extra restart distance issues with small details

[natty15d]

i had a problem with blobs at the start of a line, i added -0.2mm extra restart distance and the blobs have stopped, leaving a nice clean print.
My problem now is that im printing a part with a small crown detail on the top . With the standard wanhao i3 setting it prints perfectly, apart from the blobs at the start of the line. with the -0.2m ERD i get a smooth print but it no longer prints the tiny fine crown detail as its constantly holding back the filament. i then tickeds the box for only retract if crossing more than 3mm and the crown detail printed again.
The ERD is also causing issues where its trying to infill small tight areas and not having enough primed PLA to extrude.
Is there a setting i can use to stop this happening or change is it possible to have a retraction/retraction speed setting so that i dont need to use ERD.

[CompoundCarl]

You only want to adjust the extra restart distance until the plastic is perfectly primed when the extruder starts printing. Don't go any further than that, since otherwise you will start to see gaps and holes in the perimeters.

So if you get the adjustment just right, the nozzle should always be perfectly primed when it starts extruding (since you are always retracting and priming the exact same amount). It sounds like your extra restart distance may be a tad too large right now.

[natty15d]

Thanks, ill give that a try tonight and let you know how i get on

[natty15d]

tried pla 200 deg with -0.07mm extra restart with 1mm retraction, retraction speed is set to 30mm/s. the blobs have almost gone on the benchy3d chimney stack.
i tried printing the small repetitive crown detail with the same setting and it still wont print, there are tiny little details being printed with lots of retractions and its fine to start with but as its going around the circle its slowly emptying the nozzle or reducing the pressure and there isn't enough pla being extruded. by the time its back to the start there is just a tiny bit being extruded

[jimc]

this is the drawback with a neg restart distance. it does work but on the small details you never build hot end pressure up high enough to need it so the details are lost. you cant use neg restart with every model. most yes but not all. best thing i can tell you to do is use 2 processes. one used the neg restart but then when you get up to the part of the model where the details are then turn it off.

[natty15d]

thanks Jimc, thats kind of what i was thinking id have to do, was hoping though that there might be something id missed in the settings that was causing the blobs. looks like ill set up a couple of processes and just change them by layer.

[jimc]

If you have enough retracton then the right amount of coasting and a little wipe should take care of the blob at the start of the line without having to use neg restart. Of course your filament has alot to do with this too. Moisture will make it uncontrollable and some plastic formulations are just prone to it. Be sure you have the retract while wipe feature on and relative extrusion distances box is checked

[natty15d]

i give those a try but i think ill still have an issue with the small repetitive crown detail as they are so small. the length of the small detail is only 1mm or more so my coast will probably be more than 2mm meaning itll never actually extrude as its being told to hold back 2mm for a 1mm line.