@Nigel_Dickinson I never said anything about strain relief, In fact I said mount your board on the printer and make a loom.
I do really hate screw terminals. You are paying a price for added flexibility: the terminal connection quality is dependent on the user’s experience with the connectors, it is easy to get an inadequate mate(looks mechanically good, but only a few stands are mated), the connect doesn’t have in built strain relief, assemble time is longer, and it is not keyed allowing for improper wiring, and they can have concealed shorts. I accept that they typically have a high rated current and allow for flexibly in wiring.
Moral of the story, the experience you have with your printer is directly related to the electrical performance, if 3d printing is to be taken as more then a hobby then these screw terminals need to go away.
All Wire to Board connection systems have advantages and disadvantages. The Screw Terminal is an excellent way to connect a wire to a board with no extra tooling required. Screw Terminals are used in industrial applications all the time and are very reliable. Look on the back of any industrial PLC (Programmable Logic Controller). Anyone who “hates” screw terminals does so on purely “religious” grounds. If you “hate” screw terminals de-solder them and solder your wire directly to the board. But with out proper strain relief the wire will break anyway. Any other option using a “proper” connector would require all of us to go out and purchase an expensive crimper , and then we would get to hear all about “how to properly crimp a wire”. Followed by the inevitable “I hate Crimpers” religious rant.
@Camerin_hahn keeping in mind what @Jimmy_Edwards added, what type of connector do you prefer?
I like D-Sub, but they are expensive. They hand solder-able (not to mention crimp able). I don’t mind molex, typically i crimp then solder it, not the right way to do things. but there are a million different types of connectors in every shape and size for DC connection. I am not well versed in high current connectors.
My argument would be that the crimping should be done as part of making the kit, not by the end user. That would eliminate the discussion of “how to crimp the cable” and “everyone has to buy a crimp-er”. If you are building a kit the wire lengths shouldn’t be changing a tun. But really if you had to connect every wire on you car via screw terminals would you buy it? and if you have a screw terminal wiggle out and your car start on fire would it be the makers fault or yours?
PLCs are not meant to be manipulated common user, it is not designed to be in a home or work shop. It is designed to be used in a industrial control system. These systems are purchased, maintained, and operated by professionals in most cases. Printers are not being shipped to industrial work spaces and assembled by professionals who understand the finer points of screw terminals.
The difference between something that is a serious product and something that is a hobby is expectations, with screw terminals you cannot expect them to work without proper care and attention by the end user.
To be clear this isn’t a knock at the community, it isn’t a comment on quality or the staggering advancements that have been made by people here, it is a comment that right now the 3d printing is where computing was in the 70s-80s, and if kit makers want to become serious, they need to provide what the user expects in a finished product.
@Camerin_hahn I see your point and ALMOST agree regarding the connectors. It would be a LOT easier to just plug-n-play… But where do you stop there?
This is an electrical fault, because - as hobbyists, we aren’t all electricians…
We aren’t all mechanical fitters either - so - should every machine come assembled to reduce the risk of incorrectly assembled printers? Assembling my mendel and seeing what was involved in getting it to be true / square I was thinking the whole time: “God… this is… Involved! A LOT of people are going to have problems making mechanically-functional parts because they will be out of square / out of round / scaled incorrectly due to belt stretching / printers working at 50% capacity just because the axes are pre-loaded due to incorrect assembly.”
We aren’t all IT gurus either - but we’re expected to install software and printing profiles often by navigating system folders (I am fairly into IT - and I had to look up “how to’s” to copy my slic3r profiles from my mac to my PC)
And bottom line - we aren’t all 3D designers OR 3D printer operators - but hey if you can build it and you can hook it up and you can command it with software and you can produce G-code from an STL file… well you’ve probably got the sort of mind it takes to start 3D printing! 
I think this is the issue - I myself am REALLY sketchy on my electrical connections - if something fails, I won’t look at software or mechanical problems (unless I know they’re there) - If it’s not immediately obvious that I have a mechanical or software problem, it’s probably electrical…
I therefore, would LOVE better connectors on-board AND pre-crimped, prepared cables… But the next guy might think “Why? I can do it myself?”… THAT is what I think about assembling the mechanics of the printer… I do that at work every day, why would I want to pay for more difficult shipping and someone else to assemble it when I could do it myself, save money, save shipping costs AND learn all about the mechanics while I’m going along?
