CNC PCB milling
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You can tell by the listing title or after doing some tests either with a dial gauge or by running it and listening.
Beware 2: diameter, my 3040 came with 53mm spindle holder, single piece with z carriage, so the 48mm only needed a 3d printed sleeve, but to add a 63mm or 80mm diameter spindle some heavy mods were needed so that's one of the reasons I didn't go with them
Beware 3: weight, the frame must support it without complaining, z drop, backlash or whatever
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My 10^5*2c: get a 6040cnc with supported rails and a 0.8-2kw water cooled spindle, will serve you good for anything from pcb to alu or bronze milling, even some light steel work on the 2kw one and will save you a lot of hassle in the long run.
LE. 3020 and 3040 don't have supported rails and many don't even have ballscrews
And if you're really anal about it get the ballscrew frame only from rattm on ebay, a set of hybrid servos, a spindle+vfd+pump, a controller of your choice and you can say you have the best tool in the entry class of router cncs.
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My 10^5*2c: get a 6040cnc with supported rails and a 0.8-2kw water cooled spindle, will serve you good for anything from pcb to alu or bronze milling, even some light steel work on the 2kw one and will save you a lot of hassle in the long run.
LE. 3020 and 3040 don't have supported rails and many don't even have ballscrews
And if you're really anal about it get the ballscrew frame only from rattm on ebay, a set of hybrid servos, a spindle+vfd+pump, a controller of your choice and you can say you have the best tool in the entry class of router cncs.
@executivul Maybe I've missed it, but none of the Chinese 6040's I've seen have had supported rails. They all seem to require that as some kind of DIY "upgrade".
For that reason, I've been considering a c-beam type design. There exists a relatively cheap Chinese clone of that:
https://www.aliexpress.com/store/product/C-Beam-machine-large-Mechanical-Kit-DIY-C-Beam-machine-Large-bundle-C-Beam-Frame-kit/1752067_32846185306.html?spm=2114.12010608.0.0.55bc1dafCeSt8dor maybe the WorkBee, which seems to be an upgrade to the OX CNC (though I'd prefer something where the screw holes are already tapped):
https://www.aliexpress.com/store/product/OX-CNC-Upgrade-Version-WorkBee-CNC-Router-Machine-CNC-Mechanical-Kit-with-Nema-23-Stepper-Motors/1752067_32850266842.html?spm=2114.12010608.0.0.36611dafYZdcH4 -
@executivul Maybe I've missed it, but none of the Chinese 6040's I've seen have had supported rails. They all seem to require that as some kind of DIY "upgrade".
For that reason, I've been considering a c-beam type design. There exists a relatively cheap Chinese clone of that:
https://www.aliexpress.com/store/product/C-Beam-machine-large-Mechanical-Kit-DIY-C-Beam-machine-Large-bundle-C-Beam-Frame-kit/1752067_32846185306.html?spm=2114.12010608.0.0.55bc1dafCeSt8dor maybe the WorkBee, which seems to be an upgrade to the OX CNC (though I'd prefer something where the screw holes are already tapped):
https://www.aliexpress.com/store/product/OX-CNC-Upgrade-Version-WorkBee-CNC-Router-Machine-CNC-Mechanical-Kit-with-Nema-23-Stepper-Motors/1752067_32850266842.html?spm=2114.12010608.0.0.36611dafYZdcH4@neverdie please search for the 6040 frame only from "rattm motor", it's not stated I believe but you can clearly see in the photos with the bed beams removed that y rails are supported. X are not, but they are high diameter and pretty stiff for 40cm wide span.
Imho wheels on rails will never ever ever be as stiff and have less flex than the lousiest linear bearing. Wheels on rails are for printers and lasers.
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@neverdie please search for the 6040 frame only from "rattm motor", it's not stated I believe but you can clearly see in the photos with the bed beams removed that y rails are supported. X are not, but they are high diameter and pretty stiff for 40cm wide span.
Imho wheels on rails will never ever ever be as stiff and have less flex than the lousiest linear bearing. Wheels on rails are for printers and lasers.
@executivul You're right:
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@neverdie please search for the 6040 frame only from "rattm motor", it's not stated I believe but you can clearly see in the photos with the bed beams removed that y rails are supported. X are not, but they are high diameter and pretty stiff for 40cm wide span.
Imho wheels on rails will never ever ever be as stiff and have less flex than the lousiest linear bearing. Wheels on rails are for printers and lasers.
@executivul said in CNC PCB milling:
Imho wheels on rails will never ever ever be as stiff and have less flex than the lousiest linear bearing. Wheels on rails are for printers and lasers.
