Control board questions

Im looking to desgin and build a 3D printer. I need a board. The board has to support autoleveling and 1/32 microstepping. Im probably going to use a total of 5 steppers.

I was thinking about getting a Smoothieboard, but they are kind of expensive. Does any know of another similar board thats just about as good?

Also, if the board can control 5 steppers and I end up only using 4 steppers, could I only run 4 steppers without ruining the board?

All firmwares support autolevelling in a variety of guises and on both 8 bit and 32bit boards.

Smoothieboard and Duet (wifi/ethernet) are the premium offering now. I have two duet boards and they are very good. RRF is also a great firmware and support is very good and development is very active. But the only downside is cost.

You can try various chinese boards such as mks sbase and run smoothie, but the hardware is not open source and mks does not contribute to the smoothieware project like official boards such as smoothieboard and the Azteeg series (or ReArm) from Panucatt.

Some claim to be quite happily running 1/32 microstepping on ramps/mega combo (feasible with a cartesian machine without a graphical LCD display) which is very cheap (£20) so if you're starting out and not sure how much money you want to drop, start there. Build your printer. It will work, then if you are a bit more serious consider a smoothieboard or duet board and just upgrade it.

What about 1/32 microstepping is so appealing? I use 1/16th with hardware interpolation to 1/256 on duet and its quiet, smooth, powerful and accurate. TMC 2100 drivers for ramps can achieve this even if they are a little fiddly to setup.

If your budget is low use ramps/mega.
If your budget is high use smoothieboard/azteeg/duet.

Edited 1 time(s). Last edit at 06/09/2017 04:44AM by DjDemonD.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

If I was starting at the beginning I would use a Ramps/Mega combo but allow sufficient room for the board of you dreams to be accommodated. As DjDemonD pointed out, this combo is cheap, but in addition there are many people using it and it is easier to get solutions to problems.
I use RAMPS/Mega exclusively, but this is only because I only allowed sufficient room in my printers for those - future printers will have space for something a bit bigger than the largest 32 bit controller now available.

Mike

Thanks for the reply. I dont really have a super low budget. Im just trying to figure out what my options are.

About the 1/32 microstepping, i just want more resolution thats all. I was thinking abiut gearing down the extruder and z axis steppers but read somewhere to just get a board thats supports 1/32 microsteps.

I have two cheap DIY machines now that are quite annoying. I can get them to print kind of decently but it takes several several attempts to get it to print right.

I want to design and build better and more reliable machines. About gearing down the z-axis.... The way I was thunking about designing the machine was to have the extruder move on the X and Y and have the bed move on the Z. Instead of using the typical threaded rods, a belt would be used to move the bed which will be counterbalanced on two 12mm linear rods. The only weight the stepper would have to hold is a bit of the print. If i geared the z stepper down some it woould have even less weight to hold, which would be virtually zero weight. I just dont like the threaded rods because they are all just about bent and you have to finess the setup for the z-axis to work correctly.

As said i have two cheap diy machines with threaded rods and they are bent and get hung up very easily if i tighten down the brass threaded nuts at all.

I plan on mocking up my machines as 3D models first. Anyways, so you think I should just use smoothieboard or duet then?

Ok. I just bought the Duet Wifi. I only bought one. I figured i'd build one machine at a time. Anyways.

I'm with Duet.

A belt driven Z axis (especially counterweighted) works quite well, I have one.

The thing with microsteps is that they are to some extent the illusion of resolution. Lets say you have your head positioned at 0,0 and you ask it to move to coordinate 0.001,0.001 or even 0.01, 0.01 - nothing will happen, even if you are running genuine 1/256 (which you can on duet albeit fairly slowly, even with its fairly hefty processor) as the microsteps have to accumulate, overcome stiction in the whatever mechanism holds your axes together and then there is enough magnetic force to turn the motor. This is where I feel deltas do well, especially with linear guides, the whole mechanism is light, and friction/stiction is low its more likely to move when asked to move a tiny amount.

What microstepping beyond 1/16 is really all about is noise reduction. Thats where the 1/16 to 1/256 interpolation on tmc 2660 on duet works so well, processor overhead is low, noise is very low, accuracy is great.

I was contemplating mechanically upgrading my corexy, but instead I got a duet board installed it and the print quality jumped up a measurable amount (from the ramps/Re-arm I had before).

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Thanks for buying the Duet! For support, see the wiki at [duet3d.com] and the forum at [www.duet3d.com].

Increasing microstepping beyond about 1/16 makes the motors quieter but doesn't increase precision. If you need to increase precision on the Z axis and extruder, either use gearing (or for the Z axis, a leadscrew with a smaller lead), or use 0.9deg motors instead of 1.8deg motors. I prefer to use geared extruders anyway, they make it much easier to get enough extrusion force than with ungeared extruders.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Duet is a nice board, probably the best if you have a delta printer. I'm hoping that when smoothieboard v2.0 comes out, duet will get cheaper

Thanks for all the replies. I guess i misunderstood microstepping. Then what i need to to gear down the extruder and maybe even the z-axis.

Yea the Duet looks real nice. I like that it has wifi connectivity.

You'd get better results from 0.9degree steppers at 1/16 than regular 1.8degree steppers at 1/32.

I am a fan of the Smoothie board but have not had a Duet so a direct comparison is not possible. The most important aspects of a printer are its rigidity, the controller and the hot end. Don't skimp on those three in my opinion.

Totally agree. The frame/ case for my printer needs to be solid as hell. Going to first design something using T-Slot aluminum extrusion. I will research other structural materials I can use as well.

Im going to gear down the z-axis and extruder. I'm assuming im I can use some kind of gearing program to design some gears to import into my 3D software so that the gears can be further designed, extruded and saved to a STL for printing.

Quote
CVRIV
Totally agree. The frame/ case for my printer needs to be solid as hell. Going to first design something using T-Slot aluminum extrusion. I will research other structural materials I can use as well.

Im going to gear down the z-axis and extruder. I'm assuming im I can use some kind of gearing program to design some gears to import into my 3D software so that the gears can be further designed, extruded and saved to a STL for printing.

IMO, printed gears aren't a terribly good idea apart from maybe the extruder where backlash isn't a huge problem (can be accounted for by varying the retraction setting) and where the loads are relatively light compared to moving a (heavy) gantry.

To gear down the Z axis, the best and easiest way to do it is by using different size pulleys. For example, a 20 tooth pulley on the motor and a 40 tooth pulley on the lead screw or belt shaft will give you 1:2 gearing. I'm not a huge fan of belt driven beds moving in Z unless you devise some method to prevent the bed dropping when you remove power from the steppers.

You can use a counterweight, which I use but it's not to everyone's taste aesthetically but then I've not seen many pretty corexy machines. Or use Digital Dentist's idea and drive it from a highly geared motor which should be unlikely to allow free fall if powered off.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions