Fill Issues (Page 1 of 4)

In general you shouldn't let your layer height exceed 80% of the nozzle diameter..3 (.2963) is pretty much maximum for a .4 nozzle.

Backlash can exist on all axis.  For the Z just put a 5/16th well nut on the rod like this.

That is not what is causing your issues.  It is the backlash of the Y-axis mostly and then the X-axis.  This is caused by any play or slop in the mechanical system including your belts.

Improper steps per mm most likely

you need to calibrate steps per mm for each extruder.

no that's correct. how many steps did you arrive at?

Also, after checking the file a little bit better, the lettering is supposed to have spacing, it's the top fill on the grey I'm concerned about.

I'd recommend reducing your layer height to .2-.3mm, recalibrating wall thickness (see whether the extrusion multiplier changes...), and print again.

It looks like the filament is being pulled through the middle part of the move, and like taffy on a hook it's getting thinner in the middle and leaving gaps. The slow bits at the end where the extrusion has time to catch up look fine. I think thinner layers will help a fair bit, as both the squish into the previous layer will be improved, and the volume through the extruder will decrease.

I had some quite good results with top solid layers by reducing the width to 50-60% of the normal perimeter width under advanced settings in slic3r. You end up with the tool paths much closer together, and it works like a pad weld. If you've still got trouble with the top and need a more aesthetic result, try this and see how it goes!

Also, if your cad program has a 'quality' setting on the STL export, or a 'curve segments' or 'segment size' (they all do this differently, sigh...) I'd recommend increasing it a bit. I can see the segments in the outside of the oval (there's only about 24 there!), a few more would make it look less digital.

umm, I am no expert by any means, but, thinking this (red, bold above) might be a good share of your problem with the top fill layer?

I am running an SD4 and my slic3r settings for an 0.3 layer height are:

Layer (height): 0.2963 (as per recommended by others here)
first layer: 0.35 (i think this is a default setting?)

Solid layers
top: between 2 & 4 - changes depending on what I am printing
bottom: between 2 & 4 - changes depending on what I am printing

Extrusion width: 0.48
First layer: 110% (experimented with this one to get good tight fill without overfilling (ridges) on first layer)
everything else left at default settings.

Filament settings (assuming your filament diameter is measured?)
diameter: 1.74 (measured average)
Extrusion multiplier: 0.81 (calculated out to 0.79 with E steps/mm set at 105.75 for exactly 100mm, but in print reality it was terrible)

I am getting excellent fill coverage on all layers now, and generally much better prints overall. used to have fill and other issues, but all have been pretty much resolved with proper calibrations using the advice found in these forums. 

I think the grey is top solid, I don't see how that surface could be infill. slic3r is clever enough to work it out, otherwise I'm not sure it would manage anything much more complicated than a box hehe. Also, the rim looks like all perimeters (he's got enough to make up the whole thing) so there's no top-solid shown there, nor will there be any infill inside that.

The bottom of the cup doesn't look like 0.21mm-wide paths - this narrow width for top-solid is what I do for flat topped things every now and then, should produce lots of fine lines and merge quite nicely.

A few extra top-solid layers might help with the density? 2 is a bit light-on. Try 4 as madkow suggests?

I'm seeing something like this:

I have poured over the photos several times at this point.  I still want to see the 100% infill photos but something else is bugging me here.  The inconsistancy of that top layer is leading me to think your filament is not feeding properly.  Verify that the drive gear is not full of filament dust and that it can feed from the roll easily.  Watch the drive gear closely and make sure it isn't slipping.  What temps are you running?

Wow, thanks for all the replies. Our Workbench definitely wouldn't be where it is now without everyones help so far. I'll get the pics of the 100% infill right when I can get the bed to heat up. I posted the 2 .stl so you can have a look at them. We're running 215C for ABS. I'm feeding some filament through checking the gears right meow.