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Head drops on older VMC

camaro_dan67

Aluminum
Joined
Dec 4, 2009
Location
N.E. Pa.
I have a 1984 Kiwa excel center. When I turn off the machine the head slowly drops down about a half inch. It looks l like the machine has a counterweight hanging down in the casting. Is there supposed to be something that holds the head when the machine gets shut off? I put a block of wood between the head and the table to avoid the position being wrong for the next start up.
 

Vancbiker

Diamond
Joined
Jan 5, 2014
Location
Vancouver, WA. USA
Some machines add a brake and others do not. If you don’t have a brake and all is well with the counterweight, add a little weight to it. Most have a couple tapped holes on top for lift eyes. Great spot to add some weight.

If you have a brake, fix or replace.
 

camaro_dan67

Aluminum
Joined
Dec 4, 2009
Location
N.E. Pa.
Would the brake be on the servo motor? I looked at the counterweight it just hangs from chains down in the casting. There is lots of space around it.
 

camaro_dan67

Aluminum
Joined
Dec 4, 2009
Location
N.E. Pa.
The servo motor has 2 connectors on it.
In my Kiwa manual it does have a section on setting the gibs. It says if they are to loose the incremental travel for one pulse will be to large and to small if to tight. I could try adjusting them.
 

Vancbiker

Diamond
Joined
Jan 5, 2014
Location
Vancouver, WA. USA
If the gibs are too tight it will be shown as a "sticky" motion. One pulse will not create movement equaling the commanded movement or may not create any motion and additional pulses will look jerky as the motor works hard to overcome the drag. If too loose the movement will be smooth and equal to the increment commanded rather than too large as your manual explains. Loose gibs show as head droop, lack of rigidity, positional errors etc.
 








 
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