[Pritch]

Hello all i have recently purchased a Bridgeport series 2 and i would like to retrofit this machine myself i can do all the computer stuff but the part i am getting stuck on is:

what servo motors to get

whats the best kind of mounting hardware to use for the motors

IS it better to use the quill for the z axis cnc control or the knee? (i know there is air assisted for knee type)

This machine was never a BOSS or any type of factory CNC

any further information in general will help

[hitachibos]

i have used Anilam several times to do what your thinking.

They sell a retro kit that includes a ballscrew for X and Y,
motors for X Y Z
mounting brackets for motors
a control with some very easy to use cycles (or you can write G-code)


and the Z drives the quill not the knee

here is a link download the brochure

Anilam :: 3000M For Milling Applications

[Pritch]

what kind of servo motors did you use?
from the extensive reading i have done i think i need a servo capable of 50 in/p of torque saw them for about 650 odd dollars that run on 240 volt power
what do you think?
im thinking about going the mach3 option with a computer i'll build myself out of parts i have running around atm

[Pritch]

so after some more dredging the internet for answers i came up with the following:

gecko g320 drivers 3 of

KL34-180-90 (NEMA 34) Dual Shaft, Front Shaft
1/2"Rear shaft 1/4" 1125 oz-in Peak 90V/40A, $149 DC servo motors 3 of

Smooth stepper USB controler board to go from the computer to the break out board which will be a

CNC4PC C11 Break out board


hopefully these components will put me on the right track lol

[brian257]

I would not do a stepper system. I would use DC servos. Years ago it was a lot less expensive to do stepper, but much better today to use servo. I am using the NMEA 34 motors from Automation Technologies. They sell kits here High-Torque Stepper Motor, Stepper Motor, Driver, Stepper Motor kit, DC Servo Motor, DC Servo Motor kit, Stepper Motor Power Supply, CNC Router, Spindle, and other Components. Automation Technology Inc. Not sure why they have four in the kit, I bought separate parts and am using three. Bought one of each to test everything and will buy the other two axis soon.

I am doing the knee. The motor would not lift the knee reliably without some assistance, but I added two pneumatic cylinders from Automation Direct and now it has all the power it needs. Actually helps when going up and down.

For ball screws I used the Rockwell Automation screws. I also used their bearings.

If you search you will find a thread I started on my conversion with information. Good luck!

[Pritch]

Hey Brian that sounds like a go on those servo motors ended up going with this kit:

High-Torque Stepper Motor, Stepper Motor, Driver, Stepper Motor kit, DC Servo Motor, DC Servo Motor kit, Stepper Motor Power Supply, CNC Router, Spindle, and other Components. Automation Technology Inc

and added this smooth stepper PC to usb to breakout board

SmoothStepper USB Motion Control Board for Mach 3 Automation Technology Inc

The thing im wondering on now are what pneumatics did you use as this will need to be addressed in my retrofit

and also how did you fit the motors to the machine?

Cheers

[brian257]

These are the cylinders I got:A32140DD | Air Cylinder: round body, 2 inch bore, 14 inch stroke

They are 14" long cylinders, but I should have gotten the 12" because now my knee comes about 2" short of going all the way down. I could probably modify the brackets, but easier to just get new cylinders. I will try to remember to take some pictures of the mounting and put them here tonight. I have them connected to a Harbor Freight portable air tank and I pump that up to about 100 PSI.

So far I have only made a motor mount for the knee because I wanted to make sure the motors were powerful enough for the knee before I put them on the X and Y. I just used a 4" X 1/4" aluminum plate to mount the motor. I will try to take a picture of that tonight also. Pulleys and belts came from Stock Drive Products. I got a few different sizes and have not played with them enough yet to determine exactly what gear ratio gives me the most speed and still has enough torque.

I didn't realize that Automation Technologies had that USB board. Looks like a much better way than doing parallel ports. I have looked at a few controller boards that other companies make, but have not tried one. Let us know how that board works and what kind of speed you can get from it.

I moved in October and have been spending all my time building a new machine shop, electronics shop, and office in my hanger and making mods to my plane and it is about time to get back to working on the machine.


http://www.cnczone.com/forums/bridge...ml#post1124525
http://www.cnczone.com/forums/bridge...onversion.html
http://www.cnczone.com/forums/bridge...ml#post1124489

[Pritch]

Do you think these would be suitable/?

A32120DD-M | Air Cylinder: round body, 2 inch bore, 12 inch stroke

awesome amount of info the mounts are going to be fun to machine when i get it powered tomorrow im looking at the old stepper motors that will never be used (its a shame they are 3 phase)

im putting a to get list together this'll be fun i remember buying think it was 30 items in 2 days the postie was getting sick of knockin on me door

[mactec54]

brian257
I am doing the knee.

