Still having trouble with my tool changer

camaro_dan67 · Feb 28, 2016

I have a Kiwa Exel Center-4 from 1984 that I've been trying to get the tool changer working on. The tool changer uses pneumatic cylinders and solenoid valves to operate. The control has a selector dial on it to do individual functions of a tool change. The manual says that the sequence to do a tool change has to start with a z zero return then in mdi an m19 for spindle orientation. Then after that the sequence is the carousel moves right to engage in the tool, the spindle lets go of the tool, the carousel moves down indexes to the next tool, puts it back in the spindle, the spindle clamps then the carousel returns. When I try to do these functions I start with the zero return orient the spindle then when I command the carousel to move right. The carousel will move about half way over and just stop. I tried pushing and pulling on it and it seems to have pneumatic resistance. So what I'm thinking is the pneumatic valves are not working right. Does anyone have experience with these valves? Its a Joucomatic 24v dc valve. I had one apart and it looks like it uses electric solenoids at each end to open pneumatic ports which actually shifts the directional control valve. What can I do to get these valves working?

lowCountryCamo · Feb 28, 2016

yes you should have two valves that push oposite directions. Sounds like they are bother firing at once, or one is stuck open when the other fires.

Do you have a manual. You should have diagnostics that will give 0 or 1 when different functions are happening. That will let you see if it is being told to open or not.

camaro_dan67 · Feb 28, 2016

The only thing I have is a crude wiring diagram that I think is showing the solenoids. They are labled well on the machine but I have no sequence of actual solenoid order.

Vancbiker · Feb 28, 2016

Sounds to me like you have one or more plugged up flow control valves. Pneumatic cylinders on machines usually have a combination flow control and check valve on each port of the cylinder. The check valve allows free flow to incoming air and closes to direct air through the flow control for exhausting air. A plugged up flow control on the cylinder will only let it extend until the trapped air pressure equals the pressure trying to extend it.

wayneind · Feb 28, 2016

What kind of control on your machine?

camaro_dan67 · Feb 28, 2016

The control is a Fanuc 3m model C. Vancbiker are these flow control/check valves just inside the ports on the cylinder or somewhere else on the circuit?

machtool · Feb 28, 2016

camaro_dan67 said:
are these flow control/check valves just inside the ports on the cylinder or somewhere else on the circuit?

Normal practice is to mount them at the port on the cylinder. Occasionally you will find them mounted at the Valve.

Take a look at the cylinder ports. If the fitting there has an adjustment knob, that's your flow control. Most have a lock nut. If it wasn't locked and has vibrated closed, you will get the symptoms you describe.

Regards Phil.

Vancbiker · Feb 28, 2016

camaro_dan67 said:
.....Vancbiker are these flow control/check valves just inside the ports on the cylinder or somewhere else on the circuit?

As machtool said, most commonly a separate fitting attached to the ports on the cylinder or the valve/manifold. There are a few brands of cylinder that have the check valve and flow control integral to the caps on the cylinder. There inline versions as well but I've only rarely seen that style used on machine tools.

wayneind · Feb 29, 2016

The problem I would say is the air is not exausting from the other end of the cylinder. The dual coil directional valves are shifted one way or the other and stay in that position so you are in a sequence if power goes off. The check or flow controls could be bad but also check the directional valve on the other side of the piston it may be shifted the wrong way, remember the air is only going to exaust thru that valve if it is in the right position.

camaro_dan67 · Feb 29, 2016

Wayneind I was Thinking the same thing about the valves not moving and letting the air out. It seems as though they work only some of the time. Certain ones don't seem to work at all. Each one has a small lever at each end to manually operate them, I've pushed them many times only a few of them do a function. It also seems strange to me that the carousel moving to the left moves quick and almost to fast then when moving right it gets stopped to soon. I tried adjusting the screws vancbiker was talking about but they only made the return slam back harder there were two of those labeled flow and pressure.

NAST555 · Mar 1, 2016

First thing I would do is totally disconnect your air lines and see if you can get the carousel to move freely forwards and back. There could be something preventing it from going it's full travel.

Then I would try to isolate each valve separately to see where it's feed is coming from and disconnect them one at a time and see what happens then. I also think that maybe it isn't exhausting, as Wayne said, so check if it is meant to exhaust on the valves themselves or somewhere else in the system. The exhaust filters do clog up after a while.

