Encoder going bad?

[Captdave]

I have an 8025T control and when threading it sometimes waits before making another pass waiting on a signal other times it never misses a beat. It seems to be getting worse over the past couple of months that I have had to quit tapping with it.

I have cleaned and reseated all the connector pins and that hasn't helped. I'm not sure if the encoder is going bad or what? Are these brush type encoders that can be rebuilt or are they brush less throw a ways?

[karlbushnell]

if you think its the encoder you might want to try these guys...they rebuilt our real quick ...ORACLE ENCODER SERVICES LLC
(SOUNDS LIKE THE ENCODER TO ME TOO?!)

www.encoderservice.com

[Captdave]

The paper tag with the model number is long since worn off. Anyone have an idea as to who made these and possibly a model number or a suitable replacement? Its on an Accuslide Hardinge retrofit with a 8025 TG control.

Is there a way to bench test these?

[Al_The_Man]

If it pauses on threading, there is a possibility it is the marker pulse that may be dodgy.
If it is just a case of the encoder disk dirty, you might be lucky if you open it up and try cleaning the disk with a Qtip and denatured alcohol.
Al.

[Captdave]

This morning the plastic pulley that fits on the spindle broke into 3 pieces, may have been why I was having problems with threading, it may have been cracked and slipping on the spindle. I don't have a parts break down and I don't see anyway (fasteners) that this pulley attaches to the spindle. Is it just a snug fit or what?

Is Dynamic machine the only place to purchase parts for the Hardinge/Fagor machines?

[Fagor - Todd]

Encoder slippage on the shaft is the most common problem with these types of problems.... with most encoders, there is one marker pulse per revolution of the encoder..... when threading, the CNC enters the thread based upon its position. If it slips even a little bit, that thread is toast. Ask me how I know.

Usually its the set screw around the shaft......

As a note, if its a black encoder casing, it is more than likely a Fagor S 1024 encoder..... very common and in-stock at all times. (CMS/Upgrade used quite a few of them back in the day... but they also used others on occasion too)

good luck !

[Captdave]

Hi Todd,
I did talk to Paul at Dynamic Machine and he said that since it is still tracking the previous cut/thread, he feels like the encoder is fine it "just needs a tune up". He said to give him a call when I get it put back together and he'll walk me thru making some adjustments on the control. Not sure what he is talking about, perhaps adjusting a pot?

They did have a used pulley so hopefully I'll have it going by the end of next week.

I think I may have located an encoder if this is the correct one: http://www.cncnew.com/listings/32844.htm

[Captdave]

Got the new pulley and bored it to fit the spindle and it's back running a couple of days ago. Still has the delay like its waiting for something to catch up but right now I'm using the old school geometric die head and G36 to get the jobs finished. Hopefully I'll get a chance to get in contact with Paul an see what he may be able to help with.

[Captdave]

Replaced the spindle encoder but still has the pause when threading and now it's not following the previous thread. On the follow page (sub page of OP mode 0) its showing following error, but no additional info. Anyone know where to go from here?

I really need to get this fixed, we use it primarily for second op turning and threading almost daily.

[rcbuckwalter]

Capt Dave,
I just had the same problem with the pulley breaking into 3 pieces. It is the encoder pulley that slides over the rear of the spindle and drives the encoder. Has a 2.375" bore and 2 small holes drilled thru the OD that allow the bolts to bolt it to the spindle. Looks like it broke where the two small holes are drilled thru the OD.

Where did you ever find a pulley to replace yours? I'm looking but not finding.