 2009)

and even an Instructable! I think these were near-vertical (or could be)... but it could just be the camera angle.

 

[TEAJR66]

Wow, I turn my back for a minute!

As usual, great stuff coming out of this group.

I have to remind myself to stay focused. CNC could easily take over as my primary hobby, rather than just a tool for my planes. Squirrel!!!

 

[dkj4linux]

Wow, I turn my back for a minute!

As usual, great stuff coming out of this group.

I have to remind myself to stay focused. CNC could easily take over as my primary hobby, rather than just a tool for my planes. Squirrel!!!

Watch your step... it's a slippery slope!

 

[dkj4linux]

Okay, just to be safe... a one-piece print of the ERC cutter adapted to MPCNC tool mount...

Multi-piece on the left... not glued up yet. I simply "assembled" the parts in Tinkercad and grouped, then exported as STL... figured the virtual assembly was more secure than me trying to fit and hold things together for glue-up. I also didn't do anything to try to hide the joinery lines... thinking that where they touch the fused plastic would be at least as secure, if not more, than a glued joint. It not like it has to be overly strong...

 

[dkj4linux]

Interrupting our regular programming...

Christmas must be getting close? Totally unaware of what's going in the world, I was shocked to have two energetic elves suddenly invade my home this afternoon... and decided I needed tree(s) in my bedroom... which they said has more room for the preponderance of Christmas presents I can expect to get

Such a big job, they assured me they'd be back tomorrow... presumably to finish decorating? Hope they leave some of those presents...

 

[TheSFReader]

Yeah for Elves !!! And is that a stealthy Tux stuck on that tree ? Tux is everywhere !

 

[dkj4linux]

Yeah for Elves !!! And is that a stealthy Tux stuck on that tree ? Tux is everywhere !

Yeah, Elves are great... and quite unpredictable and entertaining. And... my, what sharp eyes you have! Tux *is* everywhere! And, I, unlike elves, am quite boring and predictable

I've been trying to talk one of those elves into painting the Tux topper (I guess he wouldn't be too stealthy then, would he?)... but, so far, her schedule has been just too busy.

BTW I hope everyone is having a happy and productive Christmas season, filled with lots of fun projects! And family... and ELVES!

 

[dkj4linux]

Getting closer...

Did I mention how small/compact this version of the needle cutter is? I've used the parts provided in the ERC TimSav kit to build this up but, of note, is the careful selection of parts Edward has used here. All the machine screws used here are 3mm but getting the proper washers is crucial... there is a smaller diameter washer for sandwiching the inner race of the tiny 6x2x3mm bearings -- without binding the outer race -- and the normal 3mm washer, that will guaranteed mess up operation of the bearings if used in place of the smaller ones. If you want to duplicate this needle cutter design... please keep this in mind when ordering parts (or buy Edward's kit ). The biggest problem I've had is handling such tiny parts with arthritic/shaky hands. I've already lost several so be sure to order [a lot] more than you need...

-- David

 

[lostphoenix]

Getting closer...

View attachment 150809

Did I mention how small/compact this version of the needle cutter is? I've used the parts provided in the ERC TimSav kit to build this up but, of note, is the careful selection of parts Edward has used here. All the machine screws used here are 3mm but getting the proper washers is crucial... there is a smaller diameter washer for sandwiching the inner race of the tiny 6x2x3mm bearings -- without binding the outer race -- and the normal 3mm washer, that will guaranteed mess up operation of the bearings if used in place of the smaller ones. If you want to duplicate this needle cutter design... please keep this in mind when ordering parts (or buy Edward's kit ). The biggest problem I've had is handling such tiny parts with arthritic/shaky hands. I've already lost several so be sure to order [a lot] more than you need...

-- David

Looking good!! Have you run it yet? I'm currently trying to drill out washers 🤪 it's not going well.

MPCNC is put together though! Doing electronic tests right now to make sure I have motors the right way. Also need to figure out firmware since I'm using printrboard instead of the ultimachine board.

 

[dehager]

Looking good!! Have you run it yet? I'm currently trying to drill out washers 🤪 it's not going well.

Community tip of the day...

Glue the washers to a scrap piece of wood with CA. Use a sharp drill bit and SLOWLY drill out the washers. A quick soak in acetone or nail polish remover for an easy clean up.

I source my washers from McMaster Carr:
Zinc-Plated Steel Washer for M2 Screw Size, 2.2 mm ID, 5 mm OD 91166A180 $1.57 per 100
Brass Washer for M2 Screw Size, 2.2 mm ID, 5 mm OD 91635A180 $2.48 per 100

 

[mach1 rc]

Community tip of the day...