Even in the case of the Rattm Motors 6040, where the z-axis is hanging off an X-axis that is dangling by unsupported smooth rod? Is it still better even then?
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@executivul said in CNC PCB milling:
Imho wheels on rails will never ever ever be as stiff and have less flex than the lousiest linear bearing. Wheels on rails are for printers and lasers.
Even in the case of the Rattm Motors 6040, where the z-axis is hanging off an X-axis that is dangling by unsupported smooth rod? Is it still better even then?
@neverdie it might be better than a rigid x axis aluminium profile dangling on some wheels all together. Then comes the profile joining piece dance.
On the cnczone forums people go like: linear rails are the best, round bars are good, wheels on rails are for toys. That is for normal milling on a small machine. These things are routers by the way, real mills are taig style and are small size and meant for steel and heavy metal milling (no pun intended). For wood, plastic, soft stuff it might be acceptable though.
For pcbs you need high precision, flatness, high rpm etc.
For wood you need large size, think of table or door pieces. Tolerances are not so tight. You won't go like: look! Your door engraving is 0.1mm off in that corner!
For metal you need precision, high rigidity and power at lower spindle speed.The classic ebay cnc is a good all around tool but excels at nothing 😁
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@neverdie it might be better than a rigid x axis aluminium profile dangling on some wheels all together. Then comes the profile joining piece dance.
On the cnczone forums people go like: linear rails are the best, round bars are good, wheels on rails are for toys. That is for normal milling on a small machine. These things are routers by the way, real mills are taig style and are small size and meant for steel and heavy metal milling (no pun intended). For wood, plastic, soft stuff it might be acceptable though.
For pcbs you need high precision, flatness, high rpm etc.
For wood you need large size, think of table or door pieces. Tolerances are not so tight. You won't go like: look! Your door engraving is 0.1mm off in that corner!
For metal you need precision, high rigidity and power at lower spindle speed.The classic ebay cnc is a good all around tool but excels at nothing 😁
@executivul
How thick is the aluminum that such a 6040 machine could mill? -
@executivul
How thick is the aluminum that such a 6040 machine could mill?@neverdie you must use a chipload calculator according to your spindle power at requested rpm, tool diameter and tool profile. Stock can be as thick as you want, the machine has about 100mm of z travel, you mill in multiple passes anyway so milling depth per pass is based on the results from calculator, experience or many broken tools.
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Interesting way to make an inexpensive closed-loop stepper motor:
https://youtu.be/s2dpCpUqGnEI think a better way to do it would be to directly couple the encoder to a dual-shaft stepper motor, but that would, of course, mean purchasing a new stepper motor. Nonetheless, these small stepper's are pretty cheap.
The other way to do it with the existing single shaft stepper but without a belt might be to use a magnetic encoder, but I can't say that I've tried that, so I'm not sure how hard the retrofit would be.
Also, I guess the main point in doing this would be to hotrod your CNC, to make it move faster without skipping steps. i.e. you probably don't absolutely need to hotrod your CNC.
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Interesting way to make an inexpensive closed-loop stepper motor:
https://youtu.be/s2dpCpUqGnEI think a better way to do it would be to directly couple the encoder to a dual-shaft stepper motor, but that would, of course, mean purchasing a new stepper motor. Nonetheless, these small stepper's are pretty cheap.
The other way to do it with the existing single shaft stepper but without a belt might be to use a magnetic encoder, but I can't say that I've tried that, so I'm not sure how hard the retrofit would be.
Also, I guess the main point in doing this would be to hotrod your CNC, to make it move faster without skipping steps. i.e. you probably don't absolutely need to hotrod your CNC.
@neverdie said in CNC PCB milling:
I think a better way to do it would be to directly couple the encoder to a dual-shaft stepper motor, but that would, of course, mean purchasing a new stepper motor. Nonetheless, these small stepper's are pretty cheap.
I never looked, but do they make a dual notched pulley? Then you would only need to buy a pulley vs an entire stepper.
Vera Plus running UI7 with MySensors, Sonoffs and 1-Wire devices
Visit my website for more Bits, Bytes and Ramblings from me: http://dan.bemowski.info/ -
@neverdie said in CNC PCB milling:
I think a better way to do it would be to directly couple the encoder to a dual-shaft stepper motor, but that would, of course, mean purchasing a new stepper motor. Nonetheless, these small stepper's are pretty cheap.
I never looked, but do they make a dual notched pulley? Then you would only need to buy a pulley vs an entire stepper.
