Cutting foam sheets... with a needle!

[Kendalf]

Back from all the distractions of the Holidays and work. I had fun with the ERC TimSav but want to tinker with lasers and have a multi purpose machine for needle cutter, pen and drag knife. So I have been messing around with an OpenBuilds Acro format machine. I finished and tested my Z axis with an ERC TimSav needle cutter with great results. I will be wall mounting this unit to free up floor space. Still need to tidy up the Z wiring but am happy with the outcome.

Big thank you to dkj4linux for the info on the J Tech Laser Plugin for Inkscape. I am running Inkscape 0.92.4 and OpenBuilds CONTROL v1.0.205 with no issues. Very clean process !!!

Very interested in this combination. I really like the TimSav but I would also like something with a stiffer frame but also more flexibility in attachments (I may want to try a laser in the future), and the OpenBuilds Acro looks like a very nice setup (wish there were more alternatives to compare with, though). Do you have a write-up on how you were able to get the TimSav needle cutter attached to the Acro mount? Did you go with the Acro 1010 kit (40"x40") or did you piece it together yourself from scratch?

EDIT: And what controller are you using for your Acro?

 

[dkj4linux]

Very interested in this combination. I really like the TimSav but I would also like something with a stiffer frame but also more flexibility in attachments (I may want to try a laser in the future), and the OpenBuilds Acro looks like a very nice setup (wish there were more alternatives to compare with, though). Do you have a write-up on how you were able to get the TimSav needle cutter attached to the Acro mount? Did you go with the Acro 1010 kit (40"x40") or did you piece it together yourself from scratch?

EDIT: And what controller are you using for your Acro?

Kendalf,

I feel I'd be remiss if I didn't mention that the MPCNC is a pretty inexpensive and versatile machine that has been the machine/vehicle of choice for most of this very lengthy and eclectic needle cutting thread... TimSav (the new guy on the block) has been the subject of only the past couple of pages.

Please, at least scan through this lengthy thread and you'll find MPCNC, FoamRipper, LowRider, Openbuild Acro, and various other machines spoken of and adapted to many different functions and tools... needle cutters, diode lasers, pen/marker-plotting, etc.

That said, I do like Edward's version of the needle cutter and have adopted/adapted it as my recommended cutter for new MPCNC users...

https://www.thingiverse.com/thing:4056438

Here it is installed on a MPCNC...

https://forum.flitetest.com/index.p...eets-with-a-needle.24251/page-144#post-524782

As you've mentioned TimSam is a minimalist machine and quite suitable for needle-cutting planes... but not real versatile otherwise. Tell us a bit about yourself, your DIY capabilities, and what you'd like to see in a machine and I'd bet we can give you some ideas and point you to some "prior art"...

-- David

 

[dehager]

Thanks ironkane,
I based it on your Z axis as it was a simple no nonsense design.

Kendalf,
This started life as an ACRO 1010 but ended up being a full size ACRO 1510. The 1010 with the Z axis was barley able to fit a full 20" x 30" sheet of DTFB (Dollar Tree Foam Board). I also have full sheets of MPF (Model Plane Foam) which are 24" x 48" and I would not be able to cut a full sheet of MPF. The most important design consideration was that I would be able to vertically wall mount the ACRO. As I have limited floor space, there would be no way I could have one if I could not wall mount it. My modified ACRO has a base frame with a sheet of 1/8" Eucatile White Tile Board (Home Depot $13) which serves double duty as a dry erase marker board. Vertical mounting required a 6.5 pound counterweight for smooth operation. I can not say enough about the Moebeast Foam Ripper vacuum board, what a convenience.

I was originally planning on using an Arduino/Protineer CNC Shield or a Raspberry Pi but decided that I just wanted it to work and not to have to tinker with it. It is currently controlled by an OpenBuilds BlackBox and Meanwell 24V Powersupply. Software I am currently using is Inkscape, JTech Laser Plugin and OpenBuilds Control.

