Can anyone tell me what I’m doing wrong. This is the first layer of a print in PLA. The layer height is 0.3mm. The external shells measure exactly 0.3mm, but the infill has waves up to 0.7mm high. The result being when the nozzle passed over the part, it caught and detached the part. The blob is where the nozzle stuck.
This only happens on the first layer. I’m using the latest Slic3r. The first layer extrusion width was 200%. I turned it down to 120%, the result was only slightly better, but enough for it to stay stuck down and add further layers. I have checked the extruder calibration and it is spot on. This only started recently after I unlogged my hot end: a E3D clone.
My guess would be height from the bed… the nozzle is too far away.
I would reduce the steps per mm on the extruder.
I think it’s too close. There is no space between the nozzle and bed so the plastic is being pushed to the sides.
yeah, if you zoom way in you can see it in over filling. That could be because the nozzle is too close or the extrusion width / filament diameter is wrong. I keep my slicer at 0 for auto on all the width settings.
For a solid filled area that large, you won’t be able to use more than 100% width with a correct layer height. You end up with too much plastic in the layer, so it flows around the nozzle, making the waves. They harden, and the extruder hits them. Most machines are flexible enough to ride over the waves for the first few layers, unless adhesion is weak. You should only need the extra plastic if your first layer is too high, or maybe uneven. With a perfect layer height you should extrude a maximum of 100%. Use more or less extrusion to compensate for a bad first layer height, or just fix it.
Excellent advice @Dale_Dunn !
Sometimes going REALLY slow (10mm/s) for the first layer can help alleviate this issue a bit… Ultimately it’s best to meticulously calibrate your extrusion settings and Z height.
Thanks for the input guys. I’ll try removing the first layer extrusion width of Monday.
Jessie: I’m printing on to blue tape with a cold bed.
Did it work with the previous version of slicer? I found that the new version wasn’t compatible with my old settings and rather than spend all the time required to identify the issue and recalibrate just rolled back.
I would stick with dale Dunn’s explanation. That is how I would explain it. My first layer height in S3D is always 100%
My printer does have a heated bed, but it takes so long to reach 60°C that I stopped using it for PLA. With the heated bed on, the first layer infill is still a little too thick, but it’s smooth and doesn’t cause any issues. Getting rid of the default first layer over extrusion looks the best course of action. I might also try increasing the the first layer temp 5° to see if the PLA will go down smoother on the cold bed. Ultimately I also need to find a 220mm circular heated bed that can reach ABS temperatures in a reasonable time.
If your bed isn’t insulated on the underside you should try that before getting a whole new bed. I’ve tried/used neoprene mouse pads, corrugated cardboard and silicone RTV as insulation and they all make a big difference (neoprene was best). If it’s still slow to heat then you might need a beefier power supply.
Slow bed heating might be worth another post. RAMPS polyfuses, undersize power supply, poor heater design, build surface material, etc. can be to blame for slow heating.
I have discussed the bed on the reprap forum thread for my printer. It turns out it was only supplied with a bed suitable for PLA.