Firmware for SCARA printer

[WannaFly]

Hi. I am new to 3D printer. I am trying to build a SCARA printer. Because of other part of the project, I have to use the Repetier firmware. I am reading your Morgan Marlin firmware to figure out what do I need to modify in the Repetier firmware. So could you please give me a guide about what did you modify in Marlin firmware, and what need to do in general to convert a normal Cartesian firmware to a SCARA firmware?

Thank you very much for your time.
Regards,

[Quentin Harley]

Hi WannaFly,

I started with deltabot kinematics and replaced it with SCARA kinematics.

It is not had, but not trivial. I just added the kinematics to another platform in one two nights…

[WannaFly]

Could you please give me a bit more details, like where can I find the information about SCARA kinematics, as well as the notations? I also don’t understand the meaning of the variables like SCARA_C2, SCARA_S2, SCARA_K1, SCARA_K2, SCARA_theta, SCARA_psi, dCal_X = 0, dCal_Y = 0;

[Quentin Harley]

I found it on the internet, but obscured in maths. I had to code it. I am not a maths teacher, so it will be hard for me to explain to you how it works.

You should be able to use the section of code and port it to Repetier.

Why do you have to use repetier?

[WannaFly]

I have to use Repetier because the SCARA work is a part of a bigger project that we have already doing in Repetier.

[Quentin Harley]

Interesting. How is the progress?

I know the deltas are implemented on repetier already, so patching it to SCARA should be relatively easy

[WannaFly]

I have modified the repetier firmware for 3 extruders, with the mixing ratio saved in EEPROM.
Sorry I am quite new to 3D printer, but is “delta” the common name for all non-Cartesian 3D printer?

[Quentin Harley]

https://www.google.com/search?q=delta+3d+printer&oq=delta+3d+printer&aqs=chrome..69i57j0l5.5850j0j7&sourceid=chrome&es_sm=93&ie=UTF-8

ROstock

[Quentin Harley]

The delta configuration was one of the first non-cartesian 3d printers to be natively supported in reprap firmware using inverse kinematics. If you replace the delta kinematics with the scara code, you should have a start.

[ate]

Hi, I am building a reprap morgan using a Megatronics V3.0 board instead of the normal ramps. In the ‘morgan armlevel’ firmware that I downloaded from github it does have an option for the ‘megatronics’, but I fear that is might be for an older version. Because when I upload the firmware with the megatronics board selected, very strange things start happening when I switch on the power.
1) Has anyone had experience with using a Megatronics V3.0 board?
2) @Quentin; is the firmware you wrote suitable for megatronics v3.0 as well?

[Quentin Harley]

Hi there!

Yes, armlevel is aging. The plan is to work to get it included into marlin head, but Not done yet.

You could look at the pins.h file of recent marlin that supports the board, and add the section to my pins.h to see if it works better.

Let us know how it goes

[ate]

Alright! it worked, I just copy pasted the pins.h section for megatronics 3.0 in like you said and it worked.

Moving on to calibrating now… hopefully I can post a pic of the build next week. It is quite a radical adaptation of the original Morgan; a freakishly tall offspring (2meters)…

[ate]

Now when I try to home, only the Theta arm moves while the psi arm remains locked in position. The psi arm does function when I move the hot end in x or y direction in pronterface.
Does this problem ring any bells?

[Quentin Harley]

It seems that the pin for the dead arm is now incorrect. Did it move previously? Perhaps use the old pins for that stepper driver.

[ate]

It is not a dead arm because I can move it around with the pronterface directional buttons, so it the pins must be okay. It is just during the homing that it stays dead. It seems that the issue must be in the bit of coding that pertains to the homing command? I have been sorting through the firmware but I am having trouble locating the bit that controls the homing.

[Quentin Harley]

The code is in Marlin_main and is part of the G28 gcode handling section

[ate]

Ah, it was just an endstop malfunctioning. I came accros this very usefull command m119 that gives you status update of the endstops:

SENDING:M119
Reporting endstop status
x_min: TRIGGERED
x_max: open
y_min: TRIGGERED
y_max: TRIGGERED
z_min: TRIGGERED
z_max: open

[Quentin Harley]

A relief! Now you can finish calibration

[albertbjames]

G’day wannafly,

I too am building the Morgan printer. I already have a Pibot Cartesian printer that uses the Repetier firmware. I have installed the Repetier onto the Pibot and done upgrades so I am familiar with the process and want to use Repetier with the Morgan that I am making. Do you still have the source for your firmware?

Alby

[Quentin Harley]

You may have to hack the kinematics into Repetier yourself…

[albertbjames]

G’day Quentin,

Thanks for your reply. I will continue with trying to get the Repetier firmware to work. I will let you know when I have success. Somebody else will benifit from my work. Please refer them to me if you want.

Alby

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