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What is your highest stabile bed temp (stock config v3 no voltage tweak or insulation under the bed) with the fans running on full power near the bed plate? I am trying to determine if I have a problem with equipment or just need to insulate the bottom of the plate. I can barely hit 53c on the plate with the fans running full just above the plate, autotune fails.

Thanks!
-Dwight

I don't have a v3, but was getting stable 90 after a long wait on a stock v2 with the substandard early v2 ATX power supply. With an actual 12 volts it will definitely do more, but I haven't tried to find the limit.

Can you extract your PID settings from EEPROM? Do you have a host software on your machine that graphs PID history?

Mine would hit 100C after about 30 minutes with a cloth on it in stock config. I never tried pre-heating with the part fans running. That is with the fan in the base running though and it does a lot of cooling. Without the towel, it would never go over about 96C.

If you're getting worse performance than that. I suggest you double-check all of the large gauge wiring in your printer and its connections, then also check the voltage of your power supply. You can turn that up to around 13.5V (just adjust the potentiometer) or so and you'll get significantly better performance.

Since I replaced the power supply with a 24V 600W (turned down to 20.5V) with 12V regulator and SSR, it will hit 110C in 3 minutes with no cloth.

I later added a temperature-based fan controller for the bottom fan, so it runs at a much lower speed than the stock config now. I did that to reduce noise, but it also makes the system more efficient as less bed heat is drawn out by the bottom fan.

Yeah, I can imagine that the layer fans of a V3 can cool the bed a lot, but why would you turn on the fans during preheating? In fact, I thought it was common to start the fans only after a few layers in the print (after bed adhesion already is a fact).

On a V2 with a 24V PS (set at 20,5V) My bed goes to 90 in less then a minute (including alu heatspreader), but I always preheat a few minutes to get temp more even over the whole bed. Heating is a whole different ballgame now! I am unsure about the max temp I can reach, but I think there are some safety settings in the firmware that would get triggered first!

Most of the parts I am printing are less than a couple inches high, and with the fans on full to minimize stringing and slump it appears that the power supply can't keep up with both the hot end and the bed. Yes I have OctoPrint that graphs the temperatures and I have fully stable temps in both the head and the bed until I turn on the funs near the bed surface. Then BOTH can't keep up. I have tried Bang Bang to control the hot end and the bed with the same issue. Based on it being both the hot end and bed, I am leaning towards it being either a week power supply or design issue and need some baseline info to know which direction to go next.

Thanks for helping!

Note: I don't have the fans on during preheating, just turned them on for an autotune to prove whether it was a PID tuning parameter or not prior switching to bang bang. I wanted the tuning environment to be as close to production as possible.

I have seen 160 degs. Does funny things to the part being printed. (v2 , 20v psu, smoking ssr).

I am having similar issues. A short time after the fan activation, my bed temp drops to around 60°C. I am going to do this mod http://forum.seemecnc.com/viewtopic.php?f=35&t=10904 from the poster above and then insulate when it is apart

I have the best luck at 60c. Does anyone know what the technical name is for the resistor on the bottom of the heat bed? Thanks!!

Foteks are not that bad. But you have to watch out for the cheap clones!

My event happened with a clone. I burned 3 of them one after the other.

So far most of the votes are in the 50-70c range. To those of you that are voting above 70c, are your machines still stock voltage no insulation? Is this temp steady state with the fans running and not a preheat temp with the bed covered?

Thanks,
-Dwight

In adding an option to the Poll....it reset the Poll. Please revote!

We had about 5 people in the 50-70 range, and 1 entry each in the other higher ranges.

teoman wrote:Foteks are not that bad. But you have to watch out for the cheap clones!

My event happened with a clone. I burned 3 of them one after the other.

FOTEK? Ok, I'll do a google search for those. Thanks

skyjuice wrote:

teoman wrote:Foteks are not that bad. But you have to watch out for the cheap clones!

My event happened with a clone. I burned 3 of them one after the other.

FOTEK? Ok, I'll do a google search for those. Thanks

I'd use the Auber Ins one. It's about the same price as a lot of the clones, but is an actual SSR. Plus there hasn't been anyone cloning them and they sell direct.
http://www.auberins.com/index.php?main_ ... cts_id=288

Shipping's not bad, and rather speedy.

Xenocrates wrote:

skyjuice wrote:

teoman wrote:Foteks are not that bad. But you have to watch out for the cheap clones!

My event happened with a clone. I burned 3 of them one after the other.

