Print Seam

I seem to be having a consistent problem with prints always having a rough or bumpy bit, I think it is where each layer starts.

I have seam position in Slic3r set to "nearest" which was the default. Do you think it will solve the problem if I change it to random or aligned or could there be a different reason for the problem?


Many thanks for any suggestions.


Brian

Well setting it to aligned would be a good test to confirm that the issue you're seeing is being caused by the seems. If these defects are the seems they should then be in a line down the object; if the defect remains the same it's something else.

I think wipe on retract might help if you're seems are that bad, but not sure.

A possible issue, if it's not the seems.
If your filament has collected a lot of moisture in it, it's possible you're seeing blowouts, this is where a high moisture spot of filament hits the hot end and the water vaporizes blowing out extra filament followed by a lack of filament.
If that's what's happening you should hear a 'pft' or popping sound occasionally during printing.

i only seem to get the bumpy bits on Cirles ,not on any other print ,Kinda annoying when you're trying to make a wheel xD

Try changing the settings of "retract on layer change" and "Wipe on retract". Both these can make matters better or worse, so it's worth trying all 4 combinations. If retraction between layers makes an improvement you can experiment with retraction length & speed to improve it further. The issue is usually due to the fact that the Bowden extruder has a lag, so when the extrusion pauses for a short while at the end of a layer, plastic continues to flow for a while causing a blob, and then when it gets moving again the extruder takes a while to catch up, causing a short lean area. That's why when printing a circular object it is sometimes best to have no retractions at all so that there is only a very short pause between layers. Other things you can try is to print the outer perimeters first - that way the layer change and hence the blobbing occurs on the inner perimeter instead of the outer perimeter. And the catchall "cure" is to print very slowly (it is not a cure, but a symptom-suppressant - still the final result is the same).

Dave

Thanks guys, that gives me several things to try, I will let you know how I get on.


Brian