Small pillars test print

[foehnsturm 956]

The issue of raised edges when printing small structures is discussed in several topics here. There is a certain risk for the nozzle tip to catch a raised edge or something else which unintentionally sticks out above the last layer. In fact these collisions not only knock down or distort down small parts sometimes but they also can displace the (at least my UM original) print bed by a few tenths of a mm.

One countermeasure is to max out cooling and to print and move really slow. But there might be other possibilities. As described in the "Autolift Kickstarter" topic, I made an autolift mount for my Merlin hotend.

I would like to invite some people here to print this small part and post a picture, to find out if the autolift feature helps to avoid this issue. Pillars are of 1, 2, 3, and 4 mm diameter, printing time is roughly 30 min.

Markus

Print time 33 min.

 

 

 

[conz 0]

Printing it right now. UM2

Maybe I have found good settings for my printer and material. But with your test object I have nearly no issue with raised edges.

IMHO with circles as a profile for the pillars, the edges are not raising that much. Maybe a quadratic profile for the pillars will lead to more intense raising. Or a more extreme angle of the pillars.

I have used the settings you mentioned on YouMagine.

PLA ColorFabb "Shining Silver"

Temp: 217°C

[EDIT: Robert's feeder]

[EDIT2: I'm using 0% infill, maybe that reduces the issue, too.]

I'm not happy with the surface. Will test a print with lower temp later.

 

[foehnsturm 956]

Of course you are right with the profile and angle. I added another file to Youimagine and will print it today.

 

[anon4321 16]

How is this different than the head lift distance on the Expert Settings under retraction?

 

[foehnsturm 956]

Instead of moving the print bed it just moves the hotend (faster, higher repeat accuracy).

With my UM original I had no luck using the head lift. Seems like the bed didn't return exactly to the same position so I got loose layers.

 

[Dim3nsioneer 484]

I agree that lifting the head should be faster due to less weight which has to be moved. However, I never had that problem with the z hop on my UM1. What z motor coupling do you use on your UM1?

 

[foehnsturm 956]

Rectangular pillars and increased angle.

Print time 45 min (speed set to 60%). With 100% (Cura settings shell, infill: 40-80 mm/s) I got a mess above 15 mm.

@Dim3sioneer,

I'm using a standard fixed coupling.

 

[anon4321 16]

One thing about the UM1 is the Z acceleration and feed rate settings are EXTREMELY conservative. Going from memory the are something like 100 and 10. I've up'ed by to 1200 and 40 so the Z axis "clicks". See http://www.extrudable.me/2013/04/02/the-myth-of-z-speed/

In this case, I could see how that would impact the result.

I could also see that backlash in the Z screw might not provide the repeatability required. However, that might be addressed by making the hop larger.

 

[conz 0]

I have printed your new file with success. And not that much bending. I have had more problems with bending before with other objects and other materials. Maybe this material didn't tend so much to bend the edges.

You can see all the flaws really strong with this material. Especially in macro shots (In reality the object looks much better).

ColorFabb "Shining Silver"

Temp:215°C

Infill: 100%

Speed: 100% (based on your values on YouMagine)

My main problem is the stringing.