Place to show off PCB Effector assemblies
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Well according to this guide http://www.engineeringtoolbox.com/wire-gauges-d_419.html 24 AWG cable with 7-24 cores should be able to handle 1.4 amps, but this seems a lot to me.
In that case 1 pair would give you 1.4A, 2 paris 2.8A and 3 pairs 4.2A.
So yes I suppose it would, its only during initial heat up that a prolonged period at max PWM occurs, after that its going to be less to maintain the temperature.
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I do believe cat6 is supposed to be 23awg (altho Im sure there are some 24 or even thinner cat6 cables out there). 1.4A per pair sounds a bit much tho…
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Well could you measure the resistance of the run of cable you intend to use, then use
W=I2R to calculate the expected wattage of heat generated?You're using 24v so you are only looking at 1.66 amps total. Although measure the resistance of your heater cartridge as my recent experience has shown they are rarely the capacity they are claimed to be even from e3d et al (30w heater was only 24w calculated by resistance).
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Don't have any equipment that can measure resistance that low… I found https://en.wikipedia.org/wiki/Power_over_Ethernet talking about different PoE standards. They have the current from 350mA to 960mA per pairs of pairs. So 960/2*3=1444mA for three pairs…
Sorry for the off topic, I'll stop this line of discussion an let you guys show of you new effecors
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PoE as far as I know underrates the current carrying capacity as it affects the data handling if the cable is operated near its maximum theoretical current handling, so I suppose sticking to those limits will be safe.
I though about adding a 3rd cable but the two braided heatproof heater cartridge wires are thinner and much more flexible than a 3rd cat5e cable would be.
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On a slightly different note, I didn't have much luck with the molex microfit connector, whatever orientation I was inserting the crimps into the housing there was no positive click and the expected retention of the cable. Is there some sort of knack to doing it? I don't seem to have any problems with duponts or the molex KK connectors?
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Looking good DJ! I am interested the plovers you are using, I have not tried ones that small before. Do they actually work with PWM? Other blowers I have tried don't.
I know you have moved the hotend cooling fan out by 10mm, if you get a chance could you see if setting the sensitivity slightly higher will solve that interference registering:
https://duet3d.com/wiki/Smart_effector_and_carriage_adapters_for_delta_printer#Programming_the_sensitivity -
On a slightly different note, I didn't have much luck with the molex microfit connector, whatever orientation I was inserting the crimps into the housing there was no positive click and the expected retention of the cable. Is there some sort of knack to doing it? I don't seem to have any problems with duponts or the molex KK connectors?
The two little barbs on the sides of the pin should lock in to the microfit housing. Its possible you are not inserting them far enough. Try pushing them in a little further (I sometimes use a small jeweler's screwdriver to push on the back of the pin)
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Hi Tony, the blowers work well and were Nebbian's (from reprap forum) idea. They will tolerate 12v and then they are extremely powerful but they shift a fair amount of air at 5v. I find I can PWM them from about 30% to 100%.
I tried sensitivities from 0 to 255 not much difference, as David said I think its that this fan is a much more powerful unit than the e3d standard one, and its is very close, and directly beneath the strain gauge. I suspect it won't be a problem for most. I would have tried the spacer but then I like the compact hotend below the effector for its reduction in effect of tilt and stability.
My connectors are holding together, just seemed so much less positive locking into place than other types of crimps/housings I've used. But I'll try that idea.
I have noticed my large nut holding the heatsink came loose and with the nimble adaptor in place its hard to get to. Makes me wonder if:
A nut can be sourced which has slots on the side which could be used to push it round with a flat bladed screwdriver for tightening purposes, I accept there is a risk to the PCB.
Or maybe we can design a 12 pointed star type locking ring type thing into the underside of the nimble adaptor once the nut is in a reasonable rotational position we could tighten the hot end heatsink into it. -
A few spots of thread lock should stop the nut coming loose.
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A few spots of thread lock should stop the nut coming loose.
Had the same issue, 1 drop of thread lock did the job.
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I wonder what the tightening torque is right for the nut? M12 thread can withstand rather large torque even aluminium one (21Nm) but I doubt FR4 and moreover a plastic washer can. Does overtightening have any detrimental effect on the strain gauge which are just accordeon shaped traces on the effector PCB around the heatsink sitting hole? As for me thread lock is not good solution for the task considering a need for hotend reassembly and fragility of the PCB with all that electronic components on it.
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We've designed the effector so that that the strain gauge traces are clear of the area that takes the clamping force. You should be able to use quite a high torque, but bear in mind that the heatsink is aluminium and the thread pitch is fine - therefore the thread depth is small too. If you are in doubt then we suggest you use a drop of non-permanent thread lock.
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Thanks! First I'm going to try a medium torque something like 10Nm without thread lock. Getting it loose then thread lock will be last resort.
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DJ - would you mind sharing the mount for the fan holders you got there? I just ordered a set. PWM-wise gimme a quick rundown of how you've got them wired when you get a chance? I don't wanna blow anything up haha
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Hi dude, sure they're in the thingiverse listing for the fan shroud https://www.thingiverse.com/thing:2490021 screw the brackets onto the magnetic stud m3 bolts with m3 nuts, and then bond the fans on with CA/super glue.
If I was going to change anything I'd edit them to allow a little extra clearance between the bolt hole at the top and the vertical section so the nut is easier to do up, but being slightly tight keeps it tensioned so hey ho.
Wiring - you can run these fans on 12v (not 24v) but probably PWM them to 50% max. but that's up to you. I find they give plenty cooling at 5v.
If you prefer to do it properly, then you can take 5v from the duet board (see schematic - I think you can use the 5v pin on the fan voltage jumper or expansion connector) wire them in parallel at the smart effector, supply the 5v positive to them, ground them back through the duet Fan 0 (by default) GND pin which then allows PWM control.
I have a buck converter instead, as at the time I built the machine I was using 12v fans on a 24v system. If you go down this route then wire the positive input of the converter to the fan 0 positive (or I suppose any Vin source), wire the negative input to the converter to PSU negative, then send the positive output from the converter (set nominally to 5v output) to the fans via the smart effector, and ground them to the fan 0 GND pin, this allows PWM control.
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Just to say I have a supply of those tiny fans, if anyone UK based wants to buy one they're in my shop:
https://www.precisionpiezo.co.uk/shopProbably not worth sending them overseas as the shipping will be too much for just a fan on its own.
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Just a side note - I've been running those for a bit, you can also buy them 12V ones in the same form factor. The airflow is simply amazing.
https://www.digikey.com/product-detail/en/delta-electronics/BFB0312HA-A/603-1112-ND/1014443 -
Ahh good to know, now I need to find them in 24V and that would be perfect!
Can your confirm if the 12V ones work properly with PWM?
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