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Sharp SV-2412 Tool Change Problem

LOTT

Hot Rolled
Joined
Nov 28, 2016
Hey guys,

Question from a long time lurker/new poster- Our 2008 Sharp SV-2412 with Oi Mate-MC control has a tool changer issue. It seems the geneva cam that rotates the umbrella tool changer is stopping about 45 degrees out of line of where it should stop. It's working, stopping the magazine in the correct spot due to the nature of the the cam, but the cam lobe/sensor tab isn't under the sensor which causes an 1810 "MAGAZINE NOT IN POSITION" alarm.

You can hit the rotate magazine button and it moves fine, and the homing sensor for Tool 1 is fine (lights up when the stud is under it). If you hold a screwdriver up to the geneva cam sensor the alarm turns off, and you can see in the picture the cam is rotated further than needed past the sensor(which, again, still leaves the magazine in the correct spot).

Geneva Cam Labeled.jpg

It looks dirtier in the picture than it is, I'm fairly confident it's not a case of chips tripping the sensor. It's the sensor NOT seeing the lobe/sensor tab that seems to be the issue.

Further background- the machine came from another PM member and is in good shape, we've been running it daily with no issues since last year. It's running off a Phase Perfect and dried air. I've read through a number of other threads and haven't found anyone with this issue. And am waiting to hear back from the technical support at Sharp, I've talked to them (or him, singular?) before and he was very helpful.

So, anyone experience this before? Could the cam be loose and slipping on the shaft? I'd expect it to be keyed or splined, but don't actually know. Maybe some kind of electrical gremlin moving it out of position?

Thanks for any help.
 

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I think I have had this problem, but is has been a while.....I think your right about the shaft, there is a little shaft with a set screw and if it comes loose it will not stay in position, and alarm out.
 
Thanks Spock. We were going to tear into it Monday, and it started working fine. Ran all day yesterday with no issues, then this morning it's back to the same problem. I don't think it's going to be a huge expensive problem to fix, but it's sure a show stopper right now.

We're pulling some sheet metal off, see what the deal is.
 
Here's a picture of the top of the cam position sensor. The wires are bent over pretty good from the wire drag chain running over it. I don't think that's the current issue, but definitely something to be aware of.

Cam Sensor.jpg
 
....... and the homing sensor for Tool 1 is fine (lights up when the stud is under it)......

You really need to verify the signal of a prox sensor in Diagnostics. Just because the light is turning on and off does not mean that the input is being read by the control.

I suspect that there is a brake system on the geneva drive motor that is not working properly to stop motor before it overshoots the sensor. I'm not familiar with Sharp so can't say what method of braking they use. There are most commonly an electro-mechanical brake on the motor shaft or a "dynamic" brake where a separate contactor is used to short the 3 legs of the motor to themselves. I'd start looking there.

The sensor with the lead getting run over by the cable track is also something to look at. Even if it is still OK now, it will cause trouble somewhere down the line.
 
Vancbiker, I just talked to a repair tech (who wasn't familiar with this machine exactly, but seemed pretty sharp) and he said the same thing about the sensor triggering the brake and something in that chain of events failing.

I was really hoping for a stripped set screw, now I get to learn about FANUC Diagnostics....
 
Another problem I had with mine, was that a wire going to the carousel went bad, and I ran all new ones to the junction box. I guess that wire can only bend so many times....I cannot remember what problem that caused but you can test them easy enough.
 
I got through to Sharp technical support, they are pretty confident the brake is worn out and allowing the cam to over travel. A new brake is in the mail, we'll see if that solves it. I'll put some kind of shield over that bent sensor wire at the same time.
 
That wire may be chafed back where you can't see it. It will certainly chafe through the way it is sitting there now...

Prox sensors aren't that expensive, doesn't hurt to have a spare on hand.
 
That's a good point, and it looks like the same prox sensor is used in several places.
 
That's a good point, and it looks like the same prox sensor is used in several places.
I have 2 Sharps. My lathe has a sensor in the turret that I've had to replace. OMRON E2E-X1R5F1 2M

I keep a spare on hand, got'em from McMaster.

I haven't checked the mill, but I bet it's the same one.
 
I have a milltronics p1 that has the same style of tool changer and I went through a similar problem. Mine was a short which caused a fried prox sensor. You can get suitable replacements from automation direct if you can decode the part number of the one you have, specifically NPN or PNP and NO or NP, and sensing distance, body dia, etc. About $30 each, so I keep some spares since there are several at various locations on the machine and (on mine) they're all the same.

Sent from my SM-N960U using Tapatalk
 
To close out this thread:we installed the new brake and it hasn't faulted out since. Vancbiker was right about the brake not engaging fast enough to stop it in place.

Thanks for all the help!
 
Have a part number question for you spock

I’ve got a SV 2412-S that I think the clutch pack on the tool changer is going, is there anyway I can message you directly to talk about this? I’m on the hunt for the part number for a replacement unit & could use a little help if you have the time.
 
the older Sharp mills were made by FIRST and after sharp started making there own machine like 5 or 6 years ago the FIRST brand is selling under a TON of other brand names ,, it should be easy to get parts for it, one of the bigger resellers of FIRST mills is WEBB ,, I would contact them
 
I’ve got a SV 2412-S that I think the clutch pack on the tool changer is going, is there anyway I can message you directly to talk about this? I’m on the hunt for the part number for a replacement unit & could use a little help if you have the time.

When you say "clutch pack", are you talking about the brake on top of the motor that spins the tool carousel?

As of a year ago Sharp was still supporting these machines and sent me a new brake, but it's 2020 now so who knows...
 
When you say "clutch pack", are you talking about the brake on top of the motor that spins the tool carousel?

As of a year ago Sharp was still supporting these machines and sent me a new brake, but it's 2020 now so who knows...

Yes the brake, I’m dealing with an intermittent problem with the tool carousel (after a tool change or homing the machine) trigger wheel that trips the proximity sensor, It’s not stopping in the same place. Some times it will stop where it should, sometimes it stops 1/2” ahead of the sensor, or maybe it’ll stop just enough to trip it or a clean 1” off (which throws the 1810 alarm). Plus, should you be able to rotate that trigger wheel at all? I can easily move it 1/4” in either direction with my finger & the set screw is tight.

I pulled some part numbers off the side of the motor last night & am planning to call sharp for pricing but I was hoping someone would be able to verify I got the right info. I threw the numbers into the google box with no luck.
 
the older Sharp mills were made by FIRST and after sharp started making there own machine like 5 or 6 years ago the FIRST brand is selling under a TON of other brand names ,, it should be easy to get parts for it, one of the bigger resellers of FIRST mills is WEBB ,, I would contact them

You wouldn’t happen to have a contact name or number would you?
 








 
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