Pressure/Linear Advance

[haydenkrause 0]

Hi Guys,

 

I have sent this request by e-mail but I want to put more pressure on you to implement this.  Request 21543.  

 

I believe Marlin now has pressure advance built in.  The ultimaker printers should be able to implement this therefore.  It would be a very welcome addition and improve print quality greatly.  

 

Thanks

Hayden 

[gr5 2,331]

Pressure advance doesn't really work for bowden printers where the feeder is so far from the hot end.  Mathematically it should work but the numbers come out to insane values that no existing feeder can match.

 

Instead one would have to accelerate more gradually in order to compensate pressure using the feeder.

 

Klipper is a nice bit of firmware that can run on any printer if you have the right cpus.  Including UM printers.  But the pressure advance feature just won't work on UM printers because of the bowden setup.

 

But like I implied earlier - there is an alternative.  But no one is doing it.  It involves controlling the true jerk of the xy movements.

[haydenkrause 0]

Thanks for the response.  I got pressure advance working well on my delta and that has an 800mm boden tube.  I would have thought the ultimaker is similar to that.  Coupled with the fact its using 3mm fillement should make it less severe. 

 

To get my delta working well i did have to slow acc and jerk down (to reduce the load on the extruder as you say).  I also had to upgrade to a duel gear extruder but the resulting extrusion was far better.  I was much happier to run prints slower to obtain higher quality as the improvement was significant. 

 

Its a shame the s7 doesnt attempt to address any of this with dd or short boden/upgraded extruder.  My theory is there is another printer in the works and the 7s is just a more robust s5. 

 

Thanks.