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@neverdie it might be better than a rigid x axis aluminium profile dangling on some wheels all together. Then comes the profile joining piece dance.
On the cnczone forums people go like: linear rails are the best, round bars are good, wheels on rails are for toys. That is for normal milling on a small machine. These things are routers by the way, real mills are taig style and are small size and meant for steel and heavy metal milling (no pun intended). For wood, plastic, soft stuff it might be acceptable though.
For pcbs you need high precision, flatness, high rpm etc.
For wood you need large size, think of table or door pieces. Tolerances are not so tight. You won't go like: look! Your door engraving is 0.1mm off in that corner!
For metal you need precision, high rigidity and power at lower spindle speed.The classic ebay cnc is a good all around tool but excels at nothing 😁
@executivul
This guy bought a 6040 CNC with supported y-axis rails (just like the RATTM one), but starting at time index 4:52 he discusses the "well known problem" of flexing on the 6040's unsupported x-axis when milling aluminum:
https://youtu.be/6a57KtmIu-4He concludes that upgrades to the 6040 (e.g. possibly a supported x-axis rail) will be necessary.
It's just a pitty that an inexpensive, already "upgraded," 6040 isn't for sale. Instead, it becomes a DIY quest.
In fact, this guy did do the x-axis supported rail upgrade, but it solved only 50% of the problem:
https://youtu.be/ABLXVCkXmpg -
@executivul
Do you suppose that linear rails, rather than supported rods, would fix this twisting problem that people seem to be having?i.e. Notionally, something like:
https://www.ebay.com/itm/Portable-Steel-MGN12H-Linear-Sliding-Rail-Block-Tool-250-550mm-CNC-3D-Printer/382360155951?var=651145928342&hash=item590670f72f:m:mah05n6MWl2QkZTLIZW2vJQ
that's made out of steel. -
@coddingtonbear What materials are you milling ?
I want to get a spindle for mostly wood, just hobby, but don't want to go too cheap, and face buying over when I realize its just not > W
@rfm69 Almost always just PCBs. Maybe sometimes some acrylic, but nothing very solid, if that's what you're asking. Those little 1610 CNCs have so many plastic parts, that I'm not sure it'd perform very well cutting anything much harder than plastic.
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@rfm69 I believe so, at least for brush motors. For brushless, I get the impression the motors are missing the electronics which tell them when to alternate their currents internally, so (it appears) you need a special driver to make them move at all. I'm not sure how, or even if, PWM fits into that. Maybe motor speed is all managed entirely through the brushless controller, and all the brushless controller wants as input is pure DC?
@neverdie Yes; brushless motors are for sure more technically complex than brushed, and usually require an external driver. Most of the time those drivers have inputs allowing you to control the speed via PWM or an analog voltage.
Adapting the 1610's woodpecker board to supply that PWM speed control signal to an external driver is super easy -- I can show you a photo of what I did to mine if it'd help.
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@executivul
Do you suppose that linear rails, rather than supported rods, would fix this twisting problem that people seem to be having?i.e. Notionally, something like:
https://www.ebay.com/itm/Portable-Steel-MGN12H-Linear-Sliding-Rail-Block-Tool-250-550mm-CNC-3D-Printer/382360155951?var=651145928342&hash=item590670f72f:m:mah05n6MWl2QkZTLIZW2vJQ
that's made out of steel.@neverdie said in CNC PCB milling:
@executivul
Do you suppose that linear rails, rather than supported rods, would fix this twisting problem that people seem to be having?i.e. Notionally, something like:
https://www.ebay.com/itm/Portable-Steel-MGN12H-Linear-Sliding-Rail-Block-Tool-250-550mm-CNC-3D-Printer/382360155951?var=651145928342&hash=item590670f72f:m:mah05n6MWl2QkZTLIZW2vJQ
that's made out of steel.Yes, but MGN15 or larger and of better quality, but that is expensive...
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@neverdie said in CNC PCB milling:
@executivul
Do you suppose that linear rails, rather than supported rods, would fix this twisting problem that people seem to be having?i.e. Notionally, something like:
https://www.ebay.com/itm/Portable-Steel-MGN12H-Linear-Sliding-Rail-Block-Tool-250-550mm-CNC-3D-Printer/382360155951?var=651145928342&hash=item590670f72f:m:mah05n6MWl2QkZTLIZW2vJQ
that's made out of steel.Yes, but MGN15 or larger and of better quality, but that is expensive...
@executivul
I guess the difficulty of finding a satisfying solution to this problem explains why milling machines are built around a stationary, highly rigid z-axis. ;)
