Servo/stepper size for Bridgeport w/ballscrews ?

[dfstrasser]

What size servo/stepper is required to run the X-Y axis on a Bridgeport type machine with ballscrews. I believe the table is 9X46 and the spindle is 2 hp. I have searched and have not found any general recommendations. I would like to go with servos but cost has to be taken into consideration. I will use Geckos for which ever I decide.

Any input is appreciated.

[Hood]

I used 916 oz/in steppers at 2:1 reduction on the manual Bridgeport I converted to CNC and then used the same motors at 2.5:1 on my Interact retrofit. Both work great with no problem, I get 2500mm/min on the Interact, the manual mill was a bit faster as it had less reduction.
Hood

[chevdrgtrk]

what about the size for servos? I found pulleys today for 1:1, 2:1, or 3:1 but I really don't want to go any further than that if at all possible, and I would like to drive the knee.......the X & Y, I have a pretty good idea, but what will it take to drive that knee? Also, mine is a little heavier with a 10x54 table

[NC Cams]

Any REASONABLY sized motor witll RUN the machine axis when you DIY retrofit them - thus, a SWAG motor selection could end up to be quite adequate.

HOWEVER, when it comes to fast rapids and abruptly quick accelerations, you need to consider how fast you ultimately want to move it in order to properly engineer the motor sizing and/or the gearing needed to connect them.

A more scientific way to SWAG the motor size is to match the motor sizing already being used on a machine with comparable performance that you're trying to achieve.

As far as Bridgeports go, the classic mill was fitted with fairly healthy servo motors when they did CNC variants that became Eztraks and/or V2XT's - I have one of each but don't know the motor sizes off hand. Can't speak for the stepper variants used on the machines that preceded them.

The following thread may also be of assisance to approximate motor size calculations:

http://www.cnczone.com/forums/showth...078#post214078

Specifically post #15

[Tywash]

Does an adapter plate need to be made for a BP Series1 Boss5 if I want to mount modern servos or is there a "bolt-on" option? I have read about needing a 5/8" shaft and that a Nema 42 is probably the best fit but not quite clear on whether this is a simple matter of taking off the 'old' and installing the 'new'.

[Dennis Storzek]

Bridgeport supplied 29 in./lbs. steppers with the Series I Boss machines, which have 2HP spindle motors. Centroid supplies 29 in./lbs. servos with their conversion kits, with 40 in./lbs. as an option. I'll leave the Imperial to metric conversion to you.

Dennis

[Tywash]

I am not talking about power. I was asking about the actual mounting plate sizes on the housings matching/bolting to the mounts on the mill.

[HillBilly]

http://ajaxcnc.com/cnc_components.htm

These are the 29 and 40 in./lbs. motors mentioned above and yes they are nema 42. I have bought them from Ajax to use on other equipment also. They are made by a well known English servo manufacturer.

Darek

[Tywash]

So you are saying "yes" these will bolt right onto a BP Series I CNC mill with no mounting plate needed? Just unbolt the old and bolt on the new?

[HillBilly]

Originally Posted by colin1544 Hello The boss 5 bridgeport with a ajax retrofit works great, the only thing you have to be prepared for is to get the keways on the timing belt pulleys that fit on the motors need to be opened up to 3/16" key as the origonal is a 3/32" woodroffe key. Also the motor mount on the Z axis needs a 1/8" spacer plate on the face as the bore in the casting is not big enough bore to accept the motor register boss. Apart from these points which are not mentioned in the instructions it is a relatively simple upgrade. GOOD LUCK Colin

I found this post.

Darek

[Tywash]

Thanks that really helps. So I am guessing from that the bolt patterns are the same. Does anyone know for sure?

[HillBilly]

This should verify it.

Darek