Can you begin retracting early?  

RE: Can you begin retracting early?

Look up "Linear Advance"

I is a Slicer option that enables LA with a M900 in the sliced code. The M900 value needs to be tuned for your filament and printer configuration.

If you really want LA to work well, consider a firmware that implements LA 1.5. There are several out there. Mine included. https://github.com/guykuo/Prusa-Firmware/tree/0.9-Degree-Stepper-Support

RE: Can you begin retracting early?

You can set M900 value for linear advance in either the filament startup g-code or in printer custom start g-code.

RE: Can you begin retracting early?

I've used every nozzle size from 0.15mm to 1.5mm and don't have the problems you're describing. I recently used a 0.80mm nozzle to print drawer inserts and got consistent if chunky results with no gaps in surfaces or walls. Unfortunately, this week my printer is down and I'm away from home. If you care to look at my PrusaSlicer profile page, I've got a config bundle with settings I've used with good results for a variety of filament sizes. That might get you started.

RE: Can you begin retracting early?

@guy-k2

I forgot to mention that I'm using a Dremel 3D45, so I don't know if linear advance is doable. If I set that in the g-code, and it isn't in the firmware, what could happen?

@bobstro

That's encouraging to know that its at least solvable even if it may require a new printer. 

RE: Can you begin retracting early?

forgot to mention that I'm using a Dremel 3D45

😧

RE: Can you begin retracting early?

Posted by: @guy-k2

forgot to mention that I'm using a Dremel 3D45

😧

Ya, I aimed for fully enclosed plug and play when I made my purchase as I planned to expand this into a print farm. It lets you tweak some stuff but I never knew how much of a difference bigger nozzles make in part strength, so now I wish I had more control over that. I just happen to like Prusaslicer compared to all the other ones I've tried. 

RE: Can you begin retracting early?

Only a [?] Guy?   LMAO ... this one is just way too funny.

RE: Can you begin retracting early?

Posted by: @david-3

 

I forgot to mention that I'm using a Dremel 3D45

Are you even using PrusaSlicer? 

RE: Can you begin retracting early?

@bobstro

Yes, version 2.0. Its the only slicer user interface I've tried that doesn't make me rip my hair out. I've never even heard of Josef Prusa until a few months ago. 

RE: Can you begin retracting early?

Posted by: @david-3
Ya, I aimed for fully enclosed plug and play when I made my purchase as I planned to expand this into a print farm. It lets you tweak some stuff but I never knew how much of a difference bigger nozzles make in part strength, so now I wish I had more control over that. I just happen to like Prusaslicer compared to all the other ones I've tried. 

RE: Can you begin retracting early?

I don't know if the Dremel firmware implements M900.

You can go to the Marlin linear advance page http://marlinfw.org/docs/features/lin_advance.html

There is a test pattern generator there. If your printer accepts M900, it should print the test pattern lines with varying degrees of linear advance. It's really easy to see LA vary the start/end pressure in those test lines. You pick the LA value that gives the most uniform extrusion result with velocity changes. 

If your printer does not implement LA, the patterns won't vary their middle segment widths.

RE: Can you begin retracting early?

Posted by: @david-3

[...] The second problem is oozing at the end of the path. Retraction doesn't seem to do anything and I've read that it doesnt work as normal with bigger nozzles. I think if I were to start the retraction process early, it might help, but I don't see that setting anywhere. Is it in this slicer under  a different name, or has it yet to be added?

The obvious question is how well the same part will print with the same nozzle using the Dremel-provided software. That printer is known for being a good printer, but very subject to manufacturer lock-in for filament. Does their software provide settings for the larger nozzle? I suggest getting it working "well enough" with their software with the larger nozzle just to rule out any printer-specific issues, then trying to figure things out in PrusaSlicer (PS).

If it prints OK with the larger nozzle with their slicer, try slowing your speeds way down in PS. If that helps, you know you've just got to find good slicer settings. If not, you need to look for more obscure settings. The Dremel is direct drive with an all-metal hotend, so at least you're not fighting Bowden retraction issues.

RE: Can you begin retracting early?

@bobstro

The 3D45 is Dremel's first 'sorta-open' printer. It does allow you to use 3rd party filament, though the internal compartment only fits their proprietary stuff. So there's a replacement door on thingiverse that has a port to run an external spool, which is what I've done. You have the option of either slicing it with their very limited cloud software, or simply sending a g-code via USB (or uploading and sending it via cloud). I got pretty good results with a 0.4mm nozzle (their default) whether using their cloud software or another slicer, but the cloud is definitely not set up for 0.8mm (Microswiss) so I have to slice it in something else. It won't even upload 0.8mm gcode properly so I only use USB now.

The best results I've gotten have been using randomized seams, a 10mm z-lift, and 10mm retraction (when using carbon fiber nylon). The surface finish is not pretty but the components mate properly and the part is strong. I also max out the perimeters so its pretty much solid, as it prints better to use 1 long continuous path than constantly moving around for infill. The thin lines for infill don't seem to cool fast enough and often get distorted. Speaking of cooling, I also find it necessary to print multiple components far apart so that the layer has time to cool before the printer comes back to add another path. 

RE: Can you begin retracting early?

Posted by: @david-3

[...] The best results I've gotten have been using randomized seams, a 10mm z-lift, and 10mm retraction (when using carbon fiber nylon). The surface finish is not pretty but the components mate properly and the part is strong. I also max out the perimeters so its pretty much solid, as it prints better to use 1 long continuous path than constantly moving around for infill. The thin lines for infill don't seem to cool fast enough and often get distorted. Speaking of cooling, I also find it necessary to print multiple components far apart so that the layer has time to cool before the printer comes back to add another path. 

Hey, one thought: Be sure to disable Linear Acceleration (LA) until you're sure your printer handles it well. Comment out any M900 Kxx commands from filament and printer startup gcode and try printing again. LA can fight other retraction-related settings (z-hop, coasting, restart length , depending on your slicer) and might account for your odd results. Disable LA and see if you get better consistency. Not every printer support LA or the same flavor of LA.

Do you know if your printer is direct drive or uses a Bowden tube? 10mm of retraction is insane for direct drive. Try turning off retraction (set it to 0) and all related options for testing. I found that 0.2mm of retraction works best on my direct drive Prusa.

RE: Can you begin retracting early?

Update: The Dremel product page says the 3D45 is direct drive. Keep retractions low.