Could I take a farmbot and occasinally convert it to a 3d printer or cnc router to offset the cost, are the stepper motor accurate enough?

1

I want a farmbot, but I also need a cnc router and a 3d printer. Could I use it for these things? I know I would need to make modifications, but in the long run could the railing, motor controller and current stepper motors get it done? The I would not have to decide and I could make my own replacement parts and mods. I would not even mind having to attached another micro controller to preserve the settings, and I could set up a known position to preserve the farmbot functionality from accuracy.

IMHO If it could do this and you could offer the kits (or order links and information) to do so as add on cost you would at a lot of customer base.

Let me know what you guys think,
Ty

2

You can absolutely convert FarmBot into a 3D printer! Only thing you would really need to add is an extruder with hotend. Also something to lay on top of the raised bed to use as a build plate. I would the also highly recommend doing an easy upgrade for auto-bed-levelling.
A second Arduino with Ramps is cheap enough get a second one for printing purposes only, and you should be able to share the Raspberry Pi with FarmBot.
It would be really cool to design a UTM attached 3D printing extruder!
Bottom line: you should be able to convert FarmBot to a RepRap for under $100. I’d definitely do that if I didn’t already have a printer!

3

Thanks you sir for your fast reply!

4

A few things:

  1. We’ve actually already done this (sort of). What we have done is taken old FarmBot parts and converted it into a large format 3D printer. We have successfully printed things with it but did run into some notable issues with extruder wobble. Basically having the z-axis extend down so far while the gantry and cross-slide move around rapidly causes a small amount of wobbling at nozzle. This doesn’t matter for FarmBot, but is noticeable in 3D prints. We mitigated most of the issue by slowing down the speed and limiting accelerations. Though you have to understand that having an all-in-one machine means that it will never do any of the individual things as well as a dedicated machine could do. So while FarmBot could be converted to a 3D printer, it won’t be as good of a printer as a machine specifically designed for printing.
  2. FarmBot’s gantry system is not really designed to support high loads in the X and Y directions at the end of the z-axis - there is too much flex. So while it may be possible to some light CNC engraving, I highly doubt you would get good results, if any at all, in converting FarmBot to a CNC router. Again, its just not optimized for that use case. You could probably do laser cutting/engraving more easily than CNC routing.
5

Thank you for your reply,

If I made a table that drought the 3d or engraving plate closer to the gantry top position do you think this would help enough to make it practical? Sounds like it might make the 3d printer part possible. Then I would have to do what to get the d engraving possible? Maybe get different stepper motors? I have looked a lot into these types of things but I have never had one myself. Any advice will be greatly appreciated.

Ty

6

Yes, making the distance from the gantry to the build plate for 3D printing and routing would help. Upgraded motors would help too, but then you would need to modify the mounting plates and get different electronics too. Again I personally think individual machines are better, but would be happy to see you develop something further.

7

If you were to suggest the beefiest stepper motor you could that still would work for all three what would it be? I want to start piecemeal-ing parts to learn how this stuff works but I dont want to duplicate purchase anything. I have all the arduino and pi stuff already. I want to get just enough rails and steppers to play around and then move on. But I want the ones I order now to be the ones I use for most things. Can I just buy some monsters steppers now and they will work for everything or would then not be precise enough or something? I am the type that does not mind spending money but I dont want to waste a single dime if I can help it.

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And thanks for your reply

9

It really depends on what you’re trying to achieve. Beefier isn’t always better. For example you want a printer to move quickly and have fast acceleration, and probably not suck a ton of power because it has to be moving for hours and hours on end. With CNC routing you need torque and holding power. With FarmBot you need to balance cost, speed/torque. Your biggest demand will be from CNC routing, so depending on what you’re CNC routing use case is, size to that. Probably a NEMA 23 or 34 is what you’ll need, unless you’re just doing light engraving in which case 17s and 23s are fine. With 34s you build up the need to upgrade other hardware like the pulleys, the belts, potentially add more wheels, etc.

If you really don’t mind spending money but don’t want to waste any, I again recommend going with separate machines. Otherwise I think you will find yourself unhappy with the results and having to go through iterations to get stuff working well, which inevitably wastes money.

10

All interesting information I will have to mull it over. I did want an all in one but I dont know now. I will have to look into things. Thanks for the input!