Question on Tool chain architecture....

I am building a reprap and in the process, starting to figure out the software toolchain. I would appreciate if someone could explain a few things:

* If I understand correctly, a typical approach would be to use some 3D design package to design the part and output a .STL file.

* (the mysterious part)...The .STL file goes into a piece of software that translates this into G-codes.

*The g codes drive something like an Arduino/stepper motor driver combo that make the steppers step and control the heaters. The Arduino/stepper has firmware to interpret the Gcodes.

* So what is used to translate .STL into Gcodes??...and really mysterious...how are the extruder specific commands such as "back up the extruder drive a little so it does not ooze at the end of a move" figured out? Are they provided by the .STL-to-Gcode conversion software? If so, that software must be configurable for 3D printer specific conversion (as opposed to a general simple milling machine Gcode converter??).

Or is there a missing step in how I described the tool chain?....maybe a Gcode postprocessor that modify the Gcode specifically for 3D plastic printers??

Enquiring minds want to know ;^)


TIA,

Steve

The arduino is a circuit board that drives all of your machine including heating and moving parts using stepper motors.

I use Solidworks to do my design stuff but you can also use Google sketchup, inventor, blender and a host of other programs listed in the wiki.

Solidworks outputs to .stl natively but if I find the part is not oriented correctly for printing then I use netfabb basic (free) to rotate it and resave as .stl.

I then use Skeinforge41 with my own settings to create the Gcode which I then input to Repsnapper which is the program that operates the printer.

All of the settings you need or in Skeinforge, I'm still perfecting my settings but they are giving pretty good results now, so just a bit of fine tuning

---

__________________________________________________________________________
Experimenting in 3D in New Zealand

Quote

* If I understand correctly, a typical approach would be to use some 3D design package to design the part and output a .STL file.

Correct. Starting with an STL is about the only way. Luckily, virtually all CAD packages feature such an exporter.

Quote

* (the mysterious part)...The .STL file goes into a piece of software that translates this into G-codes.

This part isn't really a translation in the sense of describing the same content with another language. Merely, this step calculates all the required machine head movements to let the machine produce a part with a geometry close to the one represented in the STL file.

Quote

maybe a Gcode postprocessor that modify the Gcode specifically for 3D plastic printers??

Nope. Creating the G-code is already machine-specific. You have to tell the G-code creator which nozzle size, which maximum speeds, which feature set your machine has. Editing G-code after creation is possible (it's a human readable file format) but doesn't make sense for more than minor adjustments.

Quote

how are the extruder specific commands such as "back up the extruder drive a little so it does not ooze at the end of a move" figured out?

That's a mixture of knowledge built into the G-code creator and hints you give at the G-code creator's user interface. Some features are even programmed into the machine controller's firmware, like that pull-back for anti-ooze. Other firmwares don't have anti-ooze built in, so they need anti-ooze in form of G-code.

Quote

* So what is used to translate .STL into Gcodes??

As you can guess, G-code creation is a pretty complex thing, and in the nature of open source, multiple competing solutions exist. Here's a list of the most important ones: [reprap.org]

Best idea to get started is probably to pick a toolchain somebody else uses already. This includes G-code creator, G-code sending application (a nasty little piece in between) and a firmware for your electronics. Get that working and always keep in mind, there are really complex processes behind the scenes. That done, you can try to improve print quality and speed by adjusting parameters and/or upgrading software pieces.

---

Generation 7 Electronics	Teacup Firmware	RepRap DIY