I want to put molex connectors on the fans I bought and installed. For now I'm using butt splices I crimped. Where can I get the 2 pin molex connectors used on the SD3 and SD4? They're pretty standard, but I couldn't seem to find them.

Mouser.com
part #:
640440-2
3-640440-2
3-7647002-2
I forget which ones exactly are used, but they are dirt cheap, so even if you can't use a couple, you're only out like 20 cents.

Would like to do the installation properly. Butt splices look so ghetto.

No PSI, they simply move air so that the parts can cool..

Objection - very small PSI.

Air velocity right on the plastic will align pretty well with the rate of cooling. So whether you move lots of air at 1 m/s or a tiny little jet at 1 m/s the effect would be similar.

These kind of axial fans are designed to move air over only very small pressure drops, if you put a restriction on them (such as ducting or a nozzle) the flowrate drops significantly. Using a nozzle, as you nominally reduce the nozzle orifice size (from none/infinite nozzle), the jet velocity would go up, until the fan started to choke and it then came back down again. Where that maximum point lay would depend on where you measure, the design of the nozzle and the specific fan you're using. This would be an interesting experiment if you have a hot-wire anemometer handy (I sure wish I did...).

Also, there may be such a thing as too much cooling: interlayer adhesion, warping, even pushing the hot plastic around with the jet etc. are likely if you overdo it! I think the maximum point above for the average 40mm axial computer fan will be more than enough.

The advantage of the air compressor would be the ability to target the airflow more with a tight nozzle (needing a much higher pressure drop to achieve), such that the surrounding plastic wasn't cooled unnecessarily. I think your plan is well worth pursuing.

I also designed an extruder fan holder for a 40mm fan since I didn't really like the ones out there.

Under Configuration_adv.h tab I do have this :

#define EXTRUDER_0_AUTO_FAN_PIN   -1
#define EXTRUDER_1_AUTO_FAN_PIN   -1
#define EXTRUDER_2_AUTO_FAN_PIN   -1
#define EXTRUDER_AUTO_FAN_TEMPERATURE 50
#define EXTRUDER_AUTO_FAN_SPEED   255  // == full speed

Should  I change "#define EXTRUDER_0_AUTO_FAN_PIN   -1" to "4"?
Do I have the right firmware?

RGargus wrote:

I doubt that any thing else is using SIO protocol, so the A0 could be released from CE funtion on the SD memory, and CE could be hardwired.  This would free up a fan control bit.  I dont think there would be any loss by making the CE full time.  I have not read the code, but surely those involved in development should be able to tell us the impact.

RGargus, I am not too familiar with CE function- what exactly is this?  Thanks for your input!

I appologize for not seeing this post sooner.  the CE function means chip enable.  Since the sd memory is the only device connected to that perticular bus line, it can be left enabled at all times.  The reason for a CE is to allow multiple devices to use the same communication line each in their turn.  When the chip enable to a particular device is not enabled, generally the are forced to open circuit mode on the comm line so as to not interfere with another device which may be enabled.

also some PLA's have different melt temps by a few degrees.