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Hello To All.

I have a bit of a quandary and thought I'd sample the wisdom of the group. I have searched the forum very carefully and, unless I've missed something, this issue has not been addressed. Here's the scoop.

I have a print I'd like to do that requires a great deal of precision. I am using the latest "pro" version of KISSlicer, by the way. I have successfully printed the file with ABS using a .5mm nozzle and printing in .2mm layers. "No drips, no runs, no errors" (to quote the old Krylon spray paint ad). But the print is a bit "coarse" so I'd like to print in finer layers, preferably .1mm.

I would post an image of the file but the design is proprietary, so... Nevertheless, among other things the object has two sweeping arcs in it. On the peripheral ends of these arcs, and elevated above the build platform about 10 mm, are horizontal structures that rise to a height of about 10 mm. As you can imagine, I am using support to ensure the arcs and horizontal structures build well.

I have successfully printed the file as described above (.5mm nozzle, .2mm layers, etc.). But (heavy sigh!), if I attempt to print in finer layers (e.g., .15 or .1mm layers) the horizontal structures do not build well at all. The problem occurs as the gcode starts to "bridge" the support material under the horizontal structures; the extruded ABS does not span the gaps of the support material and leaves blobs as others have described in other "bridging" posts. These blobs cause defects in the horizontal structures.

I have a .35mm nozzle. Is there any benefit to swapping to this smaller nozzle and slowly refining my printer settings until I get what I want? If so, which settings should I target first? I'm at a bit of a loss and would appreciate others' thoughts.

Bill

A friend of mine prints .07mm layers with his .35mm nozzle, and the prints are beautiful. I have no idea how it does with bridging though. He's using the EZ-Struder too, so I can't even imagine how slow that stepper motor turns when he's printing at low speed

Have you messed with the temp, flow, and speed settings specific to bridging? I haven't hunted down that mastodon yet, so I can't offer much experience based advice. Those are the "normal" culprits for failed bridging though.

Slow?! I run my bridges as fast as possible. Bridging has rarely been an issue for me.

You can try messing with the extrusion width, probably increasing it a bit, say goto 0.7 or 0.8mm, the issue is that at low layer heights the filament is stretched a great deal and will snap.
My experience with 0.1mm prints is you can do them with 0.5mm nozzles, but sometimes you have to resort to 100% infill, because solid layers will not even stretch enough to cover sparse infill.
A smaller nozzle will make it a lot easier.

I have continued to wrestle with using a .35mm nozzle on my Rostock MAX (and printing ABS in very thin layers). I have run three long (> 6 hour) prints with the layer height set at .15mm and have had good success with bridging and the other "standard" trouble issues that affect printing thin layers.

What seems to be the more important variable in this topic is the hot end temperature. Filament extruded through a .35mm nozzle seems to cool more quickly than filament extruded through a .5 or .7mm nozzle. This can keep it from bonding to lower layers/to the build plate.

Print width seems to run a close second to hot end temperature in affecting thin prints done with small nozzles. Next in importance is the issue of the spacing of support material.

In the print I am running right now the hot end temperature reads an indicated 245° on the first layer and 240° for subsequent layers; I set the bed temperature at 80°. I set my print width at .55mm for both loops and infill and my support material (in KISSlicer) is set to "fine". With these settings I can print reliably at a print head speed of 15mm/sec.

Eventually I am going to take the layer height down to .1mm. We'll see what happens then.

Bill