Help in understand the electronics needed for a custom build.

I'll start by saying thank you to everyone in advance.

I want to build a custom 3D printer and would greatly appreciate everyone's advice on the electronics components. My machine is not built yet, but I do have the mechanical components already. I have a 24" ballscrew driven slide for the x axis, a similar 11" ballscrew drive for the y axis and a small 9" ballscrew driven slide for the z axis. The x and y axis will be powered by a 3.2a NEMA 23 motor, the Z axis by a Nema 17 1.2a stepper motor. The screw pitch on the x and y axis are 8mm/turn, the z axis around 1.5mm/turn. From what I'm reading, these slides should be super precise, though not necessarily speedy.

I know nothing about software and programming so I plan to use the Makerbot 2.4 motherboard to ensure compatibility and the ability to correctly use the stepper driven extruder. The latest stepper driver board from Makerbot can only handle 2.8a. I'd like to use a 48v power supply to drive the stepper motors to get a bit more torque and speed out of them. It seems that the Makerbot driver is not an option. I have 3 gecko g203v drives sitting around, would it be possible to hook these up to the Makerbot motherboard and drive them separately with a 48v powersupply?

Thanks. Jim.

Yes, you can drive a gecko board from a Makerbot motherboard as the gecko uses step/direction control lines. You might want to look at using EMC instead of the Makerbot motherboard as EMC has been acceleration capabilities, but that is just something to think about.

Jim,

I'd suggest something like the http://reprap.org/wiki/RAMPS in part because the arduino mega is more flexible and extensible. Although you'd probably end up making your own RAM(Gecko)S which would connect the arduino mega pins with the Gecko drivers. Talk to the folk in the #reprap irc channel about that, if you are interested.

Are you doing up a T-Slot bot? We need a good one for the wiki.

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I've read the EMC is the way to go. However, I'm don't know much software at all and the thought of running Linux is a bit intimidating. I might give it a go at a later stage.

For now, if I just hook up the geckos to the Makerbot motherboard, would I encounter any compatibility issues? Am I giving up anything buy not using the Makerbot drivers? And lastly, is there a wiring diagram for such an arrangement?

Sebastien,

Thanks for your advice. Is the Makerbot mb not Arduino mega based? I think it plugs onto a Mega board.

I am building a large CNC router from extrusions, but I don't think it will translate well to a 3D printer.

A much, much simpler, less expensive, and more precise way to build a 3 axis cnc machine is to buy ballscrew driven rails and just stack them together. I spend around $100/axis for rail, ballscrew and motor. 3 axis that screws together in minutes for around $500, more precise than anything that you can buy out there.

This is my latest ebay purchase for my project.

Edited 1 time(s). Last edit at 02/27/2011 02:57AM by HereinCS.

Thanks for your advice. Is the Makerbot mb not Arduino mega based? I think it plugs into a Mega board.
Ah, so it is: http://reprap.org/wiki/Generation_4_Electronics
(I've not been paying much attention to it as to Gen 7 and Monotronics most recently.)

I am building a large CNC router from extrusions, but I don't think it will translate well to a 3D printer.
Ooh! Ooh! Yes, we definitely need one those in the wiki as well.

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I thought that the Gen 4 mother board was the latest. Perhaps I should wait a bit for either Gen 7 or Monotronics? Which s the better way to go?

I thought that the Gen 4 mother board was the latest. Perhaps I should wait a bit for either Gen 7 or Monotronics? Which s the better way to go?

This is RepRap, we don't really do official.

Makerbot would probably rather you get gen 4. Techzone, who did up Monotronics, ... would rather you get the Monotronics. And so on, and so forth.

The gen 7 dev team thinks the gen 7 board is peachy-keen.
http://forums.reprap.org/read.php?181,63487
http://reprap.org/pipermail/reprap-dev/2011-February/002926.html.

And I'd gently suggest RAMPS, after checking in on our RAMPS forum or #reprap irc. The RAMPS shield takes pololu chip carriers http://reprap.org/wiki/RAMPS and you may be able to just plug in geckos there. Maybe.

