Cutting foam sheets... with a needle!

[jhitesma]

acp - glad you like it!

That little rack WAS pretty easy, the CAD was the hardest part. I started working on a 3 shelf version with more interlocking tabs last night (Onshape document link: https://cad.onshape.com/documents/a...371a488642326a3631/e/555ac78a6769253128418fc6 ):





Still a work in progress...not nearly as easy! The foam cutting will be...but the CAD is proving surprisingly difficult....but just after I gave up and went to bed I had a small epiphany - The original version I was able to just take my original sketches that were used to extrude the parts and export them as the DXF's for cutting. This time I tried to get a bit fancier and expanded those sketches to include extra material I'll use for wrapping around the exposed edges:



See the extra 8mm section off the bottom? Seemed quick and easy. And wasn't that big of a deal, when I did the extrusion I just unselected that portion of the sketch to eliminate it from the extruded part:



No big deal. But...then I started modeling the tabs. And things got tricky. Because the parts reference off each other. I modeled the lower shelf first, then translated it creating a copy for the middle shelf, then drew the 3rd shelf on a place referenced off the middle shelf. So far so good. Then I drew the side using a side face of one of the shelfs - again straight forward. And the back and base were also fairly easy.

But...then I realized I need that little "inner support" to support the lower shelf. And while I could have just made it a rectangle and had it rely on glue. But my big plan here was to push myself and make the whole thing tabbed. But...going back and modifying the original sketches for the lower shelf and base and side to add tabs/slots that interlock got tricky. I can't just use/project from the new inner support to place the slots because the sketch for those other parts exist in the timeline before the inner support exists. And I can't move the inner support earlier in the timeline because it's referenced off those other parts. I'm stuck in a reference loop! Arrrgh!

Just before I called it a night I realized I could use booleans on the parts so I drew the inner support with tabs/slots where I wanted it and then used a boolean operation to cut a slot into the side. Cool. Except...that doesn't modify the sketch for the side. If I was 3D printing this no big deal because the part is what I need. But I'm looking to needle cut it so the sketch is what I need to generate a DXF from. Hmmm. I played with creating drawings off the parts and those can export as DXF:



But when I import them into inkscape they're all messed up So those aren't really usable for cutting from.

So at that point I decided to call it a night out of frustration.

And then just as my head hit the pillow it hit me....it's not the cleanest solution and I'm guessing there a more "correct" solution out there I just can't figure out (probably related to the drawings) but...all I need to do is create a second sketch for the side. Instead of re-using the sketch I used to create the side I just create a sketch on the face of the final part, then use/project it's outlines...boom - I've got a sketch I can export as DXF and import into estlcam or inkscape!

So I still have a bit of CAD to do to finish the last few slots/tabs...but cutting should still be pretty quick (I'm guessing around 9 minutes with the extra parts) and the final project should be even better. But...man...this is a great example of a quick easy project ballooning into a much trickier projects without appear to actually gain much complexity!

 

[jhitesma]

Andre - So hyped to hear we've caught your interest I figured moebeast being at FF two years in a row with his cutter would attract some attention but had been kind of surprised there didn't seem to be much of an uptick in interest...maybe I'm just impatient

I have my latest design almost ready to go live on Thingiverse...just need to add some more details to the description and want to work up a version with the standard 525 mount before I release it since new machines are using that design which IMHO is somewhat better than hicwic at this point.

Once that's done I'm hoping to write up an FT article to draw more attention to all of this...and try to consolidate our nearly 140 pages of discussion and development into one concise "what you need to know to replicate this" article. Partly just so there is a good reference like that...but also because FT seems to pay more attention to articles than forum posts

Ryan who created the MPCNC seems to be getting more interested in the needle cutter as well. He even added a section to his gallery page just for needle cut projects:
https://www.vicious1.com/videos/gallery/

(it's a ways down the page under PCB and above 3D Printing)

In this thread: https://www.vicious1.com/forum/topic/need-machine-ideas/ Ryan commented:

At my last job we spent months cutting a fairly complex shape out of similar foams. We tried everything and tons of different foams. I am interested to hear anything that comes out of this. We ended up using a template to mark it then scissors and the manufacturer ended up die cutting them as far as I know. The partial cut is going to be the toughest to get consistant I think.

