moebeast
Member
I can't find my Estlcam file but it was version 8 anyway, so not useful. Here are some files that may help you.
https://www.dropbox.com/sh/cxdohlcoj98pc54/AACiJDnYTzv0OYSkVKRRI4TQa?dl=0
Cutting foam sheets... with a needle!
- Thread starter dkj4linux
- Start date
I can't find my Estlcam file but it was version 8 anyway, so not useful. Here are some files that may help you.
https://www.dropbox.com/sh/cxdohlcoj98pc54/AACiJDnYTzv0OYSkVKRRI4TQa?dl=0
So one of my quads has been sitting as a pile of parts for almost 9 months since I crashed it and destroyed the frame. Which is a shame since it has brand new motors and ESC's that only have about 15 minutes of flight time on them. So decided to fire up the MPCNC and make a new frame for the parts:
It's kind of an odd setup...it feels BIG but it's actually looking like it's going to be lighter than it was before (3D printed PETG center section and 1/2" square wood dowel arms, with 1/8" lexan top/bottom plates.)
It could actually fly as it is right now - well, if I tied down the wires and ESC's to keep them out of the props:
But I'll be cleaning up the wiring before that.
And I still need to cut the second plate and print the standoffs. The final setup should be more like:
I also still have to work out how I'm going to mount my FPV gear...but that will probably be handled with some 3D printed parts.
Love having the CNC available for this kind of thing! Finally starting to feel like I can trust it for cutting stuff with the spindle. Though...workholding is still an issue. The masking tape and CA method has been working great for me - but failed miserably on this last night. Was too big of a surface and the stock has a bit of a warp to it that kept pulling it up. Parts popped up during the cut and it didn't sit level as a result so some spots cut too deep and some not deep enough. May have to resort to carpet tape for the second plate which I try to avoid since it's such a sticky mess.
It's kind of an odd setup...it feels BIG but it's actually looking like it's going to be lighter than it was before (3D printed PETG center section and 1/2" square wood dowel arms, with 1/8" lexan top/bottom plates.)
It could actually fly as it is right now - well, if I tied down the wires and ESC's to keep them out of the props:
But I'll be cleaning up the wiring before that.
And I still need to cut the second plate and print the standoffs. The final setup should be more like:
I also still have to work out how I'm going to mount my FPV gear...but that will probably be handled with some 3D printed parts.
Love having the CNC available for this kind of thing! Finally starting to feel like I can trust it for cutting stuff with the spindle. Though...workholding is still an issue. The masking tape and CA method has been working great for me - but failed miserably on this last night. Was too big of a surface and the stock has a bit of a warp to it that kept pulling it up. Parts popped up during the cut and it didn't sit level as a result so some spots cut too deep and some not deep enough. May have to resort to carpet tape for the second plate which I try to avoid since it's such a sticky mess.
blackkrystal73
Member
jihitesma said:
(I don't know exactly which spindle they're running on the rascal (I'd really love to see some of the guys working on it chime in here - Nerdnic, Sponz - you out there?), but it looks like the "standard" cheap Chinese 500w spindle. Those run about $130-$150 (Though banggood has one for just $80) The reviews I've heard about those have not been super encouraging. They do tend to be quieter than the routers from what I hear...but the power supplies/controllers are questionable and the spindles tend to have more runout than either dewalt option. They're lower RPM...but honestly the 660 is higher RPM than needed (and that lower RPM is probably a big part of the sound difference. The 660 does ~30k RPM while the Chinese spindles only do about 12-15k) I've been tempted to pick one up a few times...but they just seem to be a fairly big gamble...I've seen lots of people happy with them. But I've also seen a lot of people go back to a router because of the issues they experience with the cheap spindles. They also look like they're probably lighter...but I can't find any reliable numbers to confirm.)
Good day gentlemen.
On the Rascal we will be using a 400W spindle that will be controlled with its accompanied controller. That controller plays well with the Arduino CNC shield and lets us change the speed of that spindle at will. It will run as low as 5 RPM and as fast as 12000 RPM, and anywhere in between. It's a 48 volt DC spindle so it has a pretty flat torque curve. DTFB cuts like butter at 100IPM@5500RPM. I've been using it for two years now with out issue, it doesn't have any play or run out in it yet and I've really been abusing it.
We are recommending this Spindle.
http://www.ebay.com/itm/CNC-Router-0-4KW-Air-Cooling-Spindle-Motor-ER11-Mach3-PWM-Controller-Mount-/272582887546?hash=item3f7734c87a:g:GiIAAOSwCU1YwP8k
1). Sound. It is much quieter than a full blown router. My muffled vacuum table and steppers motors are louder than this spindle at 5500 RPM.
2.) Mess. It is true that a cutting spindle does expel chips, but honestly its a none issue unless you're cutting plywood or
MDF.