The TimSav Needle cutter just has a new back plate to mate up with the gantry plate on the Z Axis.

No plans or documentation to date but may post a build on OpenBuilds forum if time permits.

 

[dkj4linux]

An update on my printer build and lack of progress...

I'm sure some of you may be asking yourself, "Now where'd David go... and what's up with his Prusa build?"

Well, just yesterday, I've picked the Prusa printer build back up and am most of the way through getting the Extruder assembled and installed (that step is challenging, to say the least!). It doesn't yet look significantly different so no photo...

I had put the build on hold for 10 days or so while I continued to develop an idea that I had already sunk my teeth into... a rack-and-pinion (r&p) drive for MPCNC X and Y axes. I documented the design/build journey in a thread over on the V1Engineering forum, where another thread had renewed my interest in r&p, and it "lifts" off the printed r&p work I'd done on the Phlatprinter-inspired machine I played with a couple of years ago. I actually wound up printing and building an entire new Burly MPCNC over the past couple of weeks that uses r&p drive and performs surprisingly well as a pen-plotter, using just a ball-point pen... and it's entirely stock with the exception of the roller assemblies and no belts.

Here was an idea @jamiek had for the roller configuration and my latest incarnation... an uncanny resemblance, huh?

Here's the obligatory MPCNC crown being plotted...

And a few logo plots...

And a couple of rulers from @jamiek's Test Pattern Generator (these are actually TWO rulers, side-by-side and printed in opposite directions)...

The first three ruler photos show ~0.75mm long over 100mm in X so I adjusted the steps/mm by 0.9926 and it now prints rulers that are accurate when compared to a commercial metal ruler. The Y axis is handled exactly the same way. Somewhat surprisingly there appears to be little/no significant backlash... the tic marks of the side-by-side rulers -- plotted in opposite directions -- line up pretty nicely.

With time there may be significant wear and tear on the printed rack and pinion but I suspect the residue on the pinion right now (below) is probably just the roughness of the printed teeth smoothing out...

This was just one of those fun projects I love to do... pursued solely to satisfy my curiosity. Please know that this was in no way an attempt to undermine Ryan's MPCNC design... he's fully aware of it and good with it. His design is robust and proven and is the ONLY way to properly build an MPCNC. This design is totally unproven and unsupported -- a "laboratory curiousity" -- and may never appear on another machine. But I had fun and it was a blast to do!

For those interested, I did all the original design work in Onshape and the modular r&p roller bits can be seen here.

-- David

 

[Maverick29201]

Has anyone tried the CNC cutter plans on nerdnic.com called the rascal? Free plans said to cost 500.00 dollars to build. I don't have a clue just wondering.

 

[dkj4linux]

Rascal CNC is a real machine and there is a thread here on FT...

https://forum.flitetest.com/index.php?threads/rascal-cnc.37087/

 

[ironkane]

Thanks ironkane,
I based it on your Z axis as it was a simple no nonsense design.

Kendalf,
This started life as an ACRO 1010 but ended up being a full size ACRO 1510. The 1010 with the Z axis was barley able to fit a full 20" x 30" sheet of DTFB (Dollar Tree Foam Board). I also have full sheets of MPF (Model Plane Foam) which are 24" x 48" and I would not be able to cut a full sheet of MPF. The most important design consideration was that I would be able to vertically wall mount the ACRO. As I have limited floor space, there would be no way I could have one if I could not wall mount it. My modified ACRO has a base frame with a sheet of 1/8" Eucatile White Tile Board (Home Depot $13) which serves double duty as a dry erase marker board. Vertical mounting required a 6.5 pound counterweight for smooth operation. I can not say enough about the Moebeast Foam Ripper vacuum board, what a convenience.

I was originally planning on using an Arduino/Protineer CNC Shield or a Raspberry Pi but decided that I just wanted it to work and not to have to tinker with it. It is currently controlled by an OpenBuilds BlackBox and Meanwell 24V Powersupply. Software I am currently using is Inkscape, JTech Laser Plugin and OpenBuilds Control.

