Cutting foam sheets... with a needle!

[dkj4linux]

Looks great x33.

Hey David, I am preparing to use SketchUp and SketchUCam to cut out a neddle cutter mount, but I have a question.

How do I set the free travel speed, mainly the free travel Z speed, so my MPCNC does not overshoot?

Glenn,

It's been a while but I assume you are talking of jog speed (not cutting)...as opposed to feed rate (cutting)? If you click on the SketchUCAM Toolbox icon (or "Tools->Phlatboyz->Parameters") you will see all the parameters available to you... "Feed Rate" and "Plunge Rate". I don't think there are separate "jog" and "feed" rates, unfortunately.

It's possible there have been updates... I haven't looked in a while. All I can say is, while you may wish it to move faster when moving from part to part... be patient -- it'll get there eventually

-- David

 

[x33]

cutting balsa with the needle

... a nice blue catfish (me) and a good-sized drum by my buddy
...
...
Great work on the CNC machine, Joachim! It'll be nice not to be dependent on that big, under-powered CNC any longer
...
...
That "old prototype" cutter of yours ought to be placed in the museum of "unexpectedly good" KISS tools... it's already served you well. I'd still love to see one of those planes you've cut... finished up and flying ,
-- David

Hi David...please send me one of the fish per mail...the pics are making me hungry :applause:
...
...
the CNC was "a little" more work than exspected...hoping to finish the project before the flying season starts.
Pics/vids of the "Shocky60" will follow asap.
...
...
I made up my mind about this "long living" needle...may be, the secret behind is the short steel tip in the welding guide.
This part is a ~5mm long piece made from the hollow needle of a syringe...the 0,5mm music wire fits nearly perfect.
......................
......................
......................
.... Cutting Balsa Wood .....
I tried to cut some 1,5mm Balsa parts with the needle ---> the first results are not bad....have to find out the best toolpath speed (slow!!!) and the right sort of Balsa (semi-hard)...will send some pics the next days.

Joachim

 

[CaptCaveman37]

Hi all,

My Prusa should be here by the end of the month. What is the latest and greatest prototype cutter? What size motor is everyone using?

thanks

Jamie

 

[CartCurt]

I have tried different motors, but I like the DT-750 form HobbyKing. It's a bell style motor that acts like a flywheel and has lower 750 KV speed. It never gets hot and is easy to control RPMs. The best motor is one you have laying around so you don't have to buy a new motor.

Curtis

 

[dkj4linux]

Hi all,

My Prusa should be here by the end of the month. What is the latest and greatest prototype cutter? What size motor is everyone using?

thanks

Jamie

Hello, Jamie... and welcome!

I, too, am waiting on my Prusa I3 Mk2 kit to arrive... probably a few weeks away yet, however. I plan to use it to print with a few new (to me) filaments... PLA first, of course, to get it all setup/calibrated and then some nylon. I'm want to print nylon sideboards for my latest needle cutters...

I'm partial to Joachim's "KISS cutter" sideboard configuration (post #1218) and my version of it (post #1202). I like the improvement(s) it brings to the original needle cutter without adding any moving parts. Verris is getting good performance from his ball-bearing guided needle cutter as well, I believe.

Read through this thread (and others linked in early posts) long enough and you'll see that there is nothing at all sacred or critical about the needle cutter. It can be built almost any way you see fit... using a variety of materials/methods/parts. The later versions with improved guidance/control of the needle (similar to those mentioned above) will probably give you the best chance of success... and offer improved performance and longest needle life, with the least frustration. That would be my recommendation for your needle cutter.

Good luck... and let us know how it goes. -- David

 

[vastsky]

Needle cutter Toolpath summary for $tree foam - pleeeeease....

My MPCNC (X=37", Y=25", Z=4") and needle cutter is built. I am now hoping for guidance so I can get "cutting"! Searched for days, but still needed your expertise - please.

1) Creating Gcode as I understand it: Import .jpeg into Inkscape to create .dxf -> Sketchup+SketchUcam = Gcode (Are there specific settings that make it for Marlin?)

My attempt at Inkscape .dxf creation from a .jpeg yielded a complex "multipath" .dxf containing far too many lines/node points which Sketchup could make little sense of. Is there a way to simplify the .dxf to just single line/node points that simply describe the original .jpeg outlines?

