Hi guys, I just got a genuine V6 from matterhackers and I can't get it to reach 240C. It's connected to a MKS Gen L 1.0 (http://www.robotrebels.org/index.php?topic=769.0) board, which can supposedly supply 12V and 4.5A max to the extruder (54W), and the E3D has a 30W heater. I did some PID tuning yesterday at 230, and it was able to get there in maybe 10 minutes from room temp (~26C). But today, I tried to print some petg, and the heater couldn't heat above 225C, even after sitting on for 30 minutes. I don't currently have any cooling fans, just the hotend one supplied by E3D. I also have the silicone sock on. Do you guys know if there's a setting in Marlin somewhere that limits the amount of current supplied to the hotend? I was under the impression that a brand new, just assembled V6 should be able to reach 250C, minimum, so I'm very confused. I might just end up getting a 40W heater, because taking 10-15 minutes to reach the correct temp seems excessive.
Thanks,
Alex

It's probably the overtemp protection in firmware. There often is a safety margin that kicks in 5-10° below max. temp

you using a 24v heater?

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I did some PID tuning yesterday at 230, and it was able to get there in maybe 10 minutes from room temp (~26C)

that aint right, should take a little over 90sec (or so) to get up to 200C,, not 10 min

Is there a print cooling fan blowing air on the heater block?

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Could it be that you have a 24V heater? Measure its resistance to check - details on the E3D documentation site.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

o-lampe I set the max temp in Marlin (1.1.9) to 285, so I don't think that's coming in to play here
jinx and dc42 I might be using a 24V heater, I'll take it to work today and check it with a multimeter
the_digital_dentist nope, I just have the heatsink fan currently
Thanks for the quick replies guys, I hope I can get this to work!
Alex

Alright, I tested it with a multimeter and I think I have a 12V heater. It was reading 6.14 ohms, which is definitely more than the 4.8 that E3D says it should be, but it's less than the 19ohms for a 24V heater. It does also have 12V engraved on the side.
I don't know if this helps, but I measured the thermistor resistance too at room temp (~22C) and it was showing 84kohms.
I'm writing an email to E3D right now, I'll see what they have to say.
Alex

6.14 ohms gives 1.95A at 12V which gives 23.5W That seems pretty weak to me... Even the rated 4.8 ohms comes in at 30W. (As does the rated 19 ohms for a 24V heater.)

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MBot3D Printer
MakerBot clone Kit from Amazon
Added heated bed.

Leadscrew self-built printer (in progress)
Duet Wifi, Precision Piezo parts

Yeah, that definitely seems low. For any of you guys with a 12V V6, how long does it normally take to reach 240C?

Maybe the MOSFET on the MKS board doesn't switch ON fully?
It's a common problem on Ramps/Atmega-based controllers, when the onboard voltage regulator doesn't supply 5V, but only 4.5-ish.
The Fet sure gets very hot then...

Well, I just tried using the H1 pin on my board instead of H0 and nothing changed. o_lampe, I felt the mosfets while it was running (admittedly, for only about 20 minutes) and they didn't feel warm at all.

Attached is a picture from Repetier of what I just tried. It seems like my power supply may be the issue. It's a cheap LED power supply rated for 12V and 20A. Is that low for what I'm trying to use it for?

12V 20A is enough for a printer with unheated bed.

Can you provide a picture of the hotend assembly? There should be a gap between heater block and heatsink. Otherwise the heatsink will suck up all the energy.

o_lampe Well I've got a heated bed. I think I'll try printing without it, but I've had very good results with petg and a heated bed, so I might need a new power supply. Dangit.

It's not letting me attach an image (Error 413, request entity too large) even though the image is 1MB. Either way, there's a 2-3mm gap between the heatblock and heatsink.

I brought a multimeter home today and checked the voltages with various heaters on:

Heaters off: mains 9V, bed 0V, heater 0V
Just bed on: mains 7.5V, bed 6.9V, heater 0V
Just heater on: mains 8V, bed 0V, heater 7.6V
Both heater and bed on: mains 7.2V, bed 6.8V, heater 6.9V

So clearly something needs to be replaced. Do you guys think this is a power supply issue or a board issue or both?

P.S. If my board was only supplying 6.9V to the heater, that means a paltry 7.7W was being put in. Which explains the slow heating!

Power supply, I reckon.

