Second print, not quite there yet. help appreciated

Hello, any pointers on what this print is doing wrong would be appreciated. The print is of a 1cm cube. The base is 1cm per side. Height is 9mm. Top surface is 9mm per side, so it tapers a little. There are obvious gaps between layers

Settings after the pic:

#define HOMING_FEEDRATE {5000, 5000, 100, 0} 

#define DEFAULT_AXIS_STEPS_PER_UNIT   {80,80,4000,107}  
#define DEFAULT_MAX_FEEDRATE          {80, 80, 2, 4}    
#define DEFAULT_MAX_ACCELERATION      {1500,1500,100,10000}  

#define DEFAULT_ACCELERATION          1500    
#define DEFAULT_RETRACT_ACCELERATION  1500

Filament is 1.75 PLA, printed at 185 (I measured the filament to be 1.70mm so set it to that.

Extruder is a Bulldog lite, the 107 steps is accurate. Oh printer is a Reprap i3 with RAMPS and Marlin. Printed the cube with Pronterface.

First and foremost, make sure your belts are nice and tight. Next, run through the reprap calibration guide.

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[3DKarma.com] - suppliers of quality, affordable 3D printer kits and filament for the UK market.

I'm doing the calibration guide now, It's good for the most part, but vague in others. I'm struggling a bit to understand my current results.

The 3mm wiblet on the right is the best I've got so far, so i moved to the next step, printing the 0.5mm wall item. As you can see it goes a bit wrong.



I changed the layer height in slicr down to 0.15 and specified a wall thickness of 0.5 (as opposed to the default of 0) for the second print below.



So, weird stuff I don't understand.

My E steps per mm was 107. This extrudes exactly 1mm of filament per 1mm request. The E value I needed to get the 3mm brick in the first picture is (arbitrariliy) double that (214). I actually chose it in case it was something to do with stepper driver micro steps or something. But sure enough, if I retract 5mm of filament I now get 1cm of filament retracted. Any ideas?

Quote
UkIan
My E steps per mm was 107. This extrudes exactly 1mm of filament per 1mm request.

This may be your problem, depending on definiton of terms. What do you mean by "extrudes"? Is that the length coming out of the hotend nozzle, or do you mean that's how much is being pulled through the extruder, with the hotend removed? You want it to be the latter, not the former.

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MakerFarm 8" Prusa i3v
RAMPS 1.4
0.4mm E3D v6 for 1.75mm

Yes, sorry I should of been more specific (more on that in a second). That's the measure of the cold filament passing through the extruder without hot end.

On the being specific, I've learned a few important things over the last week. One is that some measures are in mm per min and others are in mm per second for example. That gave me a headache until I read the comments properly :/

I have just printed a "good" one cm cube which is 1cm on all sides and has only one very tiny flaw I can see. The top is slightly concaved, which I think is covered in the next bit of the calibration guide.

It still doesn't explain my numbers though. It's only on the extruder too, all other numbers are as expected.

Have you extruded 100mm and measured how much was actually extruded? The margin of error on extruding 1mm is too high to give a reliable result.

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[3DKarma.com] - suppliers of quality, affordable 3D printer kits and filament for the UK market.

10mm for indicative measurements and 50mm for accurate ones :/

Here's the pic of my nice cube for reference. It's pretty accurately 1cm per side. Still looks a bit like it needs a bit more feed rate though close up.What do you think?



I've asked a question here which is directly related, but felt it should go in the slicr section. Not sure.

Hazaah! Ok, perhaps this will explain everything. Hopefully you can tell me

I've been using Pronterface. I've been changing settings in Slic3r by starting it using the slicing settings menu option in pronterface. I'd then open an stl (Actually usually i'd close Pronterface and reopening it (I'm sure I read it doesn't reload the settings or something)) and print it. In this way I had to use an E value of 214.

I've just downloaded the new version of Slic3r and thought I'd try exporting a model as gcode from there.

Loaded that gcode into pronterface and it chugged along for a bit with the Extruder clicking as it couldn't force out any more goo. So switched the E down to 107, the expected setting value and huzzaah it's now printing at those settings.

While I was thinking about how it works out how thick a layer is in width and height, it occurred to me that, I'd set the printer to 0.1mm layers, but I could visibly see layers 2,3 or even 4 times that...

So What is Pronterface doing when you just import an STL?? It's clearly not honouring the slic3r settings...

[EDIT]
Yes, 25 layers in the last "good" cube = 0.4mm each which explains why I'm having to pump out twice the goo and still not quite filling all the gaps.
Thanks again
Ian

Edited 1 time(s). Last edit at 08/24/2014 01:53PM by UkIan.

Pronterface may be loading a different set of settings than the ones you're using when you run Slic3r separately. Instead of loading the STL into pronterface, run Slic3r separately with your corrected settings and export gcode, then load that into pronterface and run the print job.

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[3DKarma.com] - suppliers of quality, affordable 3D printer kits and filament for the UK market.

I wish I knew where. I've been playing with different versions of Slic3r, and they all share the same settings location, and thus settings, so f knows where Pronterface is looking.
Here's my latest print. The square at the top is my .5mm wall calibration piece, and the robot is a robot.

The robot had a few issues with support material, I don't really know how to control that yet, the slic3r settings are a bit baffling on that, but otherwise I'm quite pleased.