JKN Advance K and K2 for Bowden extruder conversion

[caall99]

I recently converted my Qidi Tech Dual printer to a dual Bowden extruder. I have been trying to dial in JKN Advance K and K2 to reduce the amount of filament extruded during acceleration and deceleration. It seems I get appreciable print quality above 1.5 for K, and 0.055 for K2. For the sake of it, I tried a value of 10 for K and saw NO difference. It leads me to believe that after a certain value it has no effect. What is the maximum value? My Bowden is still extruding too much in corners and at the end of every infill pass... even at a K value of 10. What else can I do to improve my situation?

[dcnewman]

On 15/08/2016 4:00 PM, caall99 wrote:

I recently converted my Qidi Tech Dual printer to a dual Bowden extruder.

With Bowdens, you need to have massive retraction settings (e.g., 6 - 8 mm). At that point, you're outside the scope of applicability for JKN advance which was intended for direct drive extruders. The K likely does work with Bowdens, but the heuristic relief (K2) isn't meant for Bowdens. If you have ARM electronics, you should consider RepRapFirmware as it has a pressure advance similar (nearly identical) to the K portion. But it also has a portion intended for Bowdens.

Dan

[caall99]

Would you say that sailfish firmware is not suitable for bowden extruders? If changing the k value no longer has an impact, how can i pull in my corners and generally reduce the amount of filament extruded during acceleration and deceleration? What arm board would be suitable to upgrade my Replicator 1 Dual clone to?

[dcnewman]

On 15/08/2016 6:15 PM, caall99 wrote:

Would you say that sailfish firmware is not suitable for bowden extruders?

Some people do use Sailfish with Bowdens. I do not know how successful they are or are not. Sailfish is highly optimized for a particular style of 3D printer. Part of that design is direct-drive extruders. It was not optimized for Bowdens.

? If changing the k value no longer has an impact, how can i pull in my corners and generally

reduce the amount of filament extruded during acceleration and deceleration?

Larger retraction in your slicer, not slowing down as much at corners, etc. Same as any other printer really. The blobs are caused by (1) excess pressure, and (2) slowing down too much thereby allowing more of the ever-present ooze to build up as the corner is turned.

What arm board would be suitable to upgrade my Replicator 1 Dual clone to?

The Duet 0.8.5 and Duet WiFi are nice boards. They both run RepRapFirmware. The RADDS board can run Repetier and RepRapFirmware. (However, it doesn't have ethernet or a built in web interface like the Duet's do.)

Dan

[caall99]

Hey Dan,

Thanks again for all your input. So I have the Bowden setup working reasonably well, but am still fighting some blobbing at the Z scar, and differing rates of extrusion, most notably during acceleration and deceleration.

My firmware/Simplify3D settings are as follows (this is using a dual Bowden setup - stock hot ends/nozzles, just relocated steppers to back of printer

• using a 2mm ID PTFE tubes for 1.75mm filament):

X/Y Accel: 800 mm/s^2 Z Accel: 150 mm/s^2 A/B Accel: 6000 mm/s^2

Retraction Distance 7.00 mm Extra Restart Distance: -0.25 mm Retraction Vertical Lift: 0.00 mm Retraction Speed: 80.0 mm/s Coast at End: OFF Wipe Nozzle: OFF

Print speed: 80 mm/s (but reduce to 40% of print speed for outlines)

I retract at every layer change.

Do you suggest that I increase X/Y acceleration, to reduce blobbing in corners, and/or increase the effectiveness of K and K2? I have thrown arbitrarily high values for K, (e.g.. K=14) and am not seeing much of an impact. What are maximum values for K and K2?

On Mon, Aug 15, 2016 at 9:29 PM, Dan Newman notifications@github.com wrote:

On 15/08/2016 6:15 PM, caall99 wrote:

Would you say that sailfish firmware is not suitable for bowden extruders?

Some people do use Sailfish with Bowdens. I do not know how successful they are or are not. Sailfish is highly optimized for a particular style of 3D printer. Part of that design is direct-drive extruders. It was not optimized for Bowdens.

? If changing the k value no longer has an impact, how can i pull in my corners and generally

reduce the amount of filament extruded during acceleration and deceleration?

Larger retraction in your slicer, not slowing down as much at corners, etc. Same as any other printer really. The blobs are caused by (1) excess pressure, and (2) slowing down too much thereby allowing more of the ever-present ooze to build up as the corner is turned.

What arm board would be suitable to upgrade my Replicator 1 Dual clone to?

The Duet 0.8.5 and Duet WiFi are nice boards. They both run RepRapFirmware. The RADDS board can run Repetier and RepRapFirmware. (However, it doesn't have ethernet or a built in web interface like the Duet's do.)

Dan

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[caall99]

JKN values ended up not being the problem. I resolved this issue with other tweaks... Remaining issues with Sailfish will be commented on elsewhere.