Help with horizontal surface finish

[jasperash]

Hi all, I have just started working with my new Rostock. My prints are looking ok as far as finish of vertical walls goes but my horizontal surfaces are not looking so great. If I add a raft, the raft actually looks pretty nice but the part horizontal surface is very stringy. What settings could I look at to fix it. I've attached a photo. The part on the left is the raft. The one on the right is the finished part. I'd hope the flat surface of the part would be better, not worse than the raft.

Any thoughts would be awesome!

Raft on left part on right

Thanks.

[IMBoring25]

Is that the bottom side or the top side?

If the bottom side, making raft and support from the same material as the part is tricky. Too close together, and it won't easily separate. Too far apart, and the first part layer sags into the gap(s).

If that's the top, the large surface looks pretty good. The underextrusion only shows up in the small flange. What slicer and version are you using? That may be sloppy gap fill or it may be a sign you're getting heat creep and a partial clog when the extrusion rate slows down. Are you running the PEEK fan and is it turning the correct direction?

[jasperash]

Thankyou IMboring25

Its the top side of the raft on the left and the top side of the finished part onthe right, so on the right you are looking at the finished top surface of the bottom of the part, which isn't a good result. printing is AB. Using Mattercontrol with Natterslice all srtraight out of the Rostock manual at the moment, as I only finished the build a couple of days ago.

I'm running the peek fan. The manual doesn't say anything about which way it should be turning, so I'm not sure if it could be going the wrong way? Any idea which way it should be turning. I've not yet installed the layer fan, as I only plan to print ABS for now.

I'm also having trouble with one end of the print lifting from the heat bed during the print now.

Thanks.

[IMBoring25]

The top surface of the bottom of the part is a confusing turn of phrase.

The fan should turn such that it blows air across the hot end rather than pulling it across. I thought the manual either discussed that or which way the fan should be oriented and to make sure the polarity of the wiring is correct. Those factors are easier to discern than which way the fan is turning.

Try running the hot end up to temperature and turning the extruder drive by hand (Either on a fresh start of the machine or after passing it M84). There shouldn't be a lot of resistance.

ABS lift can be tricky. Many are starting to use PEI tape. I'm still using Kapton. I'm not a fan of liquid adhesion promoters because they're messy and most aren't designed for the temperatures they'll experience and may outgas unpleasant things. Enclosing the printer and, ideally, raising the environmental temperature, will help a lot.

[jasperash]

Hi IMBoring25. Thanks for the tips. I've put Kapton down ont he glass and it seems to be doing pretty well. I also whipped up a quick wall around the Rostock from cardboard to minimize drafts. Still minor issues with ABS part lifting at one end from the raft, but I'm getting there.

Re the surface finish. That I'm struggling with!! To try explain my images more clearly, The image on the left int he first post is the raft as if you are looking down on it when it is on the Rostock. So the surface you are seeing is the upper surface of the raft. The part on the right (I shouldn't have rotated it, confusing) is also the finished part as if you are looking down on the Rostock during printing. So, the problem is that the finished flat surface of the raft is really quite nice, so I know the rostock can achieve that surface finish, but the flat finish on the actual finished printed part is very average to say the least, its rough and shows the internal support structure through it. The vertical walls are all quite nice, its the flat surface thats bad. If you zoiom in on the image, you should be able to see the difference in finish.

So, the question is, what settings in Mattercontrol can I look at adjusting to make the flat surface of the finished part look more like the quality of the raft (or even better). Its sad seeing my printed part not looking as good as the raft that it was built on!!

Hope that makes more sense.

Also I run my heat gun over the heat bed during the printing and had about a 10 degree drop from the center to about an inch in from the edge. Has anyone had success with with putting an aluminium plate under the glass?

Thanks!!