I seem to have some kind of ground loop in my Mendal. Sometimes, I'll walk up to the printer and touch the filament while it is printing and the machine will stop printing and everything freezes up, including the Ramps and Arduino. Nothing gets damaged and is fine after I reboot everything, but I've lost many a half finished print this way. I thought that I had it sorted out after I wrapped some tinsel around the metal hook that I hang my spool from and hooked it up to an overhead light box, but it has done it since. The only way I can avoid it is to touch the spool itself (I like to roll off some slack sometimes) and turn that. But if I just walk up to the machine and touch the filament itself - zap! (silent zap, but deadly) Has anybody else had this problem? Does anybody know where the loop might be and how best to create a drain for it? https://reprap.org/forum/read.php?1,201563,201563#msg-201563 Sat, 15 Aug 2026 08:42:33 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,201563,203301#msg-203301 https://reprap.org/forum/read.php?1,201563,203301#msg-203301 -------------------------------------------------------
> Hey Tek, did you work for Kodak (or maybe Xerox?)

I've been trained on both, along with several others....]]> Tekwizard General Sat, 27 Apr 2013 04:51:34 -0400 https://reprap.org/forum/read.php?1,201563,203090#msg-203090 https://reprap.org/forum/read.php?1,201563,203090#msg-203090 waitaki General Fri, 26 Apr 2013 05:37:11 -0400 https://reprap.org/forum/read.php?1,201563,203077#msg-203077 https://reprap.org/forum/read.php?1,201563,203077#msg-203077 -------------------------------------------------------
> In the winter I wear an ESD foot strap in one
> slipper otherwise I get a big spark when I walk up
> to a machine and touch it. Whether you generate
> ESD depends mainly on how dry the air is, what the
> soles of your shoes and the flooring is made from.
>
>
> Odd that touching the filament does anything as it
> is normally almost a perfect insulator. If I
> re-spool ABS with an electric drill while passing
> it through a duster it works like a Van de Graff
> generator and makes sparks about 30mm long. It
> also sparks though the casing of the drill and
> gives me a shock,
>
> Perhaps grounding the nozzle with an independent
> ground might work. I.e. you don't want the the ESD
> pulse flowing down the ground of the machine.
> Sometimes adding a 10M resistor works better for
> discharging ESD without creating a big ground
> current pulse or air-born EMP.

Thanks for your suggestions Nophead, I'll try the resistor.
Where I live, it rains all winter and the humidity is pretty high, so that's likely not the cause.

I have over the years worked repairing Xerographic equipment, and they use polymers (similar plastics) in granular form that churns in an auger manipulated trough (It's called developer material). The voltage created by this churning is critical to the printing process and is pretty predictable, and is on the order of thousands of volts. Even vacuuming that stuff up will give me some pretty bad shocks. I know from that knowledge that plastic can be a very good conductor under the right circumstances. From how it's been explained to me, and I'm no physicist, the static accumulates on the exterior of the plastic and forms a conductive skin of sorts.It is that electrical skin that is the conduit that conveys it down the filament. I'm guessing that from the nozzle, it travels to the Arduino and locks that up. I've only ever seen it do this when I walk in the room and phycically touch the filament, and since I live in a high humidity area, I'm thinking that I'm actually draining the static away, rapidly, and causing a flow through the system, rather than adding anything to it. I think the spool turing is the source of the static.]]> Tekwizard General Fri, 26 Apr 2013 05:10:03 -0400 https://reprap.org/forum/read.php?1,201563,203064#msg-203064 https://reprap.org/forum/read.php?1,201563,203064#msg-203064
Odd that touching the filament does anything as it is normally almost a perfect insulator. If I re-spool ABS with an electric drill while passing it through a duster it works like a Van de Graff generator and makes sparks about 30mm long. It also sparks though the casing of the drill and gives me a shock,

Perhaps grounding the nozzle with an independent ground might work. I.e. you don't want the the ESD pulse flowing down the ground of the machine. Sometimes adding a 10M resistor works better for discharging ESD without creating a big ground current pulse or air-born EMP.]]> nophead General Fri, 26 Apr 2013 04:20:57 -0400 https://reprap.org/forum/read.php?1,201563,203027#msg-203027 https://reprap.org/forum/read.php?1,201563,203027#msg-203027 -------------------------------------------------------
> I have never seen anything like that on my
> printer, but assuming you use a resistor heater..
> What if some of the resistor windings have shorted
> with the hotend, that could send noise up to the
> electronics via the heater circiut..


Thanks Ralf, but I use a ceramic heater and it's not shorting.

This happens in an exact way each time. If I've been out of the room it's in for awhile, and then I walk in while it's printing and then grab the filament, it stops printing the instant my fingers touch the filament. I touch it about two feet up from the moving hot end. I've gotten into the habit of first grounding my body by reaching up and holding onto a big metal light box in the ceiling. That seems to be working fine.]]> Tekwizard General Fri, 26 Apr 2013 01:20:14 -0400 https://reprap.org/forum/read.php?1,201563,202899#msg-202899 https://reprap.org/forum/read.php?1,201563,202899#msg-202899
Should be easy to check with a multimeter.

