Cutting foam sheets... with a needle!

[dkj4linux]

...
Just dreading machining the pink-foam air chamber. That's a lot of material to remove (between the channels and the pocket for the waste board to fit in) and that pink foam is even messier than DTFB to machine with a spindle

I could make it out of more pieces. Just machine the grooves and then make a rectangular "frame" that gets glued on to form the pocket...but that would result in a deeper pocket than I want. Not the end of the world but could be much quicker/cleaner to make.
...

I've not done it of course... but I've never understood the need to mill grooves in pink foam. I've always thought your needle cutter could cut dandy channels in a couple (or a few?) sheets of DTFB... one predominantly north-south, the other east-west? Laminate them with your perforated-at-the-channel-intersections waste piece and maybe a solid bottom piece? Then stick it into your wooden frame?

I'm sure I'm not seeing something...

 

[moebeast]

I've finished my vacuum pad design, but haven't put it together. The two sketches on the boards will be cut from foam board. The five channels on the right will be cut from the other piece after the two sheets are glued together. the manifold has the five 10 mm O.D. squares lofted up the 32 mm I.D. to fit my small shop vacuum hoses. The top layer will be my same 2"x2" grid of 1/4" holes I'm currently using but it starts 1" from the edge. This layer will only be taped on. I am planning to leave the bottom open and let the vacuum hold it down.

I'm also toying with making the Z-carriage compatible with a Dremel for light milling/engraving.

 

[moebeast]

I've not done it of course... but I've never understood the need to mill grooves in pink foam. I've always thought your needle cutter could cut dandy channels in a couple (or a few?) sheets of DTFB... one predominantly north-south, the other east-west? Laminate them with your perforated-at-the-channel-intersections waste piece and maybe a solid bottom piece? Then stick it into your wooden frame?

I'm sure I'm not seeing something...

I shared that idea last year and someone did it with 1/2" slots and said it worked good, so that is what I'm doing for my new machine.

 

[jhitesma]

I've not done it of course... but I've never understood the need to mill grooves in pink foam. I've always thought your needle cutter could cut dandy channels in a couple (or a few?) sheets of DTFB... one predominantly north-south, the other east-west? Laminate them with your perforated-at-the-channel-intersections waste piece and maybe a solid bottom piece? Then stick it into your wooden frame?

I'm sure I'm not seeing something...

I've thought about doing that approach a few times. But have a few concerns about it.

The biggest being getting it to sit flat. I found on the vac table waste board I made last year that once I peeled the paper off it warped horribly. Not a big deal on the waste board since the vacuum should hold it flat. (though maybe not since all the vacuum passes through it - so maybe I should add a few channels just to help hold it in place.) But without peeling the paper off I'd worry about how well it would stay together when stacking the pieces.

The main thing is I want the pink foam bigger than than the DTFB so it can help locate the DTFB on the machine in X/Y as well as hold it in Z. I could build it up out of multiple pieces of DTFB...but that just seems like it would wind up looking sloppy and be a bigger pain to assemble.

But might be a hybrid approach in there.....Pink foam as the "frame" just cut a DTFB sided hole in it. Then use DTFB to build up the channels.....hmmmm...

 

[moebeast]

Jason,
Here is my vac manifold printed. I haven't published it yet, but if you want to try it, I will send it to you.


Mark

 

[dkj4linux]

Material support

I got to thinking about support under the material and decided that, rather than a single support across the entire width, I could make individual supports and space them underneath the wasteboard and rely on the wasteboard itself to support the spans between.











Next on the agenda is to buy a couple of sticks of conduit so I can fab longer top rails... I need those 2" so that I can reach the extreme left edge of the sheet.

-- David

 

[dkj4linux]

Jason,
Here is my vac manifold printed. I haven't published it yet, but if you want to try it, I will send it to you.
View attachment 94527 View attachment 94528

Mark

Wow! That looks fantastic, Mark!

 

[jhitesma]

That printed way better than I expected. I'll probably try the long flat nozzle I already have first. Just got back from picking up some more DTFB

The boxes at the store are now 65 sheets, used to be 25 sheets. Glad I wasn't going for a full box today

 

[moebeast]

That printed way better than I expected. I'll probably try the long flat nozzle I already have first. Just got back from picking up some more DTFB

The boxes at the store are now 65 sheets, used to be 25 sheets. Glad I wasn't going for a full box today

It prints nice with the large opening flat to the build plate. It is modelled with a 1.2 mm thickness, but Cura was trying to do infill which slowed down the print horridly. I set 100% concentric infill, and it came out pretty. I want to smooth the transition from the cylinder to the lofts before I publish it.

 

[moebeast]

I shared that idea last year and someone did it with 1/2" slots and said it worked good, so that is what I'm doing for my new machine.

It was CartCurt. He was on here a couple of days ago. Maybe he will let us know if it has held up. Curtis?

 

[quimney]

Look what I got! Had a little free time and some Oilite and the assistance of a good friend

 

[dkj4linux]

Just trying to organize...

