Bottom Layer Compression

[Obious 0]

Hi All,

 

Cutting a long story short, I’ve been having problems with my prints since I bought my Anycubic Chiron that I’m having a tough time getting to the bottom of.

 

Putting it simply, I’m find in the bottom layers of my print are being compressed/over extruded to the point where there is noticeable bulging on the sides of my prints (again, only for the bottom layers though). It doesn’t matter if I tell Cura to print either 10 or 5 bottom layers (@ a 1.2 layer height), after about the 4th layer, the filament starts to become ‘wavy’ which I can put down to either over extrusion or some type of z axis compression. It’s worth noting that the rest of the print comes out perfectly.

 

This wouldn’t normally bother me but for some recent prints, I need fairly rigorous dimensional accuracy as what I’m printing is going to be functional (basically a matrix of 10, 13mm x 13mm square holes to fit 12.5mm square buttons). 

 

I’ve tried various things; lowering print temps from my normal 205c (for 40m/s prints) to 195c, extruded calibration (was fine) and generally playing with the infill settings but I can’t seen to solve it.

 

Any ideas? Let me know if you need any more info wrt my settings, this is my first post! :) 

 

Thanks 

[Guest maht]

We don't support this printer (besides a contributed profile in Cura) and therefore can't test things, but a few basic things to try:

- Check your z height calibration. If too low, material will be squashed between the nozzle and build plate/subsequent layers.

- Set horizontal expansion settings in Cura - this can compensate for initial layers spreading outwards (known as the 'elephants foot' effect).

 

Hope this helps.

 

 

[Obious 0]

15 minutes ago, maht said:

We don't support this printer (besides a contributed profile in Cura) and therefore can't test things, but a few basic things to try:

- Check your z height calibration. If too low, material will be squashed between the nozzle and build plate/subsequent layers.

- Set horizontal expansion settings in Cura - this can compensate for initial layers spreading outwards (known as the 'elephants foot' effect).

 

Hope this helps.

 

 

 

Thanks for the reply. I’ve levelled the bed about 5 times and as far as I can work out, it looks to be spot on; I’ve also checked the underside of a few prints and the all look smooth. 

 

I’m thinking about trying horizontal expansion but won’t that be applied to all layers and not just the bottom/initial layers?

[Guest maht]

20 minutes ago, Obious said:

 

won’t that be applied to all layers and not just the bottom/initial layers?

 

There's a specific setting in Cura to apply it to the initial layer only. It's called 'Initial Layer Horizontal Expansion'.