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CNC machines questions (help)

Posted: Wed 24 Oct , 2007 19:56 pm
by Vlady
Thanks very much.

V

Posted: Fri 26 Oct , 2007 9:03 am
by Triac whizz
think I've seem all this over on cnczone perhaps last year.

the binary notation is unknown to me & I think completely irrelevant to using a cnc machine :lol:

transducer? encoder yes I've heard of linear is attached to table so table position known, rotary attached motor so position infered

mach datum, = home wher it knows where it is
prog datum known point of job

H/W vfd servos cpu

s/w cad cam.....

Now if you'd bothered to get up last thursday morning you'd probably have known all this :lol:

Why not ask the prof?

and write a thousand times google is your best friend

Posted: Fri 26 Oct , 2007 9:34 am
by Denford Admin
I wish I could have got the internet to do my homework for me :wink:
Q1. Explain the binary notation used in the application of a CNC Program.
This question seems to crop up every year - it must be a throw back to the olden days of punched tape or peg boards using a binary format to store CNC programs/commands
Q2. State the purpose of a rotary or linear transducer and list advantages and limitations of each.
A rotary position measuring devices (transducer or encoder) will suffer from mechanical and backlash measurement errors, but is cheaper.
A linear device will suffer from alignment errors, heat expansion and be expensive to make... but will be the most accurate over a distance.
Q3. Explain the purpose of the “program datum” and the relevance of the “machine datum” when setting up a CNC machine.

Program datum is the position that tells the CNC where the job is (which will vary).
Machine datum tells the CNC where a fixed postion is (eg home which should never vary).
Q4. Describe the hardware and software used in CNC system.
(Should I talk about machine spindles, transducers, slide drives, machine drives, spindle drives, leadscrews, machine spindles and tools for hardware and G-code? for software?)
Yes - how about covering CAD/CAM sw as well - show the whole process from design (CAD) to programming (CAM) to simulation (CAM or CNC) then manufacture (CNC).