Denford Software & Machines

We are having problems with our microcompact router returning to home in the z axis. when home is pressed all it is doining is going down. also when page up or page down is pressed the vertical movment is very eratic. we have taken it apart and given every thing a good clean but it has not helped. Can anyone help with this?

Hi,

If the Z slide is moving downwards when homing then the chances are it is a fault on the home micro switch.

The home routine is for the slide to drive up at a fixed speed untill it hits the home switch and opens the switch contacts.

Once the switch is opened the axis reverses and drives down at a slower rate until it sees the switch close again.

In your case the switch is indicating it is open even though the switch is not actuated.

It could be that some dust is trapped under the switch contact.

Try vacuuming the switch but manually clicking it at the same time. as you click the switch any dust trapped under the contact will be released.

If you have a multimeter you can measure the contacts on ohms and actuate the switch (with the power off on the machine). You should see it go short then open. The switch normal status is Normally Closed (short).

the vertical movment is very eratic

This sounds more like a stepper drive or motor cabling problem...
You could start trying to work out what has failed by swapping the orange motor connectors with another axis,
eg,you will be driving the Z axis motor when you jog the X axis

If you still have a problem on the Z, then it must be the Z cables or the motor itself.

It could also be something to so with the brake - see this post for details:
viewtopic.php?t=456&highlight=compact

I agree with Admin, erratic axis movement is usually a broken motor wire. By removing the bottom Right Hand Side orange plug (Z axis motor) from the Baldor control card (The board with the 7 Segment display). The motor windings are in pairs and resistance reading between pins 1 and 2 should be the same as resistance reading between pins 3 and 4 if the motor wiring is OK (Usually around 2 Ohms). If there is a difference it usually is a broken wire

If the axis is moving slowly away from the home switch, then the home switch is stuck open. Usually just a good cleaning of the switch is all that is needed.
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 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 Z & Y axis you will see the machine move to the switch then slowly back off. If you use the false home and jog the X away from the switch then click on the X Home button (you will be able to manually push on the switch to open the contacts). The X axis should start to back away until you release the switch (close) then stop. The machine will think the X is homed.