Haas VF2 Dropping Tools on Tool Change - Shuttle never Advances

[runninwideopen]

Hello,

I have a 2000 Haas VF2 with 5811 hours on it. It has begun dropping tools on tool change about 20% of the time.

1. Call for tool change
2. Spindle moves up into position
3. Shuttle does NOT move in
4. Spindle releases tool, dropping it on the part below
5. Carousel rotates to new tool. (shuttle still in out position)
6. Shuttle jolts out, then back in, less than .5in
7. Machine continues operation, without tool in spindle.

No codes or red light.

I've already replaced all of the tool changer relays and cleaned the shuttle position switches the best I could.

I can't see how it could be the position switch, because if the "in" switch was stuck the machine should throw a code and stop running - it wouldn't bring the spindle back down and keep going if it thinks the shuttle is still in the in-position.

Any input or advice would be greatly appreciated! Thanks.

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[Ydna]

I don't have much experience troubleshooting a problem like this, but from your description it sounds like the shuttle-move section of the logic sequence is happenning at the wrong time. It seems like this is exactly what would happen if the "shuttle in" switch was being triggered all the time, or if the switch was wired backwards, or something. I know you mentioned replacing the switches but it seems realllllly coincidental! (but it could be a wiring problem too)

Have you tried looking in the machine's parameters screen to monitor the inputs for the tool changer? You'd probably need help from somebody else but one of you could hit the switches manually while the other guy watches the input screen for the bits to change. It might reveal something out of whack...

[haastec]

Sounds like the shuttle in/out switches to me.

While looking on the diagnostics page, manually toggle the switches and monitor for correct action.

Another posibility is the arm that brings the shuttle in/out has become disconnected from the shuttle casting. There is a roller bearing at the end of the arm that engages the shuttle casting. I have seen this roller bearing unscrew itself before.

Good luck and be sure to report back what you find.

[Machineit]

Haastec is most likely right with the switches being the issue. Spray some light oil or solvent on each one and cycle them in and out by hand and get them loosened up. Machine off of course, and then power up and try it again. I have seen this exact problem before. If that is it, get new switches as it usually will reoccur with old switches that get worn.

Mike

[runninwideopen]

Thanks for the reply. I only replaced the relays, and that was after the problem had already started. I've only cleaned the in/out switches. I will take a closer look at those on the param page and report back.

[runninwideopen]

Hey guys,

Thanks for the responses. We've spent the afternoon looking at the switches, and fortunately I was just able to recreate the issue. Unfortunately, I believe that rules out the switches which are an easy/cheap fix.

We created a tool change program that does nothing but change tools over and over again. On the diagnostic page, I was able to confirm that the switches appear to be working properly and don't seem to be sticking at all. The release to 0 as soon at the shuttle moves off of them.

Here is why I believe I've ruled out the switches:
In the middle of this tool change program, the problem occurred in the following sequence
Hey guys,

Thanks for the responses. We've spent the afternoon looking at the switches, and fortunately I was just able to recreate the issue. Unfortunately, I believe that rules out the switches which are an easy/cheap fix.

We created a tool change program that does nothing but change tools over and over again. On the diagnostic page, I was able to confirm that the switches appear to be working properly and don't seem to be sticking at all. The release to 0 as soon at the shuttle moves off of them.

Here is why I believe I've ruled out the switches:
In the middle of this tool change program, the problem occurred in the following sequence

1. Call for tool change
2. Spindle moves up into position
3. Shuttle moves in slightly, <.5". Just enough for the Out-Switch to show 0.
4. The In-Switch still showed 0 - as it had since the shuttle retracted after the previous tool change.
5. Spindle releases tool, dropping it on the part below
6. Carousel rotates to new tool. (shuttle still in out position)
7. Shuttle moves back out slightly until Out-Switch shows 1.
8. Machine continues operation, without tool in spindle.

So, in my first observation I missed point #3. In this observation, I was clearly able to see that the In-Switch was NOT telling the machine that the shuttle had moved into position before it had released the tool.