3.) Accuracy, I normally use a .032 to .050 bit to cut with. Only because it depends on what I found cheap.http://drillbitsunlimited.com/Default.aspx They both work equally well. It's become standard practice for me to cut 5 lines .050 apart where the leading edge of the wing will fold. it does this and leaves the uncut stumps, I'd say its accurate to less than .001. I don't have to cut a bevel with a knife anymore.
The V cut in the above pictures, yea, guilty... the needle does that better, but its not flying to the moon. If I cut a plane with my spindle and then cut the same plane with the needle, after it was built you'd never know that V cut wasn't cut pretty from the spindle. Its another none issue.
4.)Cost. Yea, its a little more than a needle cutter, but it isn't limited to Dollar Tree Foam Board either! I normally buy bits for $1 -$3.. they last forever.
The Rascal is a true C-beam hobby grade classic CNC style machine with NEMA 23's and steel V-groove bearings. We are using a spindle on the Rascal simply because its way more versatile than the needle. I don't think you can cut plywood, acrylic, Delrin, HDPE, fiber board, G10, MDF, balsa or any other harder material with the needle.
That being said, there is plenty of room out there for all our ideas. Better to join forces and dominate the world together...lol
I'm excited to see what people strap on the Rascal, you could add a needle cutter, drag knife, or laser and so on.
Thanks
Kevin
(I don't know exactly which spindle they're running on the rascal (I'd really love to see some of the guys working on it chime in here - Nerdnic, Sponz - you out there?), but it looks like the "standard" cheap Chinese 500w spindle. Those run about $130-$150 (Though banggood has one for just $80) The reviews I've heard about those have not been super encouraging. They do tend to be quieter than the routers from what I hear...but the power supplies/controllers are questionable and the spindles tend to have more runout than either dewalt option. They're lower RPM...but honestly the 660 is higher RPM than needed (and that lower RPM is probably a big part of the sound difference. The 660 does ~30k RPM while the Chinese spindles only do about 12-15k) I've been tempted to pick one up a few times...but they just seem to be a fairly big gamble...I've seen lots of people happy with them. But I've also seen a lot of people go back to a router because of the issues they experience with the cheap spindles. They also look like they're probably lighter...but I can't find any reliable numbers to confirm.)
Good day gentlemen.
On the Rascal we will be using a 400W spindle that will be controlled with its accompanied controller. That controller plays well with the Arduino CNC shield and lets us change the speed of that spindle at will. It will run as low as 5 RPM and as fast as 12000 RPM, and anywhere in between. It's a 48 volt DC spindle so it has a pretty flat torque curve. DTFB cuts like butter at 100IPM@5500RPM. I've been using it for two years now with out issue, it doesn't have any play or run out in it yet and I've really been abusing it.
We are recommending this Spindle.
http://www.ebay.com/itm/CNC-Router-0-4KW-Air-Cooling-Spindle-Motor-ER11-Mach3-PWM-Controller-Mount-/272582887546?hash=item3f7734c87a:g:GiIAAOSwCU1YwP8k
1). Sound. It is much quieter than a full blown router. My muffled vacuum table and steppers motors are louder than this spindle at 5500 RPM.
2.) Mess. It is true that a cutting spindle does expel chips, but honestly its a none issue unless you're cutting plywood or
MDF.
3.) Accuracy, I normally use a .032 to .050 bit to cut with. Only because it depends on what I found cheap.http://drillbitsunlimited.com/Default.aspx They both work equally well. It's become standard practice for me to cut 5 lines .050 apart where the leading edge of the wing will fold. it does this and leaves the uncut stumps, I'd say its accurate to less than .001. I don't have to cut a bevel with a knife anymore.
The V cut in the above pictures, yea, guilty... the needle does that better, but its not flying to the moon. If I cut a plane with my spindle and then cut the same plane with the needle, after it was built you'd never know that V cut wasn't cut pretty from the spindle. Its another none issue.
4.)Cost. Yea, its a little more than a needle cutter, but it isn't limited to Dollar Tree Foam Board either! I normally buy bits for $1 -$3.. they last forever.
The Rascal is a true C-beam hobby grade classic CNC style machine with NEMA 23's and steel V-groove bearings. We are using a spindle on the Rascal simply because its way more versatile than the needle. I don't think you can cut plywood, acrylic, Delrin, HDPE, fiber board, G10, MDF, balsa or any other harder material with the needle.
That being said, there is plenty of room out there for all our ideas. Better to join forces and dominate the world together...lol
I'm excited to see what people strap on the Rascal, you could add a needle cutter, drag knife, or laser and so on.
Thanks
Kevin
Mach3 is nice...but since it's $175 to license I suspect the Rascal isn't going to be using Mach3 by default. You could run mach3 to control your MPCNC as well (there are several people who've gone that route) but I can't justify the $175 for a more traditional CNC interface for the stuff I do. I'd like to do it someday....but it's pretty low on my priority list. (Much higher is building a pendant for my RAMPS to give me more Mach like control over my setup.)
