Spindle on/off under CNC software control - safety worries!

[Wombilly]

as an ex employee of www.emachcnc.com we used to use m3 to turn on spindle and m5 to turn it off, the output from the controller switched a relay, for added safety we supplied the inverter via a contactor, whose coil was switched via a key switch, as far as the HSE were concerned, as long as the facility to remove a tool ( key ) to make safe the spindle, it was deemed safe to handle.

[m_c]

Maybe



(It's been a long week!)

[Christian Knuell]

Hi,

a time delay is quite hard to implement - and you'd also need something like a beeper telling you the timer started - otherwise you'd be facing the same trouble just a few seconds later.
Voltage spikes due to interferences are no problem - a mechanical contact will not act at all as the energy is much to low (and even if - it would fall back immediately) and a solid state relay will just switch on for one cycle and then stop again.

If you really worry about it put a switch into the control or power line as suggested before. However in case of a spindle with VFD: never put a switch between VFD and spindle - you'll kill the VFD if you accidentially switch while running.

Christian

[cropwell]

In my control box I have a 3 position switch - Auto (which goes thru the relay), Off and Manual. My greater concern is that LazyCam sometimes doesn't generate the M code to start the spindle, in which case I have to hit the E-stop before the tool breaks.