Dual Extruder Upgrade - Limited Availability

[rpollack]

The next batch of dual upgrades is scheduled to ship tomorrow (8/8)

Rick

[Levi8than]

The next batch of dual upgrades is scheduled to ship tomorrow (8/8)

Rick

Any idea when you'll be taking the next batch of dual upgrade orders?
I keep checking back, but the option is grayed out.

Thanks.

[Levi8than]

My first dual extrusion test. I can see that there will need to be some work done on tuning my procedures for dual extrusion already. I'm using the sample tool change gcode from the wiki. The straightforward way has the double side effect of sometimes leaving a streak from over extrusion on reset from wherever the new tool happened to be to the point where it starts getting used (black), and also missed lines at the start of a tool change from under extrusion on reset (white).
...
An alternative would be a modification to the common extrude-and-wipe sequence, where the left extruder gets wiped on the left edge and the right extruder gets wiped on the right.

That print looks beautiful. No stringies.

My thoughts were to mount silicone spatulas on either side so that the extruder heads actually wipe on either side of the X axis.
Then yes, as you're describing add the wiping to the tool sequence. This gets rid of any tall print issues.

But I need to get my hands on a dual extruder kit before being able to test my theory.

[jsc]

Check out my "wiper" thread. More updates to come later this evening, hopefully with a nice photo.

[rpollack]

@Levi8than - I am not sure yet. I will post here when more are available.

Rick

[Dave K]

I'm going to be doing some alignment/calibration prints this weekend. I haven't seen any reports on temperature for these hot ends. I'm used to the V3b...for those of you using the V4, do you back off 20C from your V3b temps?

For me, the build went very smoothly, and I'm impressed with the quality of the parts and mechanical design.

[Levi8than]

@Levi8than - I am not sure yet. I will post here when more are available.
Rick

Thank you. I'm stoked to start trying dissolvable second filaments.

[sprior]

So far I'm using the same temps I used with V3B and haven't noticed any problems though I was no expert in judging such things.

I did notice temperature ringing with the stock dual firmware:

Temperature ringing with stock dual firmware.

ringing.png (77.97 KiB) Viewed 12061 times

So I ran PID autotune and then updated the firmware with the new values and think it has improved:

less ringing

less_ringing.png (79.35 KiB) Viewed 12061 times

[Dale Reed]

sprior,

Looks like textbook quarter-amplitude damping. (Ref: Coughanour & Koppel, senior year Chem E. control theory class...) That minimizes the integrated error (net area between the curve --- above minus below --- between actual and setpoint), but allows some overshoot and ringing. You could reduce the "P" value to about 2/3 to 1/2 of its current (autotuned) value and see how it looks. It's a slightly slower approach to setpoint, but it should resemble critical damping and approach with just a tad of overshoot and little ringing. If you cut the P value to about 1/3 to 1/4 of its current value, you'll be closer to lambda tuning, which should eliminate overshoot, take a bit longer to get to setpoint, and eliminate ringing altogether. But it's a bit slower to react to changing between extruding and not extruding (heat load changes).

I'd suggest setting P to 1/2 the current value and see if you like it. (You can always set it back if you don't!)

Dale

[3rdeyepro]

Any more dual kits available?