Once you have run through all of those checks I'm pretty sure you will find the problem even if it isn't something listed here. Good Luck!!

machtool · Mar 1, 2016

camaro_dan67 said:
. I tried adjusting the screws vancbiker was talking about but they only made the return slam back harder there were two of those labeled flow and pressure.

Explain what you were seeing as "flow and pressure". Normally you wouldn't be able to adjust pressure. It's what the pressure regulator on the back of the machine / inlet say's.

I can only think you were playing with one of the two flow controls if it's "slamming back harder" one way.

If it helps, pneumatic flow controls are almost certainly Metered Out. Full flow air is admitted into the cylinder, restriction valves limit the amount of air that can leave - throttled down. Its a back pressure restriction thing. Van BC mentioned flow controls and check valves @ post #4. The check valves let full flow air one way, metered / restricted the other. That's the slow down - one way only. You have to tickle up the opposite flow control valve.

The Engineer in me would give you a lecture in Annulus Area, One side is a pure piston, the other looses all the volume of having a rod. Flow control, for the same speed will take that into account.

How about a picture of what you have.

Regards Phil.

wayneind · Mar 1, 2016

Good advice on this thread, ATC's always follow a sequence and the designer will take steps to not let you make an out of sequence movement, I would think about the first thing that needs to happen when the tool is changed, maybe index the carousel to the correct station then machine needs to know somehow this has been done so the next step commences. You may have some air logic going on here, that schematic may be helpful for all to see if you are really stuck.
Keep us posted!

camaro_dan67 · Mar 2, 2016

Phil your right its time for pictures. I'll get some of those and start looking at the exhaust filters. I'll take pictures of the solenoids and the block I was adjusting. Anything else I should take pictures of?

machtool · Mar 2, 2016

camaro_dan67 said:
Anything else I should take pictures of?

A close up of the port on the cylinder would help work out whats there.

I think your allowed 5 pictures per post, so load them up.

Regards Phil.

camaro_dan67 · Mar 3, 2016

Ok I took pics and would love to put them on here but I sent them from my phone to my outlook account and it blocks them. How do I unblock pics in my inbox? While I'm at it how do I load pics on here?

machtool · Mar 4, 2016

camaro_dan67 said:
How do I unblock pics in my inbox? While I'm at it how do I load pics on here?

There's a section on it down in the basement.
http://www.practicalmachinist.com/vb/images-and-links/

If you want to nut through it, best option is to click the "Go advanced" tab when you next post a reply. Once there there's an :Attachment" tab at the top. Looks a bit like a paper clip. That will let you select photo's off your system.

Failing that, I'll P.M you my email addy, you send them to me, and I can put them up. That might take 24 hours, I'm out on site.

Regards Phil.

Other Brother · Mar 4, 2016

I remember working on an old Tree 5020?? once and it had the same carousel/umbrella tool changer like you are working on. On the valves there are manual buttons that you can push to fire the valve but they can also be turned to the wrong position. If left in the wrong position the valves will not function correctly. Just another thing to check. Some good advice in this thread!

Daryl

camaro_dan67 · Mar 4, 2016

Ok guys heres the latest, I took the valves off one by one and completely cleaned the whole insides out and lubed them with wd-40. I can do the whole sequence of a tool change manually except the carousel moving right to engage the tool. Just like before it struggles to move right but I found if I move one of the lines at the fitting it lets the cylinder pressure out and finishes that single sequence. I'll give the steps in order: carousel moves right, (still the biggest problem) tool unclamps, carousel moves down, tool rotates, carousel moves up, tool clamps, carousel returns. I tried an automatic tool change but it times out because of the sluggish move to the right. There is also another thing that seems to still be wrong. When I plug in the air to the machine I hear it exhausting constantly, I'm wondering if its what Daryl said that one of the valves is just shifted wrong. How do I know where they are suppost to sit idle at?

Other Brother · Mar 5, 2016

I just messed with them until the carousel functioned correctly, you can only have so many combinations. At the time I had never heard of a Tree VMC, lol. They also use these on newer Hardinge machines and when an operator manually opens the door with the little push button they will accidentally move the position of the push button. Then when they close the door via the operators panel the door will open back up when the switch is released.

On double acting valves you will have a button on both ends and they have to be in the right position or the valve will not work correctly. Some valves are labeled on or off / O and I. Some have a dot for the correct position. Good luck, I think you are getting close and look how much you have learned.

Still having trouble with my tool changer

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