Da Vinci Jr hotend max temp only 214c

Not sure there. Could be the cooling fan is doing too good a job for the heater to keep up?

Or it might be a firmware limit. XYZ's filaments melt lower than that so it's conceivable they set the max temp that low.

I don't know too much about hotend heater components, but maybe someone here does - do they tend to wear out and stop heating as well when they get older?

You could try removing the fan temporarily (just undo the four torx screws holding it on the carriage) to see if the hotend can get any hotter without cooling. Just don't run the printer that way for long. If it can't get any hotter then you know it's a firmware or hardware problem.

Another question to ask would be  is 214 the value on the display or an actual value measured with a probe. The issue in many printers is the actual versus displayed ca be as much as 30 degrees off sometimes. Especially true in cases with locked down firmware.

The correct way would be to mod the fan. If it is not a part fan then it should only blow on the feed tube and on nothing below the heat break. If it is a part/later fan then it should only blow on the part, not the nozzle. You could try putting tape over the side of the fan closet to the nozzle so only half of the fan is used. I had to do that on my Delta so it would heat.

The Jr's fan is an interesting thing. I had to replace mine as I has an accident with it during my RAMPS conversion. I ended up buying a 2-pack of 4010 12V 0.15A fans pretty cheap, but they only push 6.3cfm.

Now that my RAMPS conversion is complete, I've attempted three significant prints. The first was a small test object using XYZ nature at 180°C. No problem there. Then I switched to XYZ white, which I'm not sure but I think used a higher temp (190°C is what I'm using). That print developed an extruder clog within the first 5 layers or so, behind the heat break. I had to dismantle my extruder and drill it out of the feed tube.

My next attempt was better but not great. I reprinted the one that cligged, and most of it came out great, but it seemed to develop a minor clog on the last cm, as the top was significantly under-extruded. I was able to clear that clog without too much trouble. I only had to heat it up and use a little force to get the filament out. I then tried to clear it by snipping the last few cm of filament of the spool and feeding a good 5cm or so of filament through the extruder.

THEN I discovered the AUTO_FAN settings in marlin which basically do the same thing that the Jr firmware does by default, by keeping the heat break fan on a long as the end is hot. With that enabled, I'm trying another print. So far so good.

I'm waiting to see if I develop another clog. If I do then it's probably because my fan is underpowered and can't keep the temp down across the heat break. If I don't then it's not conclusive, but it could have been due to having the hot end up to temperature too long during heater test runs without the fan running at the right times. But it does seem like the stock fan was higher spec for a good reason.

I didn't major in fluid dynamics. Does anyone know if stacking two 40x40x10mm fans back to back will actually double (or even improve) the total CFM? Or would that just impede the total airflow? Since I have two fans on hand it might be a cheap way to increase my airflow since I also can't seem to source a higher pressure fan of this size.

I suspect that even if a weaker fan can cut it for PLA temps in my case, you might still have trouble at higher temps.

Actually, so far, the 6.3cfm fan seems to be working fine. After getting the Marlin AUTO_FAN settings worked out (so that I never have a hot nozzle without the fan running), I haven't had any more clogging issues.

The quality issues I had that seemed like clogs actually turned out to be an underpowered extruder stepper. I watched a print as it was having issues and noticed that the extruder was missing steps (there'd be a small blob that came out every 3-4 millimeters instead of a steady stream), so I tweaked the trimpot on the stepper driver up another 1/4 turn and it's working fine now.

I haven't printed with filament higher than 200C yet (I will be soon when I switch to the XYZ translucent green filament which uses 210) so we'll see if I have any issues there. But I've been printing in white at 190C a lot today (3-4 different jobs of 1-3 hours each) without a problem.

Sorry to get OT here, but back to the point, it seems like a 6.3cfm might be good enough for the stock 24W heater in the Jr. Now for your upgrade, I doubt that'll do it. 40x40x10mm fans with 11.4cfm seem to be hard to come by. I found this one on Amazon (US) but it's a 3-pin, and I'm not used to working with PWM fans, so I'm not sure how to adapt it electrically for a 2-pin connector, though I'm sure it could be done: https://www.amazon.com/Case-Fan-40mm-10 … B000BSHKKE

You'd know better than I about 3-/4-pins. I guess 3-pin fans have just have an extra RPM sensor.

Nice fan setup you've got. Did you have to remove the sides of the case or the filament spool to get their width to fit?

PWM can and does normally have three pins.. They control the speed by gating the positive or ground through a transistor driven by a PWM signal. The lower the frequency the slower the fan goes the higher the faster. The issue is that some fans don't like to start by being fed pulses and may not start. So you have to to test and see if your fans are PWM compatible. You don't need the third wire unless you have a feed back circuit that monitors fan speed or monitors for the fan being stopped and to shut down cooled circuits.

Yo lo hice poniendo un potenciómetro de 100K en paralelo al sensor de temperatura. utilizo Cualquier PLA.