I've just heard so many horror stories about the chinese spindles on various CNC boards I'm really gunshy about putting money down on one. As they continue to drop in price I become more conflicted - they're cheap enough that it's probably worth the gamble...but as the price goes down I fear the QC/Quality on them is going to as well since that seems to be the trend on stuff from China.
I've seen more than a handful of people who bought one to switch from a 911 router only to find that the 400w chinese spindle they got while lighter and quieter was also less accurate and less powerful than advertised so they went back to using their 911 or spend considerably more for a higher quality spindle.
Like I said before - I love having a spindle on my machine....just not for cutting foam. But I love the flexibility of a CNC platform and the ability to attach multiple tools to suit the job at hand. I have absolutely nothing against the Rascal and look forward to seeing the final design - I just don't like cutting foam with a spindle regardless of what machine is pushign the tool around.
And on that note, I'm making progress on the needle cutter to go in my Lowrider CNC machine - which I plan to use with a needle cutter, router, drag knife, pen holder, hot knife, and maybe even a laser engraver. Pretty much everything except a filament extruder - I like my printer just fine. 
Thanks again to @jhitesma for dropping the needle cutter design into a round DW611 router mounting hole. The wood insulating plate the mig tip screws into is made from 1/4 MDF - just cut out with a scroll saw old school style.
Next up is mounting the motor, balancing the flywheel, and needle guides. And I'm sure it was mentioned somewhere, but what size bearings are the needle cutter guides setup for?
Thanks!
Thanks again to @jhitesma for dropping the needle cutter design into a round DW611 router mounting hole. The wood insulating plate the mig tip screws into is made from 1/4 MDF - just cut out with a scroll saw old school style.
Next up is mounting the motor, balancing the flywheel, and needle guides. And I'm sure it was mentioned somewhere, but what size bearings are the needle cutter guides setup for?
Thanks!
Last edited:
Looks great for hand cut! Better than I could do by hand for sure. I still haven't printed one of those mounts (though I did cut the insulator) since I won't be getting rails for my low rider for another month or so still.
The bearings...hmm...I think they're the same size as I used for the needle on the flywheel. They call came out of the same set of dead motors
According to my notes they're: 693ZZ - 8mm OD x 3mm ID x 4mm thick bearings. (at least I think that's the part number...the dimensions are accurate.)
quimney
Member
iGull
New member
Purpose made DepronCNC
Hi
Thought someone might be interested in my new setup for cutting depron, none of which is particularly new, but maybe a slightly different take on things.
The concept was something relatively ‘cheap and cheerful’ - not at the agricultural end of the scale, but hopefully not of the over-engineered variety either - and simple It was also to be a lightweight machine, not designed at all as a traditional CNC ‘router’.
I’ve built _many_ CNC routers over the years - and a large laser too and loads of 3D printers, so have some idea about how to get it all working
One concept that I wanted to have was something standalone and untethered from any laptop/computer - just sneaker an SD card across, load the material, press a button and start cutting - a bit like a regular 3D printer.
I own a nice laser cutter, so a bit like when you own a hammer, everything becomes a nail, so it is that this machine is mostly laser cut from acrylic or ply I do own a couple of 3D printers, but I still prefer laser cut material for some (most jobs.
Sometimes it’s better not to put too much thought into designing/building and just get on and ’shoot from the hip’ once the basic construct is found
The whole machine is built around some 60x20 V-slot linear rail (a la openbuilds) - it’s not particularly expensive and really simplifies the linear guide thing - a few vee wheels and you nearly have a system. I had a couple of spare 1500mm lengths and some wheels available from a previous job, so that made the choice easier/cheaper.
Rather than build a pile of endplates for the wheels, I rotated the Y axis rail and tapped the vee wheels into the extrusion - that saved four endplates and multiple wheels too That comes with it’s own issues of course The X rails are screwed to the 18mm MDF base plate - a bit of time spent aligning them to ensure they are orthogonal makes life easier later.
A ready to roll electronic setup was wanted and I looked at using a laser controller again - they’re nice, just add a couple of axis drivers and that’s about it (will also read files from a USB thumb drive which is handy). They come with an app to convert your 2D files (windoze only sadly). However, a bit expensive for this job, so a sainsmart all-in-one ramps 3D printer board was chosen - no plug-in shields. The main reason I chose it was that the stepper inputs had screw terminals - saved me crimping all those JST connectors on the completely pluggable versions It was also nicely laid out - had to buy some driver chips, but other than that and getting an LCD board, was all quite cheap - and easy to source via fleabay here in the UK.
The whole of the Y axis depends on it’s own weight to keep things steady - sadly, when attempting to ramp up to speed, it tended to tilt slightly in X, so I added an acrylic ‘skate’ that rides in the next track down — cheap and cheerful, it works just fine
I had intended making a vac bed originally - just a pile of stopped-end slots in a piece of 25mm extruded foam and a couple of ‘computer’ fans, but having used a temporary piece of crappy 25mm re-cycled beaded foam and a few pins so far, it’s pointless as it holds down well - there is very little side thrust from the head.
