Denford Software & Machines

Microrouter Compact
S/N u00413-6
Dec. 2003
VR Milling v2.22

When the Z axis is homed, it moves to the limit switch but makes a loud grinding sound instead of stopping and the only way to stop it is to hit the escape key or open the guard. After this, the machine will not jog correctly. it only moves partially up or down.

The Home Switch for the Z axis maybe faulty or the switch is loose from its mount. The contacts are not opening properly and the stepper motor is stalling against a physical stop (the grinding noise).

The home switches are NC (Normally Closed). The machine homes by moving to the switch. When the machine pushes the switch, the contacts “open”, then the machine slowly backs away from the switch until the contacts “close”, now it knows it is at “Home”. When you “Home” the X, Y & Z axis’, you will see the machine move to the switch then slowly back off.

Turn the machine off. Use a vacuum cleaner around the switch then use compressed air to blow the remaining dust and chips out from the switch. You should then manually operate the switch several times quickly, you should hear/feel the contacts click as you operate the switch. You can also check the switch with a volt/ohm meter to make sure the contacts are opening and closing properly, if not a new home switch will be needed.

The Z Offset will have to be re-set after installing the new switch.

I think that fixed it. Thanks for the reply.

Hi, For your information. On later versions of VR Milling Ver 5, We have incorporated a testing procedure that will cut down on testing datum switches / their wiring and their input problems. Basically, in the Control Panel window in VR Milling Ver 5 while in the HOME section, press and hold in each datum switch in turn, if the correspondiing axis letter illuminates in Green in the Control Panel window, then you know that the datum switch, wiring and input is working. This little test will save you time and effort probing about with your electrical meter.