I did have to slow it down a bit to 110% the speed of my needle cutter, as I just cut a wing spar and the long single cut causes the bit to get so hot it starts melting the foam and it builds up into a hard plastic blob on the bit. I need to hook up my second router speed control to the spindle and try slowing it down a bit.
Cutting foam sheets... with a needle!
- Thread starter dkj4linux
- Start date
Michael9865
Elite member
What rpm are you running your needle at?
I ran my needle about 7200rpm, but this is with a spindle. I fixed the melting issue by using a router control and setting it around 70% speed, and dropping down to 11mm/s instead of 14mm/sec. I think I can move back to 12-13 with some more play.
I meant to cut out the DR1 plans but accidentally cut out the baby blender v2 plans.
Guess Im making both.
That wonderful feeling when all the parts fall out when you lift up the sheet. And a quick video, *which is very loud* - https://photos.app.goo.gl/JPd7gB7pKyXzG6ng7
Attachments
Hey, thanks
I currently do quite a bit with 3d printing, and I am wondering if it is similar to that. I use cura for my slicer. Do I need a slicer to convert the file to a gcode.
Thanks so much.
Thanks so much for the response. I have currently build the cutter a couple of weeks ago. I have marlin firmware on it, and I am just confused of how to upload a print job to it.
I currently do quite a bit with 3d printing, and I am wondering if it is similar to that. I use cura for my slicer. Do I need a slicer to convert the file to a gcode.
Thanks so much.
dkj4linux
Elite member
Ericrobb,
Thanks for coming back. It's good to hear you have your cutter running.
Your Marlin firmware does, among other things, gcode interpretation. A common way to run a job... a gcode sender program (RepetierHost, Pronterface, UniversalGcodeSender, etc.), installed on a PC, is used to connect and communicate with the Marlin firmware through USB and sends commands read from a gcode file. The gcode file is created with a CAM program/plugin, which creates tool and toolpath information from the CAD (design) file... Fusion360, SketchUp/SketchUCAM, Inkscape/Gcodetools, Estlcam, dxf2gcode, etc. are all used to create gcode files suitable for running jobs on CNC machines. One gothcha... your CAM program must be able to put out Marlin-compatible gcode to be of use on your Marlin-based machine; i.e. Marlin, running on a very small Arduino micro-controller, implements only a "subset" of the entire gcode command repertoire... not the entire command set.
Have you by chance built a MPCNC or LowRider? If so, the controller boards (Mega/RAMPS, miniRambo, Rambo) commonly used, also allow use of an LCD graphic display, which also includes an SD card reader. So, another option is to eliminate the PC and gcode sender program... and write the gcode file to an SD card and then select and run it from the LCD control panel.
A good tutorial (using Estlcam and RepetierHost) that shows the complete flow... Estlcam Basics. You can use other programs, of course, but this should give you a good idea of what's involved in setting up a CAM program for tools/feeds/speeds/etc, importing a DXF design file, creating the toolpaths, and, finally, saving it as a gcode file suitable for your machine.
Helpful?
-- David
I finally have my mpcnc completed! I tried out the pen and it drew the crown just like in the videos, I was so proud of my new toy, then I tried to create some of the FT plans for the MPCNC by using the online tutorials using Inkscape and Estlcam. My problem is that when I save my cnc project as *.gcode my mpcnc will start to move then it will stop with the y axis motor humming. I am attaching a sample of the gcode that I created. I hope someone can view it and point me in the direction that I need in order to get the satisfaction of being able to cut out a piece of foam board.
The gcode file you sent proved that my mpcnc is working, however I am missing something while creating my own plans. I set up my estlcam by watching Jason Hitsman youtube video. I am using a needle that is .059, however when I input that value in Estlcam it automatically changes to .010mm, I have my z step set to 8mm and my feed rate for the x and y set to 9mm per second and the plunge rate is set to 5. Is there something else I am missing? I am attaching my Estlcam project file that I am using prior to saving as a CNC project. Any help is most appreciated.
What speed were you cutting with your needle cutter Verris? With my last revision (the green one, I haven't changed it in over a year) I've been doing 15mm/s cuts (I was going to reply sooner but wanted to open one of my project files to confirm and make sure I wasn't remembering wrong.) I've actually pushed it a bit faster than that but cut quality went down and speeding up the needle any faster to try and help got a bit scary. Don't remember the RPM's I'm currently running at...it's been so long since I checked since I got it dialed into the gcode now.
