Modding Da Vinci 2.0 to print exotic filament! (PLA is working!) (Page 1 of 2)

The best and easiest mod is to increase that threaded tubes thermal mass to nearly three times the hotends thermal mass. Either through heatsinks and airflow or adding additional metal. The gap between the PCB and the nut holding the tubes in place is pretty big. You could machine a block of steel or aluminum to that size so that both tubes slip or even thread through it and then add a heatsink and fan to the exposed side of the block.

The problem with all the Da Vinci printers right now is that the thermal mas of the heater is greater than the thermal mass of the the feed tube. If you look at and after market hotend that can do PLA and other material you will see that the thermal mass and even the physical mass of the feed tube is much greater than the heater block in is usually done by fins which is the same as a heatsink.

Did you try some of the existing replacement fan shrouds and not have any luck, or did you go straight to moving the fan? For example, this: http://www.thingiverse.com/thing:623274 apparently has provided some with good results - I'm about to mount them to my Duo today.

Actually, I tried tape round the sides of the fan to begin with (crude shroud) and it did help a bit but I still found that PLA would swell and jam now and again.
With the fan moved parallel to the heatsink, I've not had a single jam and I'm able to print slower and at lower layer heights (could only print reliably at 0.3mm previously).
If you look at the pictures I posted of the new mod you'll see there's nothing at all covering the extruder heatsink and gears.
I think this is allowing the heat from the heatsink to be cleard better with the fan blowing across it instead of just blowing the hot air back down on to it as it does in the stock position.
There also seems to be air being deflected down to the nozzle and I think this is also helping cool the barrel just above the nozzle. This is roughly where the PLA seems to swell and jam without any mods.

I have tried your method of moving the fan lower and I saw improvement in bed adhesion and model sharpness.  But however, I have attempted to print a 50mm Stanford Bunny but about 1/3 of the way through and it basically started to trip in extruding consistently, every few millimeters or so and it would not extrude.  This may be due to overcooling the head but I'm not sure, I never had that problem when coating the filament with oil, but it made a mess and it would never stick to the bed.  I am also using Shaxon PLA if that makes any difference.

I will try some other things and see if anything improves,
    Cheers

Here I printed this http://www.thingiverse.com/thing:11622, see the layers where the filament was tripping.

What temps are you using ?
It might be that you need to bump up the extruder temp slightly.

If you look at the pictures I posted, you'll see the fan is simply attached to the back of the carriage with some blue putty. I didn't put any screws back in.
Bit rough an' ready but I'll probably knock up a bracket to attach it in the same place when I get time.
I've not had any jams at all with Glowfill (PLA), Woodfill and Bronzefill since using this method.

Ok I raised the heat to 220c and now after going through half the first layer the extruder started to click.  No filament came out so I am thinking it could be, 1) The filament near the gear drive is getting soft 2) Still overcooling.

But I'm not sure, I'll keep trying and see what else comes up.

Definitely, I was thinking the same thing and was wondering if I could add a small plate of metal underneath both sides of the gears.  So when you feed filament through and extrude, if it ever follows the gear and starts to buckle, the filament will hit one of those plates and will continue moving in a mostly straight line.  I will look around and see what I can come up with...I have been busy with school lately.

I have succeeded in printing PLA again, this time using painters tape as glass is a little hard to stick to unless the bed is leveled perfectly, and I also use a bit of oil to get the filament going.  Using 220c extruded and 50c bed with default slic3r speed.  I also used zip-ties instead of a screw or scobo's ingenious putty mount, using one through the bottom left hole to hold it in place and another one going through the top left hole to pull it up so it does not meet parallel with the hotend.  One letdown to lowering the fan is it also moves it out a little bit, so I  can't move the mount all the way back or the fan will get crushed (or squeezed).  I keep the door open, and I took off the top lid for better airflow and easier to feed filament (I use an external spool holder that feeds through the back). 

Thanks for you guy's help, hopefully we'll get NinjaFlex going soon!

There could also be the issue of cheapo filament.  I used Shaxon PLA and I'm wondering if that is the problem too, $24.99 for 1kg.  For now printing with PLA is more like hit or miss, either it goes smooth or some of the layers jam the extruder.
Still experimenting....

~Dom

I am talking about their PLA, as I once compared it with a friend's MatterHacker's PLA and it really showed a difference.  Shaxon was very flexible for being called PLA compared to MatterHacker's stiff and "snappable", Shaxon's also smelled a bit different; like somewhat smelling candy with a hint of ABS smell (very odd).

Just a quick update for anyone who tries my fan mod above with PLA.
I went back to printing ABS for the first time in a while and had issues with delamination and nozzle blocking. I moved the the fan back to the stock position and all is well again.
It seems the fan is doing a bit too good a job of cooling the head in that position so make sure you move it back when you go back to printing ABS.

Details of my latest mod using extra heatsinks here .... http://www.soliforum.com/topic/9643/bro … e-davinci/
This is giving me the best results yet.