I then suggested the needle cutter - and picked up a piece of foam like they were working with to test and confirmed the needle cutter works perfect on it. Not sure how well it would do at 3/4" thick - but at least with 5-6mm thick pieces I tested on it cuts even better than DTFB since the foam is softer and there's no paper to deal with. I'm curious to see if they end up trying it as I think it could be just the ticket for what they're trying to do.

Honestly having built an official FT laser cut kit and quite a few needle cut planes I prefer the needle cut foam since it doesn't have the undercutting the laser results in. I don't think the needle would be very practical for mass production - but...I don't know how long FT's lasers take per-sheet so it's hard to say. With the latest cutter improvements and speed increases maybe it's not far off. For home use the needle definitely seems superior to me though. And you can always strap a low power laser on for etching and cutting firewalls and such. I still kind of want to rig up a way to mount the laser and the cutter at the same time - account for the offset in software and be able to cut with the needle but switch over to the laser to do markings without having to swap tool heads. Then again maybe I just need to bite the bullet and learn to do tool changes and workpiece alignment so I can use the laser to decorate both sides of the foam...hmmm...

I meant to finish the thingiverse posting last night...but got sucked into working on the ink rack which took far longer than I expected. Hopefully tonight I can finish the thingiverse post and start on an article....

 

[Andre]

Nice, I look forward to the submission to thingyu.

I'll warm up the printer

Andre.

 

[97tj-neil]

"and try to consolidate our nearly 140 pages of discussion and development into one concise "what you need to know to replicate this"

This is exactly what I have been waiting for. My son and I have our MPCNC up and running now, and have cut a couple of test parts with the router. We want to make a needle cutter, and brought home a whole box of water proof foam board from FliteFest. The length of this thread is a little daunting, so a summary would be fantastic. Thanks for all your work on this.

 

[rockyboy]

I have started printing parts for a Lowrider CNC (rather than the MPCNC) and have a parts order for the things I'm missing arriving from http://www.vicious1.com later this week. I'll get a build thread started here on the forum for the CNC once all the parts arrive and the assembly fun begins.

So yeah, I'd LOVE an article summarizing a lot of this work too - and I'm also eagerly awaiting the new file in Thingiverse. :applause:

One thing I know I'll need to modify a bit is the mounting for the needle cutter. Since the Lowrider has a flat plate instead of the MPCNC vertical mounting slots, I'll need some method of holding the needle cutter that hopefully doesn't introduce a weak point at a specific horizontal printing layer. Or maybe I just epoxy the new design down to a thin piece of wood and move on with cutting... yeah - that sounds pretty good too.

 

[moebeast]

Andre, yes, that was me, and you did look pretty beat when you came by. It took about 1.3 kg of PLA and about a week to print my last set of parts. I assume you have 25 mm conduit in your neck of the woods, so I suggest following the links for parts on the Vicious1 site instead of searching Thingiverse directly. All my components came from Amazon and eBay.
Mark

 

[jhitesma]

Rockyboy - I'm looking forward to that. I've been seriously considering doing a low rider but haven't made it a big priority. I figure it would be better for the size and would give me more of my table usable when I'm not cutting things. If you want I could work up a modified version of my cutter designed to mount to the lowrider...I have a few ideas on how to tackle that.

It was a bit tight for time...but I managed to complete v2 of my ink stand over lunch:



I added flaps on the fronts of the shelves, base and back that folded back over hiding the cut edges. I also shrank the tabs down to 4mm to better match the thickness of DTFB, added that 3rd shelf, and tabbed everything so it actually holds together quite nicely without glue (though I still glued it). Oh, and I added hot glue "feet" because I had the glue out

The flaps I stole right from some FT plane designs that use that approach. Came out clean - but my rushed lunchtime glue job could have been prettier:



There are a LOT of tabs on this design now! It really does hold together very well with no glue. Assembling is a bit trickier though. Hint: Add the bottom last, and the sides just before that for easiest assembly.



Holds all my ink and room for a little bit more:



There are two things I'm not 100% happy about though.

1) I should have added a support under the lowest shelf, total oversight. Not the end of the world but would make it a lot stiffer and nicer.

2) I wish I could clean up the cut edges of the sides better. Since they're curved, and both the inside and outside is visible anything I could think of was going to leave some kind of seam visible. The best I could think of is to wrap from the inside over to the outside and then laser cut some panels to over the sides - but it would still leave a seam along the outside edge and the bits over the curve would need slits in it so still not perfect. Another option would be a strip over the top folded over both sides...but then I'd have to put panels over both the inside and outside...and would still have a seam along both sides. Probably the cleanest option but still not perfect. Oh well.