The main Y axis head has a front plate that has a pile of holes tapped M4 to allow the possibility of fitting different ‘process’ heads to it (I’m thinking pens/diode lasers/drag knives here).
The ‘perforator’ head is just like all the rest of them in this forum - I used 0.7mm (22SWG) piano wire with a 0.6mm M6 MIG nozzle (the nozzle doesn’t have an internal taper and is a nice fit). The stroke on the rotating disc is 12mm which should cover all the items I intend to cut. The piano wire is quite long (min 70mm to the top of the nozzle at bottom stroke) - ensuring it is as far away as possible from the MIG nozzle to reduce sidethrust - and the subsequent heating of course. I didn’t add any guiding. TBH, I wanted to keep it as simple as possible - I think a ‘scotch yoke’ arrangement to give the vertical motion would be better - but this arrangement is much simpler, you just have to put up with the ’side effects’ I did use the simple ’wire wrap’ technique, but rather than the painful cutting of a groove around the perimeter of a bearing, I just used two bearings with a washer trapped between that was slightly thinner than the wire so it doesn’t drop through - simples. I’m thinking that a slightly different mechanism that would use sewing machine needles would be good - maybe rip the head off an old Singer machine )
One slightly different arrangement is that I don’t have a ‘proper’ Z axis on this machine, I added a regular 9mm servo to the head (albeit a digital metal geared one that was to hand The servo simply moves (12mm) the whole motor about an M4 fulcrum screw - driven by a servo output on the ramps board - as is the ESC.
Initial tests showed that the nozzle was a bit hot (surprise - not melty hot, but hot to the touch, so I soldered on some brass plate cooling fins - that works just fine for now - in a 17degC ambient, the head only reaches 31degC throughout a complete 15min cut - less than body temperature In an ambient of 22degC today, the head was 41degC after 25 mins - still fine - the motor was just an ambient 22degC.
The only issue with using a copper MIG nozzle is that you eventually end up with some copper oxide dust getting on to the pristine white foam. I did consider a water dripper early on to cool things down - that worked OK, but when mixed with the copper oxide, you get this horrible mess A teflon sleeve might be OK - I did turn down an acetal (delrin) version of the mig nozzle, but there wasn’t that much improvement and it did tend to wear very quickly - ovbiously due to the sidethrust of the wire.
Feeds are 1000mm/min (this isn’t a production environment and I can drink coffee while it does it’s thing and the perforator motor is running about 50% pulsewidth to the ESC. The motor is a hobbyking SK3 2826/980kv - used for no other reason than that I had one spare and the kv was about right. 980kv on 12v at 50% PW should be around 5800 RPM’ish (as a guesstimate, I do have an optical tacho, I’ll drag it out of the flight box and check later - on depron, the cuts are really nice and vertical - all the parts stay nicely put without creating tabs — a tad more strokes/min might be better, but this works perfectly fine for now. The perforator is certainly better than a laser on either depron or the brown FT foamboard - no undercutting of course - and my machine is so big it can take the full 1250x800mm grey depron sheets we get here in the UK (white is 1000x700mm for some reason ???).
Other than the usual minor adjustments to the marlin firmware, it’s basically stock - enabling another Z servo to the normal single and changing some texts/speeds/directions really.
It would be nice to have a tidied up interface as you really don’t need very much for this machine. Being able to position the head in XY using the knob is all that I find necessary really (I have the gcode reset that position as 0,0 at startup).
The toolchain and final gcode output is another matter completely of course
I use Adobe Illustrator for everything 2D - it’s next to perfect (mostly for the laser - I use Fusion360 for 3d stuff) . I must own all the CNC apps known to man (certainly for the mac at least - illustrator is probably the best - although the extremely cheap ‘Affinity Designer’ is practically up there with it now.
You can output most formats from illustrator - the common ones like dxf and svg are the simplest and plain text based. There is no direct gcode output from illustrator (to my knowledge at least ?) - although you can use the ‘illustrator like’ Inkscape (I use that term loosely which does have a gcode plugin. I do know about Sketchup - and SketchuCAM (or phlatboyz scripts as it was known) as I was involved in writing a couple of the plugins for it - I may still consider this route as I can modify it to give what I need for my machine.
However, the primary issue is that anything that outputs gcode, won’t output any of the ‘Z’ commands necessary to interpret the codes required by the RAMPS board servos/ESC :-(
I guess that some of the major CNC apps like Aspire or Vcarve etc could have a ‘post’ written to suit, but that isn’t in the spirit of this machine
OK, what I have done for now is this …
Create your file in whatever cad/graphics app is your preference, set the colours to black for a ‘full’ cut and 50% grey for a ‘half’ cut (Easel will set the cut depths based on the colour values - see next). Export/Save the file in SVG format (standard vector graphics).
