motor and gear ratio question

[reefy86]

can i ask what the advantage is having say a 1605 ballscrew driven with a 1:1 ratio compared to being driven by the motor its self with no belt?

sorry if this sounds like a dumb question

[Muzzer]

The only obvious difference is that it allows you to install the motor in a more convenient position. You often don't want the motor sticking out on the end of the ballscrew. And in some cases, the table would clash with the motor.

[reefy86]

The only obvious difference is that it allows you to install the motor in a more convenient position. You often don't want the motor sticking out on the end of the ballscrew. And in some cases, the table would clash with the motor.

i thought as much but just needed to ask. thank you

[JAZZCNC]

There are two main reasons really, one of which can be very important if using older analog drives or really cheap nasty drives.

The main reason for a using belt connection is to reduce resonance which can and does affect performance on older stepper systems, resonance can cripple performance to the point it can half the speed of the machine.

The second reason is like what Muzzer suggested in that it allows the motor to be turned inside or placed to suit the machine better.

[reefy86]

There are two main reasons really, one of which can be very important if using older analog drives or really cheap nasty drives.

The main reason for a using belt connection is to reduce resonance which can and does affect performance on older stepper systems, resonance can cripple performance to the point it can half the speed of the machine.

The second reason is like what Muzzer suggested in that it allows the motor to be turned inside or placed to suit the machine better.

noted thanks again

[Muzzer]

It's worth noting that many of the smaller toothed pulleys seem to bear only a passing resemblance to the specified tooth profile. I'm talking about the things that are produced from lengths of toothed stock (made in a factory somewhere in China), then cut to the correct width and machined up with bores, bosses etc. I bought several of the HTD3 pulleys from reasonably reputable UK-based "bearing and pulley suppliers" recently and found that they all had narrower teeth / wider valleys than they should, with the result that I ended up with a lot of backlash. So this is another possible outcome from introducing a belt between the motor and ballscrew. The larger pitch pulleys from the likes of Fenner seem to be much more precise but there may not be room to fit one of those where it's needed. In the end, I had to make my own toothed pulley in order to get the final backlash down to a sensible level.