I have a hurco bmc 20 (19920 and im a newbie big time).
Here is my problem.
If i put an indicator in the head and zero it on an edge in Y. Then jog the Y axis with the wheel in tenths say in the positive direction, the indicator will read what the screen says. Now when i change direction (turn the wheel the other way) the indicator jumps .002" and the readout does not. as you continue turning both the indicator and the readout show the same amount of movement. Now you stop, as you just turn the wheel in the oposite direction it will do it again. then continue on reading the same distance change as the screen. (you can feel the table jerk if you rest your hand on it when you change the wheel direction) Of course the total distance moved is not close because of the jump at the direction change. The X axis does not do it, and the Z does not either. The problem just started today. Rebooted and no luck the problem is here for good. Has anyone seen this before, or have an idea of what direction i should be looking at for this issue?
thanks
Darren

Darren,
First of all I would check the couplings between the servo and the ball screw and the external encoder and servo. Pay special attention at the encoder to motor flex coupling for loose screws, leafs rivets, broken leafs. Be double sure that no backlash is present between the two.
Your BMC 20 should have a double set of encoders per axis, one is part of the servo motor, and the second is external, attached to the back of the servomotor, this is the one You shoud pay attention.
Also on Your next post let us have little more information about Your machine ... Year model, control type....color .... :-)
Somebody here will know

Good luck
A.M.

Thanks for the reply. The machine is a Hurco BMC-20. 1992 model year. Ultamax 3 controler. Its my first machining center so forgive me for having little knowlege about what we are talking about. lol Im going to pull the covers and inspect the flex coupling as you recomended.
Hopefully i dont make it worse! :)

Darren,

How did the inspection go?

A.M.

Sorry for the delay, been swamped at the shop. Ok i inspected the machine per your advise. Couldnt fnd anything wrong. I ended up calling a service tech in. He could not find an issue with the machine. However he compensated the y axis for the movement issue. It now works and repeats perfectly. I asked the tech if he could show me how to adjust the setting. He of course told me no and it was a Hurco tech trade secret..... WTF
Anyway he is eager to make service trip if ever i find it needs an adjustment again.
Does anyone know how to get to this scren on the Ultimax 3? Seems like a guy would want to be able to adjust if ever comping for machine wear over the years

Hi blown, what the tech guy really meant, but didn't want to offend you, was that he was a trained technical "expert", whereas it would be like pushing sh1t uphill with a sharp stick if he tried to explain the hows and whys of machine fixing, commonly called tricks of the trade.

Just be thankfull that with your limited knowledge you can only get better, and who knows, one day you will have the experience to know what makes the beastie tick, in the meantime, just a phone call away, there's a guy out there that will get the job right first time without having to ponder on the mysteries of the machine's innards.

The long and the short of it is, you can do more harm than good when a machine misbehaves, if you don't know what you are trying to fix.

This is a lesson to all who would pay little for a machine, expect big things of it, and then wonder why the end product isn't up to industry standards.
A pox on the cheap foreign imports.
Ian.

Hi blown, what the tech guy really meant, but didn't want to offend you, was that he was a trained technical "expert", whereas it would be like pushing sh1t uphill with a sharp stick if he tried to explain the hows and whys of machine fixing, commonly called tricks of the trade.

Just be thankfull that with your limited knowledge you can only get better, and who knows, one day you will have the experience to know what makes the beastie tick, in the meantime, just a phone call away, there's a guy out there that will get the job right first time without having to ponder on the mysteries of the machine's innards.

The long and the short of it is, you can do more harm than good when a machine misbehaves, if you don't know what you are trying to fix.

This is a lesson to all who would pay little for a machine, expect big things of it, and then wonder why the end product isn't up to industry standards.
A pox on the cheap foreign imports.
Ian.


That is what I call answering a question!:bs: Are you the Repair Man?

And now to answer what was asked! Yes there are accessible Screens that can be accessed to make adjustments. I don't know the access word but I will find out.
We have made adjustments on our BCM20 and VMC64 or numerous occasions when it was called for.