y axis question

[supershingler]

when my machine is homing and asks for a specific bit which i load as promoted. it does it touch down on the keyboard side and then goes to the bit plate side. when it comes back to the keyboard side after touching the bit plate it jumps back and forth a couple of time before it comes back to the keyboard side.

i just did a calibration but it didnt change anything. it seem to be carving alright but the back and forth motion isnt normal.

all help appreciated

kendall

[Digitalwoodshop]

When it is at the bit plate at the right, is the bit plate extended all the way out and more importantly did it touch the bit plate? The bit must touch the bit plate. If it misses because the bit plate did not come out all the way OR stop short of touching and reverse it could be dirt on the rails or chips in the Z Belt cogs.

Missed bit plate will give you a load bit message over and over because it thinks you did not load a bit.... The Computer looks at that bit plate tip hit to tell it the bit length and that there is a bit installed.

Most common reason that the bit plate did not come out is because the wires from the right cover switch are out of place and the Z Motor cooling fins are hitting it.

More on this search "bit loading" or "bit plate" using the " ".

OR.... If all this is normal with over 400 posts I see now it could be a worn Y Gear Box Bearing. Remove the Y motor and check the sleeve bearing on the Y gear box big plastic gear. The Sleeve wears and lets the big plastic gear rub in the U shaped area it sits in. It also skips teeth to. If you have a old Z Motor the gear box can be removed from it and placed with the gear on the Y motor for a cheap fix.

OR.... A bad Y Encoder

AL

[DocWheeler]

Al,

On the subject of encoders; I found that when stopping my machine to vacuum it out, I often got lines in my carving. I reasoned that the encoder was reading a slightly different depth for some reason and suspected dust was getting into it.
So - I decided to check it out. Being of advanced age and a bit "touched-in-the-head", I took the top off and removed the three machine screws from the back of the Z encoder. I found about a thimble-full of fine dust inside of it.
It was upon reassembly that I found that I had not noted (the old-fart problem) that the bottom two screws had nuts placed in the aluminum housing (that I had not seen and were now hiding somewhere).
In case anyone else makes that same mistake, get two 6-32 X 1" long flathead machine screws, they fit in the holes in the plastic cover and will self-thread into the aluminum housing!

[Digitalwoodshop]

Good Job Doc,

I wished LHR sold a variety pack of screws... I know I am missing some.

Here is a picture of the encoder for the New Guys. The encoder has lines in a clear disk and when the motor turns it counts pulses.

In one picture you can see the lines in the shadow from the sun.

AL

See in picture 1 how carbon dust builds up on the Encoder. This could cause Z Stall's.

[PCW]

Good Job Doc,

I wished LHR sold a variety pack of screws... I know I am missing some.

Here is a picture of the encoder for the New Guys. The encoder has lines in a clear disk and when the motor turns it counts pulses.

In one picture you can see the lines in the shadow from the sun.

AL

See in picture 1 how carbon dust builds up on the Encoder. This could cause Z Stall's.

Al

Thanks for the pictures and this is my first look at of the encoder. Servo motors are new to me. On my other CNC it has stepper motor's and that is what I am use to. It is a long learning process but at least it is enjoyable for me.

The servo's are a lot faster than the stepper motors by a long shot.