The TimSav Needle cutter just has a new back plate to mate up with the gantry plate on the Z Axis.

No plans or documentation to date but may post a build on OpenBuilds forum if time permits.

View attachment 156708 View attachment 156709 View attachment 156710

That is pretty badass! What a space saver. Wish I had a bare wall available that my wife would let me use.

You should really check out Lightburn https://lightburnsoftware.com/ You can go from .png to burning wood in just a couple of minutes. No GCode to generate and run, just set your power and feed rate and go. Ungroup your image and you can assign different power/feed settings to different layers to mark, fill and cut. It even supports mounting a camera to 2D scan an object and convert it to a laser job. I've tried the other suggestions from JTech and this blows them away.

 

[Kendalf]

I feel I'd be remiss if I didn't mention that the MPCNC is a pretty inexpensive and versatile machine that has been the machine/vehicle of choice for most of this very lengthy and eclectic needle cutting thread... TimSav (the new guy on the block) has been the subject of only the past couple of pages.

Please, at least scan through this lengthy thread and you'll find MPCNC, FoamRipper, LowRider, Openbuild Acro, and various other machines spoken of and adapted to many different functions and tools... needle cutters, diode lasers, pen/marker-plotting, etc.

Tell us a bit about yourself, your DIY capabilities, and what you'd like to see in a machine and I'd bet we can give you some ideas and point you to some "prior art"...

-- David

I've definitely been reading bits and pieces from this thread and any other sources that I can find on these. I'm always impressed at the ingenuity and inventiveness shown in those who have built these things. For me personally, I'm handy with electronics and familiar with computers, Raspberry Pi, Arduino, etc. But with other hardware I'm more of a LEGO/Ikea follow instructions and build from a kit type of person and not very capable at fabricating. So while the MPCNC and FoamRipper are intriguing, the cutting/drilling of conduit or stainless steel tubes and other fabrication steps that are part of those builds is less my forte, and so I'm more inclined to the pre-fabricated kits like the OpenBuilds Acro.

 

[Kendalf]

Kendalf,
This started life as an ACRO 1010 but ended up being a full size ACRO 1510. The 1010 with the Z axis was barley able to fit a full 20" x 30" sheet of DTFB (Dollar Tree Foam Board). I also have full sheets of MPF (Model Plane Foam) which are 24" x 48" and I would not be able to cut a full sheet of MPF. The most important design consideration was that I would be able to vertically wall mount the ACRO. As I have limited floor space, there would be no way I could have one if I could not wall mount it. My modified ACRO has a base frame with a sheet of 1/8" Eucatile White Tile Board (Home Depot $13) which serves double duty as a dry erase marker board. Vertical mounting required a 6.5 pound counterweight for smooth operation. I can not say enough about the Moebeast Foam Ripper vacuum board, what a convenience.

I was originally planning on using an Arduino/Protineer CNC Shield or a Raspberry Pi but decided that I just wanted it to work and not to have to tinker with it. It is currently controlled by an OpenBuilds BlackBox and Meanwell 24V Powersupply. Software I am currently using is Inkscape, JTech Laser Plugin and OpenBuilds Control.

The TimSav Needle cutter just has a new back plate to mate up with the gantry plate on the Z Axis.

No plans or documentation to date but may post a build on OpenBuilds forum if time permits.

That is an awesome set-up! Space and storage consideration is something that I've been looking at for my home. Does the platform swing down to use, or does it actually work in that vertical orientation? Do you have plans to utilize the Acro for other things besides cutting foam board?

