The only thing we’re looking for in a retraction test is stringing right?
So in this example should I be setting retraction length to 0.2mm?
Many things cause stringing. Retraction is rarely one of them. As a general rule, if you have stringing, the first things to look at are filament wetness, extrusion flow rate/pressure advance, and extrusion temperature. Too much of any of these will result in stringing.
Also, some filaments like PETG are prone to stringing and require really accurate tuning of flow and PA and temperature to eliminate it.
I’ve been 3D printing for more than 15 years. Took me a while to get the hang of it in the early days. But I’d say I haven’t messed with retraction in at least 10 years. Probably more. Upping retract to address stringing is a band-aid solution for another underlying issue. The slicer defaults should work perfectly.
Looking at the picture you posted, I’d say your flow rate is a touch high. Pressure Advance might be a little bit off, too.
Yes, the flow rate was supposed to be 0.92 I think but I set it to 0.94 because I was intending to use it in vase mode. It’s printed with a 0.8mm nozzle btw. I will do another pressure advance test but I find it much harder to understand than doing PA test with a 0.4 nozzle. I wonder if the test’s speeds were meant for a 0.4 nozzle.
Retraction length’s default value for generic PLA is 3mm. I feel like that might cause problems if according to the picture I posted stringing starts after 1.7-1.8mm.