3D printing using UCCNC

[A_Camera]

I have ordered some necessary parts to be able to use my CNC as a 3D printer. In the meantime, I have connected a 4th stepper and enabled the 4th axis, since that must be used as the filament feeder and done some dry tests. I had a look at the 3D plugin, but I must admit, I don't know what that is doing, other then starting the spindle, which was pretty scary because I didn't expect that pushing the fan on button actually would start the spindle. Anyway, here are a few questions.

What is that pluging actually doing and why is it needed?
Is there any documentation of that plugin somewhere?
Is it really necessary, and if yes, for which purpose?
It seems that I still need to use Slice3r to create Gcode, or is that wrong?
Anybody using this plugin?
How do you calculate the feed rate of filament for optimal results? Trial and error?

Thanks.

[cncdrive]

Hi Josef,

The only documentation we have which however covers the working of the plugin pretty well is in the plugin on it's help page.

The plugin saves the position of the stop point XYZA axes when you cycle stop and then moves the Z axis up to a predefined position.
The Z axis up movement saves the filament to stuck onto the workpiece, because the head is lifted up as soon as you Cycles stop.
So, then you can move the machine axis around, make maintance work, fix filament problems etc.
Then if you pressing the Cycle start again then the XYZ axes move to the point where you stopped the machine and the A axis resets it's value to the saved value without motion and the machine continues executing the g-code file. The A axis sets it's value without movement because the A axis supposed to be the filament feeder motor and if you rotated the feeder motor because you had a filament issue then it has to set the axis position back to the stopped value, so when the g-code is Cycle started again then the filament feed can continue from there.

The plugin was developed for Stepcraft and I'm sure there are several Stepcraft users who using it.
We have over 2000 UCCNC users with Stepcraft machines and probably many of them have the 3D printer attachment.

Here is a quick video: https://www.youtube.com/watch?v=32brucRde2Q

[A_Camera]

Thanks Balázs for the answer. This is going to be my autumn activity, if nothing comes in between. Currently gathering information and buying/making what I believe is needed.

[cncdrive]

Hi Josef,

No problem.
One more info for you is that Stepcraft is using the Repetier host to generate the g-codes: https://www.repetier.com/
I don't know the details, this is the only thing I know, but you could give it a try to see how it works.

[A_Camera]

OK, thanks. I'll have a look.

[A_Camera]

Some more questions regarding 3D printing...

M106 turns on the fan and M107 turns it off. Is there a way to change so that the spindle is not started? It seems that it always starts/stops the spindle, just like the M3 S24000 command. Why is that so? I'd like to be able to define an output, which would be connected to a relay but not through the M3 command.

Of course, one way would be to edit the generated G code for 3D printing and create a new macro in UCCNC, but M106/M107 seems to be a standard fan control code.

[cncdrive]

Hi Josef,

The M106 and M107 using the spindle PWM. The UCCNC has a few PWM outputs, the Spindle PWM, the laser PWM and the analog outputs which are also PWMs, just smoothed out on the -5LPT board.
So, we selected the Spindle PWM for the 3D printer fan control, because:

1.) A 3D printer has no spindle motor, so the spindle functions are free to be used in such machines.
2.) The laser PWM has a fixed 100kHz frequency which can be too fast for many 3D printer controller boards.
3.) The analog outputs are not available on all of our controllers, it is only available on the UC300 and UC300ETH boards and when we developed the M106/M107 it was developed mostly to be used with the UC100 on Stepcraft machines, so we could not use the analog outputs.

We could probably add more PWM outputs if needed, but the question is if it is really required?
Also we could probably build separately working and commanded PWMs from the spindle control commands, but again the question is if it is really needed and by that I'm just refering to the point 1. above, that on 3D printers there is no spindle and if you using your CNC machine to 3D print you could simply create a separate profile file and use different pins on the spindle control to control the cooler fan.

[A_Camera]

Szia Balázs és köszi a választ...

Don't worry about the above. I have already solved with two nice and simple macro. Even added a LED to my main screen to show the status of the fan. Anyway, I understand what you are saying that a 3D printer is not using a spindle, and this is true, but only for dedicated 3D printers. I will make a 3D printer head and when I want to use my machine as a 3D printer I will just swap the spindle but don't want to make other modifications which are related to the spindle, which is why I am not going to use the built in M106 and M107, as these will start the spindle and send Modbus commands to the VFD, even though it is not going to be used when 3D printing. Anyway, no big deal, I will just replace the M106 and M107 and all the other necessary macros with my own, calling differently.

[A_Camera]

Just in case somebody reads this...

I gave up the idea of using my CNC as a printer/CNC combo. I bought a super cheap 3D printer and will start with that. I believe it is better this way. The printer got delivered just two days ago, I am very happy with the contents of the large box so far and will improve the details as I assemble it, plus after the assembly, if I am not happy with parts of I will change or improve the design. Once I am done, I may build a second version out of aluminium, but for now I will be happy with testing 3D printing on this plastic fantastic 160 USD machine.

http://www.ebay.com/itm/Duty-free-Geeetech-Acrylic-Reprap-Prusa-I3-Pro-B-3D-imprimante-MK8-LCD2004/231911254318?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Delivered to my door two days after placing the order, well packed, not only the box but also inside, every part in individual plastic zip-bag, the acrylic parts are laser cut nicely and precisely, a complete list of parts with pictures to identify each part and so on. The only thing they did not include was building instructions but I don't think that will be necessary for me and there are also some YouTube video to watch if I need some help. I would preferred printed description, but it's no big deal.