Z-scars? Or something else?

[3dPrintingMD]

Winner Winner Chicken Dinner !!!

So that worked very well, I can not tell where any end/start point on at all. Nice job boss !!!!

[Jules]

Whew! Thank goodness! (The next step was gonna be tightening up any excess play in your X-axis belt.)

[thegammaray]

I lost a few days to a Windows 10 upgrade, but I'm printing again today. Unfortunately, the "optimize start points for fastest print speed" option has been selected on all of my prints. I'm pretty sure it's the default in S3D because I don't remember changing it on either installation.

Sorry to throw a wrench in your victory. I'm not real broke up about the z-scars, though. I didn't buy the printer for aesthetic prints anyway, so it's not a big deal for me. I really appreciate your collective efforts.

[Jules]

I lost a few days to a Windows 10 upgrade, but I'm printing again today. Unfortunately, the "optimize start points for fastest print speed" option has been selected on all of my prints. I'm pretty sure it's the default in S3D because I don't remember changing it on either installation.

Sorry to throw a wrench in your victory. I'm not real broke up about the z-scars, though. I didn't buy the printer for aesthetic prints anyway, so it's not a big deal for me. I really appreciate your collective efforts.

Did you try the other settings i posted earlier? We've had a couple of successes with those so far.

[thegammaray]

Did you try the other settings i posted earlier? We've had a couple of successes with those so far.

Yeah, I tried those. Actually, one of my original assumptions is incorrect. With every little setting change the software seems to change the optimum layer change point, thereby changing the location of the z-scars. I tried it with the settings you posted, and the back ends up smooth because the z-scars are moved to the crease of the wing where they're really hard to see. I only found them with an off-angle flashlight. Then I went back to my original prints sans infill, and I found the z-scars in the same place. Turns out printing without infill isn't a magic ticket after all; it just happens that on this model, the layers change in a fortunate location.

Can you check your prints again, with particular attention to textured surfaces that might disguise the z-scars? Are you sure there's no sign of them?

[Jules]

Did you try the other settings i posted earlier? We've had a couple of successes with those so far.

Yeah, I tried those. Actually, one of my original assumptions is incorrect. With every little setting change the software seems to change the optimum layer change point, thereby changing the location of the z-scars. I tried it with the settings you posted, and the back ends up smooth because the z-scars are moved to the crease of the wing where they're really hard to see. I only found them with an off-angle flashlight. Then I went back to my original prints sans infill, and I found the z-scars in the same place. Turns out printing without infill isn't a magic ticket after all; it just happens that on this model, the layers change in a fortunate location.

Can you check your prints again, with particular attention to textured surfaces that might disguise the z-scars? Are you sure there's no sign of them?

Well, yes, you can see them on the back in the same place that yours show up. There is always going to be a fine mark at the spot where the layer starts - you can't get around that. Very fine marks appear on the back of the owl, but you can see from the picture that i posted, unless you get a magnifying glass, and a flashlight, you aren't going to see them. Yours are very deep, and they might indicate that you are under-extruding a little bit. It's the only thing i can think of, if you are using all of the same settings that i posted.

Did you put the code that modifies the acceleration into your Starting script?

[thegammaray]

Well, yes, you can see them on the back in the same place that yours show up. There is always going to be a fine mark at the spot where the layer starts - you can't get around that. Very fine marks appear on the back of the owl, but you can see from the picture that i posted, unless you get a magnifying glass, and a flashlight, you aren't going to see them. Yours are very deep, and they might indicate that you are under-extruding a little bit. It's the only thing i can think of, if you are using all of the same settings that i posted.

Did you put the code that modifies the acceleration into your Starting script?

Yeah, I tried adding the acceleration modification to the starting script. I've left it there because it didn't seem to do any harm, but it didn't change the z-scars either. Most recently, I tried playing with the "extra restart distance" to try to fill in the missing material, but it only added lumps next to the ditches. The z-scar seems to be left at the end of a layer, not the beginning. I even tried entering a negative coast value, but the software won't let me.

I don't think I'm under-extruding. My test squares measure pretty much spot on. Is there another technique I should be using to gauge my extrusion amount?

I'm starting to think that the z-scars on my model are normal, and they just look more prominent in my pictures because I used a macro lens and lighting to deliberately highlight them. I dunno. Mine are smaller than the ones on the primate head that was included with my M2, though.

[3dPrintingMD]

If they are at the end, you should try doing a wipe.

[jsc]

You want a negative extra restart distance, not a negative coast value.

[Jules]

Mine are smaller than the ones on the primate head that was included with my M2, though.

You must have really good eyes!