Anything else I can look at?

Thanks!

Tom

[haastec]

Hey guys,

Thanks for the responses. We've spent the afternoon looking at the switches, and fortunately I was just able to recreate the issue. Unfortunately, I believe that rules out the switches which are an easy/cheap fix.

We created a tool change program that does nothing but change tools over and over again. On the diagnostic page, I was able to confirm that the switches appear to be working properly and don't seem to be sticking at all. The release to 0 as soon at the shuttle moves off of them.

Here is why I believe I've ruled out the switches:
In the middle of this tool change program, the problem occurred in the following sequence
Hey guys,

Thanks for the responses. We've spent the afternoon looking at the switches, and fortunately I was just able to recreate the issue. Unfortunately, I believe that rules out the switches which are an easy/cheap fix.

We created a tool change program that does nothing but change tools over and over again. On the diagnostic page, I was able to confirm that the switches appear to be working properly and don't seem to be sticking at all. The release to 0 as soon at the shuttle moves off of them.

Here is why I believe I've ruled out the switches:
In the middle of this tool change program, the problem occurred in the following sequence

1. Call for tool change
2. Spindle moves up into position
3. Shuttle moves in slightly, <.5". Just enough for the Out-Switch to show 0.
4. The In-Switch still showed 0 - as it had since the shuttle retracted after the previous tool change.
5. Spindle releases tool, dropping it on the part below
6. Carousel rotates to new tool. (shuttle still in out position)
7. Shuttle moves back out slightly until Out-Switch shows 1.
8. Machine continues operation, without tool in spindle.

So, in my first observation I missed point #3. In this observation, I was clearly able to see that the In-Switch was NOT telling the machine that the shuttle had moved into position before it had released the tool.

Anything else I can look at?

Thanks!

Tom

You need to be able to manually toggle the switches by hand and watch the diagnostics screen at the same time. You are looking for any lag in time for the switch to change from 0-1 or 1-0. The other thing you are looking for is the switch to have the wrong reading either 1 or 0 at the wrong time. This could mean something internal to the switch is causing a false trigger or release.

I am still pretty sure you are looking at a switch issue, but you are not going to see it by testing the way you did.

[runninwideopen]

Hello,

I did do a manual test too by pressing the switches with my fingers and neither switch ever delayed to respond or showed the wrong value.

After that is when I did the test I described. Could you explain why that test wouldnt be definitive the way that we did it?

Thanks.

[haastec]

Hello,

I did do a manual test too by pressing the switches with my fingers and neither switch ever delayed to respond or showed the wrong value.

After that is when I did the test I described. Could you explain why that test wouldnt be definitive the way that we did it?

Thanks.

Because to determine if you have a faulty switch reading you need to know when exactly when the switch was pressed or released and verify that reading by watching it on the display. It's a 1 man job; press and release the switch many many times and watch the screen. I just replaced a X-Axis home switch that had a delay that was a fraction of a second. None the less it caused big issues because the home positon would fluctuate all over the place. Bad is bad, and it will almost always get worse.

My money is still on the shuttle in switch. Something is telling the machine that the shuttle is in place allowing the drawbar solenoid to activate. There could be other highly unlikely circumstances causing this, but 99% of the time the condition you are describing is the switch. This will take a little work, but you could reverse the shuttle in and out switches. If it is the switch like I am saying, it should develop a different alarm but there is a chance that the system may ignore the false reading to, all depends on how a potential false reading falls in the T/C cycle. Warning, those switches can be a bit of a pain due to the location of the cable anchors.

Shuttle switch is P/N; 32-2010 @$81.00. Up to you to decide if its worth the gamble on a new switch or keep troubleshooting. I have been wrong before though.

Lastly, just to confirm, use a mirror or position yourself so you can safely view the switches from above. Make sure that the shuttle arm isn't disengaging from the shuttle casting and rotating to trigger the shuttle in switch. Based on your comments I don't think it is, but please confirm this.