I found that it was simpler to just import the .jpeg into Sketchup and draw over the image. This new drawing is then used by SketchUcam to create Gcode, however, SketchUcam seemed unable to render a believable toolpath. I ended up exporting my Sketchup drawing as .dxf, then used Estlcam on this .dxf to manually select and create Marlin Gcode toolpaths.

Hoping for a strategy to render .pdf into Marlin Gcode as well.

2) Tool settings for the needlecutter.

What toolpath speed do you find works well? Any other pre-cut setup or settings info appreciated. My needle extends about 6 to 7mm beyond the end of the MIG welding tip guide. Z = 4". I can figure out the needle cutter speed easy enough.

3) Preparation for a cut.

How do you set the origin and the Z height in relation to the foamboard? Is there a simple way to confirm that you have the correct placement of the foam board so as to accurately predict where the cutting will take place? Are there other pre-cutting checks you regularly make such as confirming that the X and Y axis rails are in fact parallel to the frame rails? I always do a trial run and can print from Repetier or an SD card "headless". It seems that using Repetier allows you to set/change toolpath rates before running a cut job. Each axis of my MPCNC is equipped with "zero" end switches that are easily moved along the axis.

Perhaps there may be a Gcode routine that would send the tool out to each projected corner of the foam board? That may be a useful routine.

Would removing the paper from the $tree board make for more precise cutting? It can become a bit wonky with the paper off.

Still on the steep of the learning curve. My eyes are bleary from reading this terrific thread. Trouble is that I discover waaay too many other cool distractions (lasers!!) to investigate rather than staying only focused on extracting the info I originally was hunting for!

 

[jhitesma]

My MPCNC (X=37", Y=25", Z=4") and needle cutter is built. I am now hoping for guidance so I can get "cutting"! Searched for days, but still needed your expertise - please.

Hang in there...you're close!

1) Creating Gcode as I understand it: Import .jpeg into Inkscape to create .dxf -> Sketchup+SketchUcam = Gcode (Are there specific settings that make it for Marlin?)

My attempt at Inkscape .dxf creation from a .jpeg yielded a complex "multipath" .dxf containing far too many lines/node points which Sketchup could make little sense of. Is there a way to simplify the .dxf to just single line/node points that simply describe the original .jpeg outlines?

I found that it was simpler to just import the .jpeg into Sketchup and draw over the image. This new drawing is then used by SketchUcam to create Gcode, however, SketchUcam seemed unable to render a believable toolpath. I ended up exporting my Sketchup drawing as .dxf, then used Estlcam on this .dxf to manually select and create Marlin Gcode toolpaths.

Hoping for a strategy to render .pdf into Marlin Gcode as well.

The key is you need paths not bitmaps. So coming from a .jpg is going to be tricky. Re-drawing like you did is probably going to give the best results on something that's a .jpg. From PDF you can just import PDF into inkscape and a lot of them (like FT's) still have vector paths in them so you just have to "ungroup" them to work with them. It is possible to embed bitmaps into PDF's though so you could come across PDF's that can't be easily converted (most likely they'd be scans of old printed plans or such.)

I didn't have much luck with SketchUcam and have never been huge on sketchup. So my workflow is to use estlcam to generate gcode using MPCNC settings as suggested by the vicious1.com site.

2) Tool settings for the needlecutter.

What toolpath speed do you find works well? Any other pre-cut setup or settings info appreciated. My needle extends about 6 to 7mm beyond the end of the MIG welding tip guide. Z = 4". I can figure out the needle cutter speed easy enough.

I don't have access to my settings right now so I can't really answer this one

3) Preparation for a cut.

How do you set the origin and the Z height in relation to the foamboard? Is there a simple way to confirm that you have the correct placement of the foam board so as to accurately predict where the cutting will take place? Are there other pre-cutting checks you regularly make such as confirming that the X and Y axis rails are in fact parallel to the frame rails? I always do a trial run and can print from Repetier or an SD card "headless". It seems that using Repetier allows you to set/change toolpath rates before running a cut job. Each axis of my MPCNC is equipped with "zero" end switches that are easily moved along the axis.

Perhaps there may be a Gcode routine that would send the tool out to each projected corner of the foam board? That may be a useful routine.

Would removing the paper from the $tree board make for more precise cutting? It can become a bit wonky with the paper off.

Still on the steep of the learning curve. My eyes are bleary from reading this terrific thread. Trouble is that I discover waaay too many other cool distractions (lasers!!) to investigate rather than staying only focused on extracting the info I originally was hunting for!

