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How To: Correctly Set the Right Hand Nozzle Gap on the Dual

Posted: Wed Oct 14, 2015 8:20 pm
by Jules
Finally figured something out! :D

You will get much better printing results with a dual system if you set the height for the right nozzle depending on how you plan to use it.

Caveat: The write up assumes that the bed has been leveled and the Z-stop has been set for the left hand nozzle (Hot End 0) before beginning. If you leveled using the right nozzle, use the instructions below to adjust the left nozzle.

Different Colors of the Same Filament

If you plan to use the machine to print filaments that print within the same temperature range, (ex: dual color printing with 2 colors of PLA), do the following:

1. Clean any drips off of the nozzles if you have extruded through them. (Tweezers are good for this while the nozzle is cooling off.) You need a clean flat nozzle surface for this.

2. With the extruders and bed cold, slowly raise the plate up past the Z-End Stop, until it actually touches the left nozzle. (Nozzle 0.) Tape the Z-Knob into place so that the bed doesn't move.

3. Loosen the screw that holds the right Hot End (1) in place, and press it down with a small hex wrench until the right nozzle also contacts the plate.
(Do not let the Hot End rotate in the holder). Check the gap from eye level. There should be none. Tighten the screw.
Gap 1.jpg
Cold set. Both Nozzles touching.
Different Filaments in each Extruder

If you want to use the left extruder to print one kind of filament, and the right extruder to print a different kind of filament with a widely different temperature range, (ex: left extruder PLA, right extruder PETG) you need to set the height of the right nozzle while everything is heated up to the correct temperatures, in order to maintain the relative height of the gap between the plate and each nozzle. (Not doing so will have you constantly adjusting Z-Offsets, or worse, will cause gaps and poor print quality when both are used at the same time.)

1. Remove the plate from the bed if you have any kind of applied surface on it, and turn it over so that the bare glass is facing up. You do not want to hit plastic or tape with a hot nozzle. Clip it in place.

2. Heat the bed up to 60°C. (You don’t need to take it all the way up to PETG or ABS temps, which might damage the surfacing material underneath, but if it's bare glass on both sides, you can use an average bed temp for the two filaments.)

3. Loosen the screw that holds the right Hot End (1) in place, and raise it slightly in the seat before lightly tightening. (Do not let the Hot End rotate in the holder.)

4. Heat each extruder to the correct temperature for what you will be printing out of that nozzle.

5. Retract any loaded filaments completely and clean off the tips of the nozzles.

6. When everything is at temperature, carefully raise the plate up past the Z-End Stop, until the bare glass actually touches the left nozzle (Nozzle 0). Tape the Z-Knob into place so that it does not allow the bed to move.

7. Carefully (gonna be really hot in there :shock: ) loosen the screw that holds the right Hot End (1) in place, and press it down with a small hex wrench until the right nozzle also contacts the glass. (Don’t let the Hot End rotate in the holder.) Check the gap from eye level. There should be none. Tighten the screw.

If you let the plate and nozzles cool in place you will see a larger gap under the hotter nozzle, which is what you want. Now when you set a Z-Offset it will apply equally to both nozzles, despite the different filaments and temperatures. :D
Gap 2.jpg
Hot set after Cooling off.
And the proof is in the pudding...(whatever that means :lol: ).

I printed a PLA calibration square with high PETG infill, just because i wanted to see if I could....Yep! It worked. :P
Gap 3.jpg
Purple PLA square with PETG infill. Just because.
Perfectly! :D
Gap 4.jpg
Water fill flat.
(By the way - not advocating PETG as infill for PLA - they don't bond. This was just to see if the gap setting method worked correctly.) :D

Re: How To: Correctly Set the Right Hand Nozzle Gap on the D

Posted: Wed Oct 14, 2015 10:29 pm
by Matt_Sharkey
I don't have a dual extruder, but a great write up anyways. I like that you show the necessary pictures in your write ups, but you don't go overboard. Keep up the good work!

Re: How To: Correctly Set the Right Hand Nozzle Gap on the D

Posted: Wed Oct 14, 2015 10:31 pm
by Jules
Thanks Matt! :D

Re: How To: Correctly Set the Right Hand Nozzle Gap on the D

Posted: Thu Oct 15, 2015 12:53 pm
by PcS
Yes very nice work Jules keep them coming. Some day if I ever master one extruder I might think about the second !!!

Re: How To: Correctly Set the Right Hand Nozzle Gap on the D

Posted: Thu Oct 15, 2015 2:59 pm
by Jules
Thank you most kindly! :D

You'll definitely want the dual upgrade once you're ready... next week? (I think you're more than ready now! :lol: ). It has so much more potential!

Dedicate a Saturday to it and you'll be running with a dual.

We do still need some write-ups on using S3D with it though. (Got one cooking.) Getting all of those processes set up is the hardest part of the whole deal. :shock:

Re: How To: Correctly Set the Right Hand Nozzle Gap on the D

Posted: Thu Oct 15, 2015 3:47 pm
by Tim
Jules wrote:We do still need some write-ups on using S3D with it though. (Got one cooking.)
Hmm, was that comment directed at me?

Re: How To: Correctly Set the Right Hand Nozzle Gap on the D

Posted: Thu Oct 15, 2015 4:04 pm
by Jules
Tim wrote:
Jules wrote:We do still need some write-ups on using S3D with it though. (Got one cooking.)
Hmm, was that comment directed at me?
Yeah, dude! Where the heck is our write-up? :lol: ;)

I've got scads of notes so far, but nothing strung together yet. (Definitely still in the learning phase.) I keep getting side tracked with testing out theories when I run across something new or unexpected.

Which happens a lot. :roll:

Re: How To: Correctly Set the Right Hand Nozzle Gap on the D

Posted: Wed Jun 28, 2017 8:20 pm
by DrRobot
Thanks for the nice write up! So what do you think is the reason that hotter temperature brings the nozzle closer to the bed?

Re: How To: Correctly Set the Right Hand Nozzle Gap on the D

Posted: Thu Jun 29, 2017 3:54 am
by Jules
More nozzle expansion at the higher temperature.