Really rough benchy wall corners (blobbing?)

[benjaminhill]

[img]https://i.redd.it/nu7amaq0bj9y.jpg[/img]

I've been trying to get a decent print from my Rostock Max v2, using a spool of clear PETG. The stringing is pretty bad, and the wall corners are very bad (the blue highlights in the benchy). In an effort to fight stringing I upped the retration a bit from defaults, and dropped the temp down to 240 as per the range in http://airwolf3d.com/2015/12/05/3d-prin ... nd-tricks/

This one was printed with support material, cut with Simplify3D, .2 layer height, all default settings for retraction and fan. Rostock Max v2, upgrade E3D All-metal v6 HotEnd Full Kit 1.75mm Universal, .4mm nozzle. SainSmart PETG 3D Printers Filament.

I don't mind the stringing, I can pull those off. I slightly mind the blobs (bow of ship) and really mind the edges, when I try to print a fidget w/ hinges it completely binds up. You can see near the top-right of the blue area the edge is ok, but then as you go down from there, it looks really bad.
Open to any tips, will post follow-ups as it improves!

[bimmersix]

If you have S3D, try enabling "Coast at End", maybe 0.5mm, and align seams near the back under the "Layer" tab.'

Try printing at a lower speed, too. See if any of those help.

[benjaminhill]

What do you think of "Coast to End" vs "Wipe"?

[bimmersix]

I've used Coast with good result and haven't needed to try Wipe yet, but try them both as they could both have a positive effect.

Temps are also so variable between different thermistor setups that you may be able to dial the nozzle temp back still.

When trying to fix a problem like this, approach it patiently and by changing one variable at a time. It's frustratingly slow but the results are worth it.

[benjaminhill]

AHHA!

I didn't have any retraction. Adding 8mm of retraction helped a HUGE amount.

[Xenocrates]

AHHA!

I didn't have any retraction. Adding 8mm of retraction helped a HUGE amount.

I'm going to ruin things for you momentarily by pointing out that more than ~2.5mm of retraction greatly increases the likeliness of a jam with an E3D hotend, since the E3D doesn't have nearly as long a PTFE liner as the old stock hotend, and thus can have plastic grab the metal walls and the junction between the nozzle and heatbreak more easily. I would suggest dropping it down to around that level, playing with the speed, and some other things to see how well it works.