 

[ironkane]

I've definitely been reading bits and pieces from this thread and any other sources that I can find on these. I'm always impressed at the ingenuity and inventiveness shown in those who have built these things. For me personally, I'm handy with electronics and familiar with computers, Raspberry Pi, Arduino, etc. But with other hardware I'm more of a LEGO/Ikea follow instructions and build from a kit type of person and not very capable at fabricating. So while the MPCNC and FoamRipper are intriguing, the cutting/drilling of conduit or stainless steel tubes and other fabrication steps that are part of those builds is less my forte, and so I'm more inclined to the pre-fabricated kits like the OpenBuilds Acro.

I bought the 40 x 40 (1010) and cut 10" off of two pieces to make it more DTFB sized. Took the two pieces I cut off and made the Z axis like dehager did. Although I coughed up the dough for the gantry plate instead of printing it when I bought the wheels and the like.

Besides cutting foam board with a needle cutter, I have a JTech 4.5w laser that cuts acrylic really well. With air assist, I can cut 5mm hardwood ply. Although that can take 15 to 20 passes. Still trying to get it in the 10 to 15 range ( 1/4" acrylic). Does a good job on leather. Etched glass with it by first painting it flat black. Worked, need to refine settings. Love the laser, want to get the 7w. I also have a sharpie pen mount for drawing and have plans to print a mount for a drag knife so I can cut vinyl decals.

The only things I want to change on the Acro is laser cut some new acrylic feet to make it taller. And laser cut some acrylic plates to mount on the inside of the cross bar to reduce the load on the v-wheels axles. It was designed to only drag a beam of light around. Not needle cutters, pens and drag knives.

If you don't have a 3D printer, you can cut 1/4" acrylic pieces and parts. You don't "have" to have a Z axis for cutting acrylic, it's just takes longer. Definitely buy a commercial aquarium on Amazon for your air-assist. You'll definitely want air and a Z for cutting thin ply.

 

[Kendalf]

I bought the 40 x 40 (1010) and cut 10" off of two pieces to make it more DTFB sized. Took the two pieces I cut off and made the Z axis like dehager did. Although I coughed up the dough for the gantry plate instead of printing it when I bought the wheels and the like.

Besides cutting foam board with a needle cutter, I have a JTech 4.5w laser that cuts acrylic really well. With air assist, I can cut 5mm hardwood ply. Although that can take 15 to 20 passes. Still trying to get it in the 10 to 15 range ( 1/4" acrylic). Does a good job on leather. Etched glass with it by first painting it flat black. Worked, need to refine settings. Love the laser, want to get the 7w. I also have a sharpie pen mount for drawing and have plans to print a mount for a drag knife so I can cut vinyl decals.

Do you have a Thingiverse link to the needle cutter and mount you use to attach to the Acro?

I also came across the Eleksmaker Mega with a 24" x 24" work area. At $250 (with ManaSE controller and stepper motors) it looks like a cheaper alternative kit to the Openbuilder Acro. It's not quite long enough for a full DTFB, but I'm comfortable with the idea of rearranging pieces in the plan in Inkscape and not cutting out of a full 20x30" sheet of DTFB. I've seen several posts of people who have the smaller Elekslaser kits, and I even saw @dkj4linux post about using the Eleksmaker ManaSE controller with the TimSav, though I haven't seen anyone mount a needle cutter to the Eleksmaker yet, so I'm unsure how feasible it would be. Perhaps just a matter of designing and 3D printing a mounting plate to attach the needle cutter?

Adding a more powerful laser is certainly something I would consider in the future, not for cutting foam board, but for other projects.

 

[ironkane]

Do you have a Thingiverse link to the needle cutter and mount you use to attach to the Acro?

I also came across the Eleksmaker Mega with a 24" x 24" work area. At $250 (with ManaSE controller and stepper motors) it looks like a cheaper alternative kit to the Openbuilder Acro. It's not quite long enough for a full DTFB, but I'm comfortable with the idea of rearranging pieces in the plan in Inkscape and not cutting out of a full 20x30" sheet of DTFB. I've seen several posts of people who have the smaller Elekslaser kits, and I even saw @dkj4linux post about using the Eleksmaker ManaSE controller with the TimSav, though I haven't seen anyone mount a needle cutter to the Eleksmaker yet, so I'm unsure how feasible it would be. Perhaps just a matter of designing and 3D printing a mounting plate to attach the needle cutter?

