Quote Originally Posted by Trakyan View Post
Linear rails aren't bad, but I feel like it's a bit of a sledgehammer to swat a fly scenario. Lots of printers with round rails produce great results, even ones that are indistinguishable from those made on printers with linear rails. It's up to you, but I feel that many people go for linear rails because for the same reason they like to buy fancy cars. At the end of the day you're squirting molten plastic from a 0.4mm bore, and 0.2 is considered a good fitting tolerance, if your round rail can't hold that tolerance it's bent. The biggest practical advantage linear rails have on a 3D printer is that they can be fully supported, so on longer spans there isn't the bendy and flexible bit in the middle that can wobble under inertial forces (or sag if its not appropriated sized, but the rails on a delta are vertical so they wont sag).

This is even more so the case with idlers, pulleys and belts, the cheap stuff from china works fine and is manufactured to much higher tolerances than your printer will be outputting. Belts can sometimes cause problems from what I've heard with the rubber wearing off the belt, or not having fibre reinforcement but I've never run into these issues myself. Any difference someone claims between a chinese idler bearing and a name brand one is entirely in their head.


I don't know how much money, if any, you'll save buying a 24V bed vs line voltage, but at that size/power requirement I can virtually guarantee you'll spend more money than you saved on a 24V power supply that can handle that much current.
The reason for the linear rails has been gone over but it's also to enable a speed increase basically. The more sturdy and less flex the faster you can print without losing resolution.

As for the idlers/pulleys and belts, belts are important because the cheaper the belt the less fiber and more elasticity which is bad for accuracy and print resolution. The idlers and pulleys themselves are fine buying cheap but its the bearings that make the difference. I bought a bunch of cheap ones and all the bearings were crunchy and not smooth. They would be better to just use bushings than terrible bearings. I ended up going to the hobby store and buying good RC car bearings and fixed the issue but its a pain. better to just buy decent ones with better bearings.

While these things all seem like small details, they add up and end up compounding to cause problems that can be avoided.

For the heated bed, I completely agree it would probably be cheaper to buy the mosfet than to buy a 24V power supply that would do the job. I'll probably do that.