DIY CNC

Cool, I will probably go with the parallel port in the meantime, then. I should have enough I/O with the parallel port to control my x, y, and z axes and my spindle, right? I'm just looking for a yes or no regarding the timing issue and whether it would be a problem or not in making that part (assuming I have 15000-20000 nanoseconds jitter).

Logthor wrote:

Cool, I will probably go with the parallel port in the meantime, then. I should have enough I/O with the parallel port to control my x, y, and z axes and my spindle, right? I'm just looking for a yes or no regarding the timing issue and whether it would be a problem or not in making that part (assuming I have 15000-20000 nanoseconds jitter).

Yes, I have started a video series on a parallel port control board from scratch. This is the first of 3

This is new for me as I've only used Mesa and Ethercat before.
Spindle is working fine with 0-10v control, There is enough inputs for estop, probe, home switches and outputs for coolant, mist etc so it will be complete.

The plan is to redo the spindle to use RS485 Modus and eventually migrate it to Mesa and even Ethercat. This is more of a training video than for a specific machine although I'll eventually build one for it.

 

Anecdotal evidence: I had issues getting a 100ppr encoder to work reliable at 600 rpm. The cheap BOB seemed the issue, the system was loosing signals.

The Mesa Card fixed the problem and I have not the slightest interest in trying to figure out what went wrong, only point (I should have spent the money earlier)

20000 pulses (if I am correct and did not make a mistake) It would limit a 1/8th 200ppr stepper motor with my lead screw (4mm pitch) to approx. 3000mm/min. This is in my book good enough for a sherline, but some commercial machines run approx. 10x that speed.

@logthor: The stl you posted, will be a nightmare to machine .

For the simple stuff I'm doing with my bob, I don't think it'll be an issue. I'm well aware of what a nightmare it'll be to machine. The model needs a lot of love.

zeeshaninsight wrote:

@logthor: The stl you posted, will be a nightmare to machine .

Glad someone else looked!

With some spindles, its not possible to fit an encoder (I've had a couple) but thread milling solves the thread cutting dilema on all machines and is much easier on small machines.

rodw wrote:

... but thread milling solves the thread cutting dilema on all machines and is much easier on small machines.

Those things are magnificent and make tapping possible on low torque/power spindles.