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Safety of custom 3d printed components in high current environments

iClick

iClick

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Jan 17, 2024
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Melbourne, Australia
I'm considering purchasing a 3D printer (Creality Ender-3 V3 SE) and using it to print (amongst other things) parts for my solar builds. The first project that has driven this idea is for a custom bus bar incorporating ANL fuses. The file can be viewed here: Thingiverse Fuseholder for 5x40 copper bar

I'd like the bus bar to handle at least 400 amps but I'm unsure of the most appropriate filament to use as I understand that not all are completely non-conductive if they contain certain additives. My other concern is what may happen if there was excessive heat (above 70ºC) to the structure. Would it start to melt/deform and cause issues?

I like the idea of being able to manufacture cable guides, terminal protectors, BMS holders and so forth but only if safety concerns are addressed.

If anyone has successful experience in 3D printing high current parts I'd love to hear your feedback. (Also, if the Creality printer I linked above would be a good 1st printer for a newbie)

EDIT: extra images
 

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You certainly don't want your plastic to be melting down. PLA will soften and distort being left in a hot car in summer. ABS is used in automotive trim components like bumper covers, etc., so I would stick with that or a higher temp filament.

I don't know anything about that printer, but it has a 100°C heated bed, so it can print ABS and some others.
 
Asa would be a decent choice, easier to print than abs... but you probably won't be happy printing either of these on an ender 3.
Upgrading to a k1 or at least using an enclosure will help.
 
Really hard to tell what's holding the end of that fuse, there's not much strength to 3D-printed plastic, and you'd want to be able to use the appropriate torque to hold your wires to a 150A fuse, for instance. I doubt the conductivity of the plastic will be an issue, unless you use something filled with carbon fiber, but strength and melting are definitely concerns.
 
windsurfer said:
Asa would be a decent choice, easier to print than abs... but you probably won't be happy printing either of these on an ender 3.
Upgrading to a k1 or at least using an enclosure will help.
Click to expand...
Budget is defiantly an issue. I'm prepared to spend the AUD $300 (plus material) to begin with. In my little research online, it seems that many of the problems that plagued the previous Ender 3 models have been addressed with the V3-SE so hopefully it will be passable for my infrequent use (with a DIY enclosure if necessary)
wpns said:
Really hard to tell what's holding the end of that fuse, there's not much strength to 3D-printed plastic, and you'd want to be able to use the appropriate torque to hold your wires to a 150A fuse, for instance. I doubt the conductivity of the plastic will be an issue, unless you use something filled with carbon fiber, but strength and melting are definitely concerns.
Click to expand...
I agree with you on the strength of the printed plastic. Not so much the torque on the bolts, but any pressure applied to the holder from twisting if large cables are terminated on an angle into the terminals.

EDIT: I've updated the 1st post to include more images
 
Trying to save $ on the printer is false economy. Within a couple of months the amount you spend on filiment will easily eclipse the printer cost. Additionally care and feeding of an ender 3 will cost you significantly more than maintenance on a better printer.

Strength is a matter of design, materials and print parameters.
 
Personally, I don't think I'd 3D print any parts that are going to actually experience any kind of strain/have anything substantial mounted to it.

I'd be sketched out using that fuse holder.

I could see 3D printing shrouds, protective covers, airflow guides. Also, definitely agree on picking a filament that's high heat resistant.
 
iClick said:
I'm considering purchasing a 3D printer (Creality Ender-3 V3 SE) and using it to print (amongst other things) parts for my solar builds. The first project that has driven this idea is for a custom bus bar incorporating ANL fuses. The file can be viewed here: Thingiverse Fuseholder for 5x40 copper bar

I'd like the bus bar to handle at least 400 amps but I'm unsure of the most appropriate filament to use as I understand that not all are completely non-conductive if they contain certain additives. My other concern is what may happen if there was excessive heat (above 70ºC) to the structure. Would it start to melt/deform and cause issues?

I like the idea of being able to manufacture cable guides, terminal protectors, BMS holders and so forth but only if safety concerns are addressed.

If anyone has successful experience in 3D printing high current parts I'd love to hear your feedback. (Also, if the Creality printer I linked above would be a good 1st printer for a newbie)

EDIT: extra images
Click to expand...
I read this and couldn't imagine printing a busbar...

Heh.
Reading skills are a thing...

Make CERTAIN any loads you put on this have adequate cable size to support them. Oversize the busbar material keep things cool.
Have good insulating material under the bolt heads.
 
I've 3D printed semi-structural static components in ABS. They've held up extremely well (8 years and counting)

In-fill of 75%. In areas where I had to screw into the parts, I printed a hole and bonded in solid ABS rod in 1/4 and 3/8" sizes and drilled the requisite hole.

I would consider printing this, BUT I would thoroughly test it with multiple tightenings/loosenings before committing.

If budget really is a driving factor here, you could buy bus bars for cheaper than a 3D printer, and you'd have parts WAY sooner and at a dramatically lower investment in your time.
 
IMO, bad idea....