Adding a more powerful laser is certainly something I would consider in the future, not for cutting foam board, but for other projects.

I wouldn't try to talk you out of a more budget friendly option. I'll give some observations though. The machine bundles like the Acro on OpenBuilds are pretty good deals. If you were to take their parts lists for a build and price it all out, you'll find that they're not marking it up because it's a kit. Which is great because you don't have to create the shopping list and you're paying the same price as if you bought the individual pieces.
The V-Slot rails are cheap. Around $60 or so. The Acro plate kit is $27. So just building a basic frame is only around $100. What really costs you is all the other connectors, motors, electronics, pieces and parts. All a bunch of relatively inexpensive items that add up. The MPCNC has the same issues. They all do. From the MPCNC site "Total Cost… if you have a 3D printer Under $370, $475 if you buy the printed parts from here." You're not going to get a fabulous price on any CNC.

So with that Eleksmaker, you're getting that V-Slot frame and electronics at a reasonable price. The laser isn't suitable for cutting anything but the thinnest of materials. But if you want to just mark/engrave cutting boards, you'll have fun. But you can a 7w laser on Banggood for $130. What the life expectancy of that laser? I dunno, but a 7w laser from JTech is going to set you back $675. You can buy 5 cheap Chinese lasers for that price. I'm sure that Jay could tell you why you should spend the big bucks. The answer is probably going to revolve around safety and reliability.

I know nothing about the ManaSE. It's $32. The OpenBuilds BlackBox is $170. Others fall in between. Back when I built my Acro, OpenBuilds was selling a Spark Concepts CNC XPro and the latest one http://www.spark-concepts.com/cnc-xpro-v4-controller/ is $120. It's a nice GRBL board. There are a lot of controllers out there. Do the homework.

So what you should be looking for is a solid, straight and parallel frame and electronics that don't produce the magic smoke that is budget reasonable. If you have a 3D printer, you can save some money on some of this build.

As for the needle cutter and mount, there are a lot of choices from simple to elaborate. As long as the needle cuts foam and doesn't break constantly, you're doing good. If you have a 3D printer, you should definitely get AutoDesk Fusion 360. I don't have a Thingiverse link for a needle cutter or mount because I designed my own. Lol, I think I'm being generous in calling it a design. I've got pictures somewhere in this thread. dehager and I have very similar designs for the Z axis and mount. I'm using an OpenBuilds aluminum plate and he printed his. My Z plate has four projecting screws that I use to mount the various tool head plates. I think mine is a little bit faster/easier to swap out tool heads. My needle cutter falls on the KISS side of the spectrum. I like the current designs that have come out. Very inventive.

On a final note, there's nothing to stop you from buying the Eleksmaker and buying some longer V-Slot rails and a roll of timing belt to get the frame to a size that cuts a full sheet of foam board. That's about $40 more. It's easier and more convenient when setting up your plans.

You can then use the laser to cut the Acro plate kit out of acrylic to customize up. Browse the 147 pages of this thread and get inspired.

 

[Kendalf]

Thanks for those detailed points, @ironkane! I'm already leaning towards the Acro kit, though direct from a Chinese seller rather than through OpenBuilds. "Bulk Man 3D" has the Acro 1000mm x 1000mm mechanical kit for $279 (shipping included). This includes 3 NEMA 17 stepper motors, but it does not include the wiring kit that comes with the OpenBuilds kit. I can separately add the GRBL UNO Wiring Kit for $106+ which adds all the wiring, Arduino Controller, and the same Meanwell 24V Power supply that OpenBuilds sells. That comes out to a total of $385, vs. $482 (+$25 for a similar Uno + shield controller) for similar hardware from Openbuilds. I should be able to save more by just getting the wiring kit for $58 as I already have a couple Uno and should be able to scrounge up a suitable power supply.