I run the following gcode for needle startup when controlled through a RAMPS servo output:
M280 P0 S0 ; Start outputting pulses to allow ESC to init.
G4 S5 ; 5 second pause to allow the ESC to initialize - may need more or less time
M280 P0 S85 ; Set ESC to 70 degrees (since it thinks it's talking to a servo)
G4 S5 ; 5 second pause to allow ESC to come up to speed and stabilize - may need more or less.
The two big gotchas I remember running into with the servo was a jumper on the RAMPS to supply 5v and having to enable it in the marlin config before flashing...though it's been so long now I don't remember the details of either.
(And it looks like my comments on that code are out of date as I say "70 degrees" but the command is for 85. Originally I was running much slower cuts and it was when I got confident with the new cutter and started pushing speeds on both feeds and the RPM that I bumped it up.)
moebeast
Member
Here is the tool settings I use. I use mm/min since that is what will be in the Marlin file. You can also use the "Replace" tool in NotePad to change feed rates in your gcode files.
I ran your project with this tool setting and generated this file.
I was cutting at 9mm/sec with the needle cutter, but I had never really tried changing it, that just worked well. I'm back up to 17mm/sec with the spindle now. Turns out I was just a bit too low and was not cutting the top sheet of paper, just spinning the rounded part of the bit on it.
Oh wow...didn't realize you were going that slow. Think 11mm/s was what I used to run with my original setup...but it's been so long I don't remember for sure. Don' think I still have any old gcode kicking around to confirm though.
dkj4linux
Elite member
For those following or interested, my carriage/Z-axis and needle cutter for FoamRipper are now up on Thingiverse
https://www.thingiverse.com/thing:3582124
I think I got everything. Please let me know if something is missing and/or unclear.
Thanks!
-- David
https://www.thingiverse.com/thing:3582124
I think I got everything. Please let me know if something is missing and/or unclear.
Thanks!
-- David
Hi all. I recently built an OpenBuilds CNC machine and added a needle cutter using the Improved Needle Cutter found on Thingiverse. I’m not a modeler (though my dad was an RC modeler big time) so I’m not building aircraft but I can see doing a glider or two in my future.
I’m using the cutter to create organizers/inserts for my collection of board games to make it easier to set them up and take them down.
I’ve been able to cut out a few things but not without problems. I’ve been reading your forums for a while to try and discover what I’m doing wrong.
I did have problems breaking needles and following advice got a tach only to find I was spinning at only about 5000rpm. Moving at 540 mm/min I still couldn’t finish a cut without breaking a needle. The needles were breaking up near the bearing. I use a wire bender to put about 1 ½ coil to slip over the bearing. I’m using .025 piano wire
I ended up slowing down the rpms to about 3500/4000 rpm with a speed of 300 mm/min. I did manage to cut everything out without breaking the needle but the cutter appears to be struggling. When I see in the forums many of you are running at rpms of 6000 or more, I can’t help thinking I’ve got a problem; just don’t know where to look.
I’m also having a problem that I’m not cutting all the way through. I end up using an Xacto knife to finish the cut on the back. Obviously I’m not setting my Z axis correctly which is my leads me to ask. When you set the z-axis home location, do you do with the needle fully extended? I did that last night and then had cutter plunge 7mm to start each cut. Since the difference between fully extended and fully retracted is about 10mm, the cut should have gone through with 3mm to spare.
I'm normally a pretty good problem solver but I'm missing something here.
I’m using the cutter to create organizers/inserts for my collection of board games to make it easier to set them up and take them down.
I’ve been able to cut out a few things but not without problems. I’ve been reading your forums for a while to try and discover what I’m doing wrong.
I did have problems breaking needles and following advice got a tach only to find I was spinning at only about 5000rpm. Moving at 540 mm/min I still couldn’t finish a cut without breaking a needle. The needles were breaking up near the bearing. I use a wire bender to put about 1 ½ coil to slip over the bearing. I’m using .025 piano wire
I ended up slowing down the rpms to about 3500/4000 rpm with a speed of 300 mm/min. I did manage to cut everything out without breaking the needle but the cutter appears to be struggling. When I see in the forums many of you are running at rpms of 6000 or more, I can’t help thinking I’ve got a problem; just don’t know where to look.