Using the nice free (can’t get cheaper than that) online Inventables ‘Easel’ app (you’ll need to create an account (free, it’s opensource) import the file. You’ll need to set the parameters for you particular machine of course - there are plenty of help files/vids available - a child of five could manage it Set up your cut depths - easel assumes a max cut for black and a half cut for 50% grey - linewidths are unimportant. I don’t bother with an offset for foam, I just cut down the line centre - you’re not making parts for Spacex or the military here and the adhesive is thicker than the wirewidth Easel is a full CNC controller if you wish BTW (for GRBL based controllers). Once all setup, you can export your gcode file.
However, as I don’t have a Z axis as such on this machine, I need to open up the gcode.nc file in a text editor and search and replace the exported gcode with the correct commands. A simple parser could be written to do this automagically, but I haven’t gotten around to that level of automation yet - search and replace literaly takes a couple of mins doing it mandraulically, so not sure if it is worth the effort - I don’t cut or build depron models every day I just keep a text file with the needed commands and cut and paste as necessary with a wee bit of a gcode pre/post amble.
I _have_ tried other online and local CAM apps, most can’t import svg files and when they can, can’t differentiate colour/shade to determine cut depths - YMMV as they say
If you have a ‘real’ cnc machine, then you’ll have yoiur own prefs no doubt
I could use DXF of course, but there are more flavours of DXF than they have ice cream at the local store
Once the gcode is edited, dump it on an SD card and stick it in the machine, load it up with depron, line everything up and watch the buzzing machine go - that’s about it really (apart from some simplified comments about the gcode that is))
If you have any questions/comments feel free to keep them to yourself LOL)))
Thanks to all who have posted info on this forum thread that made my life a wee bit easier - you know who you are
There’s also a vid here on youtube …
https://youtu.be/bY4YnIyu8cE
Also just noticed (too late sadly that Barton Dring across on buildlog.net has created a driver board designed for drawing machines/lasers etc - uses grbl, but the neat thing is that it is designed to use a servo for the Z axis - as in some of the drawing machines (polargraph etc if you have seen them).
Apologies for the lengthy post.
Cheers
Neil
Hi
Thought someone might be interested in my new setup for cutting depron, none of which is particularly new, but maybe a slightly different take on things.
The concept was something relatively ‘cheap and cheerful’ - not at the agricultural end of the scale, but hopefully not of the over-engineered variety either - and simple
It was also to be a lightweight machine, not designed at all as a traditional CNC ‘router’.I’ve built _many_ CNC routers over the years - and a large laser too and loads of 3D printers, so have some idea about how to get it all working
One concept that I wanted to have was something standalone and untethered from any laptop/computer - just sneaker an SD card across, load the material, press a button and start cutting - a bit like a regular 3D printer.
I own a nice laser cutter, so a bit like when you own a hammer, everything becomes a nail, so it is that this machine is mostly laser cut from acrylic or ply
I do own a couple of 3D printers, but I still prefer laser cut material for some (most jobs.Sometimes it’s better not to put too much thought into designing/building and just get on and ’shoot from the hip’ once the basic construct is found
The whole machine is built around some 60x20 V-slot linear rail (a la openbuilds) - it’s not particularly expensive and really simplifies the linear guide thing - a few vee wheels and you nearly have a system. I had a couple of spare 1500mm lengths and some wheels available from a previous job, so that made the choice easier/cheaper.
Rather than build a pile of endplates for the wheels, I rotated the Y axis rail and tapped the vee wheels into the extrusion - that saved four endplates and multiple wheels too
That comes with it’s own issues of course The X rails are screwed to the 18mm MDF base plate - a bit of time spent aligning them to ensure they are orthogonal makes life easier later.A ready to roll electronic setup was wanted and I looked at using a laser controller again - they’re nice, just add a couple of axis drivers and that’s about it (will also read files from a USB thumb drive which is handy). They come with an app to convert your 2D files (windoze only sadly). However, a bit expensive for this job, so a sainsmart all-in-one ramps 3D printer board was chosen - no plug-in shields. The main reason I chose it was that the stepper inputs had screw terminals - saved me crimping all those JST connectors on the completely pluggable versions
It was also nicely laid out - had to buy some driver chips, but other than that and getting an LCD board, was all quite cheap - and easy to source via fleabay here in the UK.The whole of the Y axis depends on it’s own weight to keep things steady - sadly, when attempting to ramp up to speed, it tended to tilt slightly in X, so I added an acrylic ‘skate’ that rides in the next track down — cheap and cheerful, it works just fine
I had intended making a vac bed originally - just a pile of stopped-end slots in a piece of 25mm extruded foam and a couple of ‘computer’ fans, but having used a temporary piece of crappy 25mm re-cycled beaded foam and a few pins so far, it’s pointless as it holds down well - there is very little side thrust from the head.
The main Y axis head has a front plate that has a pile of holes tapped M4 to allow the possibility of fitting different ‘process’ heads to it (I’m thinking pens/diode lasers/drag knives here).
