More secure power terminals
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We're looking at using a different type of power and bed heater connector for future designs. Unfortunately it's hard to come up with a good solution that doesn't add £8-£10 to the retail cost of the board. Reliable PCB-mounting power connectors are not cheap, except for blade terminals and terminal blocks.
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I'll second this – for the price of the board I was disappointed with both the terminals that were used. Additionally on my board I found all four of the terminal blocks were not correctly soldered while fully seated against the board. In other words, the blocks were able to rock back and forth since the bottom was not flat against the board.
If possible please can you email me (info@duet3d.com) with a picture of the terminal blocks from the side. I will highlight this to our manufacturers as it not acceptable.
One point to make is that the terminal blocks for power in and the bed (while I agree they do need anti torque stubs) are rated to 35A. as David says power connectors above 20A that are reasonably priced and suited for automated manufacture are not particularly cheap.
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this is probably too costly
but guys spring loaded terminals are sweet….
and no one out there has them integrated, its always tight as helljust like old times..! some things just work..!
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Are the ring terminal power supply style connectors cheap? Those seem to be a good balance of keeping the wires in place while applying a good amount of pressure. The ring terminals are pretty easy to crimp as well.
What exactly happens if you soldered to that connection? Does it generate uneven amounts of heat because of the current? All I know for sure is that it's not supposed to be done for that reason?
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Just to add to the conversation - since I don't see that I would be connecting/disconnecting the wires from these connections on a regular basis they seem adequate to me - I simply grasp the connector while tightening the screws and all is well.
Frederick
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We're looking at using a different type of power and bed heater connector for future designs. Unfortunately it's hard to come up with a good solution that doesn't add £8-£10 to the retail cost of the board. Reliable PCB-mounting power connectors are not cheap, except for blade terminals and terminal blocks.
You should check out the wire connectors used on the MB2 breakout board, I use it on my CNC machine and it is a pleasure to work with. They are spring loaded… I also ended up with a situation where i put too large of ferrul in and needed to remove it. attempting to do so on the Duet would most likely snap the connector off but the MB2 was solid.
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For what it's worth I've used some name brand high current industrial power supplies that have the same issue when you really tighten the screws.
What sort of connectors are you looking for? Wurth makes some 20A pluggable terminal blocks (Model 313 it looks like) that go for about $1 for the block/plug pair (2 pole). I've never used wurth (phoenix contact for me) but they don't seem like a bad deal.
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The Width ones you mention, 313 series, mate with connectors that are themselves screw terminals by the look of it. The issue there is you now double the potential failure points while still having the screw terminals. You do have the advantage of being able to plug and unplug the power connector however once installed this should be a rare event.
I am not saying the screw terminals are perfect, just that I am not a fan of the screw terminal+plugs as a replacement.
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yes the power terminals are very bad - for an 200 bucks Board
on my anet Board i soldered XT60 connectors on it
and for small power - small wago Terminals (without Screws)maybe this is usefull:
Wago typ 2706-102- 6mm² - 41A - Print - 2pol - with actuating lever
only 1,50 €
https://www.buerklin.com/de/anschlussklemme/p/09h3600
https://www.buerklin.com/en/terminal/p/09h3600Greetings from Hamburg
Ingo - 6mm² - 41A - Print - 2pol - with actuating lever
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Like I said, we're looking at alternative connectors for the next generation - the current Duets don't have enough space for anything else. I already have some samples of lever-operated terminal blocks, and we are evaluating XT30 connectors too. We're also considering the same type of screw terminals that most PSUs have.