I use the lower left corner as my origin, I set my Z by extending the needle manually as far as it will go and then lowering Z on the machine until it just barely touches the foamboard. I don't use any endstops - I just turn the RAMPS on when I have the head positioned at 0,0,0 and have a shortcut I added to Marlin's LCD menu that lets me tell it the current position is 0,0,0 which I use when I don't want to unplug/replug the machine to set the origin.

I believe some people set the waste board as 0,0,0 and then reference off of that for Z. But I like referencing the top and defining the depths of cuts on my paths as it makes the most sense to me. There's more than one "correct" way to do things though

I don't remove the paper, with speeds setup correctly and a good sharp needle I get cleans cuts through it.

When I'm preparing my files in inkscape I start by creating a 20"x30" document to place all my parts on. I try to leave about 1/4" border around the edges though to have room for the T-pins I use to hold down the board.

Oh, when setting Z I usually don't do it in the corner since the corners are frequently squished a bit. Instead I manually push the toolhead out about 4" from either edge and set my Z there - then pull it back to position over x=0,y=0

I was going to make a video showing how I prepare cuts...but then Verris found some tricks to make it all quicker/easier and was talking about making a video so I slacked off on my plans. But then I got him distracted rebuilding his quads so maybe I'll have to do a video after all.

 

[dkj4linux]

My MPCNC (X=37", Y=25", Z=4") and needle cutter is built. I am now hoping for guidance so I can get "cutting"! Searched for days, but still needed your expertise - please.

1) Creating Gcode as I understand it: Import .jpeg into Inkscape to create .dxf -> Sketchup+SketchUcam = Gcode (Are there specific settings that make it for Marlin?)

My attempt at Inkscape .dxf creation from a .jpeg yielded a complex "multipath" .dxf containing far too many lines/node points which Sketchup could make little sense of. Is there a way to simplify the .dxf to just single line/node points that simply describe the original .jpeg outlines?

I found that it was simpler to just import the .jpeg into Sketchup and draw over the image. This new drawing is then used by SketchUcam to create Gcode, however, SketchUcam seemed unable to render a believable toolpath. I ended up exporting my Sketchup drawing as .dxf, then used Estlcam on this .dxf to manually select and create Marlin Gcode toolpaths.

Hoping for a strategy to render .pdf into Marlin Gcode as well.

2) Tool settings for the needlecutter.

What toolpath speed do you find works well? Any other pre-cut setup or settings info appreciated. My needle extends about 6 to 7mm beyond the end of the MIG welding tip guide. Z = 4". I can figure out the needle cutter speed easy enough.

3) Preparation for a cut.

How do you set the origin and the Z height in relation to the foamboard? Is there a simple way to confirm that you have the correct placement of the foam board so as to accurately predict where the cutting will take place? Are there other pre-cutting checks you regularly make such as confirming that the X and Y axis rails are in fact parallel to the frame rails? I always do a trial run and can print from Repetier or an SD card "headless". It seems that using Repetier allows you to set/change toolpath rates before running a cut job. Each axis of my MPCNC is equipped with "zero" end switches that are easily moved along the axis.

Perhaps there may be a Gcode routine that would send the tool out to each projected corner of the foam board? That may be a useful routine.

Would removing the paper from the $tree board make for more precise cutting? It can become a bit wonky with the paper off.

Still on the steep of the learning curve. My eyes are bleary from reading this terrific thread. Trouble is that I discover waaay too many other cool distractions (lasers!!) to investigate rather than staying only focused on extracting the info I originally was hunting for!

Thanks, Jason, for jumping in with all the great info. It's been a while since I've done any of this and was racking my brain trying to compose something intelligent to respond with...

Ed, Jason is spot on with the comments about JPGs and PDFs. I've done nothing with JPGs. Thankfully, most plane plans seem to come as PDFs and are readily handled in any of several ways. Inkscape handles PDFs readily as Jason said... to convert to DXFs and can even generate gcode with the JTech plugin for laser engraving/cutting. Another option (and I seem to be in the minority here) "pstoedit" works well for me, as a Linux user, to quickly create DXFs from PDFs. For planes and needle-cutting, SketchUp/SketchUCAM can work nicely... from DXF input and then outputting Marlin-compatible gcode if a couple of settings are properly set. I can check on them if you are interested.

Tool settings for the needle cutter... for tool offset, if/when needed, I use 0.7mm (0.027") as my tool diameter, as my needle is 0.025" music wire. A feed rate of 600 mm/min works well... as 6000-8000 rpm is easily attained and gives nice clean cuts in DTFB (paper on), giving at least 10 perforations per millimeter.