The ‘perforator’ head is just like all the rest of them in this forum - I used 0.7mm (22SWG) piano wire with a 0.6mm M6 MIG nozzle (the nozzle doesn’t have an internal taper and is a nice fit). The stroke on the rotating disc is 12mm which should cover all the items I intend to cut. The piano wire is quite long (min 70mm to the top of the nozzle at bottom stroke) - ensuring it is as far away as possible from the MIG nozzle to reduce sidethrust - and the subsequent heating of course. I didn’t add any guiding. TBH, I wanted to keep it as simple as possible - I think a ‘scotch yoke’ arrangement to give the vertical motion would be better - but this arrangement is much simpler, you just have to put up with the ’side effects’
I did use the simple ’wire wrap’ technique, but rather than the painful cutting of a groove around the perimeter of a bearing, I just used two bearings with a washer trapped between that was slightly thinner than the wire so it doesn’t drop through - simples. I’m thinking that a slightly different mechanism that would use sewing machine needles would be good - maybe rip the head off an old Singer machine )One slightly different arrangement is that I don’t have a ‘proper’ Z axis on this machine, I added a regular 9mm servo to the head (albeit a digital metal geared one that was to hand
The servo simply moves (12mm) the whole motor about an M4 fulcrum screw - driven by a servo output on the ramps board - as is the ESC.Initial tests showed that the nozzle was a bit hot (surprise
- not melty hot, but hot to the touch, so I soldered on some brass plate cooling fins - that works just fine for now - in a 17degC ambient, the head only reaches 31degC throughout a complete 15min cut - less than body temperature In an ambient of 22degC today, the head was 41degC after 25 mins - still fine - the motor was just an ambient 22degC. The only issue with using a copper MIG nozzle is that you eventually end up with some copper oxide dust getting on to the pristine white foam. I did consider a water dripper early on to cool things down - that worked OK, but when mixed with the copper oxide, you get this horrible mess
A teflon sleeve might be OK - I did turn down an acetal (delrin) version of the mig nozzle, but there wasn’t that much improvement and it did tend to wear very quickly - ovbiously due to the sidethrust of the wire.Feeds are 1000mm/min (this isn’t a production environment and I can drink coffee while it does it’s thing
and the perforator motor is running about 50% pulsewidth to the ESC. The motor is a hobbyking SK3 2826/980kv - used for no other reason than that I had one spare and the kv was about right. 980kv on 12v at 50% PW should be around 5800 RPM’ish (as a guesstimate, I do have an optical tacho, I’ll drag it out of the flight box and check later - on depron, the cuts are really nice and vertical - all the parts stay nicely put without creating tabs — a tad more strokes/min might be better, but this works perfectly fine for now. The perforator is certainly better than a laser on either depron or the brown FT foamboard - no undercutting of course - and my machine is so big it can take the full 1250x800mm grey depron sheets we get here in the UK (white is 1000x700mm for some reason ???).Other than the usual minor adjustments to the marlin firmware, it’s basically stock - enabling another Z servo to the normal single and changing some texts/speeds/directions really.
It would be nice to have a tidied up interface as you really don’t need very much for this machine. Being able to position the head in XY using the knob is all that I find necessary really (I have the gcode reset that position as 0,0 at startup).
The toolchain and final gcode output is another matter completely of course
I use Adobe Illustrator for everything 2D - it’s next to perfect (mostly for the laser - I use Fusion360 for 3d stuff) . I must own all the CNC apps known to man (certainly for the mac at least
- illustrator is probably the best - although the extremely cheap ‘Affinity Designer’ is practically up there with it now.You can output most formats from illustrator - the common ones like dxf and svg are the simplest and plain text based. There is no direct gcode output from illustrator (to my knowledge at least ?) - although you can use the ‘illustrator like’ Inkscape (I use that term loosely
which does have a gcode plugin. I do know about Sketchup - and SketchuCAM (or phlatboyz scripts as it was known) as I was involved in writing a couple of the plugins for it - I may still consider this route as I can modify it to give what I need for my machine.However, the primary issue is that anything that outputs gcode, won’t output any of the ‘Z’ commands necessary to interpret the codes required by the RAMPS board servos/ESC :-(
I guess that some of the major CNC apps like Aspire or Vcarve etc could have a ‘post’ written to suit, but that isn’t in the spirit of this machine
OK, what I have done for now is this …
Create your file in whatever cad/graphics app is your preference, set the colours to black for a ‘full’ cut and 50% grey for a ‘half’ cut (Easel will set the cut depths based on the colour values - see next). Export/Save the file in SVG format (standard vector graphics).
