How to adjust 2 nozzles at a same level??

Are these screw treads above the head? They should have been adjusted before attaching the head connections.

http://www.fabric8r.com/forums/showthread.php?745-SOLUTION-to-FILAMENT-FEED

I had the same problem with the mill machine tools when should put them to zero. I don't own an automatic tool storage so these should be changes and repositioned at certain stop points while the mill is work in progress. I have searched for a reasonable way to do this fast and in a reliable way, as much as possible in a fully replicable condition.

Take a small PCB square plate (almost 1x1cm ) and solder there a piece of wire. Clamp the second wire on one of the two nozzles then on the other, doing this operation when at your eye things already seems "perfect"

Connect the two wires with a 10$ tester while it is in the position to check the wire conductivity.

Make a fine regulation of the first nozzle until you hear the "beep" then move the clamp on the other metallic end part of the second nozzle and to the same.

At this point both of them are at the identical zero point with at least +/- 0.001 accuracy. Pay attention to stop the regulation just as you hear the beep and not to press more the nozzle position as the distances are very small.

I think that with a couple of experiments you can reach perfect results. Then if you have a spare Arduino unused device yo can do something more sophisticated e.g. a beep and a LED and so on and the tool can be installed permanently nearby your 3D printer.

Please note that this is just the method adopted by the expensive tools to manage the auto-zero feature of the tools in the mill machines and 3D printers. If you want a very high precision replace the small PCB square with a conductive metallic block (as far as what I see in your nozzle images a 2x2x2 cm Aluminium block maybe perfect) and crew the reference wire to one side of the block.

Enrico

Hi, Enrico

     Thank you for your reply. Could you please leave a picture of that tool? What is its name?

LoL

It's name is "tester + 1cm2 PCB +two wires + 1 clamp" ... As the self alignment tool is something like what I have done and is very expansive, with a minimal experience when the system "beeps" it is very simple to make one by yourself as I have done. I'll try to explain in few words by steps:

1. measure the two nozzle distance (suppose it is 2.5 cm)
2. cut 1x3 cm copper PCB. You can be almost sure that is perfectly flat.
3. solder to one corner of the PCB a 30 cm wire
4. (just to make things perfect) make the classical simple circuit with Arduino of the LED lighting when a push button is pressed
5. connect the wire from PCB to the Arduino digital input port instead of the button and wire the LED to the Arduino digital out
6. solder the second wire of the same length from the GND of the Arduino (or the VCC depending on how your sketch works to light the LED) to a crocodile clamp.
7. now connect the crocodile clamp to the first nozzle (the lower one) and move down on the plate until you touch the PCB. As the LED lighten, stop.
8. connect the crocodile clamp to the second nozzle, we expect that LED is off.
9. regulate with attention the second nozzle with the control screws until the LED lights again.

That's all, at this point you are reasonably sure that the two nozzles are at the same height. As far as what I have experienced using this silly method, with few tries you can reach a prevision of about +/- 0.002 mm

Let me know if it works for you. Enrico

Thank you for your answer, Enrico. But it would be better if there is a photo of that tool. I can't find it on the Internet.

Hello Cheung!

As I told you before you can't find this specific tool I described just as this has been done by me. Please check the links below to have an idea of how the principle works. I have done the same with a PCB and a silly contact, nothing more.

http://www.cnccookbook.com/CCMillTipsTechniques.htm

http://es.aliexpress.com/item/NEW-PACK-OF-2-Z-Axis-Auto-Zero-Touch-Plate-CNC-Router-Mill-Mach3-Engraving/1757239512.html

And the following image (using the PCB as explained before)

Good photo! Thanks Enrico

Thanks Clem,

this ia a very primitive version. The only thing that should be absolutely well known is the thickness of the PCB as when the tool / nozzle is at zero point, the z-axis should be sent down of the support thickness to reach the real zero of the surface. In the case of the nozzles this detail is meaningless as you need only to align the two pieces together, I suppose.

Enrico