[weisyboy]

not quite cnc but i didn't know where to ask.

so iv gt a mobile Lucas sawmill that is operated manually. ie i walk back and forth all day pushing the frigin thing. [nomedia="http://www.youtube.com/watch?v=bYnpVAHi0oE&feature=fvw"]YouTube- Portable Sawmill[/nomedia]

i want to automate it. so it works like this one [nomedia="http://www.youtube.com/watch?v=a_yjXn4o5iU"]YouTube- Portable Sawmill - Automated Swingblade Mill (ASM)[/nomedia]


3 things need to be automated.

feed. forwards reverse variable speed. this moves the blade threw the log wile it cuts.


horizontal sizing. this moves the powerhead/blade across to adjust teh width of board that is cut.


blade swing. only needs to be horizontal or vertical.


Feed : i was thinking of running a chain down each track and running a drive shaft with a cog on each end along the front of the carriage and putting in a variable speed electric motor.

Blade Swing: i was planning on using a 2 way air ram/actuator to swing the blade over and back. but after researching on servos/steppers i have found electric actuators that could do the job and would eliminate the need for an air compressor. but i cant find any that are strong enough.

horasontal sizing: now this is the bit that has me stumped.

the mill has a chain running across the front and is moved by turning a handle (not fitted in pic)

i need to be able to move the power head accurately (withing bout 1mm or so).

it needs to be able to move from where it is (any point on rail) a set amount in either direction.
if im cutting a log into boards i need to be able to make movements of different amounts.

eg: make cut, move right 100mm, make cut, move right 50mm, make cut, move right 200mm, make cut, move right 38mm, make cut, move right 12mm, make cut, move left 12mm.

now that would be very hard if everything is indexed from one side.

i would really like to have a key pad that i can just key in the movement i need and it dose it.

i was thinking a stepper motor setup with a cog running on the chain. so that each step is 1mm or something. when 25mm is keyed in the motor dose 25 steps.

but then i was told that steppers are not accurate an i should use servos but i dont know how they work.

any ideas boys or am i dreaming.