[peteeng]

Hi TiBoy - I'm guessing the ratio, as in the video the belt is closed up in a casing. Unless its a gearbox but unlikely to be a gearbox. The quote max speed is 8000rpm so maybe its a 5000rpm servo and smaller ratio? They do steel with light cuts. The vids look good but there are machine aspects that are poor. Like they run the ballscrews directly to the motors with no thrust bearing, so motor life is at risk specially if shock loaded. They use a leadscrew for the Z for some reason as well. The machine assembly videos are quite good so you see how they are doing various bits of the machine. I suppose if its in a commercial environment and gets a few 1000 hrs on it the owners will know. It does have some vibration as in one vid you can clearly see the chatter in the finish then it gets cleared in the spring cut...

In regard to the pulley diameter you pick a small pulley that works then get a big pulley to suit. 3:1 is common on various things. So you must have a space problem?

There are heaps of routers cutting steel videos and small hobby mills that confuse me. But they are cutting light and fast. Then you maybe able to cut a few things but it must take its toll on the machine. There are even ShapeOKO cutting steel! But not like real mills. I'll have to give my router a shot at steel... Peter

Some thoughts:
1) Its a small machine with a heavy damp base. Many small machines like this are quite light so can get excited easily
2) The gantry rails are across the gantry diagonals. This makes the bearings as far apart as possible plus, it puts the moment centre through the shear centre of the gantry which is quite good. ie this geometry has the least twisting tendency
3) the saddle is highly webbed across the cars so is very stiff. That's if the real saddle looks like the CAD saddles on their site. I just found a picture of the saddle and it looks like an aluminium casting. very solid.

https://youtu.be/-g4_5-AmjpM

[Titaniumboy]

Hi TiBoy - I'm guessing the ratio, as in the video the belt is closed up in a casing. Unless its a gearbox but unlikely to be a gearbox. The quote max speed is 8000rpm so maybe its a 5000rpm servo and smaller ratio? They do steel with light cuts. The vids look good but there are machine aspects that are poor. Like they run the ballscrews directly to the motors with no thrust bearing, so motor life is at risk specially if shock loaded. They use a leadscrew for the Z for some reason as well. The machine assembly videos are quite good so you see how they are doing various bits of the machine. I suppose if its in a commercial environment and gets a few 1000 hrs on it the owners will know. It does have some vibration as in one vid you can clearly see the chatter in the finish then it gets cleared in the spring cut...

In regard to the pulley diameter you pick a small pulley that works then get a big pulley to suit. 3:1 is common on various things. So you must have a space problem

Thanks for your thoughts on the MR-1 and how it gets away with cutting steel. Doing super-slow baby cuts in steel isn’t really a problem for the home gamer if it means being able to make a part as versus not being able to make a part.

My mill uses 5M HTD pulleys and belt. The motor pulley is 63 teeth (94.7mm flange OD and 24.6mm inside flange width) and the spindle pulley is 38 teeth (64mm flange OD and 17.5mm inside flange width) with a 17mm wide HTD belt. The servo motor is 3000 rpm and 1.2kW.

I was told by Novakon that the spindle pulley couldn’t get any smaller because “the power of the servo motor is significant and to properly transfer the motor torque to the smaller pulley, the diameter and the number of teeth engaging the belt drive is a factor. There is not much room to enlarge the motor pulley and the size of the smaller spindle pulley can’t be reduced for practical reasons. To make the ratio any larger would also limit the maximum size that can be tapped due to loss of available torque delivered to the spindle”.

I would happily trade away some rigid tapping capability for increased rpm.

[Mogilogi]

The vids look good but there are machine aspects that are poor. Like they run the ballscrews directly to the motors with no thrust bearing, so motor life is at risk specially if shock loaded. They use a leadscrew for the Z for some reason as well.

Hi peter, this one of the places i will be fixing, will be using BK BF blocks to support the ballscrew to take the force away of the motor, having ballscrew for the z axis.

3) the saddle is highly webbed across the cars so is very stiff. That's if the real saddle looks like the CAD saddles on their site. I just found a picture of the saddle and it looks like an aluminium casting. very solid.

It's cast iron saddle as they mention.