For what it is I'm happy - but may still try a v3 with the extra support and something to clean up the edges of the sides a bit more.

All my work files (exported DXF's, combined DXF and inkscape SVG with all parts, estlcam 10 project, gcode) are here: https://drive.google.com/open?id=0B5JVPXZ3vDfBUGZBUE9MTGRKNVU if anyone wants to build one.

 

[jhitesma]

I assume you have 25 mm conduit in your neck of the woods, so I suggest following the links for parts on the Vicious1 site instead of searching Thingiverse directly.

Maybe Verris will chime in...(or maybe it's answered in his previous posts) he's in .ca and build a needle cutter MPCNC so should know what size conduit is easily obtained up there.

 

[rockyboy]

Rockyboy - I'm looking forward to that. I've been seriously considering doing a low rider but haven't made it a big priority. I figure it would be better for the size and would give me more of my table usable when I'm not cutting things. If you want I could work up a modified version of my cutter designed to mount to the lowrider...I have a few ideas on how to tackle that.

That would be awesome! 3D modeling is a skill I haven't learned very much of yet

No big rush - it's likely to be two weeks or so till I have all the rest of the Lowrider assembled.

Thanks!

 

[jhitesma]

That would be awesome! 3D modeling is a skill I haven't learned very much of yet

No big rush - it's likely to be two weeks or so till I have all the rest of the Lowrider assembled.

Thanks!

Do you plan on using the 611 plate? I'm thinking I could make something that drops in and mounts like the 611 so you can swap from router to cutter.

I haven't tried importing a DXF into onshape yet so this gives me something new to play with/learn as well

 

[jhitesma]

I've published my latest cutter on Thingiverse: https://www.thingiverse.com/thing:2450613

I included a hacked together 525 mount version...I'm not very happy with it...but without redrawing the entire cutter body from scratch it's probably the best I'll manage. I'll work on a nicer 525 version at some point...but it's not super high on my priorities list. Still debating if I'd rather do a lowrider or upgrade my current machine to 525 spec

I tried to include lots of details in the description to help others recreate the cutter. I may add some more details about cutting speeds and motor RPM - but my wife is bugging me to come to bed and I didn't want to put off publishing it another day

 

[moebeast]

Still debating if I'd rather do a lowrider or upgrade my current machine to 525 spec

Easy solution is to change the "or" to "and" I'm happy that I upgraded mine. The X-Y is stiff and square. I was having the same issue with having to hold it square before powering the steppers, plus the tool mount is way better. I think you can just do the center section without messing with the rollers or corners. I did every piece on mine, but I was looking for things to print at the time.
Low Rider looks cool, but I don't have the space. I printed one for a co-worker, but I don't know if he has it running yet.

 

[jhitesma]

Easy solution is to change the "or" to "and" I'm happy that I upgraded mine. The X-Y is stiff and square. I was having the same issue with having to hold it square before powering the steppers, plus the tool mount is way better. I think you can just do the center section without messing with the rollers or corners. I did every piece on mine, but I was looking for things to print at the time.

I wish AND was an option, but space is a serious issue. Though if I did do a low rider I'd probably dig my old 2' conduit pieces back out and end up building a smaller portable MPCNC for milling. That size is easy enough to store and transport.

And yeah, I do plan on doing the center section first, though I also want the new rollers/stepper mounts and at that point may as well do the whole enchilada

Low Rider looks cool, but I don't have the space. I printed one for a co-worker, but I don't know if he has it running yet.

I want to do a low rider because of my limited space. Since it only uses rails in one direction it would mean when I'm not using it I can push it to the back of the table and have the table available as a workspace. Right now I'm REALLY lacking a work table. The 12" or so between the short edge of my MPCNC and the edge of my table is the only place I have available. ...and I used every inch of that building my explorer wing. I really want to finish my balsa RV-3 but just don't have room to work on it right now

 

[rockyboy]

Do you plan on using the 611 plate? I'm thinking I could make something that drops in and mounts like the 611 so you can swap from router to cutter.

