I recently build my first 3D printer. And so far I am very happy with my K8200 although I have some issues with my 3D printer configuration.
The first issue is that the first layer won’t stick to the bed. To overcome this issue I have added a glass plate of 3mm on the heat bed. With the glass plate, I was able to level the print bed. I have increased the heat-bed temperature to 60 degrees and lowered the homing distance of the Z-axis to 0.13 mm. With this configuration, the prints stick to the glass plate. Velleman uses a value of 0.25 mm in their manual. I am at half that distance. I am wondering if it is normal to reduce the distance or if there are better solutions.
The second issue I see is that the diagonal fill pattern does not seem to be evenly. The first image below shows an error in the first layer. The second image shows the top of a cube.
I have the feeling that the printer is not extruding enough plastic. I have measured the exact thickness of the filament and updated this in the slic3r settings. I am using 3 mm PLA which measures 2.85 mm. I have the feeling that this improved the fill lines somewhat, but am not satisfied with the results. What else can I do to improve the printing of the diagonal lines?
The last issue I have no solution for is that diagonal or curved structures are not smooth. The lines and arcs in the XY plane are nice and smooth. But as soon as the z-axis is involved, the curves and diagonal lines are not smooth at all. See below an image of a GoPro mount I have printed. As you can see, the hole in the mount and the round piece is not printed very smooth.
You may not have the correct filament settings in Repetier host.
you should very carefully check your filament diameter and put the correct size in the slicer settings. (which it sounds like you have done)
From your photos it looks like the printer is not extruding the correct amount of filament, that would also explain why your first layer in not sticking to the bed correctly.
You can try adjusting the extrusion multiplier to fine tune the amount of extruded filament.
Keep increasing it until its obviously printing too much filament.
The knurled bolt that forms your extruder mechanism is not a precision component, both the basic bolt diameter and the depth of knurl will vary. The tension on the filament roller changes how far the filament is pressed into the knurl, so that affects the effective diameter too. You should calibrate your extruder, there’s quite a nice video here; youtu.be/YUPfBJz3I6Y?list=UUb8Rd … ROUVg46h1A
Thanks for the replies. I measured the thickness of the PLA and entered that value in Slic3r. I left the extrusion multiplier at the default value (1.15).
Next I watched the video to calibrate the extruder. I did an extrusion length test and I measured that the actual extruded lenght is around 10% less. So I need to update the settings. When I tried to retrieve the steps per millimeter value with the M503 command however, I did not get a reply from the printer. Just an “ok”.
I am using repetier 0.84 and Merlin firmware 1.0
Can you tell me how to retrieve the settings so I can calculate the new steps pr mm?
Next I will try adjusting the extrusion multiplier like Paul suggested and see if I can improve the prints.
You can check and change the steps/mm in Repetier-Host’s top menu by going to Config -> Firmware EEPROM Configuration.
The steps/mm for the Extruder motor is probably 600, so if it’s extruding 10% too little filament, use 600/0,9 = 667 steps/mm
It’s the top right box.
When you adjust the extrusion multiplier afterwards, make sure your z-axis is reliable/stable so you don’t get misrepresentative results when trying out different multipliers. (I printed dozens of 20x20x8mm boxes)
The top layer might turn out ugly, not because the amount of material extruded is incorrect, but because the z-axis problems cause a difference in layer height throughout the print.
Basically, look into Z-axis wobble and all that fun stuff before you try to finetune the extrusion multiplier.
