PROPER cable relief on the bed would help with the movement…
I soldered the wires to my bed and screw-clamped them in connectors pictured above on my Melzi board… I remember soldering the bed-end and thinking “yeah… I’m BAD at soldering, but that’ll be enough - tug tug - yeah, it’s pretty solid…”
Nope…
You need a good connection for good conductivity…
I found that over time, my conductivity got worse and worse - the cable heated up more and more - my bed would only achieve lower and lower temperatures. THEN I blew out the connector on the board… thinking this was the problem I replaced the connector… It would still get VERY hot while in use - and I looked at my heated bed… I REALLY reckon the problem started there, the connections were still ‘soldered’ - but they were black… I cleaned and re-soldered the bed (now that I’m a professional solderer with my few weeks experience :-P) and instantly got +15 degrees C…
@Jarred_Baines good advise! I will take a look at the bed tomorrow. So you soldered wires onto the bed then had a separate connector to attach the main cables to the ramps board?
I’m not too bad at soldering so I think the connection there is good. But I am concerned that the thick cable is putting undue stress on the solder joint.
I would love to see someone do a good run down on good wire and joint management on the prusa. Everyone always writes up the mechanical construction and neglects the electronics!
Ultimachine.com invented RAMPs and is absolutely awesome when it comes to customer support. RAMPs 1.4 is the end of the road for RAMPs I think. RAMBO has taken its place. @Johnny_Russell
@Toby_Thornton Rambo vs azteeg x3? Bit of a price difference but if you were building a new machine right now with an eye for quality what would you go for?
@Charles_Reiche@Robert_Koppl@Eclsnowman tining wires that are intended to be used in screw clamps is actually a fairly bad idea. The problem is that solder tends to creep under load and therefore will creep away from the contact points and leave you will loose wires after a while, which is why for example the DIN prohibits this practice. By the way, that’s the same reason why aluminum cable is banned for mains wiring.
Mount your electronics and do a decent job of the loom, RAMPS at least uses a terminal rated for the current (if only just), loads of electronics boards don’t, I see some using beefy molex pins, or doubling up on 0.1" spaced pins, all totally inadequate.
This spot is the only really dangerous part on a printer. If using RAMPS, keep the wiring secure, also don’t tin or significantly twist the wire end, or over-tighten. Just do it right and your RAMPS will be safe.
Slight twisting is not bad, but crimped lugs / soldered terminal pins are standard in all the medical equiment I work on… Just tinning not allowed. Lots of intermittent problems down that route, especially where some current draw can be expected.
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-----Original Message-–
From: “Nigel Dickinson (Google+)” <@>
Date: Tue, 25 Feb 2014 01:56:06
To: <@>
@Nigel_Dickinson excessively twisted wire gets broken strands in screw terminals and crimps, increasing the resistance. Tinned wire that is not to be soldered to another thing is just inflexible, makes point contacts, melts, and also corrodes too quickly. Hence why wire is not twisted or tinned in good electronic equipment. For IMC/QC contacts you absolutely must have streight, un-freyed bare wire in the crimp.
@Bracken_Dawson corrosion is due to damp.
Second your telling me industry standards are wrong.
Third if your solder is melting your really drawing to much current.
Fourth flexing shouldn’t be at the connector if it is you may damage your circuit board.
I agree with @Bracken_Dawson . I do not recommend tinning power wires before inserting in to screw terminals. A soldered tip is very hard, and the screw terminal can’t compress the tinned wire to make the best possible connection.
The strands of bare wire (and we should be using stranded for flexibility, I’ve never seen otherwise though) will compress to make the connection over as much of the surface area of the screw terminal as possible.
Ferrules are good when they are crimped square (or at least with the squarer faces normal to the axis of the screw), since they can also flex the same way the bare copper can.
Everybody can do whatever they like in DIY… I like it that way.
I printed more than 25 kg of filament using RAMPS 1.4 and the prusa heated bed and all is well. So far anyway… I don’t think the problem lies at RAMPS specifically.
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-----Original Message-–
From: “Nigel Dickinson (Google+)” <@>
Date: Tue, 25 Feb 2014 03:26:43
To: <@>
@Tony_Olivo sorry but how does a stationary wire creep. Things work loose due to vibration. And if you are using a board thats in an vibration area spring loaded clamps should be used.
After all creep can occur on bare wires to.
Strain relief can be gained by using a largish cable tie as the support, and some small ties to strap it to the cable. Even better if you can secure the large tie near the termination as well.
Woah. Ok so there’s a bit of debate here then. As I read the above it seems to be best to not twist the wire too tightly in the terminal do not tin it and then zip tie the wire to the frame as close to the terminal as possible?
What about at the bed end? Zip tie the wire to the frame near the bed on the y axis leaving enough loose for the bed to move?
@Nigel_Dickinson , I wasn’t saying anything about vibration and strain relief, just whether or not the wire should be tinned. I agree that for high vibration environments spring clamps and ferrules are best.
I think strain relief is absolutely necessary here, and wasn’t saying otherwise.
