Hotend only reaches 180 with new Micromake Delta

Hello,

I've built a Micromake delta and everything seems to work fine except that the hotend can't get past 180 degrees. There is a fan that is constantly running that if disabled will allow the hotend to get hotter, but without the fan the PLA further up softens and can't push through the hotend. If I set my heated bed to >0 then the hotend can't get hot at all. I've gone through and double-checked all my connections and made sure the screw terminals had solid connections with the wires (in case it was a current/power problem) but that seemed to have no effect. I physically disabled the heated bed but the hotend still couldn't reach above 180.

What would be the next best thing to diagnose? The heat cartridge? Maybe the power supply is weak - should I hook up a different/beefier power supply? This is my first 3D printer build so I'm not really sure what to do. Any tips from some more experienced gents would be great! Thanks.

Edited 2 time(s). Last edit at 08/29/2016 12:53AM by ryul.

Get a multimeter if you don't have one already, and measure the voltage at the power input terminals to the electronics. Assuming you have a 12V system, then it should be close to 12V even with the bed heater on. I suspect you are getting a lot less.

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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].

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dc42
Get a multimeter if you don't have one already, and measure the voltage at the power input terminals to the electronics. Assuming you have a 12V system, then it should be close to 12V even with the bed heater on. I suspect you are getting a lot less.

Good thinking! I am reading 11.37 on the power supply's screw terminals when the printer is unplugged, 10.27 with it plugged in and nothing except the cooling fan running, and 8.65 when I've set it to preheat for PLA. Is that normal? I should probably mention that I am using the Cura software provided by Micromake as well - is there a better alternative?

EDIT: I am reading 8.5 volts on the screw block terminals that connect the wires that go to the heating cartridge when it is set to preheat for PLA. The whole system is pulling 0.166 amps while idle, and about 2.24 while preheating for PLA. I've still got the heated bed physically disconnected.

Edited 5 time(s). Last edit at 08/29/2016 12:37PM by ryul.

Either that PSU is shot, or woefully underrated for your print needs

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meq123
Either that PSU is shot, or woefully underrated for your print needs

I was thinking that that might be the case. It is a 12v 16.5 amp but I wonder if it is malfunctioning. The voltage is (a bit) low, especially when current is being drawn. I am currently swapping out the heating cartridge. I've been wondering if the temperature sensor has been malfunctioning (that it is under-reporting how hot the hotend is getting) and/or that the cartridge itself is a dud. If that doesn't fix it I am going to hook the power supply up to something else to see how much power I can draw out of it. If the power supply is OK then I am going to blame the control board, because I can't think of what else it might be xD.

Edited 2 time(s). Last edit at 08/29/2016 05:06PM by ryul.

Temp sensor will only cause the heater to be switched on or off (via RAMPs), so that has no extraneous effect on the PSU.

You said you were reading ~2amps current which is fair (or low) for a 30-40W 12V element.

Still sounds like the PSU to me.

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meq123
Temp sensor will only cause the heater to be switched on or off (via RAMPs), so that has no extraneous effect on the PSU.

That's good to know. It means the problem is almost certainly not the temp sensor. It was still drawing 2 amps after it peaked at 180 degrees, which if the sensor was under-reporting it wouldn't do - it would turn of completely. Thanks!

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meq123
You said you were reading ~2amps current which is fair (or low) for a 30-40W 12V element.

Still sounds like the PSU to me.

Yeah, I definitely agree. I am going to test it as soon as I get a chance. How much power are those heating cartridges supposed to draw anyway?

Edited 1 time(s). Last edit at 08/29/2016 05:14PM by ryul.

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ryul

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meq123
Temp sensor will only cause the heater to be switched on or off (via RAMPs), so that has no extraneous effect on the PSU.

That's good to know. It means the problem is almost certainly not the temp sensor. It was still drawing 2 amps after it peaked at 180 degrees, which if the sensor was under-reporting it wouldn't do - it would turn of completely. Thanks!

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meq123
You said you were reading ~2amps current which is fair (or low) for a 30-40W 12V element.

Still sounds like the PSU to me.

Yeah, I definitely agree. I am going to test it as soon as I get a chance. How much power are those heating cartridges supposed to draw anyway?

Alright, so I hooked it up another 12v power supply from china (the ones for the LED strips) and it too dropped to 8v when any significant amount of power was drawn. I hooked up an old atx power supply I had sitting around. 13 amps max (3 amps below what the original psu could do) but it maintained much closer to 12v under load, and was able to get 210 out of the hotend and 60 out of the heated bed, but I couldn't get the hotend past 210 without disabling the heated bed. Sounds like I need to get a bigger ATX psu.

The Chinese LED PSUs are fine in my experience as long as they are adequately rated. For a typical 12V printer with a 10A bed heater, I suggest a 25A one.

Cheap ATX PSUs typically have very poor regulation on the 12V output. Good brands such as Corsair are better but cost a lot more.

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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].

Quote
dc42
The Chinese LED PSUs are fine in my experience as long as they are adequately rated. For a typical 12V printer with a 10A bed heater, I suggest a 25A one.

Cheap ATX PSUs typically have very poor regulation on the 12V output. Good brands such as Corsair are better but cost a lot more.

I want to preface this by saying that I am not saying you are wrong, just sharing what has happened the past few days.

