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New plugin: who is smart enough?

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Hi there, i am currently struggeling with some retraction heavy print.

(one of them involving a sharp pointed church tower)

And i'm running into some problems.

As i near the tip of the tower one would expect a blob of molten PLA forming at the tip, but wat i get is severe under extrusion.....

I was hoping someone on this forum whas smart enough to write a plugin which would enable me to play with my retraction/de-retraction....

Somehowe i get the feeling that when i'm printing the tip of a sharp print, the de-retraction is in practice somewhat less then the retraction.

But where repetier host has an extra option to de-retract more than retract, Cura does not.

So i tried to write a plugin myself, but however how experienced i am at understanding G-code, "this challenge is beyond my skill"

P.S i dont use ulti-gcode bur marlin/reprap......

gr Cor :mrgreen:


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Priming more then retraction does not really solve the problem. Most likely this material you "lost" is ending up somewhere else, which is what you might want to address. Print temperature could be a huge influence here, so you might want to print cooler.


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You dont want to retract too much. 3-5mm is gives good results.

If you retract too much, you will suck air into the nozzle far enough it would make a bubble poping noise when it comes out.

Your travel speed may be too high, unless your belts are as right as a guitar string then you are OK.

For those speeds i would recommend an upgrade from standard belt and puleys to wider once :)


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Hmmm... maybe I should have mentioned I have GT2 belts and pulleys in my UMO (direct drive) as well and that I made sure the belts run in the middle of the pulleys (something that Ultimaker completely missed when they produced my UM2... :sad: )

I agree on the retract distance. I think I set it to 4.5mm on both UMO and UM2. However, on swap retraction on the dual extrusion UMO I never had such a poping effect. I work with 12mm there as more results in a clog.


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Depending on the nozzle and the melting areal.

E3D has very little pre-melt and about 7-8mm of the nozzle entire lenght.

You dont want to go anywhere near the top of the nozzle, you want the retraction about 2mm away from the highest point of the nozzle inside, so that melted plastic never reaches the top and posibly leaks out.

So that means i have about 5mm of retraction safe zone.

|__| |__| Top of the tip

| | | |________

| | | |

\ | | / safe

\ | | / zone for retraction

\| |/ ________


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