That leaves the additional cost for putting together a needle cutter and/or laser. It's been a lot of back and forth weighing the options of needle cutter vs laser. Needle cutter is excellent for foamboard, with clean and complete cuts in one pass once dialed in, but it would not be usable for other things. Diode laser could be used for etching and cutting other materials (I would like to do some acrylic work), but it wouldn't cut completely through white foamboard (which is my primary purpose). Plus the inherently greater safety requirements with lasers (goggles, shields, cooling and ventilation, etc.). But it's a LASER!

What it seems to boil down to is if I only want to use the CNC for cutting foam board, the needle cutter is the way to go (simpler, safer, and more budget friendly). But if I have firm plans for doing etching and cutting materials other than foam board, I need to look into a laser suitable for the task.

 

[ironkane]

Thanks for those detailed points, @ironkane! I'm already leaning towards the Acro kit, though direct from a Chinese seller rather than through OpenBuilds. "Bulk Man 3D" has the Acro 1000mm x 1000mm mechanical kit for $279 (shipping included). This includes 3 NEMA 17 stepper motors, but it does not include the wiring kit that comes with the OpenBuilds kit. I can separately add the GRBL UNO Wiring Kit for $106+ which adds all the wiring, Arduino Controller, and the same Meanwell 24V Power supply that OpenBuilds sells. That comes out to a total of $385, vs. $482 (+$25 for a similar Uno + shield controller) for similar hardware from Openbuilds. I should be able to save more by just getting the wiring kit for $58 as I already have a couple Uno and should be able to scrounge up a suitable power supply.

That leaves the additional cost for putting together a needle cutter and/or laser. It's been a lot of back and forth weighing the options of needle cutter vs laser. Needle cutter is excellent for foamboard, with clean and complete cuts in one pass once dialed in, but it would not be usable for other things. Diode laser could be used for etching and cutting other materials (I would like to do some acrylic work), but it wouldn't cut completely through white foamboard (which is my primary purpose). Plus the inherently greater safety requirements with lasers (goggles, shields, cooling and ventilation, etc.). But it's a LASER!

What it seems to boil down to is if I only want to use the CNC for cutting foam board, the needle cutter is the way to go (simpler, safer, and more budget friendly). But if I have firm plans for doing etching and cutting materials other than foam board, I need to look into a laser suitable for the task.

Not bad options. Let me throw you another resource for V-Slot rails. https://8020.net/
Also a few pics from my build process. If you're up to a little soldering and crimping, you may want to do your own wiring. Amazon is a great resource for supplies. After seeing it on Thingiverse, I used aviation connectors, silicon wire, JST connectors and crimpers on a 3D printed chassis box.

My Needle Cutter

some details on pages 115-117


And Hell Yeah! Lasers are fun!

 

[Kendalf]

@ironkane That's a great setup! I'm handy with a soldering iron, but I'll most likely still get the wiring kit just to be sure I have all the different kinds of wires/connectors needed to hook everything up first. Then maybe I can tinker with better enclosures, etc.

I think I also want to rig up a z-axis like yours and @dehager, utilizing short pieces cut from the aluminum rails. Would either of you be willing to share Thingiverse links and BOM for your z-axis? I tried searching through this thread but didn't find anything more specific besides @ironkane's post of his completed z-axis.

 

[ironkane]

@ironkane That's a great setup! I'm handy with a soldering iron, but I'll most likely still get the wiring kit just to be sure I have all the different kinds of wires/connectors needed to hook everything up first. Then maybe I can tinker with better enclosures, etc.

I think I also want to rig up a z-axis like yours and @dehager, utilizing short pieces cut from the aluminum rails. Would either of you be willing to share Thingiverse links and BOM for your z-axis? I tried searching through this thread but didn't find anything more specific besides @ironkane's post of his completed z-axis.

