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What takes priority, gcode or firmware  

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JonB
 JonB
(@jonb-2)
Active Member
What takes priority, gcode or firmware

Hi all

I'm new to 3D printing and have some basic questions.

I've built a Prusa i3 style machine with an Melzi board and Marlin firmware.

My first print was a perfect cube which was supplied as a gcode file. The quality was excellent.

My second print was a model cat I downloaded as an stl file and sliced with Repetier and loaded to the SD card. The quality was awful.

I looked at the gcode for both objects and the cube seemed to have a whole page of data relating to every imaginable setting. The cat gcode had none of this information just a few lines of settings and then the motion code.

Am I right to assume that the gcode takes priority over any firmware settings and the quality of the slicing process has a direct impact on the quality of the print?

If this is the case, why does the firmware offer any control settings? Surely it would be better for the gcode to handle it all?

Secondly, I've downloaded Slic3r and place it in expert mode. Is this the right thing to do to try an replicate the quality of the gcode that I found in the original cube file?

Postato : 31/12/2017 6:10 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: What takes priority, gcode or firmware

generally speaking the
Gcode describes 'What to do' and the

Firmware describes, 'How to do it'

if the Gcode is well matched to the printer's capabilities, then you will get a good result.

if the Gcode tries to drive the printer too quickly, or use excess layer height or wrong temperatures or simply do the perimeters in the wrong order, then the firmware will be unable to comply, and the model will suffer.

some Gcodes can directly affect the firmware, again, this can be beneficial if handled well, and disasterous if handled badly...

the original Prusa i3 is supported by versions of Slic3r which are optimised for their printer.

you could try using the prusa edition of slic3r for slicing your models and see if the quality improves

as your printer is not an original prusa i3, we can only offer general information. your supplier may be able to help more. or try Tom Sandladerer on youtube, he gives loads of information for all sorts of printers.

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Postato : 31/12/2017 6:27 pm
JonB
 JonB
(@jonb-2)
Active Member
Topic starter answered:
Re: What takes priority, gcode or firmware

Joan

Thanks for your comments. I think I will start by taking the settings from the file that printed well and copying them across to my version of Slic3r. I didn't realise there was a Prusa version. I'll try that.

Thanks

I'm sure I will have more questions to follow.

Jon

Postato : 31/12/2017 11:33 pm
JonB
 JonB
(@jonb-2)
Active Member
Topic starter answered:
Re: What takes priority, gcode or firmware

Joan

Wow. I downloaded the Prusa version of Slic3r, reran the model and the first print was perfect. That's done the trick.

Thanks

Jon

Postato : 01/01/2018 11:27 am
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: What takes priority, gcode or firmware

Cheers Jon.

glad to help!

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Postato : 01/01/2018 1:33 pm
JeffJordan
(@jeffjordan)
Utenti Moderator
Re: What takes priority, gcode or firmware

yes jonathan, just to shed some light onto the topic:

the *.stl file describes the geometry of the part that you like to print.

the *.gcode is a file, that tells the machine what to do (as joan already explained). so after all, the gcode is some kind of machine specific.
a *.gcode file could as well be for a cnc-machine, a laser engraver.... or a 3D printer.

in case of 3D printers we need a so called "slicer" to convert an *.stl file into a (print specific) gcode file.
this file does not only contain the "movement" commands, but commands to heat up the heatbed, the extruder (maybe the information which extruder to use, in case of multi-extruder printers or if you've got a multi material upgrade) and the filament specific settings (like extruder and heatbed temperature).
a good overview of the available commands inside a gcode file could be found here.
but because the manifold options that you can set up at your slicer, most of the slicer programs use the option to document the settings inside the gcode file with lines starting with a semicolon. but the printer only sees the lines without ";".

btw.: because the geometry description inside the *.stl file often is incomplete, our slicers are capable of repairing these files. but sometimes they aren't, especially when the *.stl file is generated by a scanner or picture based process. best results of *.stl files could be generated when using a 3D design program, where the model is build up from scratch (even by geometric equations, like at openscad).

dem inscheniör is' nix zu schwör...

Postato : 04/01/2018 3:09 pm
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