Overheating power supply on large prints

I've had my Huxley 3D printer for a few months now, most of the time giving very good output.
Lately however I have this issue with the power-supply overheating. This happens when I print something very large. After > 2 hours printing, the buildup of heat is just to much which causes the power-supply to shut-down completely leaving my Huxley without power. After cooling down, the power-supply will start giving amps again.

Currently I'm printing at 185 degrees celcius for the hot-end, and 57 degrees celcius for the heated bed. I also connected 2 x 15 cm PC fans to the 'fan' connector to cool down the print itself.

Power supply states that it delivers 19V and 6,32 A. It is the 'original' from reprapro.com, but with labels on it about being a replacement power supply for laptops and is made in China.

Does anybody have any ideas as of why this is happening? Is 6 A insufficient? If so, why would this be the 'standard' for the Huxley and has anybody else seen this issue? Or is it reasonable to assume I have a faulty power-supply and should be looking for a replacement?

roady -

Your power supply at 19V and 6A is about 114W (watts) capacity: Wattage equals Volts times Amps (W=V*A). Sometimes you will see a power supply rated at "VA" rather than "W", because the terminology is equivalent.

That being said, I am assuming that you are printing PLA, which does not require a heated bed. You could likely print PLA all day with the heated bed set at 0 degrees (off) and plain masking tape on the printbed. I wipe mine with a dab of rubbing alcohol on a paper towel after smoothing the tape in place with a green abrasive pad. PLA adhesion is really good on this surface at ambient temperature.

I think you are at the limit of your power supply's capacity when you run a heated bed, or perhaps exceeding it. Try running PLA without a heated bed and see if your power supply overheats. If it still overheats, it is likely faulty. My power brick is about 70W capacity. I run PLA for hours with no heated bed and good adhesion as described above. The power brick itself becomes warm, but remains steady.

Others have suggested that a 6' x 6' heated bed and a hotend together require 220W-240W minimum. -Phuzzy

roady: They should run for long periods of time without getting hot, even with the heated bed set at 100C for ABS. Email reprappro tech support on 'support at reprappro dot com', and we'll work out if it's a machine problem (short circuit drawing too much current) or PSU (probably the more likely).

Ian
RepRapPro tech support

Phuzzy Logic Wrote:
-------------------------------------------------------
> roady -
> That being said, I am assuming that you are
> printing PLA, which does not require a heated bed.
> You could likely print PLA all day with the
> heated bed set at 0 degrees (off) and plain
> masking tape on the printbed.

I have been using blue tape before, which is indeed very capable of sticking PLA to the bed. However, getting the PLA stick to the bed isn't the reason I'm using a heated bed. With large prints, warping becomes an issue. A heated bed combats this warping, at least partly and that is why I use a heated bed.

> I think you are at the limit of your power
> supply's capacity when you run a heated bed, or
> perhaps exceeding it. Try running PLA without a
> heated bed and see if your power supply overheats.
> If it still overheats, it is likely faulty.

The Huxley is standard equipped with a heated bed, and it's a feature I have to use for this particular print, so your suggestion wouldn't solve my problem. Good to know is that I just tried a print, while keeping the PSU in top of an aluminium case, which dissipated most of the heat away. That (nearly?) worked, but I don't feel like this is 'standard'.


reprappro Wrote:
-------------------------------------------------------
> roady: They should run for long periods of time
> without getting hot, even with the heated bed set
> at 100C for ABS. Email reprappro tech support on
> 'support at reprappro dot com', and we'll work out
> if it's a machine problem (short circuit drawing
> too much current) or PSU (probably the more
> likely).
>
> Ian
> RepRapPro tech support

I will do. Thanks.

Sounds like your power supply is faulty. Probably lucky it switched off, rather than starting a fire.

I agree with needing the heated bed for larger prints with PLA. Small, quick prints are fine onto blue masking tape, but larger prints will warp and lift.

I've been trying impact-modified PLA. Unfortunately this is prone to warping on larger prints, even on a heated bed. Yet the same print using normal PLA is fine.

roady -

In your original question, you asked if 6A was enough, and I am saying that it most likely is not enough. You may have damaged your power supply by overloading it. -Phuzzy

Phuzzy Logic Wrote:
-------------------------------------------------------
> roady -
>
> In your original question, you asked if 6A was
> enough, and I am saying that it most likely is not
> enough. You may have damaged your power supply by
> overloading it. -Phuzzy

That might very well be true. Thank you for your view on this.
I have submitted an email to reprappro and am awaiting a response. If 6A is indeed insufficient, then I have been getting the wrong PSU together with my Huxley (it was ordered as a single package). Or the other explanation is that the PSU itself is faulty and needs to be replaced. I tend to think the latter, because I haven't seen other Huxley owners with these issues and I assume they will have the same (type of) PSU as I have. Anyway, as soon as I have an answer from reprapro as to what is actually going on, I will post it here as a future reference to others that might have similar issues.

To follow up: reprapro has replaced my PSU and all is well since then
Indeed I have been dealing with a faulty PSU...