Surface Finish

I have a Lulzbot Mini (type 1, no LCD), and it works well, but I find I am unable to get a good surf finish. The top ends up looking rather like an old vinyl 78 record (except the lines are not curved!). This occurs with both ABS and PLA, but considerably worse with the ABS. I have adjusted the extrusion temp from 200 to 240C, but don’t see any difference. I have dried the filament in the oven over night at 80C. Still no difference. Any suggestions? Thanks?

Could you post some photos of the results of your print? Troubleshooting surface quality issues without a visual example can get tricky because of differences in terminology, getting a look at exactly what you are seeing really helps to clear that up.

Thanks for your reply. Here are a couple of photos: (Can only get 1 photo to attach!), but they are much the same.

More pictures may help… but that looks like overextrusion. Try reducing the flow rate to 95-97%.

Thank you I will try reducing the extrusion rate.
Meanwhile here is another photo:

Hmm… I’m still trying to figure out what that diagonal seam might be… It looks like the nozzle dragging across the surface, but that typically produces a straight line (well, more straight line).

Turn the fan on to help set the plastic, if its not on already. I like 8-20% for ABS (past 4 layers @ .3 Layer height), if PLA it should on.

Hopefully its just a bit of overextrusion.

I tried various Flow %ages (extrusion rates): 100%, 95%, 90% & 85%. 90% clearly gave the best (flattest) result, both visually and by feel. I also tried 105% for the initial layer, but eventually went back to using 100%. (Changing two parameters at once is always folly). I have tried photographing the differences, but that doesn’t really show how great the improvement is. Visually the change from 100% to 90% flow rate made a big difference…but it is still not perfect! I will hold to 90% for the moment and adjust other parameters (one at a time) to see how far I can go. I will try adjusting the fan rate and layer height too. Thanks for all your help. I appreciate it. I will keep trying and should I eventually achieve a gorgeous smooth ABS surface, I will definitely let the forum know!

Glad it helped.

Reducing the flow rate too much can affect the layer adhesion and reduce the strength of the project - increasing extrusion temps by a degree or two can help. It can also affect dimensional accuracy (smaller dimension). I like to stay near 95% as a minimum.