Have you tried disconnecting the power supply and measuring its output? What sort of power supply are you using?

Yeah, I'm pretty sure it's the power supply too. It's also a cheap chinese LED psu (it says S-240-12 on the side) and I've been wanting to replace it for a while now. I disconnected it from the board today and found it had an output of 9.2V.

I'm looking into ATX power supplies now. Are there any brands I should avoid?

Also, how do you calculate how much power the board and steppers need when choosing a power supply? I know my bed needs around 9.5A and the heater around 2.5A, and I've been looking at a psu with a 12V 28A max output.

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found it had an output of 9.2V.

the PSU should have small potentiometer near the terminals, turn that and you can adjust the voltage output to 12 V.

For power calculations, there are certainly things that you can figure on.

In general, you should be aware of worst case, though this isn't likely, it's nice to have the peace of mind to be able to deal with it.

The heated bed is probably the biggest power hog, they can be up to 120W, so at 12V that's 10A. (I've seen some that are towards 250W before they go to ones that use an SSR and are powered by mains electrical.)

The hot end is next at 30-50W. Let's say 50, to let you get a more powerful one, so that's about 4A. So we're at about 14A

Your motors will be currernt limited, most of these cap out at about 1.5A for the drivers. Most of the motors won't take this much, but if you're running 2 Z motors, it could happen. Say 5 motors (X, Y, Z, Z, E) since even if you have 2 extruders, it's really unlikely that you'll be running both at once. the voltage rating on the steppers is irrelevant that's another 7.5A in the REALLY unlikely case that you're driving all 5 motors hard. (I don't think that there's G code that even possibly CAN do this, but hey, we're talking worst case, right?)

Now your electronics need a bit of power. Usually fed by 5V, but an arduino will take a 12V feed just fine. The main feed line is limited to 1A there, and if fed by USB, it probably won't count on more then 500mA. if you have an LCD controller on your RAMPS (or equivalent) it might want another amp , though I doubt it.

So worst case, you're still under 25A, or 300W. Most ATX PSUs are rated for 90% or more of their power on the 12V rail, so a 400W ATX power supply should have no problems whatsoever of covering your power needs. A 300W PSU would PROBABLY manage, when you consider that the motor loads aren't continuous, plus we were pretty generous when it came to estimating some of the other loads. Even the big loads are only constant during the heating phases, and are intermittant while the system is running.

If you can still buy a name brand ATX PSU of less than 400W, I'd be amazed. I generally see even cheap PCs with 500W+ PSUs, and I could probably get one for practically free from someone wanting to upgrade.

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MBot3D Printer
MakerBot clone Kit from Amazon
Added heated bed.

Leadscrew self-built printer (in progress)
Duet Wifi, Precision Piezo parts

jinx I feel really dumb for not trying that first. It didn't change the output voltage at all though, and I don't know why. It was putting out 9.2V along the whole 12V rail no matter which way I turned the potentiometer.

SupraGuy Yeah, I'm planning on 14A max for the bed + heater, 1.5A*4 steppers makes 20A max, plus around 1A for the board/fans/screen. I found a 400W psu (https://www.newegg.com/Product/Product.aspx?Item=9SIA9ZN5KE3529) that's rated for 28A on the 12V line. I think I'll get this one unless you know someone willing to part with one for free

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and I don't know why. It was putting out 9.2V along the whole 12V rail no matter which way I turned the potentiometer.

BIN IT!.. but before that . and am not sure it will help but, there may be a slide switch on the side for either 110V or 220V outlets check it matches your region.

Oh my god I feel so dumb right now. It was set to 220V and I switched it to 110V (I live in the US) and it worked perfectly. 11.7V supplied to the heater and bed, and they both heated up 10x faster than I've ever seen.
Thanks a ton for the help jinx! I think I finally have a fully functioning printer!

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aflactheastronaut
Oh my god I feel so dumb right now. It was set to 220V and I switched it to 110V (I live in the US) and it worked perfectly. 11.7V supplied to the heater and bed, and they both heated up 10x faster than I've ever seen.
Thanks a ton for the help jinx! I think I finally have a fully functioning printer!

Well done! You won't be the first nor the last to make that mistake. It's worse when you leave it at 110v and plug it into 230v -> farewell poor PSU.

Edited 1 time(s). Last edit at 08/27/2018 07:53AM by David J.