What are you naming your machine, btw?

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Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

You'll not be giving up anything by not using the makerbot drivers, especially since the makerbot drivers are not going to work well with a 3.2 amp stepper, as you've noted yourself earlier. In fact, you'll be gaining a much more robust driver and midband resonance suppression, which will be a useful benefit on the machine you are building. I'm not aware of a preexisting connection diagram, but it would be pretty straightforward. Once you've chosen a controller board and firmware, post up a list of components and I'm certain someone will help you sort out the connections.

You certainly could use a RAMPS board as a breakout board, but it is really only going to provide a thermistor circuit (not needed for a CNC router) and some MOSFET drivers for a couple of heaters (also not needed on a CNC router), so there is little to be gained. Connecting the outputs from an controller board directly to the gecko drivers is pretty reasonable.

One final pitch for EMC (and then I promise not to mention it again in the this thread). Part of the problem with using the Makerbot board for the controller is that the GCODE support is somewhat limited. Many cam programs will generate GCODE tailored to EMC simply by selecting the correct machine profile. I know that GCODE is supposed to be universal, and it is, mostly. It is that "mostly" that causes a lot of headaches. This is probably more of an issue with a mill than it is with a router, however. And if the cam software you are planning on using is known to work the controller/firmware you choose then it is a non-issue.

Another thing consider is that you'll want a real emergency stop button. The plastic extruder machines are pretty low power and as such the safety considerations are pretty minimal. Between the larger steppers that you are using and the much more "dangerous" tool head (a router), you'll want to spend more time thinking about how to mitigate the hazards.

Finally, I assume you are familiar with CNCZone.com. If not, you'll want to spend some time on the site as they have a lot of information concerning DIY CNC machines, as well as CNC in general.

One final pitch for EMC (and then I promise not to mention it again in the this thread).
Actually, it's compulsory to talk up EMC as long as you then do up some more notes here:
http://reprap.org/wiki/EMCRepRap
and here
http://forums.reprap.org/list.php?155

but it is really only going to provide a thermistor circuit
Jim's machine is going to paste as well as cut, so the thermistor and heater-mosfets (and general reprap-ramps or reprap-gen4 compatibility) will be handy. He can save a tiny bit by ordering it "hold-the-pololus".

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Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

Thanks for your advice. Perhaps I'll take another look at EMC. Which brings up another question. Do I have to use a Makerbot mother board at all? Can I just use say a Gecko g540, which has 4 axis and a built in parallel port breakout board. I'm not a programmer so I looked at Makerbot motherboards just as a turn key solution, but if I don't have to use it, than that's all better. Can ReplicatorG or a similar program work without Arduino based boards? Will I be able to have extruder function if I don't use the Makerbot mb? I already have Mach3, can I use that instead of EMC?

SebastienBailard Wrote:
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>
> 'Jim's machine is going to paste as well as cut'

I'm actually going to use this particular machine to print only. I already have 2 routers.

Thanks for your advice. Perhaps I'll take another look at EMC. Which brings up another question. Do I have to use a Makerbot mother board at all? Can I just use say a Gecko g540, which has 4 axis and a built in parallel port breakout board. You will need something like an entire RAMPS or Gen 4 Electronics board in order to heat your extruder head and control its temperature. Or you can use the extruder controller board from Gen 2, as per:
http://reprap.org/wiki/EMCRepRap
I think.

Basically, your Gecko g540 doesn't know what a thermocouple or thermistor is. And since you want to hold the extruder(s) at a particular temperature ...

I already have Mach3, can I use that instead of EMC?
Dunno. Since we've got docs and devs that know how do to it with EMC,
http://www.reprap.org/wiki/EMC_Arduino
I would suggest using EMC.

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Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

Oops - my mistake about this being about a router.

With EMC you would need/want to use a breakout board and drivers - EMC will not work with the Makerbot mainboad (or any other USB based microcontroller board). A G540 would work well. However, with EMC or Mach3 you'll still need an Arduino (or the like) to control the temperature of the extruder and/or bed, so EMC/Mach3 become a lot less compelling. I'm not aware of anyone controlling the temperature directly from EMC, so Sebastien is right to push the more traditional designs.

