1 Topic by batmaster

  • batmaster
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Topic: Bulging at bottom of part?

Since switching to repetier i was having annoying problems with bulging in the first 5-10 layers.  I was constantly messing with my bed leveling and do offsets to my z and really not getting anywhere. 
Then i noticed what the problem was, in the custom gcode of slicer it had:

G1 Z5 F5000;

I guess this was added as a clearance in the event your bed leveling was really off.

Unfortunately what this did was introduce backlash into the first bit of the part until the slack was taken up since these machine use a standard threaded rod vs a ballscrew.

So i replaced that code with:

G1 Z-1. F5000 ;
G1 Z0. F5000;

Which moves the bed up past 0 1mm then back down to 0 to take up the backlash.  Results below, before change on left after on right.  I figured i would post incase anyone else has this issue.

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2 Reply by FrozenRC

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Re: Bulging at bottom of part?

Good find, whats interesting is if you look at luc's start g-code over on voltivo, second post http://voltivo.com/forum/davinci-softwa … de-scripts he doesn't have any of that, his start and end is quite different.

3 Reply by FrozenRC

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Re: Bulging at bottom of part?

Thought I would confirm now that I have printed something since your post that this definitely solves the issue!  Thanks a bunch for this.  The issue gets real troublesome when trying to fit tight pieces together

4 Reply by batmaster

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Re: Bulging at bottom of part?

Yea for sure glad i could help.  It has totally transformed my printer.

Today im messing with some acetone vapor smoothing will post results later but its very exciting.

5 Reply by Antonious

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Re: Bulging at bottom of part?

Just arrived to Repetier-host (installed today) and lost with the gcode question and more things (I think there is some lack of information for the "after flashing" ), so some doubt about this thread:

Where have I to go to do this change?

Thanks.

6 Reply by batmaster

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Re: Bulging at bottom of part?

if you are using slic3r you go to:

Slicer-> Configuration-> Printer Settings-> Custom Gcode

This applies to the start gcode section.


It Had:

G28; home all axes
G1 Z5 F5000; lift nozzle

Now mine looks like:

G28 ; home all axes
g1 y180 f3000; (i added this so my nozzle comes up to the front so i can clean it real quick while everything is heating up.
G1 Z-1 F5000 ;
G1 Z0. F5000;

The last 2 lines are what im referring to in my original post.  Be sure that your bed is level as this will approach only a few tenth above your bed.

7 Reply by Antonious (edited by Antonious 2015-09-27 23:41:02)

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Re: Bulging at bottom of part?

Ok.

And if you use Cura, could work the same start gcode?

8 Reply by batmaster

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Re: Bulging at bottom of part?

yes, if i recall in my cura it had a lift of 15mm before it started printing, so its the same solution.

9 Reply by Antonious

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Re: Bulging at bottom of part?

My Cura start G-code is the following:

; Default start code
G28 ; Home extruder
G1 Z15 F{Z_TRAVEL_SPEED}
M107 ; Turn off fan
G90 ; Absolute positioning
M82 ; Extruder in absolute mode
{IF_BED}M190 S{BED}
; Activate all used extruder
{IF_EXT0}M104 T0 S{TEMP0}
G92 E0 ; Reset extruder position
; Wait for all used extruders to reach temperature
{IF_EXT0}M109 T0 S{TEMP0}

How would you change to improve in the same way you did?