bp serie1 cnc conversion

[Himse]

hello to you all ..
i have during the last month convertet my old bp serie 1to cnc with mach 3

The machine is 28 years old i`ve bought 1 year ago ..for 25 years it had been milling cast iron .

This is the first time i`ve worked with motion control and cnc so i will proberly make alot of mistakes.. but learning by doing...

I started by getting a computer from work a dell 2.8 ghz 1gb ram ... that or to
be enough

I bought 3 12nm nema34 step motors with drivers from motioncontrol
http://www.motioncontrolproducts.co.uk/

I have geard them 5-1 with ribb belt for more torque and less speed. see pic ..

I use the knee for z axis. as chich2 suggeted i mounted 2 63mm pneumatik pistons ( stroke 400 mm) to overcome the weight of the knee ...
works like a chame .. rapid feed 1500 mm/min .. repeat acuracy 0,02mm

The y axis ways is worn so the table can twist a little . so i plan to mount a set of hepco inear rails like THK HSR.. i now this will raise the table some but i can live with that...
I have a repeat acuracy at 0,01 mm and a rapid feed of 2000 mm/min fine for now...

The x axis ways is not worn...but the lead screw is worn out.. 0,4mm backlash so i have to buy a new ball screw ..

I plan to mount the rails at the same time as i change the lead screw to a ball screw.. i might as well change both lead screws to ball screws

I have also bought a mpg from cnc4pc but havent installt it yet..

More to come ...
Rasmus

[klxrcr]

pneumatik.... I like it, thats way better than we spell it in English!

I know steppers are not that fast, but what kind of feedrate can you get (on x & y) with the 5 to 1 reduction? Do you expect to have any backlash/vibration problem with the air assisted knee and an acme screw?
Looks good but I'd take the sharp corners off of the motor mount plates.

I'm working on a series 1 retro right now and am thinking about using the knee because I don't trust an extended unlocked quill.

25years of milling cast iron, sounds dusty.

keep up the good work!

[Himse]

I use microstepcontroller at 800 step/rev . that givs a max rapid speed of
approx 3000mm/min but i have set the max for both x and y axis at 2000 mm/min = approx 78in/min.
not much but fine for now ..

I dont use the pneumatik piston to lift the knee.. just asist to lift the knee .. the knee weighs approx 250 kg with table .. i use a vented air regulator at 45-75 psi .. that remove most of the weight but not all so gravety eliminats backlash ...

About the sharp corners .. thay have been boxed in to keep stuff out of the belt ..