Just a thought..]]> Ralf General Thu, 25 Apr 2013 13:51:30 -0400 https://reprap.org/forum/read.php?1,201563,202742#msg-202742 https://reprap.org/forum/read.php?1,201563,202742#msg-202742
I know that plastic will conduct if the voltage is high enough, and turning on a spool can generate that. My spool is suspended from the ceiling 4 feet above the printer.

I too am using a laptop (netbook actually) but I think that it might be the Arduino that is locking up.

I guess I could link every metal object in the printer together and connect it all to ground, but that would kind of take away something from the whole printed plastic parts concept for me. I'm sure it's a ground loop and if it's form can be discovered, it could be drained away from a single point.

I am using a 100 amp 12 volt server power supply that is well grounded. (Yes, I know that's a bit big, but it was dirt cheap).

Maybe it would help if I put the machine inside a metal box? Or would that just trap the static more?]]> Tekwizard General Thu, 25 Apr 2013 00:34:22 -0400 https://reprap.org/forum/read.php?1,201563,202674#msg-202674 https://reprap.org/forum/read.php?1,201563,202674#msg-202674
What should I be connecting to earth to make things more stable?

As far as I can tell, it seems to be the USB connection that is shutting down, because the firmware still seems to be happily managing nozzle and bed temperatures.]]> Greg Frost General Wed, 24 Apr 2013 17:40:54 -0400 https://reprap.org/forum/read.php?1,201563,202276#msg-202276 https://reprap.org/forum/read.php?1,201563,202276#msg-202276 Maxx Mayhem General Tue, 23 Apr 2013 15:16:46 -0400 https://reprap.org/forum/read.php?1,201563,202260#msg-202260 https://reprap.org/forum/read.php?1,201563,202260#msg-202260
Ben]]> plexer General Tue, 23 Apr 2013 14:32:47 -0400 https://reprap.org/forum/read.php?1,201563,202256#msg-202256 https://reprap.org/forum/read.php?1,201563,202256#msg-202256
Since I've done all this, I don't think I've had a single freeze up and rarely scramble the display.]]> Knimrod General Tue, 23 Apr 2013 14:21:06 -0400 https://reprap.org/forum/read.php?1,201563,202215#msg-202215 https://reprap.org/forum/read.php?1,201563,202215#msg-202215 lazzymonk General Tue, 23 Apr 2013 11:52:15 -0400 https://reprap.org/forum/read.php?1,201563,202214#msg-202214 https://reprap.org/forum/read.php?1,201563,202214#msg-202214 -------------------------------------------------------
> Yes, I mean hook the frame to "earth ground" not
> just negative side of the power supply.
>
> Is your power supply properly grounded?

My power supply is well grounded and I have hooked parts of the frame to it's chassis.
The problem with grounding the Mendal frame is that all of the rods are inserted into plastic parts, which of course are di-electric. I'd have to take apart the entire machine to electrically join the rods in some kind of meaningful fashion. I'm not sure how I'd securely connect to the hardened steel smooth rods...

I wrapped my tinsel around the two upper rods that the filament passes between and connected the other end to the power supply, and it has frozen up since then.

Has anyone else had their machines freeze up due to ESD?]]> Tekwizard General Tue, 23 Apr 2013 11:47:51 -0400 https://reprap.org/forum/read.php?1,201563,201731#msg-201731 https://reprap.org/forum/read.php?1,201563,201731#msg-201731
Is your power supply properly grounded?]]> tmorris9 General Mon, 22 Apr 2013 00:25:11 -0400 https://reprap.org/forum/read.php?1,201563,201691#msg-201691 https://reprap.org/forum/read.php?1,201563,201691#msg-201691 -------------------------------------------------------
> How about grounding the printer. It sounds like
> you have a floating ground.

I guess that's what I mean by a ground loop.
Do you mean wire the frame to ground?
I'm guessing the boards are grounded since the ESD goes through them.]]> Tekwizard General Sun, 21 Apr 2013 18:27:21 -0400 https://reprap.org/forum/read.php?1,201563,201669#msg-201669 https://reprap.org/forum/read.php?1,201563,201669#msg-201669 tmorris9 General Sun, 21 Apr 2013 16:26:21 -0400 https://reprap.org/forum/read.php?1,201563,201609#msg-201609 https://reprap.org/forum/read.php?1,201563,201609#msg-201609 akhlut General Sun, 21 Apr 2013 11:40:15 -0400 https://reprap.org/forum/read.php?1,201563,201563#msg-201563 https://reprap.org/forum/read.php?1,201563,201563#msg-201563
Sometimes, I'll walk up to the printer and touch the filament while it is printing and the machine will stop printing and everything freezes up, including the Ramps and Arduino. Nothing gets damaged and is fine after I reboot everything, but I've lost many a half finished print this way. I thought that I had it sorted out after I wrapped some tinsel around the metal hook that I hang my spool from and hooked it up to an overhead light box, but it has done it since. The only way I can avoid it is to touch the spool itself (I like to roll off some slack sometimes) and turn that. But if I just walk up to the machine and touch the filament itself - zap! (silent zap, but deadly)

Has anybody else had this problem?

Does anybody know where the loop might be and how best to create a drain for it?]]> Tekwizard General Sun, 21 Apr 2013 06:58:40 -0400