FOTEK? Ok, I'll do a google search for those. Thanks

I'd use the Auber Ins one. It's about the same price as a lot of the clones, but is an actual SSR. Plus there hasn't been anyone cloning them and they sell direct.
http://www.auberins.com/index.php?main_ ... cts_id=288

Shipping's not bad, and rather speedy.

Thanks for that info, but I'm looking for that little Resistor on the bottom of the Rev 8 heat bed that limits the voltage to the LED. Know what I mean?

skyjuice wrote:

Xenocrates wrote:

skyjuice wrote:
FOTEK? Ok, I'll do a google search for those. Thanks

I'd use the Auber Ins one. It's about the same price as a lot of the clones, but is an actual SSR. Plus there hasn't been anyone cloning them and they sell direct.
http://www.auberins.com/index.php?main_ ... cts_id=288

Shipping's not bad, and rather speedy.

Thanks for that info, but I'm looking for that little Resistor on the bottom of the Rev 8 heat bed that limits the voltage to the LED. Know what I mean?

560 ohms, .25 watt. here for ~70 cents.

Xenocrates wrote:

skyjuice wrote:

Xenocrates wrote:
I'd use the Auber Ins one. It's about the same price as a lot of the clones, but is an actual SSR. Plus there hasn't been anyone cloning them and they sell direct.
http://www.auberins.com/index.php?main_ ... cts_id=288

Shipping's not bad, and rather speedy.

Thanks for that info, but I'm looking for that little Resistor on the bottom of the Rev 8 heat bed that limits the voltage to the LED. Know what I mean?

560 ohms, .25 watt. here for ~70 cents.

That's what I'm looking for!!! Thank-you "Xenocrates"!!!!! Have you ordered from them before? Shipping speed?

skyjuice wrote:

Xenocrates wrote:

skyjuice wrote:

Thanks for that info, but I'm looking for that little Resistor on the bottom of the Rev 8 heat bed that limits the voltage to the LED. Know what I mean?

560 ohms, .25 watt. here for ~70 cents.

That's what I'm looking for!!! Thank-you "Xenocrates"!!!!! Have you ordered from them before? Shipping speed?

Many many times. I actually ordered something from them just before I found you your link. Like most sites, they have a bunch of options, but with their cheapest, it usually goes out the next business day, with only occasional delays and usually faster, and I've yet to be more than around 5 days without part in hand, even going with the cheapest option.

Xenocrates wrote:

skyjuice wrote:

Xenocrates wrote:
560 ohms, .25 watt. here for ~70 cents.

That's what I'm looking for!!! Thank-you "Xenocrates"!!!!! Have you ordered from them before? Shipping speed?

Many many times. I actually ordered something from them just before I found you your link. Like most sites, they have a bunch of options, but with their cheapest, it usually goes out the next business day, with only occasional delays and usually faster, and I've yet to be more than around 5 days without part in hand, even going with the cheapest option.

Good to hear and to have a supplier for these little guys and other stuff. Thanks!

If that resistor is missing the only consequence is that the bed LED won't work. Everything else should continue to work, including the bed heater.

Radio Shack is no longer a useful electronics store, but simple 1/4 watt resistors is something they probably still carry. Could save you a $5 shipping charge for a 70 cent part, plus you get it faster.

Don't get the Fotek. Too many clones around. They have been known to pump up the price to hide the fact that they are clones.

I would recommend one of the other brands recommended. (One that is a mosfed based solution).

I have built my own, but it is not worth the hassle.

I have insulated under the bed and it helps a bit, but now considering enclosures and 24V vs bumping up the voltage on the existing power supply. I prefer to print on glass and with ABS I need more temp...

With no layer fans on, first layer printing and reflective bubble insulation under the bed it appears that 93 degrees is my steady state temp. Started at 110 with an insulated cover to get it up to temp.

This is running the 10/9/16 firmware, I am going to try bang bang next to eliminate any PID parameter issues.

-Dwight

morgandc wrote:I am going to try bang bang next to eliminate any PID parameter issues.

Better go for dead-time for the bed. In my experimentation bang-bang keeps circling around the set temp with an undershoot and an overshoot of 3 to 4 degrees C. That means that the difference between the highest and lowest set temp (of 60C in my case) is 6 to 8 degrees, and that is really visible in the layers of your print. Dead-time is a perfect manager for a heated bed. Refer to this to dial it in. Only one parameter is involved.

https://www.repetier.com/dead-time-control/