To the best of my knowledge none of the Reprap/Makerbot hosts currently work with a parallel breakout board. They all expect a microcontroller to do the actual pulse generation (and GCODE interpretation, for that matter).

In theory Mach3 should be usable in place of EMC, but I have not used Mach3 so I am not 100% certain.

I use EMC to control a Taig mill that I've had about a year. It uses gecko G251s as the drivers and I've constructed an extruder which I use on the mill (also control from EMC). It works well but the feed rate is rather limited due to the Taig.

I've just completed a Sell's-style Mendel with parts printed on the Taig (it has only taken a year or so...). As I've tried to keep costs down I went with polulo based drivers. Although it is possible to burn up a gecko is rather difficult. I burned out three pololu's by looking at them sideways (I still have not figured out what I did wrong, but I obviously did do something wrong). Once the pololu's are correctly wired and as long as none of the stepper connection break the pololu boards are fine, it is just that they are really easy to break if you are playing with the wiring). If money was no concern I would probably buy gecko's to drive Mendel, but they really would be overkill for a standard Mendel and the midband resonance suppression never kicks in on a Mendel (due to the belt driven hardware it simply never spins the motor fast enough to matter). I considered using EMC to control the Mendel but I have an interest in experimenting with different firmware and controller boards, so I have not.

In theory you can use high speeds on a ballscrew driven axis if you accelerate a lot, which both EMC and Mach3 will handle well. However, I found on the Taig that even through the A-axis (driving the extruder) was synced with the movement during acceleration, the resulting parts had very odd flaws due to uneven plastic flow. I believe the problem is caused in large part by the large lag between the application of force on the plastic going into the extruder and the filament being ejected from the extruder. However, that is only a theory. It might simply be a limitation of my extruder.

whatever you use, be sure to use a hex buffer, or inverter for each line out of ardunio/mega or whatever to the optically isolated inputs of your controller. or better yet use a controller that is not optically isolated as input current is really low to those pins. Arduino is noisy, and does not provide enough current to run some optical isolators without modified firmware. the parallel port specification guarantees 20ma to each pin, but under certain conditions the arduino port will be unable to handle such a huge current draw from each of its pins.

the G540 is Optoisolation on all LPT signal pins. The arduino is capable of up to 50ma per pin, but there is a limit per port for how much current each port that uses pins can handle.


Emc2 is the most powerful opensorced way to go currently. you could also control the extruder temp with an arduino, and have the 4axis of your Gecko G540 use the 5d code. XYZEF is federate. Skeinforge dimensions settings will directly encode it to 5d code for you, and replace.cvs will change E to A axis

whatever you will have the best of the best. slow it down a little your 3d printer will melt from your feed rate.

my apologies.
'open sourced'
'XYZEF F is feed rate. '

Not sure if this may help.

Built a Mendal based machine using 24 volt steppers with separate driver PCB's which are driven from an Arduino Mega 2560 processor. Refer to below link.

Still working away with updating more data about this machine when time permits..


[www.google.co.nz]

Edited 3 time(s). Last edit at 02/28/2011 03:39PM by RepRot.

Thanks for all the input guys. It seems that a makerbot motherboard with geckodrives is the way to go. I have both the gecko g540 and g203v. Would the issue of signal strength be more problematic with the g540 than the g203v? I don't mind springing for 3 new drivers as long as they would work better. Any recommendations?

You should probably send gecko an email and ask them what the current requirements are for the inputs. I looked around on their site but was not able to find a spec.

What would happen if I drive a 3.2a motor with a driver capable of only 2.8A?

HereinCS Wrote:
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> What would happen if I drive a 3.2a motor with a
> driver capable of only 2.8A?


You just won't get the maximum torque capable of the motor, that's all. No biggie. Be careful that the motor driver doesn't over heat though if you use it at the max 2.8A current though.

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