Wednesday, 16 May 2012

The search for software

03/03/2012
OK so I decided to search around for some software installation guides, found spacexula’s great video on you tube on how to setup Pronterface with SFact, Pronterface being the host control program and SFact being a derivative of Skienforge the slicing & GCode creation software.

Followed the guide to the letter (also discovered freenode IRC in the process of following this guide, this will be useful later I am sure)

Also reversed the extruder coil wires to fix the extrude direction issue.

 Tested Pronterface with SFact and to my amazement it works (well sort of) this is the first time since I upgraded the electronics from PIC to Gen3 that the machine has responded to a print by attempting to print something.

I was using the widebar .stl from the RepRap Wiki tweaking page, and the first layer looked extremely promising, firstly the machine lays down an outline/border to encompass the whole object being printed, it then attempted to print the outline of the widebar followed by diagonal infill, this all looked great, and other than the fact that it was moving so fast that the whole machine was shaking and wobbling from the inertia, another big step forward.

After examining the aborted (after second layer) print I concluded the following.

1)     Extrude speed not correct (my bodged stepper motor onto DC style extruder screw thread feed mechanism will need some serious firmware tweaks as the Mendel firmware is expecting a Geared extruder mechanism)

2)     X Y & Z speed way to fast (after a quick look at the firmware I found the stepper settings for a Darwin were different from the default Mendel settings, commented out the Mendel settings and copied the Darwin Stepper section down from the Darwin settings above in the configuration.h file, this did slow things down but did not appear to change the scale of the object being printed. And I may be wrong but the widebar seemed a little small)

3)     I really need to get a geared extruder!

OK so  after I had tinkered with the extrude speed a little I discovered that the manual extrude button in Pronterface exhibits weird behaviour, about every third click it would spin the extrude stepper for a reasonable amount but the next two to three clicks just give a stalling stepper sound (not good) this is definitely a software issue (although it looks like the stepper is jamming) as if I switch to using Repsnappers manual control the extrude button works fine every time and gives a pretty reasonable extrusion (after I lower the extrude speed and length considerably) proving that the extruder is not mechanically jamming.

Seeing as my only remaining serious mechanical issue is control over the extruder I decide to by a geared extruder mechanism.

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