That's not a good idea, they are not designed to be used as a Z axes, it can be powered for positioning

[Pritch]

i recall reading somewhere that factory made bridgeports that had cnc had a pneumatic lift in the z axis knee to assist with servo/stepper motor automation whats wrong with the idea?

my current motors have a z axis stepper motor attached to em but i severly doubt i will be able to power it with the current setup



Brian i was wondering what was the site for the ballscrews and hardware?

some photos of your pneumatic set up would be very interesting to see

so far have decided on this list of gear

3-Axis NEMA34 1125oz in 72V/20A PSU G320X Gecko Driver $1230
SmoothStepper USB Motion Control Board for Mach 3 $155
A32120DD-M CYLINDER 2in BORE 12in STROKE DBL ACTING DBL END MOUNT MAG PISTON $95

[mactec54]

Pritch
i recall reading somewhere that factory made bridgeports that had cnc had a pneumatic lift

That is correct but it was only powered for positioning, not for use as a Z axes, ( it also moved very slow )

The column & contact area of knee was, not designed to move any faster than with the crank handle for the knee, when they are powered & used as a Z axes they ware the column really fast

Powered & used for positioning is OK, there are some Zone members that have done this before mostly only for positioning

[brian257]

Get the A32120DD, not the one with the -M at the end. the -m has a magnetic piston for position sensors and the price is a bit higher so unless you need the sensor go with the cheaper one. I also got the pivot mounting brackets and rod clevis from them.

Do you think these would be suitable/?

A32120DD-M | Air Cylinder: round body, 2 inch bore, 12 inch stroke

awesome amount of info the mounts are going to be fun to machine when i get it powered tomorrow im looking at the old stepper motors that will never be used (its a shame they are 3 phase)

im putting a to get list together this'll be fun i remember buying think it was 30 items in 2 days the postie was getting sick of knockin on me door

[brian257]

Nothing wrong with CNC on the knee that I know of. Several people have done it with good results.

For the ballscrews and bearings I used Rockford. Bridgeport Kits - Rockford Ball Screw

Their bearing kit is BRP-7204. They don't say it, but the kit includes both the X and Y bearings so you only need one kit. I just returned the second one I bought by mistake. Best to buy the screws and bearings through H&W Machine Repair. I deal with Debbi there and she is great.

Make sure that you get the right X axis screw. The Bridgeport power feeds have the screw short on the power feed end and no hand wheel mounting on the feed end. If you have no power feed or a retrofit power feed then you need the type of screw that has the handle mounts at both ends.

I also recommend that you order the lead chart with the screws. That gives you measurements of the innacuracy of the screw so you can program that into Mach 3 and compensate for any innacuracy. It must be ordered with the screws since if you don't order it they will not measure the screws and you will have to ship them back to get a chart later.

i recall reading somewhere that factory made bridgeports that had cnc had a pneumatic lift in the z axis knee to assist with servo/stepper motor automation whats wrong with the idea?

my current motors have a z axis stepper motor attached to em but i severly doubt i will be able to power it with the current setup



Brian i was wondering what was the site for the ballscrews and hardware?

some photos of your pneumatic set up would be very interesting to see

so far have decided on this list of gear

3-Axis NEMA34 1125oz in 72V/20A PSU G320X Gecko Driver $1230
SmoothStepper USB Motion Control Board for Mach 3 $155
A32120DD-M CYLINDER 2in BORE 12in STROKE DBL ACTING DBL END MOUNT MAG PISTON $95

[brian257]

I agree that you will wear out the Z axis faster if you are drilling a zillion holes and move the axis fast all the time, but I think for the average home machinist not running the machine all the time that it will be fine and you won't have near as much Z axis movement as you would with a manual operated machine that is in a shop working 8 hours a day. I do think that a properly working oiling system must be used on all axis when converting the machine to CNC.

Oh, remember to order some new wodruff keys for the screws. You will likely have to beat out the old ones and they tend to wear anyway so best to get new. You can find the part number on the H&W web site. You will also need some extra oiler line to go to the new ball screw nuts and maybe some fittings sinch the old lines don't reach the nuts where they connect.

Pritch
i recall reading somewhere that factory made bridgeports that had cnc had a pneumatic lift

That is correct but it was only powered for positioning, not for use as a Z axes, ( it also moved very slow )

The column & contact area of knee was, not designed to move any faster than with the crank handle for the knee, when they are powered & used as a Z axes they ware the column really fast

Powered & used for positioning is OK, there are some Zone members that have done this before mostly only for positioning

[mactec54]

brian257
I also recommend that you order the lead chart with the screws. That gives you measurements of the inaccuracy of the screw so you can program that into Mach 3 and compensate for any inaccuracy.

Mach 3 does not do a good job at doing this, if you are successful in doing this, there is a lot of other people that would like to know how you achieved it

[Pritch]

the majority of the z axis works going to be moving small increments anywhere from .2 mm to 3mm but then again if i get it working perfectly i might do some helical milling also but the majority of its working life is going to be small movements not this huge up down hole drilling stuff if i have to do alot of that i will probably use the cnc to put the work piece where i need it then just use the spindle handle to manually drill

i really wanna see some photos though it should be good to see what people have done

[brian257]

Here are some pictures of the cylinders and attachment. The bottom brackets are the ones that Automation Direct sells for the cylinders. The top forks come from Automation Direct. The brackets I made of steel.

The motor mount for the Z was just made from an aluminum plate. I was thinking it would be temporary just to figure out what pulleys I need and make sure it works OK, but it works pretty good. Might add some sides to it to make it less flexible and maybe a plexiglass guard for the belt. There are pictures of others that people have done here that look good.