direct driven or belt driven

[jeremy0203]

Gonna be converting my g0704 and was wondering if one is preferred over the other. I was planning on 570 motors.for all 3 axes. Besides the ability to use Dif pulley ratios and not sticking out as far would there be any other benefits to one over the other.

[rpovey]

With pulleys you can set trade speed for torque by changing the ratio.
With pulleys you don't need flexible couplers.
Direct drive is simpler, and has no issue with belts slipping/stretching.

Hoss seems to manage fine with 570's all around and direct drive Z, it's what I intend to do if/when my mill ever shows up.

[Starleper1]

Direct drive is a much simpler design and setup. You can get more torque with pulley reductions. You will lose some speed though.

I prefer belt driven. Looks cleaner, you don't have the motor sticking off the top of the column.

[woffler]

I am using both pulley on x and direct drive on y and pulley on z . As has already been said direct drive is always easier and less to go wrong, as far as set screws coming loose and belts stretching . A lot of guys are using belts and pulleys because they are using undersized motors that are cheaper ! and because of machine constraints the x motor would be in the way or something to that effect but the the pulley set up looks cool it just depends how much is in your budget .On a direct drive system you need a bearing housing a motor mount and a coupling .On a belt and pulley system you are going to have to buy or make pulleys and buy belts and believe me it can be a real headache trying to get the right ones the first time, it is just a lot simpler for a beginner to get started with direct drive and design your en-closer around your direct drive system if you intend to use flood coolant. Man that was a lot of hot air, good luck

[photomankc]

It's going to be a lot shorter path to getting going with direct drive and I can haul mine around at over 150IPM with 425oz steppers on my machine. I have not hit any mechanical limit just the software stepping limit on EMC at 8 microsteps. The 570 don't need reduction to cut or rapid so beyond the cleaner look and maybe less overall length I don't see the need. Aesthetics are part of it too though so if that's the way you want it looking and feel like spending the time, no reason not to.

[SCzEngrgGroup]

Belt reduction is typically used with servo motors, not steppers, as servos have lower torque, but higher RPM. The only reason to use belts with a stepper are to solve a packaging problem (to get the motor to a more convenient location), or to compensate for a poor component choice or system design (motors too small, load too high, inadequate motor drivers, inadequate power supply, etc.). If doing it for packaging, a 1:1 ratio would normally be used to avoid loss of top-end speed. You CAN trade off torque for speed, or vice-verse, but it's really far more economical, and a lot less work, to buy the RIGHT components from the start, and design the system properly. These forums are littered with posts from people who went "cheap" and spent a small fortune and a huge amount of time and effort dealing with an unreliable machine that is the inevitable result of scrimping on critical components and failing to follow good design practice.

Regards,
Ray L.