I’m also having a problem that I’m not cutting all the way through. I end up using an Xacto knife to finish the cut on the back. Obviously I’m not setting my Z axis correctly which is my leads me to ask. When you set the z-axis home location, do you do with the needle fully extended? I did that last night and then had cutter plunge 7mm to start each cut. Since the difference between fully extended and fully retracted is about 10mm, the cut should have gone through with 3mm to spare.
I'm normally a pretty good problem solver but I'm missing something here.
dkj4linux
Elite member
Edojr,
Thanks for stopping in.
Back in post #2440, I show how I setup the cutter for a job. I usually set the cutter rpm to something in the 6000-8000 rpm range and use 600-610 mm/min for my feed rate. This insures about 10-15 perforations per mm of linear travel and gives clean cuts in DTFB. Also, note that I find the surface of the foam with the needle cutter running... the change in sound is obvious and, when it just touches, that's where I set my "Z-home" (Z=0).
If you're feed rate is too high and/or your cutter speed too low, you could be dragging your needle through the foam (it's not fully exiting the foam fast enough to keep up with the forward travel) and, if bad enough, bent/broken needles will result. Too long a needle can be problematic as well... you may see excessive trailing or bending of the needle. Your cutter speed seems way low, but it seems you're adjusting the feed rates that should allow you to cut kinda okay... a 10 to 1 ratio of cutter speed to feed rate should keep you out of trouble. But you really should be able to increase your cutter speed up to 6000 rpm or more...
Do you do anything to try to keep the needle on the bearing race when cutting... a groove, super-glue, a keeper of some sort, etc.? Can your cutter free-run comfortably at 6000 rpm or more? Also, are you keeping the foamboard flat against the spoilboard?
Pictures of your cutter setup, flywheel, a freshly-prepared needle, etc. would help immensely.
-- David
Thanks for stopping in.
Back in post #2440, I show how I setup the cutter for a job. I usually set the cutter rpm to something in the 6000-8000 rpm range and use 600-610 mm/min for my feed rate. This insures about 10-15 perforations per mm of linear travel and gives clean cuts in DTFB. Also, note that I find the surface of the foam with the needle cutter running... the change in sound is obvious and, when it just touches, that's where I set my "Z-home" (Z=0).
If you're feed rate is too high and/or your cutter speed too low, you could be dragging your needle through the foam (it's not fully exiting the foam fast enough to keep up with the forward travel) and, if bad enough, bent/broken needles will result. Too long a needle can be problematic as well... you may see excessive trailing or bending of the needle. Your cutter speed seems way low, but it seems you're adjusting the feed rates that should allow you to cut kinda okay... a 10 to 1 ratio of cutter speed to feed rate should keep you out of trouble. But you really should be able to increase your cutter speed up to 6000 rpm or more...
Do you do anything to try to keep the needle on the bearing race when cutting... a groove, super-glue, a keeper of some sort, etc.? Can your cutter free-run comfortably at 6000 rpm or more? Also, are you keeping the foamboard flat against the spoilboard?
Pictures of your cutter setup, flywheel, a freshly-prepared needle, etc. would help immensely.
-- David
Thanks for getting back so soon. Yes I did cut a groove in the bearing with my dremel and grinding wheel. I've not had a needle come off but they seem to break near the coil. I use a pair of pliers designed for bending wire to put the coil on the needle. I suspect I was breaking needles with an rpm of under 5000 but moving at 540mm/min as when I got my tach, I thought I had the rpms way to high when the setting I was using was slower than 6000.
I hold down the foam core around the edge with metal spring clamps that look similar to what is on jumper cables (just no teeth). I like the idea of a vacuum table, but I have a small CNC 250mm x 300 and the build table moves for the y axis. If I were to use a vacuum table to hold down the foam it would need to move and maintain vacuum.
I wish I had seen your post about running the cutter to set the Z axis, seems like a no brainer because yes you do notice the change in sound.
I don't have a good picture with me, but can upload one later tonight on tomorrow.
I hold down the foam core around the edge with metal spring clamps that look similar to what is on jumper cables (just no teeth). I like the idea of a vacuum table, but I have a small CNC 250mm x 300 and the build table moves for the y axis. If I were to use a vacuum table to hold down the foam it would need to move and maintain vacuum.
I wish I had seen your post about running the cutter to set the Z axis, seems like a no brainer because yes you do notice the change in sound.
I don't have a good picture with me, but can upload one later tonight on tomorrow.
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