My experience the past few days was quite different. I received two power supplies with the printer I bought: a 12v 6 amp power-brick and a "12v" 16 amp LED strip power supply. The 12v 6amp one was able to get the hotend hot enough but failed to have enough power to do both that and the heated bed, which is why when I purchased the heated bed they included a larger power supply. Sadly, the larger power supply didn't have the voltage to get the hotend hot enough (it dropped to 8v when a load was applied). I thought "OK, so I got a dud" right? Wrong. I had another I'd bought for another project rated at 20 amps and it did the same thing and the printer didn't work any better.

The ATX power supply was one I picked up at a junk store and is undoubtedly a cheap junker one - 13 amp max on the +12v line? Yeah... even cheap ones these days come with 25 or 30 amp 12v lines. I hooked it up and the printer worked - the heatbed got to 60 and the hotend to 210 - and I tested the voltage and it was very close to 12v even under load. It is pretty clear that the issues with the LED ones were caused by their inability to maintain 12v under load.

Did I happen to get two duds? Possibly, but unlikely. I wouldn't recommend those PSUs - just fork out another $30 and get an ATX power supply! That's my experience anyway.

Edited 2 time(s). Last edit at 09/02/2016 04:46PM by ryul.

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ryul

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dc42
The Chinese LED PSUs are fine in my experience as long as they are adequately rated. For a typical 12V printer with a 10A bed heater, I suggest a 25A one.

Cheap ATX PSUs typically have very poor regulation on the 12V output. Good brands such as Corsair are better but cost a lot more.

I want to preface this by saying that I am not saying you are wrong, just sharing what has happened the past few days.

My experience the past few days was quite different. I received two power supplies with the printer I bought: a 12v 6 amp power-brick and a "12v" 16 amp LED strip power supply. The 12v 6amp one was able to get the hotend hot enough but failed to have enough power to do both that and the heated bed, which is why when I purchased the heated bed they included a larger power supply. Sadly, the larger power supply didn't have the voltage to get the hotend hot enough (it dropped to 8v when a load was applied). I thought "OK, so I got a dud" right? Wrong. I had another I'd bought for another project rated at 20 amps and it did the same thing and the printer didn't work any better.

The ATX power supply was one I picked up at a junk store and is undoubtedly a cheap junker one - 13 amp max on the +12v line? Yeah... even cheap ones these days come with 25 or 30 amp 12v lines. I hooked it up and the printer worked - the heatbed got to 60 and the hotend to 210 - and I tested the voltage and it was very close to 12v even under load. It is pretty clear that the issues with the LED ones were caused by their inability to maintain 12v under load.

Did I happen to get two duds? Possibly, but unlikely. I wouldn't recommend those PSUs - just fork out another $30 and get an ATX power supply! That's my experience anyway.

12V 6A is too small to handle any 3D printer IMO. The starting point is about 12V 10A or 24V 5A for printers without a heated bed. Most 12V bed heaters take 10A or more, making 12V 20A the absolute minimum for a 3D printer with a heated bed. It's best to have some margin, and a 25A PSU costs very little more than a 20A one, which is why I recommend 12V 25A as the starting point. Your 12V 16A PSU was probably simply under-powered for your printer. Caveat: it's not impossible to design a small printer that needs less power than this, but such printers are not common.

The problem with cheap ATX PSUs is that they use the same transformer to drive both the 12V and 5V rails, so the regulation of them is not independent. When you draw a lot of power from 12V and very little from 5V, as 3D printers do, this causes the 12V rail to drop. This is not necessarily a problem, but if your bed heater has marginal power already, it can make the bed very slow to heat up.

If you've been put off Chinese LED power supplies, you can pay more to buy a Meanwell one instead.

Edited 1 time(s). Last edit at 09/03/2016 06:39PM by dc42.

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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].

Quote
dc42
12V 6A is too small to handle any 3D printer IMO. The starting point is about 12V 10A or 24V 5A for printers without a heated bed. Most 12V bed heaters take 10A or more, making 12V 20A the absolute minimum for a 3D printer with a heated bed. It's best to have some margin, and a 25A PSU costs very little more than a 20A one, which is why I recommend 12V 25A as the starting point. Your 12V 16A PSU was probably simply under-powered for your printer. Caveat: it's not impossible to design a small printer that needs less power than this, but such printers are not common.

Yeah, definitely.

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dc42
The problem with cheap ATX PSUs is that they use the same transformer to drive both the 12V and 5V rails, so the regulation of them is not independent. When you draw a lot of power from 12V and very little from 5V, as 3D printers do, this causes the 12V rail to drop. This is not necessarily a problem, but if your bed heater has marginal power already, it can make the bed very slow to heat up.

That's interesting. The one I was using would cause the printer to reset if I plugged a fan in near it, so its regulation was very poor.

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dc42
If you've been put off Chinese LED power supplies, you can pay more to buy a Meanwell one instead.

I've got myself a 600w atx with a single 50a +12v rail, although the individual lines have some kind of current-limiting function so I have to connect multiple lines together. I am definitely going to watch out for that issue you mentioned though, about drawing a bit from the +5v rail causing the 12v to drop. I figure I'll just power everything (including the board) from the 12v if it turns out that using the 5v rail does that.

Edited 1 time(s). Last edit at 09/23/2016 07:27PM by ryul.