I don't have limit-switches on my MPCNC and like being able to set the origin where I need it for any particular run. I jog X and Y to where I want my origin and then Z-zero at the top of the material. I simply turn on the needle cutter and lower the Z-axis until the needle starts "tickling" the top of the material... you can't miss the change in sound when it touches the material. With everything then positioned as desired, I reset the Arduino with the switch on the RAMPS board... no power cycle needed unless it's more convenient.

Setting the CAD/CAM workspace to the size of the material helps greatly during layout of your parts. If you're not sure of a particular gcode file, you can always "air-mill" the job above the material to insure everything stays in-bounds.

Once you've found a routine and done it a few times it'll become "second-nature" to you... easily remembered and fun.

Congrats on getting your machine and needle cutter built. As Jason said... you're very close. Hang in there and let us know how we can further help

-- David

 

[vastsky]

Jason and David - You guys are the BEST!!



Fellas all of this makes perfect sense. I hope to have time to do some cuts this week. Stay tuned!!

Ed

 

[vastsky]

This is a informative and humorous video about CNC. It actually made quite allot of sense!

 

[dkj4linux]

I'm still around...

Between recent golf and fishing outings and waiting patiently for my Prusa I3 Mk2 to show up, I decided to attack a couple of little upgrade projects I've threatened in the past...

First, immediately after ordering the new printer, I inexplicably decided that I had waxed pretty silly revealing that I had a Prusa Mendel I2 (3mm, 0.5mm) that I no longer used... so I printed/built a new Gregs Wade extruder and converted the printer for 1.75mm filament and a 0.4mm nozzle. It works pretty nicely. Of course, had I not procrastinated, I might not have been able to justify ordering another printer. Oh, well... but one cannot have too many 3d printers

Old extruder...


New extruder and hotend...


X-carriage stripped of the old...


and the new extruder/hotend installed...


Then I pulled out my extremely flimsy Makeblock X-Y v1 plotter... (cute video, though... )

and started stripping it to see what could be done to make it more useful. I liked the Makeblock concept in the beginning but their version 1 "X-Y plotter" was so flimsy, inaccurate, and poorly designed it barely worked with nothing more than a pen attached. I've got my original 2.8 watt laser sitting idle and thought possibly a dedicated laser engraver/cutter could be built on the Makeblock frame... and using the somewhat novel belting method Joachim used on his new CNC. I've printed additional parts as needed and now have the X and Y axis assembled and near-ready for testing...























The machine is still going to be extremely light-weight and fitting a Z-axis/laser on that small X carriage is going to be a real trick but it's been fun playing with it for the last couple of days.

More to come...

-- David

 

[dkj4linux]

Light-weight Laser engraver/cutter update

Given a little more thought, I decided that the X-gantry rail orientation should be vertical rather than horizontal... to better accommodate the relatively tall form-factor of the laser housing I eventually plan to mount. So, I set about assembling/disassembling, ad nauseum, all the bits and pieces until I had the rails in a vertical orientation...

Before...


After...


X-idler end...


X-motor end...


Reoriented gantry rails...


Belted up similar to Joachim's new CNC...


Anchored end of gantry...


Driven end of gantry...


Initial tests, however, revealed a fatal flaw(s) in my light-weight machine when configured this way...

When powered up and exercising the Y-axis, the driven end of the gantry visibly moves before the anchored end... resulting in the gantry racking/skewing/flexing each time there is a change of direction. Manually pulling the belt segments near the motor (last photo above) indeed reveal this flaw... much like pulling/pushing on the tip of a fishing rod with the handle anchored. Flimsy components, too little belt tension, belt-stretch, etc all play a part... but I also found with a bit of Google-ing (https://web.archive.org/web/20160423072846/http://blog.fabtotum.com/blog/2014/04/04/belts-and-stuff-experiences-to-share) that that is indeed a problem with the H-bot (and similar) belt setup, which I think this is most related to...

Apparently Joachim's setup doesn't exhibit this because his machine is considerably heavier, better built, and far more rigid than mine... and not being pushed beyond its limits. From my reading, all these are necessary ingredients for this belt setup to work...

