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What is wrong with first test print?  

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Andybx
(@andybx)
Eminent Member
What is wrong with first test print?

Does anyone know what is wrong with this first test print. I built the kit and received the congratulations message but this test print appears to have small holes in the walls?

Any suggestions would be welcome!!

Posted : 03/05/2019 10:03 am
Vojtěch
(@vojtech)
Honorable Member
RE: What is wrong with first test print?

Those holes are so called 'seams'. It's where the perimeter move of the printing head ends and the head moves to the next perimeter, infill or next layer. They are unavoidable, but there are settings (like slowing down the print, changing jerk/acceleration settings, changing linear advance, printing hotter and more, it's a whole rabbit hole to get lost in) that can help you minimize their visibility. Also the default Prusa Silver PLA made by Filament-PM is not forgiving, the metallic effect is making these much more visible. On many other filaments you won't notice them as much.

There is one setting in Slic3r that you should look at in particular and that is Print Settings -> Layers and Perimeters -> Seam position. This setting allows you to select where the slicer plans the seams to make them less visible. Nearest gives the fastest prints with least head movement, Aligned tries to bunch them together, Random randomizes the location on the print and Rear puts them all on the back of the print.

There is only one mode in which there are no seams and that is the Spiral vase mode (in the same tab). That however only works for very simple objects where a horizontal cross section always has a continuous perimeter. In this mode, there is only one perimeter and no infill, creating a hollow object - a vase.

Posted : 03/05/2019 10:49 am
Andybx
(@andybx)
Eminent Member
Topic starter answered:
RE: What is wrong with first test print?

Thanks for your reply but dont think they are seams they are small holes in the walls. Bit disappointed with the first print when my other £300 printer is producing better quaility prints.

Sure it's a case of tweaking a few bits though and I'll be happy. I'll play around tonight and see if I can figure it out.

This post was modified 5 years ago by Andybx
Posted : 03/05/2019 11:44 am
vintagepc
(@vintagepc)
Member
RE: What is wrong with first test print?
Posted by: andy.b17

Thanks for your reply but dont think they are seams they are small holes in the walls. Bit disappointed with the first print when my other £300 printer is producing better quaility prints.

Sure it's a case of tweaking a few bits though and I'll be happy. I'll play around tonight and see if I can figure it out.

Asking for help and then refuting the answer you are given doesn't change the fact those are the seam marks from where the Z height changed....

Posted : 03/05/2019 11:51 am
Andybx
(@andybx)
Eminent Member
Topic starter answered:
RE: What is wrong with first test print?

I wasn't refuting the advice but to me it doesn't look like seam marks. Maybe I'm wrong and appreciate any advice but I've not seen holes (seam marks) like that before. 

On my other printer seam marks appear pronounced (zits) and this looks like gaps. Thought the test files would be perfect lol

Posted : 03/05/2019 12:00 pm
vintagepc
(@vintagepc)
Member
RE: What is wrong with first test print?

Well, it's the opposite of a seam zit - this is what happens when not enough filament is extruded at the start or stop (a zit is too much). Try tightening your extruder door tension; that made it go away for me. 

Posted : 03/05/2019 1:01 pm
Andybx
(@andybx)
Eminent Member
Topic starter answered:
RE: What is wrong with first test print?

Thanks I appreciate that. I'll give it a go when I get home tonight. I thought it was something to do with under extruding but it's difficult to gauge the tightness for the bondtech gears.

Thanks again 

Posted : 03/05/2019 1:18 pm
vintagepc
(@vintagepc)
Member
RE: What is wrong with first test print?

Sure- and it's not entirely intuitive to realize that tightening them changes the radius of the gears' "bite" into the filament and therefore affects the amount extruded slightly. If it continues to persist then the settings to play with would relate to coasting and pre or post-extrusion, depending on whether it's happening where the layer starts or ends. (can be tricky to tell, but you'll have to visualize the direction the extruder is travelling and maybe print some different parts - e.g. a cube with no infill or top, with "aligned" seams will likely be informative since it will start on a corner, and then the face which the problem appears on will tell you whether it was the start or the end of the path.)

Posted : 03/05/2019 1:30 pm
Andybx liked
Andybx
(@andybx)
Eminent Member
Topic starter answered:
RE: What is wrong with first test print?

Thanks for the advice I tighten the screw and printed the benchy and aside from one rear corner that still suffered a slight seam gap its perfect.

Need to play with the extruder gear tightness a little but starting to love the prusa already.

Thanks again 

Posted : 03/05/2019 7:06 pm
vintagepc
(@vintagepc)
Member
RE: What is wrong with first test print?

Glad we could help - and welcome to the club!

 

There are other settings you can play with, of course - coasting and "extra length on restart" for example. These can be used to dial things in but note that values can be very filament specific owing to differing properties of different brands.

Posted : 03/05/2019 7:38 pm
Andybx
(@andybx)
Eminent Member
Topic starter answered:
RE: What is wrong with first test print?

Thanks again!! Still not perfect but you can see a slight hole so might tighten the extruder gears a little more....

Now to perfect the Z height adjust so it's perfect....

Posted : 03/05/2019 7:52 pm
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