Circle looks off

I noticed when I was printing a vertext that the circles didn't look right. I've got it set for 2 shell layers so there is a total of 3 layers around an interier circle. I noticed that when it printed the shells that they slighly overlapped the perimeter and kind of created a cone. Is this because of my perimeter overlap setting.

I think I'm still having problems with backlash and the infill is not quite touching the circle shells. I've been working on this for the better part of the week and think I've actually made things a little worse than when I started. My X asix seems to travel smoothly so I don't know what might be causing the backlash, or if that is even what my problem is.

sounds like you are using skeinforge? if so in carve settings lower your perimeter width over thickness, so it knows your width is thinner, and will space the plastic closer together. also change it in fill ->thickness over width to a lower value.
if no improvement keep lowering the thickness over width to a lower value. this is a value that tells skein where to start and stop infilling because something is there, and it is this wide. undersized it if you must

also i turn off stretch, but some people like it. with infill still not touching at the end, there are two more solutions. 1 slow down your federate, or increase your flow rate. if flow rate is not enough to push the plastic down, it wont stick, it will peel.


1 secret i use alot is enable backlash settings to x .015 and y .015. this cause a slight slow down at each corner intersection, meaning slightly more plastic goes down. so if you need backlash settings, set them a tiny bit higher. this is skienforge under lash


i have not invested much time other that the default settings for reprap host. if you are using that, then increase your fill rate, and look here for extrude setup for reprap host [reprap.org]

another thing to note, i am assuming your extruder is level. if it is not level, then extrusion will tend to run through the side that has least flow resistance, and not on the other side. meaning uneven placement of material.


I'm kinda jumping around a bit here. I'd do it basically in the order below.

1 - make sure extruder nozzle is level. non level means extrusion squeezes out to the side, offsetting extrusion unevenly
2- don't start prints at above 34mm/s if you have not got it working yet. no more than 16mm/s if you do not have heated platform and are using abs, or hdpe. you can change this in folder speed.
3- add or increase backlash settings by .015 enable backlash in lash settings
4- change flow settings, or lower feed rate - you want a little more plastic put down.
5- change carve perimeter width over thickness, typical is 1.8
6 - change fill ->thickness over width to same value as carve

in my humble opinion - this is what i do, it may vary from user experience. your mileage may vary.

Thank you so much. There is a lot there to try and it will probably take a while. I didn't even know about the backlash settings.

I had a little problem with some plastic escaping out the seam between the nozzle and the barrier. I had to reset my thermocouple wire and I must have loosened that fitting. So I ended up takeing some parts off to fix that. Hopefully, that is good now. I noticed when I turned the X axis motor my hand, the gear looked like it had a little wobble. It looks like some layers of the gear may have seperated or I may have had the belt on too tight and bent it or something. Anyway, I have some spare gears I bought from so I'm putting that one on. A little wobble in the X axis my have contributed too.

I don't think extra shells would cause cone shaped holes. Without seeing the part to know exactly what you mean, what you are describing sounds more like a shrinkage problem. What temperatures are you using? What material?

If your layer thickness is not uniform throughout the print, this might cause each layer to smoosh flatter and wider, which would cause slanted edges. I'm currently thinking this is what has caused my prints to have slanted outer walls. I need different measuring tools to get some dimensions and actually verify this theory though.

As far as backlash, are your belts tight? Do the pulleys slip on the shafts? These were the key things that caused gaps on my parts. It can be tough keeping the belts held tight while you clamp them down, so you might try using zip ties or something like that to pull it tighter after you get things clamped. I saw a picture of a simple way to do this somewhere, wish I could find it again.

My pulleys did not have a spot for a set screw, so I used a couple of drops of super glue to fill the gap between the flat spot on the shaft and the ID of the pulley. The glue holds it in place during use, but it is not glued so much that it will not break free if I pry on it.

If there is backlash on your extruder gears, that could also cause gaps when it retracts and restarts. If your gear teeth are not too sloppy, you might be able to fix some of it by sliding the gears closer together so they mesh better. Otherwise, you might have to fiddle with extruder retraction settings to keep the melt zone pressurized before the extruder starts moving again.

the zip ties are used in example here [reprap.org]




good luck!