All is not lost, however... so, now, off I go looking into CoreXY, which supposedly overcomes the limitations above. Isn't this fun? -- David

 

[Michael9865]

Anybody considering trying the new 7000mw from Would it be powerful enough for white DTF?
http://www.banggood.com/EleksMaker-...-Engraver-Machine-p-1127310.html?rmmds=search

 

[wild.bill]

Look carefully - that laser does not focus. You need to adjust Z to get it focused.

 

[dkj4linux]

Light-weight laser engraver update...

After seeing visible gantry skew as previously configured, I started reading up on CoreXY and reconfigured my Makeblock-based machine as closely as possible to the reference diagrams at http://corexy.com/theory.html. I was extremely pleased to see nice smooth movement with no visible gantry skew with small, fast, 1mm movements in Y, with the new configuration

I'm was also shocked that with only a few printed part (the yellow bearing flanges/bushings and X-carriage), the rest of the machine used only parts that came with the version 1 Makeblock plotter kit... with parts left over! What an upgrade... it was basically a toy and virtually useless as originally designed and built!

Using Marlin's CoreXY functionality, the Arduino Mega/RAMPS board set, and a Chromebook running Ubuntu, I'm a happy camper! I hope to power up the laser and run some initial tests tomorrow -- David

 

[dkj4linux]

Lightweight CoreXY 2.8 watt laser engraver -- first burn and test

Quick and dirty -- and shaky (sorry) -- first burn and test of my new Lightweight CoreXY laser engraver...

I've not implemented a real Z-axis on this machine. Thankfully, the mounting collar and shape of the laser housing allow manual height adjustment pretty readily so I don't think it's a big deal... i.e. many "store-bought" laser engravers nowadays seem to use this configuration.

Everything seemed to go pretty well during this test. I need to calibrate each axis yet but everything seems really close so don't forsee too many problems going forward. -- David

 

[CaptCaveman37]

Prusa is here and assembled. Gonna run through some test prints and then time to print a needle cutter.

Jamie

 

[dkj4linux]

Prusa is here and assembled. Gonna run through some test prints and then time to print a needle cutter.

Jamie

Congrats, Jamie. I look forward to hearing about your progress. I'm still waiting patiently for mine to arrive -- David

 

[dkj4linux]

Lightweight CoreXY 2.8 watt laser engraver -- circle test

I used Inkscape and JTech's laser plugin to generate a "circle test" -- three circles inscribed in squares 100mm, 150mm, and 200mm. My circles did indeed turn out circular rather than oval and the dimensions of the squares was spot on. I thought maybe the angled belt segments attached the X-carriage might be a problem but it appears that the symmetry of situation may be its saving grace...

So, somewhere along the way, my daughter asked if the laser could do a small cross-stitch pattern (approximately 1" square with 14 x 14 grid of holes) such as this...



and indeed it can...





All in all, I'm pleased that this project went together so smoothly and painlessly... and has rescued the little Makeblock machine from obscurity. I'm also very impressed with the cleanliness and operation of the CoreXY configuration... especially with such a lightweight frame. Add in the fact that the same ArduinoMega/RAMPS boardset and Marlin firmware I have used previously with MPCNC is already set up to handle CoreXY as well just blows me away... :applause:

Now, bring on the Prusa I3 Mk2...

--David

 

[jhitesma]

Looking great David! I haven't been using my laser much because I'm a little frustrated with the G2 lens. Seems like I have a harder time cutting than people who went with the 3 element - even though the G2 is supposed to be more efficient. I'm guessing it's the slightly larger spot of the G2 that disperses the energy over a larger area. Need to pickup a 3 element to try but hasn't been a high budget priority because I decided to build a new nano quad instead. (been having a lot of fun learning Onshape and redrawing that eggbot as well as designing this new nano quad frame...which flew for the first time last night!)

I did get to give the MPCNC a bit of a workout last weekend however. My daughter wanted to have a birthday party for the two goldfish she won at the county fair last year since it's fair time again. She's not only managed to keep them alive but they've grown so much we had to move them from their 10 gallon tank to a 30 gallon. Anyway, my wife agreed to this fish party as long as it had a very limited guest list. Even so my daughter wanted to do it right. Cupcakes, a craft project (they made fishtanks out of construction paper decorated with glitter and markers), and "pin the tail on the fish" which was where the MPCNC came in

I found a nice fancy goldfish SVG which I used the MPCNC to draw onto a sheet of DTFB. Then made slightly smaller versions of it's tail which I used the laser to engrave and cut from posterboard. The kids loved it

I really need to catch up on some of my projects. Just haven't had a lot of time to get out to my shop to work on them the past few weeks