Using the nice free (can’t get cheaper than that) online Inventables ‘Easel’ app (you’ll need to create an account (free, it’s opensource) import the file. You’ll need to set the parameters for you particular machine of course - there are plenty of help files/vids available - a child of five could manage it
Set up your cut depths - easel assumes a max cut for black and a half cut for 50% grey - linewidths are unimportant. I don’t bother with an offset for foam, I just cut down the line centre - you’re not making parts for Spacex or the military here and the adhesive is thicker than the wirewidth Easel is a full CNC controller if you wish BTW (for GRBL based controllers). Once all setup, you can export your gcode file.However, as I don’t have a Z axis as such on this machine, I need to open up the gcode.nc file in a text editor and search and replace the exported gcode with the correct commands. A simple parser could be written to do this automagically, but I haven’t gotten around to that level of automation yet - search and replace literaly takes a couple of mins doing it mandraulically, so not sure if it is worth the effort - I don’t cut or build depron models every day
I just keep a text file with the needed commands and cut and paste as necessary with a wee bit of a gcode pre/post amble.I _have_ tried other online and local CAM apps, most can’t import svg files and when they can, can’t differentiate colour/shade to determine cut depths - YMMV as they say
If you have a ‘real’ cnc machine, then you’ll have yoiur own prefs no doubt
I could use DXF of course, but there are more flavours of DXF than they have ice cream at the local store
Once the gcode is edited, dump it on an SD card and stick it in the machine, load it up with depron, line everything up and watch the buzzing machine go - that’s about it really (apart from some simplified comments about the gcode that is
))If you have any questions/comments feel free to keep them to yourself LOL
)))Thanks to all who have posted info on this forum thread that made my life a wee bit easier - you know who you are
There’s also a vid here on youtube …
https://youtu.be/bY4YnIyu8cE
Also just noticed (too late sadly
that Barton Dring across on buildlog.net has created a driver board designed for drawing machines/lasers etc - uses grbl, but the neat thing is that it is designed to use a servo for the Z axis - as in some of the drawing machines (polargraph etc if you have seen them).Apologies for the lengthy post.
Cheers
Neil
Thanks for the measurements @jhitesma! I think I've only got 10mm's running around at the moment, so I might go with wood for the needle guide for the first try at it.
And thank you Neil for sharing such a detailed write up! I do have a couple questions for you though - hopefully you won't mind too much if I don't keep them all to myself.
a) I see the servo on the perforator head, but I can't quite make out how it's used to set Z height (or if indeed that's the function it performs).
b) Could you share more details on your G code modification steps? I'm very close to making first cuts with a DIY Lowrider CNC machine of similar characteristics and capabilities, and need to figure out what tweaks are appropriate for my machine - which is often helped along by seeing what others have had success with.
Thanks!
And thank you Neil for sharing such a detailed write up! I do have a couple questions for you though - hopefully you won't mind too much if I don't keep them all to myself.
a) I see the servo on the perforator head, but I can't quite make out how it's used to set Z height (or if indeed that's the function it performs).
b) Could you share more details on your G code modification steps? I'm very close to making first cuts with a DIY Lowrider CNC machine of similar characteristics and capabilities, and need to figure out what tweaks are appropriate for my machine - which is often helped along by seeing what others have had success with.
Thanks!
TheSFReader
Member
Congrats and Yes please some additional detail on the Z axis work would be great ! (A closeup photo from the front would be fabulous)
I had thought about using a serv like you do, but hadn't seen a good way to move up/down the Z axis without a whole sliding assembly.
As far as I understand Rockyboy, the nozzle doesn't change height, but only the motor, which is mounted on the center of a mobile plate, with a single screw on the left side, which serves as a pivot point and to keep the plate vertical, and the servo moving its right side up/down.
This setup wouldn't work well as well with a different cutting head (laser, drag knife) since it adds a small amout of horizontal shift, but a small non-vertical alignment is already part of the needle cutter concept so total win !
I had thought about using a serv like you do, but hadn't seen a good way to move up/down the Z axis without a whole sliding assembly.
As far as I understand Rockyboy, the nozzle doesn't change height, but only the motor, which is mounted on the center of a mobile plate, with a single screw on the left side, which serves as a pivot point and to keep the plate vertical, and the servo moving its right side up/down.
This setup wouldn't work well as well with a different cutting head (laser, drag knife) since it adds a small amout of horizontal shift, but a small non-vertical alignment is already part of the needle cutter concept so total win !
iGull
New member
a) I see the servo on the perforator head, but I can't quite make out how it's used to set Z height (or if indeed that's the function it performs).
b) Could you share more details on your G code modification steps? I'm very close to making first cuts with a DIY Lowrider CNC machine of similar characteristics and capabilities, and need to figure out what tweaks are appropriate for my machine - which is often helped along by seeing what others have had success with.