Glue the washers to a scrap piece of wood with CA. Use a sharp drill bit and SLOWLY drill out the washers. A quick soak in acetone or nail polish remover for an easy clean up.

I source my washers from McMaster Carr:
Zinc-Plated Steel Washer for M2 Screw Size, 2.2 mm ID, 5 mm OD 91166A180 $1.57 per 100
Brass Washer for M2 Screw Size, 2.2 mm ID, 5 mm OD 91635A180 $2.48 per 100

View attachment 150899 View attachment 150900

Cool tip

 

[dkj4linux]

Looking good!! Have you run it yet? I'm currently trying to drill out washers 🤪 it's not going well.

MPCNC is put together though! Doing electronic tests right now to make sure I have motors the right way. Also need to figure out firmware since I'm using printrboard instead of the ultimachine board.

No, I haven't run it yet... and probably won't ever cut foam with it. I'm no longer actively building and flying... and really don't need another needle cutter. I've built many needle cutters in the past and, with this particular design being put through its paces pretty heavily now with the popularity and number of ERC TimSav machines being built, I don't personally feel the need to test it heavily myself. I'm inclined to let Edward's design continue to prove itself out in the active RC community... and let the evidence speak for itself.

I am, however, very interested in seeing this design adapted to other CNC machines... hence, the MPCNC-adapted one I've presented here. Edward has done an immense amount of work developing and documenting his design and I'd love to see it become a sort of "standard" cutter design to recommend to the numerous folks who've visited this thread in the past, looking for a needle cutter recommendation. Until now, I've most often pointed folks to Jason's (@jhitesma) improved cutter... but with the motor he used being somewhat difficult to find now, Edward's design (which borrows from the many designs presented in this thread) now seems a better candidate. It's documented well and uses readily-available (online) parts so folks who want to build one for themselves should find the going easier than in the past.

That's my hope, anyway...

-- David

 

[Guy S.]

I’ve been following the needle cutter thread for a few weeks now, and think I’m going to start on mine soon. Probably ordering Edwards kit, or something based on it. Looking at the way the cutter assembly is designed, does anyone think there would be any benefit to keeping the guide (mig gun tip) a consistent distance from the work, and just moving the motor and guide bearings up and down. Seems like it could help with some of the inconsistencies some people seem to be having with cut quality. The tip of the needle would be truer as it enters the foam, and the guide wouldn’t be subject to any of the slop needed for the up down movement. The length of the guide should be plenty long to keep the needle inside the guide even when it is raised. Thoughts?

 

[dkj4linux]

I’ve been following the needle cutter thread for a few weeks now, and think I’m going to start on mine soon. Probably ordering Edwards kit, or something based on it. Looking at the way the cutter assembly is designed, does anyone think there would be any benefit to keeping the guide (mig gun tip) a consistent distance from the work, and just moving the motor and guide bearings up and down. Seems like it could help with some of the inconsistencies some people seem to be having with cut quality. The tip of the needle would be truer as it enters the foam, and the guide wouldn’t be subject to any of the slop needed for the up down movement. The length of the guide should be plenty long to keep the needle inside the guide even when it is raised. Thoughts?

Guy,

I personally believe the inconsistencies people, especially in the ERC TimSav camp, are seeing in cut quality is probably due to the much higher feed rates that have been recommended to them. For years, I have recommended a factor of 10 (cutter speed to feedrate)... 850 mm/min for 8500 rpm, for good cuts in DTFB (10 perfs/mm)... while most of Edward's followers are trying to run at 2000 mm/min, which should yield only 4-5 perforations per mm. This would result in quite a bit of variation in cut quality. I'm also unsure how many folks have actually purchased a tach and know what their cutter speed really is... and that is one of the most common problems folks encounter with their first cutter.

I also doubt that moving the motor independent of the guides is all that necessary. The required movement between score- and through-cuts is really just a few millimeters... and it's hard enough to keep the foamboard flat while its being cut to not see that amount of guide-to-surface variation anyway. But folks have successfully done what you propose as well... most notable being Neil's depron cutter, a very nicely built machine presented here a couple of years ago.

I like Edward's actual cutter head. It's based on a proven configuration, is small/compact, easy to build and adapt to other machines, the cutter itself is extremely well-documented, and it's being tested, right now, as no other single cutter design we've ever seen. I really hope it will prove out and become the basis for a "standard" cutter design that can be recommended to folks who come by, wanting to build their own needle cutter.

-- David