It’s difficult because it’s a kit that has to cater to ALL types of people. And there’s mechanical, electrical and software engineering at play here!
Thankfully I also know where all the electrical connections ARE (having built the printer) and know where to look for points of failure… If I had a ready-built printer I might not know this!
@Jarred_Baines you make a good point. We certainly don’t want to go too far with ‘finishing’ a kit purely because it insulates the user from the internal workings of the machine, and given how temperamental 3d printers are its almost essential to know how they work. This was one of my main problems with the Makerbot, they pitch it as a ‘turn key’ sort of device, but in reality it still needs lots of maintenance tweaking and modifications to get a good result from.
However, I do think there are things that should be improved in kits, especially where failure to do something properly can result in catastrophic results. If you mess up the mechanical assembly then chances are your machine just won’t work as intended, but its probably not going to completely destroy itself. If you fail to configure the software correctly you aren’t going to destroy anything, maybe waste a bit of filament but thats about it. Whereas if you mess up an electrical connection you can not only destroy your electrical hardware but run the risk of far more serious issues such as fire and injury.
@Ben_Delarre agree, the user definately needs to know how to and be able to maintain their printer. But equally they should not need to make too many design choices, your first printer is a step onto a massive learning curve and you should not be expected to choose everything correctly. This means it’s worthwhile getting the possibly only real dangerous part hard to get wrong.
I did get it wrong on my first printer, I made a Gen7 board and it uses a weedy molex connector for the HBP which fairly recently melted. Looked up the datasheet and it’s apparently only good for a few amps, not 11A!
My favourite at the moment is the screw terminal used on RAMPS (~12A). I’d like a higher rated connector but there isn’t one readily available enough that people can source it everywhere, that I know of. Answers on a postcard?
I’m going to replace the Gen7 (which is also corroding as there is no solder resist on it, just bare copper) with a Teensylu that has the screw terminals. I’m morally opposed to using a shield on an arduino for a non-prototype application. I did consider designing my own electronics board, but while it has things I don’t like, the Teensylu meets most of my requirements and is actually a fantastic layout, it would take my many iterations to better it. Also there are about 10 too many boards out there already.
Yeah, thinking about it, simple connectors would be good… It’s not like the end user is required to “check the straight rods with a micrometer and make sure they are round and the same size all along”…
That requires EVERY person making a printer to have a micrometer (at their extra cost) just to do this one task…
Same deal for the wiring… It’s not rocket science to crimp an end onto the cable - but it would save 1000’s of people from having to buy crimping tools!
First time I disassembled my hot end I looked at the directly-soldered wiring and thought “Oh… 
S#*%…” - I planned then-and-there to put a connector on near the hot-end to make it easier to fix / change later… (haven’t had to take it off since though
So I looked back at this thread and one of my long winded posts didn’T post. So brief summary.
I like dsub connectors, they can be either crimped or soldered and support up to 5 amps a line. I realize that that is less then screw terminals, but the connector is keyed. I posted a few other connectors Molex etc but I am not an expert on this subject. And I really don’t want to type that much on my phone.
Second, I posted about the difference between a hobby and a tool, rep rap printers are a hobby, if we want the kits to be considered a tool we need to meet the expectations for a tool. One expectation I have is that the electronics should not explode, another is fool proof wiring. Along with that the kits should have these connectors pre fitted, there should be no need to buy your own crimper. I realize that this does go against the rep rap mentality of everything being diy and self replicating. But really if you can make a quality hot end in your garage you probably can crimp a wire, but it makes the printer more accessible.
The difference between a improperly fitted screw terminal and a properly fitted on could be a house fire, where a improperly assembled printer will simply damage itself. The same goes with software mostly, if you are not mucking with the firmware safety settings, then the worst thing that most people do is run the hot end into something.
The moral of the story is not having connectors leaves the printer firmly in
Hobby territory, the expectation is that you will tinker with it. Changing to a pre fitted connector moves it towards serious tool.