Thanks!
a) What the servo does is move the plate that the motor is attached to. The plate has a fulcrum screw at the top left and a regular ball link at the bottom right - it just pushes on the ball link to achieve a 'Z' axis - in effect, moving the 'needle' position up and down. It has 12mm of stroke when fully down, but when cutting depron, it only needs to be 6mm + whatever gap you leave below the nozzle - 1.5mm in my case - plus a bit to ensure it goes fully through - about 1mm, so 8.5mm in total (gap is just to allow for any discrepancy in height across the table/depron thickness). I haven't machined the top of the sacrificial foam base to make it flat as it's not a 'proper' CNC machine and I don't have a router attachment for the head - although I could probably cobble something up - life's too short though and a 1.5mm gap does the same job in this case
))b) The gCode mods are simply to replace the G1 Znnnn linear move commands with M280 Px Snnnn commands (servo control) - as I don't have a stepper controlled Z axis, I just do a find then cut and paste. I only have three positions, UP DOWN HALF - UP being fully retracted, DOWN being down enough to cut through the depron and HALF for a half or 3/4'ish cut . You could add as many as you like of course or waste the rest of your life modifying stuff to do it automagically instead of being out flying
) All the commands are available in the Marlin gcode listings. I'll need to look at the lowrider machine, looks more interesting than mine Cheers
Neil
TheSFReader
Member
I have been wondering about an arduino-like "disguising" as a stepper driver (using the same connections step,dir, 5v Gnd) and piloting a servo for the Z value...
Even better would be to update the marlin software and transfer Z moves to servo positions (and simulate endwitches) piloting the servo pins on the ramps board...
That would allow use of "lightweight" cutting/tracing heads on the common Platform...
Even better would be to update the marlin software and transfer Z moves to servo positions (and simulate endwitches) piloting the servo pins on the ramps board...
That would allow use of "lightweight" cutting/tracing heads on the common Platform...
dkj4linux
Elite member
Wow, Neil! I love your machine!
I'm particularly excited about the pivoted Z-lift mechanism... looks from the video that it works quite nicely. I think that would work quite nicely on the Phlatprinter-inspired machine I'm working on
Rather than wooden sde-boards or somesuch... I've found the little laser-cut wooden stack (detailed in post# 1419 and later) above and below the guide platform to be quite effective in reducing the heat in the welding tip... the point of greatest friction can be moved from the metal guide proper to a point considerably above and the needle constrained to near straight-line motion in/through the welding tip.
I'm sure we'll all have a bunch of questions over the coming days... you've brought some really neat ideas to the party!
Thanks for your post... and welcome to the playground!
-- David
I'm particularly excited about the pivoted Z-lift mechanism... looks from the video that it works quite nicely. I think that would work quite nicely on the Phlatprinter-inspired machine I'm working on
Rather than wooden sde-boards or somesuch... I've found the little laser-cut wooden stack (detailed in post# 1419 and later) above and below the guide platform to be quite effective in reducing the heat in the welding tip... the point of greatest friction can be moved from the metal guide proper to a point considerably above and the needle constrained to near straight-line motion in/through the welding tip.
I'm sure we'll all have a bunch of questions over the coming days... you've brought some really neat ideas to the party!
Thanks for your post... and welcome to the playground!
-- David
iGull
New member
iGull
New member
Attachments
quimney
Member
Neil,
Very nice machine! I have been preparing to build a lightweight machine just to cut foam for planes for quite some time, something I could just hang on the wall when it was not in use.. Your design is the closest that I have seen. I love the simple v wheel design, skipping the bottom wheels with just a tab in the slot to keep it from falling off is brilliant. Gravity is enough for a machine like this. I have some traditional extrusion rail (not the v-rail) just lying around that I am planing to use so I'm just going to make wheels that fit in the groove and will accept a 608 bearing for mine but I am definitely going to copy the hold-down. I really like the z servo too but I know I would tire of editing the gcode every time. I'm going to think about that for a while... there has to be a way to fake it. Maybe an Arudino based ESC controller that reads stepper pulses and translates that to servo commands instead... maybe it only runs the motor whenever the z is not at the top to simplify things even more.
Great Job! thanks for posting it, I am inspired!
Very nice machine! I have been preparing to build a lightweight machine just to cut foam for planes for quite some time, something I could just hang on the wall when it was not in use.. Your design is the closest that I have seen. I love the simple v wheel design, skipping the bottom wheels with just a tab in the slot to keep it from falling off is brilliant. Gravity is enough for a machine like this. I have some traditional extrusion rail (not the v-rail) just lying around that I am planing to use so I'm just going to make wheels that fit in the groove and will accept a 608 bearing for mine but I am definitely going to copy the hold-down. I really like the z servo too but I know I would tire of editing the gcode every time. I'm going to think about that for a while... there has to be a way to fake it. Maybe an Arudino based ESC controller that reads stepper pulses and translates that to servo commands instead... maybe it only runs the motor whenever the z is not at the top to simplify things even more.
Great Job! thanks for posting it, I am inspired!
moebeast
Member
Thanks for the details Neil! I can see a heatsink like that in my future too
I put some fins on mine and they work incredibly well. I just used aluminum flashing. If you bent the sheet, they will stay in place without solder. But Neil's are way better looking than mine.
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