[Jason3]

Heh, no - it's not speeded up (and I did apologise for the camera work...) Programmed feedrate was 9,000 mm/min, of course it will not maintain that at sharp changes of direction.

As Ray says, it's cutting wood - not a difficult cut by any means. My point in showing it was only to illustrate why a mill that can follow the programmed path accurately at higher feed rates might be beneficial when cutting complex 3D surfaces, that being relevant since the OP has said he cannot easily accommodate a 1,000 lb machine.

Regards,

Jason

[bebob1]

You simply CAN'T lump all dovetail machines into the same bin! The quality of the dovetails makes a HUGE difference. And the Tormach has Turcite on the ways, which also makes a HUGE difference, greatly reducing sliding friction, and allowing the ways to be tightened up much further before stiction becomes a problem. The difference in quality, and precision, between the typical Chinese mill with milled dovetails, and something like a Tormach with precision-ground Turcite-coated ways is night and day, and can easily be better than a poorly build machine with linear ways.

Regards,
Ray L.

Did you read the post at all? At what point did I 'lump them all together in the same bin'. My response was pretty measured and fair. I informed the OP that tormach uses dovetails. It may seem obvious he didnt yet know that considering his OP said he didnt like dovetails yet talked about getting a tormach.

[kd4gij]

I was working on a racing gocart For my son. Looking at the wheel hubs and bearing blocksand outher parts I thought It would be esay way to make alittle extra cash as I have the machines to do it. Ha. checked the prices on line and was shocked. $26.99 for a pair of front hubs with bearings. The material would cost me more than that. Not trying to discurage just saying.

[bebob1]

Heh, no - it's not speeded up (and I did apologise for the camera work...) Programmed feedrate was 9,000 mm/min, of course it will not maintain that at sharp changes of direction.

As Ray says, it's cutting wood - not a difficult cut by any means. My point in showing it was only to illustrate why a mill that can follow the programmed path accurately at higher feed rates might be beneficial when cutting complex 3D surfaces, that being relevant since the OP has said he cannot easily accommodate a 1,000 lb machine.

Regards,

Jason

Its a nice looking mill.

Thats pretty fast if its in real time, but even if it was programmed for 9000mm/min feed its probably never actually reaching full speed provided the cut part seems quite small?

The video looks to me to be sped up though. Since it does shake quite dramatically. Its hard to imagine someone unnaturally shaking that much holding a camera. The video would make more sense if it was sped up since the natural manual shaking is exagerated once the video is sped up.

But you said you geared it up to increase the speed of travel as a function of servo rotation? Doesnt resolution of cutting deteriorate when you increase the speed especially resolution is lowered if you gear it up since each degree of rotation of the servo generates a larger displacement? Normally for high accuracy you should lower the feed rate right? Especially considering the degree of look-ahead your controller has? What controller do you use for driving the servos? Delta Tau?

[Jason3]

Its a nice looking mill.

Thats pretty fast if its in real time, but even if it was programmed for 9000mm/min feed its probably never actually reaching full speed provided the cut part seems quite small?

The video looks to me to be sped up though. Since it does shake quite dramatically. Its hard to imagine someone unnaturally shaking that much holding a camera. The video would make more sense if it was sped up since the natural manual shaking is exagerated once the video is sped up.

But you said you geared it up to increase the speed of travel as a function of servo rotation? Doesnt resolution of cutting deteriorate when you increase the speed especially resolution is lowered if you gear it up since each degree of rotation of the servo generates a larger displacement? Normally for high accuracy you should lower the feed rate right? Especially considering the degree of look-ahead your controller has? What controller do you use for driving the servos? Delta Tau?

Yep, it will be reaching full speed - or close to it - though not when contouring the sloping parts on the planar finishing pass as the top is not rounded so there's a sudden change of direction. It is a small part, but that was the point. I was optimising the acceleration settings, for some of my customers running their machine hours a day on parts that size this stuff really matters.

As for the camera shake - well, what can I say. I don't know why it was shaking like that. Too much coffee in the cameraperson? I have a video cutting the same part in plastic somewhere, with a stopwatch stuck to the table for skeptics...

The motors are direct drive to the ball screws, there's no physical gearing. I was referring to the electronic gearing (or input scaling) within the servo drive, where the commanded move is multiplied and divided by a specified ratio. This does not change the pitch of the ball screw or the resolution of the encoder - the drive still sees the full resolution, and will keep the motor rotation accurate within the specified error limit.

Anyway, we are getting a bit off topic. Well sort of...

Regards,

Jason

[RobbyA]

The prices of the wheels and parts that you can buy is incredibly cheap. My stumbling block is how suitable the parts are for my particular application. eg: the brake mounts on the parts I'm looking at are too light on for circuit racing. A lot of existing parts I can use from other racing applications, but some are just not suitable.
Jason, can you PM me with some pricing for a machine base, and also for servo packages and spindle packages.
Regards
Rob