3d printing can be an art, don't expect your first 20 parts to be useful. Probably more until you get the printer dialed in.

And the pictures they use in advertising that are a long way from start.

Switching between filament types I have different hot ends I swap in.

And were I contemplating bus bar holders I would oversize the bus bar to keep it cooler.

Poly carbonate filament, quarter cubic infill, 50 to 75%.

And make sure to rotate the part so the layer oppose the expected stress. And think out of the box on this, setting it on an angle with supports for instance

Like eggo said, it will be cheaper to just buy what you need.

Just my opinion
 
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Damn bro. A bazooka isn't needed for everything! :p

PC is not a beginner material, and the linked printer would not do it.

IMHO PC is overkill. The plastic on my purchased bus bars is definitely inferior to PC.
 
sunshine_eggo said:
Damn bro. A bazooka isn't needed for everything! :p

PC is not a beginner material, and the linked printer would not do it.

IMHO PC is overkill. The plastic on my purchased bus bars is definitely inferior to PC.
Click to expand...

Actually I print PC with an ender 3, of course it has a meanwell psu, better steppers, better bed, dual axis verticals, diagonal braces, new hot end, and a klipper main board. So other than the frame hardly resembles its poor original cousin.

And it took me a year to work up to it from PLA

One problem the OP noted is many filaments contain carbon as part of the color. So they are pretty much all slightly conductive unless you buy a type that specifically made for printing PCB. The carbon helps filament melt and flow smooth. Injection molded parts don't need this because they run hotter

And I like bazookas
 
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windsurfer said:
Trying to save $ on the printer is false economy. Within a couple of months the amount you spend on filiment will easily eclipse the printer cost. Additionally care and feeding of an ender 3 will cost you significantly more than maintenance on a better printer.

Strength is a matter of design, materials and print parameters.
Click to expand...
I've read the lacklustre reviews for the older Ender 3 series printers however I'm prepared to gamble that the new versions have improved and addressed the previous issues. I just bough the Ender 3 V3 KE which has better specs than the 1st model I linked. (300ºC printing, improved rails/supports etc) and I was able to purchase this at A$340 (USD $218) At that price I'm happy to invest in more filament for practice/tests. I will also build an enclosure for fumes and to retain heat for better ASA/ABS printing.
robbob2112 said:
IMO, bad idea....

3d printing can be an art, don't expect your first 20 parts to be useful. Probably more until you get the printer dialed in.

And the pictures they use in advertising that are a long way from start.

Switching between filament types I have different hot ends I swap in.

And were I contemplating bus bar holders I would oversize the bus bar to keep it cooler.

Poly carbonate filament, quarter cubic infill, 50 to 75%.

And make sure to rotate the part so the layer oppose the expected stress. And think out of the box on this, setting it on an angle with supports for instance

Like eggo said, it will be cheaper to just buy what you need.

Just my opinion
Click to expand...
All good tips. I will most likely just purchase a off the shelf busbar/fuse holder and reserve the printer for other cosmetic uses.

I just wasn't happy with the exisiting options as I felt the busbar was undersized for my application and I hoped that there was a filament available that met the specs for strength heat and non-conductivity so I could use my own over-specced built version.

Safety is the reason for my post in this sub-forum and I was seeing if I could safely DIY a unit that exceeded the current I wanted to use in my particular application.

This is one commercial unit I was hoping to use but it's only rated to a max current of 250 Amp: Victron Fuse holder 6 way MEGA fuse
Another option is this using MIDI fuses rated up to 300 Amp Bussmann Input Module

However stealing chrisski's comment below, I would need a much larger fusible option for my scenario (3000W 12v inverter)
chrisski said:
Inverter Wattage divided by low voltage cutoff divided by inverter efficiency multiplied by 1.25 for headroom.

3000/10/.85*1.25=441 amps
Click to expand...
 
If you do 3000watts, I highly and most strongly recommend 48v. Wires are 1/4th the size, fuses 1/4th the size, connection resistance results in 1/4th the loss. If you have a 12v load get a buck converter to run from.

You can force it to work at 12v or 24v, but there are things youvhave compromise to do it.

That printer is a large step up from my v1. First suggestion, don't mount the spool on top like they show. It shakes enough you will get wavy lines in the prints. The only part I am missing is the linear rail on the X-axis.
 
robbob2112 said:
If you do 3000watts, I highly and most strongly recommend 48v. Wires are 1/4th the size, fuses 1/4th the size, connection resistance results in 1/4th the loss. If you have a 12v load get a buck converter to run from.

You can force it to work at 12v or 24v, but there are things youvhave compromise to do it.
Click to expand...
Again, I agree with all your points. However the scope of my project has grown since I purchased the 4 x 304 A/H cells. My aim is to make a powerful portable all-in-one universal powerstaion for use on film/photography sets. (see attached pic) The added bonus will be to take it away camping and use a induction hotplates (x2) so I can hopefully ditch taking gas bottles.

Right now everything will fit in one rolling case - battery, inverter and 100w AC charger and if possible, I will squeeze in a DC-DC charger. Right now it's a brute and verging on too heavy to be practical.