Thanks. If it's a wiring kit sized to the machine you're assembling, go for it. Otherwise you'll be making extensions. Which is adding to potential points of failure. If you have a bad solder splice or mechanical splice and conductivity is impaired, it could lead you to scratching your head like Chevy Chase in Christmas Vacation.

What you're building is pretty much this --> https://openbuildspartstore.com/c-beam-xlarge-linear-actuator-bundle/ but much slimmer.

BOM is easy enough.
2 Lengths of V-Slot 20x20 rail
V-Slot Gantry kit https://openbuildspartstore.com/v-slot-gantry-kit-universal/
Lead screw https://www.amazon.com/Copper-Coupler-Hexagon-Bearing-Printer/dp/B07S1LKMQ6
Nema 17 https://www.amazon.com/dp/STEPPERONL/?tag=lstir-20
T-nuts https://www.amazon.com/dp/B07KSFB7BG/?tag=lstir-20
Nutblock https://openbuildspartstore.com/nut-block-for-8mm-metric-acme-lead-screw/
Some M5 screws
I don't have a .stl file handy. But really, get Fusion360 and you can create your own. Alternatively, you can use acrylic or even wood for the top and bottom pieces. Drill a hole on each and and holes for the Nema 17. Screws to connect to the V-Slot ends https://openbuildspartstore.com/self-threading-screws-m3-10-pack/

But if you're really pressed for it, I'm sure I can find the files. If you have a 3D printer, you should progress beyond printing other peoples stuff. Fusion360 is not very hard to get the basics on. Lot's of videos online to get you started.

It's as simple as adding a sketch to your drawing. You click and drag a square. Set the dimensions. Do the same thing for your holes. Close the sketch and in the main view, you grab the face of your square and drag it up to the desired height and presto, you have a 3D part. That's an oversimplification, but it really is that simple.

Steve

 

[Springer]

Just a tidbit for you guys thinking of using a drag knife. I was really interested in one until I got into a discussion where they were talking about how knife software is special to move the head around to achieve sharp corners. At that point I gave up and worked more with the 2.5 watt laser dkj4linux suggested. I found that I could cut the Michael's type vinyl decal sheet perfectly at 70/255 power and 350mm/min speed. It cuts the vinyl and adhesive but not the clear backing film. In the attached pic, the names and N numbers are all laser cut. A friend was over a few days ago and asked about how it cut cloth (his wife is a quilter) so we tried it and got a great fine smooth cut. While you may find different power and feed settings work best, it is worth a try!

 

[dkj4linux]

Just a tidbit for you guys thinking of using a drag knife. I was really interested in one until I got into a discussion where they were talking about how knife software is special to move the head around to achieve sharp corners...

Hey, Mike! Good to hear from you!

Donek Tools has a line of heavy-duty drag knives and used to have some really good videos showing their use. They don't seem to be pushing that part of their business anymore, however... but they do still have a free download of an Excel spreadsheet which can be used to post-process a gcode file to add corner actions required to improve sharp corners in thick materials.

Check this post for an explanation of why the corner compensation is needed with a drag knife... especially when cutting thick materials with a heavy duty knife with sizable offset. But I think the simplest way to illustrate why the corners tear and get mangled with a drag knife is to simply stab the butter with the tip of a steak knife, score a straight line, and then twist to make a corner.

-- David

 

[Springer]

Heh, love your butter analogy. My opinion, drag knives are a cool tech, and if one likes to tinker may be fun to figure out how and when to add in the "extra moves", but after I ran the little laser focus routine you showed me how to do, and get the point focus, super fine line, the laser cuts both vinyl and colored packing tape so well, I have no need for another decal cutter!

 

[dkj4linux]

I finally finished the MK3S printer build and then printed a few fit check parts for r&p MPCNC... they all look pretty good and are dimensionally correct.

A really nice machine. I really like it... though I do wish the steel sheet they included hadn't been green!

-- David