I haven't tried importing a DXF into onshape yet so this gives me something new to play with/learn as well

Yep - planning on the 611 plate so I can drop a router into it as well as the needle cutter. Got my bearings in last night and bolted up all the rail guides for that piece - printed out the 611 plate pattern and will be cutting it out of 1/4" MDF on the band saw soon. I figure if I can't get all the MDF plates aligned just right by hand, hopefully the first build of the Lowrider will be able to work well enough to cut it's own precisely aligned replacement parts

I want to do a low rider because of my limited space. Since it only uses rails in one direction it would mean when I'm not using it I can push it to the back of the table and have the table available as a workspace. Right now I'm REALLY lacking a work table. The 12" or so between the short edge of my MPCNC and the edge of my table is the only place I have available. ...and I used every inch of that building my explorer wing. I really want to finish my balsa RV-3 but just don't have room to work on it right now

Yeah, this is the factor driving my decision on this too - I don't have room for a big single use piece of equipment, but when it does double duty as a work table I think I can work with it. But it's still going to require a significant workshop cleaning / realignment which I'm not looking forward too.... *sigh*

 

[jhitesma]

Yep - planning on the 611 plate so I can drop a router into it as well as the needle cutter. Got my bearings in last night and bolted up all the rail guides for that piece - printed out the 611 plate pattern and will be cutting it out of 1/4" MDF on the band saw soon. I figure if I can't get all the MDF plates aligned just right by hand, hopefully the first build of the Lowrider will be able to work well enough to cut it's own precisely aligned replacement parts

Still a work in progress...but....





The blue piece on the bottom would be the wooden insulator - sized to fit into the 70mm circle in the 611 plate.

Still need to refine the guide bearing mount...and I kind of want to open up the bottom some more...but the wood circle would block that anyway so not sure it's worth doing.

Just thought I'd show a little work in progress (Had to think about a coding issue at work which usually means I need to do something else to let my subconscious work on the problem CAD is a nice "something else" )

This is in my existing onshape document...just a new branch "611 mount" and a new part studio in that branch.....

 

[Verris]

And I saw my first live needle cutter at Flite Fest.
I think we all know what my fall/winter project will be.

A.

Hey Andre,

If you need any help or want to play with it, I live in Kanata and have one built that I've been using for a while. I've also got a full extra set of all the hardware and some of the electronics I can give you a good deal on if you want. I ended up not wanting to wait for some of the slower parts to ship from China and sourced them locally so I have a lot of extras.

 

[rockyboy]

Still a work in progress...but....

The blue piece on the bottom would be the wooden insulator - sized to fit into the 70mm circle in the 611 plate.

Still need to refine the guide bearing mount...and I kind of want to open up the bottom some more...but the wood circle would block that anyway so not sure it's worth doing.

Just thought I'd show a little work in progress (Had to think about a coding issue at work which usually means I need to do something else to let my subconscious work on the problem CAD is a nice "something else" )

This is in my existing onshape document...just a new branch "611 mount" and a new part studio in that branch.....

Oh man - that's awesome!

Now I need to watch your onshape video and start learning how to use it, and get an STL file output

I'm thinking that wood circle on the bottom can eventually become something with some wagon wheel spokes to open it up / reduce mass of the moving head (it'll be easy to mill out on the Lowrider to improve itself of course).

Thank you!

 

[jhitesma]

Oh man - that's awesome!

Now I need to watch your onshape video and start learning how to use it, and get an STL file output

Well, let me finish the guide bearings first

But getting an STL out is pretty simple. You just right click on the part in the list at the lower left corner and select "Export"

It will be more obvious once I go through and name the sketches/features/parts on that design.

I'm thinking that wood circle on the bottom can eventually become something with some wagon wheel spokes to open it up / reduce mass of the moving head (it'll be easy to mill out on the Lowrider to improve itself of course).

Ahh, good point, I didn't want to get too fancy because I didn't want make it hard to make...but I didn't stop to think you'll have a CNC machine at that point so you can just mount up the router and machine it I'll put a bit more effort into making that nicer

 

[jhitesma]

Yeah, that's looking neater:



Except...I'm running into the same problem I had with my fancier "normal" cutter idea. The side supports are on planes defined by the guide bearing support...but I'd rather create the guide bearing support after the sides so I can blend it in better...but I can't define the planes without the bearings support. Going to have to think about this one.

And those spokes should be 8mm wide instead of 5mm so LED strips can fit under them....

Still need to do cutouts in the sides too....hmmm...

 

[jhitesma]

So...spokes are still only 5mm which may be a bit narrow to put LED's on...but...otherwise...what do you guys think:









Kind of makes me want to start on a low rider more than a 525 upgrade