Static discharge resets in the middle of a print
 
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Mike B
(@mike-b-3)
Eminent Member
Static discharge resets in the middle of a print

I’ve had this twice now - I opened my enclosure and had static discharge from my finger to the top of the case and the printer beeped and reset.  The print resumed successfully thankfully but is there something I can do to protect against this?  Obviously I can put something grounded nearby and make sure I touch it first but shouldn’t the enclosure be grounded too?

Prusa MK4 since Jan 2024, Printables: @MikeB_1505898

Posted : 17/02/2024 7:13 pm
JP Guitars
(@jp-guitars)
Estimable Member
RE: Static discharge resets in the middle of a print

Ground it yourself

Posted : 17/02/2024 7:17 pm
Mike B
(@mike-b-3)
Eminent Member
Topic starter answered:
RE: Static discharge resets in the middle of a print

That is my obvious course of action - but I'm wondering why that would cause a reset?  Is there a current path that shouldn't be there?  I have trouble believing it's an RF issue.  Is this the case being connected to the PS and therefore spiking the ground for the logic boards?  Does nobody else have this problem?

Prusa MK4 since Jan 2024, Printables: @MikeB_1505898

Posted : 17/02/2024 9:54 pm
Hello
(@hello)
Noble Member
RE: Static discharge resets in the middle of a print

 

Posted by: @mike-b-3

That is my obvious course of action - but I'm wondering why that would cause a reset?  Is there a current path that shouldn't be there?  I have trouble believing it's an RF issue.  Is this the case being connected to the PS and therefore spiking the ground for the logic boards?  Does nobody else have this problem?

It will happen to every mk3s+ or before printer. Ive seen many people that have this happen Bassicly just touch the top of the psu first that will ground yourself. This is why the new mk4 has a ground wore from motherboard to psu.

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Posted : 18/02/2024 7:58 am
Turnpike
(@turnpike)
Active Member
RE:

This still happens on the MK4, particularly when inserting the USB drive into the controller.  I've learned to prevent this by touching an exposed screw on the printer or something nearby to dissipate the charge I've built up. 

If it is helpful, I can offer a longer explanation from a 47-year background in electronics and computer engineering.  It's winter in my hemisphere, and with very low humidity comes the risk of building up electrostatic charges just moving around, rolling your chair, etc.  These are not inconsiderable values of voltage, and can approach 15,000-20,000 volts at the extreme end, although with at minuscule values of Current (the "dangerous" part). The "zap" that is startling and annoying to you is very disruptive to electronic micro-controllers like those used in a 3D printer, because these devices operate at very tiny charge states across their integrated circuits, and they are not surrounded by as much component packaging as, say, a full size home PC.  That static charge transferring from your body can easily wipe or flip those charge states so that the device detects an internal error and reboots.  USB interfaces, in particular, are among the most sensitive to this, because their design was not well thought-out, and provides a very easy path for that charge to route into the USB controller (and sometimes into the CPU core).  I suspect, but have not checked to be sure, that these micro-controllers are also built using "floating ground" construction techniques due to the very low DC voltages involved, and that also makes them prone to this type of accidental disruption.

 When changing out USB drives, it's good practice to always find a way to dissipate your charge before putting your fingers close to the USB insertion point.  You could always try to avoid building up a charge, although you will never know because you can carry a substantial personal electrostatic charge and feel nothing.  You can also add a humidifier in the space with your 3D printer, but that comes with it's own set of challenges for filament 🙂 .  There are ways to reduce the potential for this happening at the engineering level either by providing a more robust ground path, or a large metal backplane or dissipation device to dissipate charges that might be transferred to the processor, but that adds complexity and cost, and if the charge does not alter the lifespan of the device, it my not be worth that effort.

Hope this added to the conversation.

 

This post was modified 2 months ago by Turnpike
Posted : 18/02/2024 7:36 pm
Mike B
(@mike-b-3)
Eminent Member
Topic starter answered:
RE: Static discharge resets in the middle of a print

Thanks for the explanations.  I am indeed using a MK4, and within an enclosure.  I'm not even touching the printer - just the enclosure!  I'm learning to touch the metal desk it sits on before touching the enclosure which seems to prevent the issue.  I suspect I'm going to need to ground the enclosure to a ground wire in the wall outlet (the bare metal wire, not the neutral).

I'm comparing this to my MacBook Pro, which I regularly zap on its metal case with nary a reaction from the computer.  Seems to me there must be a way to at least make touching the enclosure safe.

Prusa MK4 since Jan 2024, Printables: @MikeB_1505898

Posted : 19/02/2024 1:43 am
Diem
 Diem
(@diem)
Illustrious Member

Your MacBook, or any laptop, is designed to be touched frequently by users who may have a large static build up; you said yourself, it has a metal case which forms a Faraday cage ... some laptops have the metal as a foil layer stuck to the inside of the case.

A full protection for a 3D printer would require a microwave oven style cabinet.  You should do fairly well with an enclosure directly grounded with a resistive connection to the printer inside.  Or just put a grounding point beside the printer (add a resistor to reduce the 'zap') and make a habit of touching it first.

It sounds as if in your case, @mike-b-3, you might be able to ground it to the bench.

Slightly off topic: The XL, with the large metal frame, has excellent grounding and although the electronics are not obviously protected it's almost inevitable that you will touch a grounded part before affecting them.

Cheerio,

 

 

 

Posted : 19/02/2024 7:32 am
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