Ooze free start with Slic3r?

Hi folks,

I really like the starting gcode that Chris has implemented in Skeinforge. Now that I'm starting to learn Slic3r I would like it if the printer starts out the same way as it does with Skeinforge. I see that with Slic3r you can insert custom start and end gcode. Can you just use the same code as written in the Start_PLA.gcode? I'm sorry if this question is answered before, because I can remember a post about custom gcode, but seem unable to find it.

Thanks heaps,

Niels

Edited 1 time(s). Last edit at 01/04/2014 06:18AM by Nilez.

Yes, just copy and paste it into the custom GCode area. Do not be tempted to remove the Relative Extrusion MCode that is repeated by Slic3r later.

I do the same for the end GCode also to control the bed fan. Works out-of-the-box.

Regards,
Neil Darlow

Edited 1 time(s). Last edit at 01/04/2014 06:45AM by neildarlow.

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

Wow, that is terrrific! Ok so leave the relative extrusion part in there, got it. Thanks Neil!

Edited 1 time(s). Last edit at 01/04/2014 07:04AM by Nilez.

Yup, This works well.
I use the commands below as a custom start

G1 Y100 X-25 F4000
G1 Z0.05 F30000
M190 S80
M109 S200
G1 Z0.1 F30000
G1 X50 E5 F200 ; make a thick line to prime extruder
G92 E0 ; reset extruder

I still find that the skirt line is needed to be sure the extruder flow has stabilised.

Couple of points/questions
1. I had to change the start position a bit, as my first version used to launch one of the bed bulldog clips across the room when the fan duct caught it!
2. I found that the head stays at the temp set by the M109 command when it starts the print, even if I have specified a different head temp in the slic3r filament settings. Not sure why yet...

Richard

Hi Richard, thanks for the tips! Your second point is very important for my current print since I need to play a bit with finding the right temperature.

You can use

M109 S[first_layer_temperature]

in your start gcode rather than setting an arbitrary number.

I think the reason the flow is not stable until after the skirt is because you are using 200C instead of 185C. It is much better behaved during warmup at 185C.

The fan duct should always clear the bed clip if the handles are removed but I don't think that was necessary with my original start code was it?

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[www.hydraraptor.blogspot.com]

Quote
nophead
I think the reason the flow is not stable until after the skirt is because you are using 200C instead of 185C. It is much better behaved during warmup at 185C.

Hmmm, could be, although I had similar behavior at 185, not that it is a problem. I have been experimenting a bit with the temperature for the green faberdashery filament you kindly supplied. Somewhat counter intuitively (at least to me..) I have more issues with structures with low bed surface areas coming unstuck mid-print with higher temps, perhaps the hotter PLA is stickier? My theory was that hotter extrusion would mean less viscous plastic, and therefore less dragging on the top of the structure as the head moves on to another section, but I guess not.
Right now 185/180 seems to be working well on my test lego cubes, although to be safe I'm also doing a 1mm Z lift before moving to try and reduce lateral forces. I tried a few test prints at what I thought were different temps before I realised the 200 degs I had set in my custom code seemed to be overriding the values I had put in the slice3r settings.

Quote
nophead
The fan duct should always clear the bed clip if the handles are removed but I don't think that was necessary with my original start code was it?

Nope, your original start code in skeinforge is fine, I think I broke it when I moved it to slic3r. Initially I had forgotten to set the origin to the center of the bed, which lead to all kinds of messy fun..
I'm trying to wean myself off the GUI delights of slic3r and into the modular joys of skeinforge, with reasonable success, although I am missing the brim function. I must try out the modified skirt.py module

QuackingPlums (Great username) : Thanks for the gcode advice. I am still very much a gcode novice, although the cheat sheet at [thingiverse-production.s3.amazonaws.com] is a great help.
Is the[first_layer_temperature] replaced by the value set in slic3r before the custom gcode is written to the output file? (can't test it right now on my work machine..)

Richard

P.S Apologies to those of you in the UK, you seem to be getting our Icelandic weather..

Quote
Mendelevium
Thanks for the gcode advice. I am still very much a gcode novice, although the cheat sheet at [thingiverse-production.s3.amazonaws.com] is a great help.
Is the[first_layer_temperature] replaced by the value set in slic3r before the custom gcode is written to the output file? (can't test it right now on my work machine..)

Yes, it's a substitution variable. I can't remember where I found the list of supported variables, but [first_layer_temperature] and [first_layer_bed_temperature] are both supported.

I did notice that Slic3r inserts three comma-separated numbers for the extruder temp even though I only have one extruder configured:

M109 S235,205,205

The value in my settings is 235, so I don't know where it got 205 from. The Mendel90/Marlin firmware doesn't seem to mind though.

EDIT:
Oh, and I just checked; it appears that if you have an M109 command in your custom start code then Slic3r will not put one in for you, which is why it appears to ignore your first layer temperature setting.

Edited 1 time(s). Last edit at 01/06/2014 08:07AM by QuackingPlums.