Print quality for very small parts

K8200 3D Printer K8200 - Issues while printing
1

Hi, can someone help. I`m trying to print a small aztec pyramid from Thingiverse 20mm x 20mm x 10mm, but the top area about 3mm square and 2mm tall comes out as a blob of melted pla. have tried different settings without any real change. hopefully someone will have settings that will work please help

2

Hi, some parts are just beyond the limits of settings, if so you’ll need to take the extruder away from the part to let it cool before the next layer. There are a few ways to do this:

  1. Save and open the gcode in to note pad, search and find Z moves, paste in a little subroutine type thing that retracts->moves away->moves back (ideally in such a direction that the fan blows onto the part).e.g.
    G1 F3900.000 E-3.00000
    G1 X100 Y190 F900.000
    If you need more time you can make it do a little dance by adding something like this:
    G1 X120 Y190 F900.000
    G1 X80 Y190 F900.000
    G1 X120 Y190 F900.000
    G1 X80 Y190 F900.000
    Depending on the slicer and the start postions you have set you may need to add a move to take the extruder back.
    Random start shouldn’t need it.
    Fixed start will so G1 X (last postion before Z) Y (last postion before Z).
    Then undo the retract:
    G1 F3900.000 E3.10000
    It’s not as had as it sounds as most can be pasted.

  2. Possibly a little less time consuming. Print a second part so that the extruder moves away. I have used a little bridge so it doesn’t use to much filament. i.e. it builds two posts until I need to get to the point that I need extra time to cool, then bridges between the posts.

3

Thanks for the good advice, ive managed to paste a subroutine into each layer of a small block im trying to print, it looked good but after about 10 layers the next few layers come out incomplete missing lots of fillament. Could the retraction of the fillament at each layer leave the extruder with air gaps in the fillament ( fillament flows out of the extruder during the first couple of subroutines )

4

Hi, I think your probably correct in your observations, but glad to hear that you have got some improvements.
Can you link some details of the part your trying to print (possibly a photo of the fails), your hot end arrangement and nozzle size, the material you are using and temperature, the cooling arrangement and retract settings please.

5

Hi Barnabybear
Sory for not replying sooner have been on hols
Cant add photos, dont know how ?
http://www.thingiverse.com/thing:129616 is the link to the small pyramid and the small block is a cube 7mm X 7mm X 7mm
Im using the standard hot end arangement for K8200, with green PLA, temperature 180,K8200_Nozzle_Fan_65, retract setings as in your previousE-3.00000`. Hope this is what you wanted.
Any more help would be most welcome

6

Hi, I had a go at printing that item, to be honest it is pushing the boundaries of the standard setup. If you are going to regualy print items that small you would need a different extruder with finer nozzles.
That said I managed a half decent attempt. PLA @ 200 deg first layer then 190, 0.5 nozzle 0.25 layer height and a bridge postioned so the fan blows onto the main print cooling it, whilst print the bridge. The one at the back was printed without the bridge.

The bridge is bigger than I would normaly use but it was one I had drawn and I just roughly scaled it to fit.

7

Hi, thanks for that
you`r results are a bit better than mine
i will try printing with a bridge and see what i get, fingers crosed.