Not getting 100% infill from MatterControl

[DaveBot]

Hi Guys -

After way too much travel, I'm finally using my Rostock Max V2 to make some actual parts. These are going to be structural plates for a project made with longish pieces of OpenBeam, so I wanted to print them at 100% infill for strength.

While I don't think it'll make any difference in terms of actual strength, the infill from MatterControl isn't actually coming out 100%. The machine was under extruding a little on the bottom layers, so I cranked the flow multiplier up to 130% on the LCD panel while it was printing. Unfortunately, it had already finished with the bottom layer, so I'm not sure if that was enough or not.

I don't think what I'm seeing is under extrusion, but maybe it is? The two passes of the perimeters join nicely, but the infill has a pattern of little triangular holes. Watching the machine print, the extruded tracks would have to be a *lot* wider to join up with each other.

Is this just a consequence of using triangular infill at 100%? Should I use grid infill instead, if I want to get a true 100%? (I'll try that tomorrow, but I wanted to ask and see if you guys thought that I'm just still under extruding, maybe save me some time fiddling in the wrong direction.)

The attached photo is pretty poor (didn't want to pause the machine, wasn't confident it'd start up again properly), but you can get an idea of what the gaps look like nonetheless.

Thanks for any wisdom you might have to share on this! Past bedtime here in Atlanta, so I'll have to respond to any requests for further info tomorrow.

(FWIW, I'm printing at 60mm/sec in ABS at 228C with a bed temp of 90C, 0.25mm layer height with the stock nozzle (0.5mm?) ABS is from IC3D. I calibrated the filament feed when I built the machine, but haven't checked it recently. I think I need a hub of some sort for the filament spool; there seems to be a fair bit of tension on it as it's being pulled off the spool. As best as I can tell from holding a finger on the filament as it's feeding, though, it seems to always be moving in sync with the rotation of the extruder wheel.)

Thanks in advance for any insights!

[DaveBot]

Actually, one further piece of information: The printer just got to a point where it's printing a top layer on some areas of the part. I must have gotten the extruder calibration way off, because I was still getting under extrusion with flow rate set to 130%. Cranked it up to 190% (!), and the extrusions for the top layer are connecting to each other nicely now. Some places where the part extends further upward are still getting infill with the little triangular voids in it, though, so I'm really thinking it isn't an extrusion problem that's causing them. Grid infill tomorrow, but LMK if it could be some setting I have that's off somewhere...

[Nareikuk]

Have you tried setting the top and bottom layer count to a large number? Matter control prints infill, even when set to 100% and so will leave little holes. You can see this in the layer view in matter control.

[DaveBot]

Ah - didn't think of looking at the layer display, but thought as much from how it was printing. Great suggestion with the top and bottom layers. Thanks!!