The next version will defiantly be at least 24v as that is becoming the industry standard for the film industry and if I go that route, I will need to separate the inverter/chargers into their own cases.

The issue I'm facing now (aside from the DIY fuse/busbar) is working out what is the correct safe minimum for cable sizes. At the moment I only have a 1500W inverter and I'm really just future proofing the system. I may only go to a 2000W 12v inverter however the idea of using a 3000W inverter was to have more headroom. I wouldn't anticipate needing to use all 3000W for very long at all and the worse case scenario would be using 2x induction cooktops at the same time. I would just need to be aware of the amps they would be pulling and keep under the inverter cutout.

I have no issue with using 4/0 cable however I haven't used it before and I'm worried about the bend radius needed to keep everything in the one case. I think I'll have to compromise somewhere and maybe the smart decision would be to drop down to a 2000W inverter and 3/0 cables.
 

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iClick said:
Again, I agree with all your points. However the scope of my project has grown since I purchased the 4 x 304 A/H cells. My aim is to make a powerful portable all-in-one universal powerstaion for use on film/photography sets. (see attached pic) The added bonus will be to take it away camping and use a induction hotplates (x2) so I can hopefully ditch taking gas bottles.

Right now everything will fit in one rolling case - battery, inverter and 100w AC charger and if possible, I will squeeze in a DC-DC charger. Right now it's a brute and verging on too heavy to be practical.

The next version will defiantly be at least 24v as that is becoming the industry standard for the film industry and if I go that route, I will need to separate the inverter/chargers into their own cases.

The issue I'm facing now (aside from the DIY fuse/busbar) is working out what is the correct safe minimum for cable sizes. At the moment I only have a 1500W inverter and I'm really just future proofing the system. I may only go to a 2000W 12v inverter however the idea of using a 3000W inverter was to have more headroom. I wouldn't anticipate needing to use all 3000W for very long at all and the worse case scenario would be using 2x induction cooktops at the same time. I would just need to be aware of the amps they would be pulling and keep under the inverter cutout.

I have no issue with using 4/0 cable however I haven't used it before and I'm worried about the bend radius needed to keep everything in the one case. I think I'll have to compromise somewhere and maybe the smart decision would be to drop down to a 2000W inverter and 3/0 cables.
Click to expand...

Cable bend radius is. Generally 1x the dimensions of the cable. Something like this helps bend it.


You can buy 4/0 lugs with an offset up to 90 degrees left, right, up, down. This keeps the cable unkinked and gives a tight turn.

For inductive loads like saws, motors, and other similar you can getaway with the startup current using a LF (low frequency) inverter and it will carry on. The cheaper HF inverters generally will fault when you try.

Induction cooktops work by rectifying the AC voltage then they put the DC current into a tuned tank. This coil is magnetically coupled to the cookware. All that can be summed up to say there is no startup surge like a motor causes.

For connecting between cases I would use SB350 mounted on both cases and as short a cable as is practical between them with SB350 on both ends. You can go smaller but the price delta isn't huge.

For bus bars you can fabricate them or order directly from a metal supply shop.
 
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If you are used to 3D printing functional parts (use higher temps and less cooling for better strengths), a 3D printed bus-bar carrier should work out from the mechanical side, though I would avoid PLA.
PETG or ABS would be my choice, though filament is flammable, and could ignite at high temps (loose lug for example). I ordered some flame retardant filament for that purpose, to be on the safe side.
I expect FR-ABS to be nasty toxic and difficult to print, an absolute case for an enclosure. We'll see.
 
If your ducks are in a row otherwise, just wanting a neato new toy is all the reason you need, just get the 3D printer and enjoy. No need to find a justification for it.

My girlfriend looked into 3D printing because she paints models and figurines, and would like to be able to "just" print whatever she wanted herself. About three minutes of research revealed that 3D printing is an entire occupation/hobby/endeavor on it's own, there's no just (implying simple or easily executed) anything about it. Girlfriend said NOPE, no interest in the 3D printing side of it, she only wanted the figurines. Instead she buys what she wants from folks on Etsy. We also have a couple friends who are into 3D printing, and charge reasonable amounts to print whatever she wants. For the amount she prints, she probably came out way ahead on cost too vs. buying a printer and printing herself. Definitely ahead on time.
 
As long as wiring is sized right and your using terminals that will carry the expected current without getting hot, you'll be fine. I designed and 3d printed a power distribution box with out of ABS to charge my Zero with 2 chargers from a 240v source. It has terminals for l1, l2 and N that mount on heat inserted knurled brass threads and splits the grid 240v off to a cable for the onboard charger and for the additional charger. I've used it constantly over the past 4 years without any issues, even at one public charge station with low voltage where it was pulling more amps than I was expecting (the case was hot but the cables and terminals were solid). ABS has the highest glass temp out of the popular filaments, I would stick with that.

I would strongly suggest printing more perimeter lines as thats where your strength really comes from. 1.2mm at a minimum if using .4mm nozzle.
 
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