Modified hot end davinci 1.0

How much does it shift your z offset down?

**** PLEASE READ ALSO MY POST AT THE END - THIS MOD DOES NOT FULLY WORK ****

I did a similar mod, but instead of using the XYZ screw I've used a "standard" 40mm long, M6 PTFE tube screw. The advantage of the PTFE inside is that the filament has no chance to stick inside the screw hole - I had it once and it is hard to get out!

One problem when using an M6 screw is that it will not fill the 8mm hole inside the aluminum block. So I bought a 8 x 6 x 1mm aluminium tube in the next home improvement store (Hornbach). This tube has a 8mm outside and 6mm inside diameter and perfectly fills the gap. All you need to do is cut a 10mm piece from the tube, remove the burr and slide it over the M6 screw.

I've also added two washer heat sinks below the aluminium block, these special washers are made from aluminium and will provide additional cooling to the screw.

Between the heat block and the heat sinks I've inserted a Pertinax(TM) washer to termally isolate these two devices. I made these on my own from a bigger sheet of Pertinax(TM) I get from an Electronics store (Conrad - similar to RadioCheck).

At the nozzle you can see my latest "invention" - it's a heat block insulation / shield! I've mounted a small Pertinax(TM) plate to shield the heat from the printed parts - especially on small parts the heat from the hot end will not let the applied filament cool down. I fixed the plate by using the screw on the heat block that clamps the heat cartrige. To insert or remove the hotend I will need the remove this heat shielding - but no big deal!

Here is a picture of my mod:

Some of you might say I've inserted the tube screw the wrong way and that the side where there is no thread for a few millimeters need to go inside the heat block and the side where you can spot the white PTFE inside need to go on the cold end side.

Actually I've tried both and I prefered as shown in the picture. The reason is that I had trouble that when removing the filament I pulled out the PTFE tube as well two times. The only way to make sure the tube will stay inside is to mount it the way as shown in the picture! But to ease inserting the filament I've enlarged the hole and drilled a coutersink on the top. Now it's very easy to insert the filament and the PTFE tube stays inside!

In the meantime I've inserted a teeth washer between the M6 nut and the aluminium block to avoid that the temperature changes will loose the nut. This also avoid that the complete heat block unit is twisting when you replace the nozzle!

I purchased all the parts for this mod from this nice store: https://shop.stoutwind.de/ If you are located in the EU I can highly recommend this store! I get the parts the next day for almost the same price as buying from China! I had a nice chat with the owner, a young guy starting his own business, go and support him!

Here is the parts list (in German) if someone like to do the same mod:

    1 Stück Aluminium Heizblock im E3D v6 Stil - Klemmaufnahme für 6 mm Heizpatronen   
    1 Stück Halsschraube mit Absatz - M6 x 40 mm - mit PTFE-Einsatz - für 1,75 mm Filament   
    2 Stück Modulare Kühlrippe für M6 x 1 Rechtsgewinde   
    1 Stück MK8 Messingdüse Ø0,4 mm - für 1,75 mm Filamente - M6 x 1 mm Gewinde   

I used the chance to replace the heat cartige and termistor as well. The reason was that the XYZ heat cartige is much longer and only got 35W - the new cartige is only 20mm long and got 40W - the hot end will heat up much quicker and less wasted heat. The stock XYZ termistor is quite big and will not fit into the heat block hole. Therefore I changed the termistor as well - if you would like to use the stock thermistor you will need to drill a bigger hole. I would recommend to order these parts along:

    1 Stück Thermistor mit Kabel - 100 kOhm - Beta-Wert 3950 K - radial
    1 Stück Heizpatrone 12 V - 40 W - Ø6 x 20 mm
    1 Stück Hochtemperatursilikon bis 350 °C - schwarz - 21 Gramm Tube

As you can see on the picture I directly soldered the new termistor to the PCB - I had lots of trouble with loose contacts in the past and therefore prefered to have it soldered. To fix the termistor in place you will need heat resistant silicone, all can be found in the store see link above. When you heat up the first time you may notice some smoke, it's from the silicone no need for any concern!

The main problem with reusing the stock XYZ screw like you did is that it got a fine pitch tread - but the tread in the majority of other heating blocks is a M6 standard pitch tread! You will need to buy a tread cutter with fine pitch and cut the upper part again to make the stock screw fit! But cutting a thread on top of another tread is not very durable! I would recommend changing to a complete new screw that got a M6 standard pitch tread and you will get the benefit of the PTFE coating on the inside that is a big help!

About print quality: The main improvement is that I can now use different nozzle diameters starting from 0.2 up to 0.8 mm https://shop.stoutwind.de/MK8-Messingdu … urchmesser - that is a BIG improvement to the quality!!! The stock diameter of 0.4 is the "one size fits all" but depending on the part you like to print a different nozzle diameter finer or coarse will improve the results!

And in addition the costs for a replacement is a fraction of the standard XYZ nozzle - so I'm not looking back to the stock parts and can highly recommend this mod!!!

One point I've missed to mention: With this mod the automatic calibration is not working anymore as there is no contact at the nozzle! You will always need to calibrate the print bed by using the manual way with a sheet of paper! Saying this another issue came to my mind: You will also need to switch off the z-autolevel in the firmware or at least remove the stored values by sending M322 (Reset autolevel matrix) to the printer. Otherwise the z-axis will do some unwanted micromovements. https://github.com/luc-github/Repetier- … issues/145

I'd love to see a drop in E3D v6 that works well...

The drop in one for the pro is using the davinci fan to cool the heatsink. That is what that fan shroud is for.  However it does not have a layer fan. while you don't have to have one it is nice on pla (even abs if you can control when its on or not)

I have to add one comment to my mod I've suggested (see above - before this thread went OT): I had a lot of trouble with clogged hotend with this mod! The main problem was that the PTFE tube is going all the way down into the heat block. The tube just ends before the nozzle - usually there are a few mm with no PTFE tubing. Because I had the problem that the PTFE tube is getting loose and pulled out when I exchange the filament I reversed the screw so the PTFE tube is forced to stay inside the screw.

Anyway - the problem was that the melting zone becomes very small and when I use the standard 2mm retraction the melted fliament is pulled back into the PTFE tube where it cools down and after a while partially clogged the hotend.

I switched the retraction OFF and now it works well - had no problem since then! So if someone will try the same mod or has trouble with clogged hotend spend a thought on the possibility that the melting zone can also be too small what can cause trouble with retraction. Usually people (including me) are worried about the melting zone becomes too large ... I've just want too add this as it took me a couple of time (weeks) to finally come to this insight!

@ scobo: I think that the reason why your old mod became unreliable is the same issue I had and is caused by too long retraction values!!! In the Slic3r Software there is a standard value of 2mm - the stock firmware uses only 1mm (I found this by reverse engineering the g-code)!

The problem is that too much melted filament is pulled back and after some printing time jammed the tube. The E3D nozzles are a bit taller and the melting zone is bigger - this makes the standard 2mm from Slic3r fitting better.

I recommend everyone who got problems with jammed hotend to have a look at the retraction value as said before the value from stock firmware is 1mm!

After several tries to improve the stock hotend I finally accepted that all my tries to improve the stock hotend were not be fruitfull. I had it working for some prints but then some new trouble come up - finally I changed to an E3D bowden hotend. I've designed a very nice fixture to make the E3D V6 hotend fit into the stock carriage, maybe someone of you will find this helpfull: http://www.thingiverse.com/thing:1613566

Sorry for confusing you it was a work in progress experience and I've learned a lot. I have to agree that there is a reason why the E3D V6 is the defacto standard for hotends!