Jog speed circle test demonstrating fairly large range of motion... X and Y, no Z

Also, in an effort to collect and organize my work, I've uploaded most of the STL's for this machine to Thingiverse and linked this thread for build details...

https://www.thingiverse.com/thing:2528032

And, as indicated, this thing is indeed still very much a work in progress

-- David

 

[jhitesma]

Jealous Quimney! Gotta talk to my friend with the lathe one of these days and see if I can't bribe him into making me a beauty like that!

David, that machine is looking great! My hobby budget doesn't start to rebuild until around Halloween right now but it's already getting earmarked for too many things


Just to prove I don't hate spindles I mounted mine up with the new improved 660 mount tonight and cut some MDF for my friends CNC in progress:

First piece off the machine, came out just about perfect. MDF doesn't pocket very cleanly...but a few drops of thin ca and a bit of sanding it should be just fine for his initial machine build:



Printing the STL of that part was estimated at 2 hours...which usually means closer to 3 since octo doesn't estimate very accurately in my experience. But on the CNC it only takes:


Yeah, the setup time is a bit longer on CNC. It took me about 10 minutes to do the CAM, compared to maybe 2 minutes to open a file and slice it for 3D printing. But still a lot less time overall. I did both the front and rear X axis plates in less than 30 minutes start to finish:



Seem to finally have a handle on my Z axis issues too - didn't even cut the blue tape (I used the tape both sides and glue the tape together method of work holding) but both parts came off easy. Did have a tiny bit of "flash" in a few areas but nothing I can't live with.



There was a slight mistake though on the 2nd part due to me trying to nest them too tightly. Which was entirely avoidable if I had saved my work in estlcam as I went along. After cutting the first part I was going to use it to reference where to put the second part - but accidentally hit open instead of insert when importing the DXF for the second plate - which in estlcam starts a new project and I hadn't saved my work so far So I had to guestimate where I had placed the first plate on the machine. I was close...but the second plate has one little corner missing on one of it's "ears" due to me nesting it just a hair too close to the first part. You can see it on the lower left corner. Oh, and yeah the top left ear is just a tiny tiny bit too short for the same reason. But the part should still be usable.

Probably won't get to go out to the shop the rest of the week - wife has evening meetings so I'm on kid duty. But next weekend I should be able to cut the rest of his plates for him. Can't wait to see how it goes.

But I just send him David's new machine while I was typing this and now he's talking about selling his big printers and vinyl cutter to make room for that to go with his in progress CNC

 

[TEAJR66]

I made a little progress today. The needle cutter is assembled and works. Pretty happy about that part of it.

 

[CartCurt]

It was CartCurt. He was on here a couple of days ago. Maybe he will let us know if it has held up. Curtis?

I am still using the original design. I did have to change out the waste board once about a month ago. That was after cutting over 30 sheets of foamboard. The design was cut with my needlecutter in a couple of hours. I glued the two channel sheet together and glued that to a solid bottom sheet. The waist board with holes is held in place with masking tape but the vacuum would do the job just as well. I placed it all in a frame that allows me to easily put in a sheet of foamboard already aligned for cutting. I hooked the shopvac to the side with a flat reduction tube. With the vacuum table I am able to make accurate depth cuts across the entire sheet of foamboard.

Curtis

 

[dkj4linux]

I am still using the original design. I did have to change out the waste board once about a month ago. That was after cutting over 30 sheets of foamboard. The design was cut with my needlecutter in a couple of hours. I glued the two channel sheet together and glued that to a solid bottom sheet. The waist board with holes is held in place with masking tape but the vacuum would do the job just as well. I placed it all in a frame that allows me to easily put in a sheet of foamboard already aligned for cutting. I hooked the shopvac to the side with a flat reduction tube. With the vacuum table I am able to make accurate depth cuts across the entire sheet of foamboard.

Curtis

Outstanding report, Curtis. Thanks!

 

[bigALUSMC]

Look what I got! Had a little free time and some Oilite and the assistance of a good friend

View attachment 94542 View attachment 94543

If only these were available to us common folk....lol.

 

[dkj4linux]

If only these were available to us common folk....lol.

I've always been a fan of Shurakair's needle cutter. I always felt these custom guide were the secret to the precision of his cuts. With built-in lube, friction-heat from movement of the needle in the guide is probably non-existent... and, even if it wasn't, his cutter is built on a massive heat sink. There's nothing at all wrong with any of this... but it's out of reach for most of us.

Excessive heating of the needle guide is almost a thing of the past with the improvements made to the basic cutter in recent months. "Pre-guides" (bearings, sideboards, pins, etc.) are easily added which constrain the motion of the needle to near straight-line motion before it gets to the main guide. Jason and others report that their needle guides are little more than warm to the touch after cutting a sheet of foam... nothing like before when it would be too hot to touch.

Welding tips and inflation needles can still be used very effectively. Just make sure that you add "pre-guides" of some sort to your needle cutter build and you'll be fine. -- David

 

[bigALUSMC]

Thank you sir. I am looking at a few options.... either the LowRider, MPCNC or the RTR with customer support STEPCRAFT cnc machine. The Stepcraft is way pricey but worth it to me to make sure I do not have a paper weight. I can run machines but layout, troubleshooting, electronics and housing of such is my demise lol.

 

[jhitesma]

The custom oilite guide may not be necessary. But it's just so darn sexy I still want one even though I'm not fighting heat problems anymore