Help 'Clocking' a Toolchanger Arm

Long story short, I have a smaller drill/tap/mill machine that crashed the toolchanger (not of my doing). The machine is an '89 and it was a previous semi-hidden repair. After digging into it more, I see why they did what they did and was able to repair the damage and hopefully keep it from happening again. The tool changer is controlled all mechanically. I finished the repair, re-assembled the machine and have it working semi-reliably. The problem is, every 10-12 tool changes, it drops the tools, which makes me thing the arm is not 'clocked' or set correctly.

I'm trying to figure out a good method to identify and set where the arm should be. I was an idiot and didn't mark it when it came apart, thinking there would be a keyway or something to basically re-align it. After seeing how it goes together, I'm stuck. The mechanicals to the tool changer are in the gear box, with the shaft that sticks out down between the spindle and the tool changer. The arm and 'claws' use a clamping system of a stack of tapered split wedge type sleeves that tighten down to pinch the arm to the shaft. After it's tightened down, you basically have to loosed the whole thing and break the tapers, re-set everything and re-install to put it back. There's no way I've found to make small adjustments and test.

So I'm trying to figure out a good method to figure out where the arm should be initially.

This was essentially the damage. It bent the pocket the claw was in. I was able to straighten and re-weld and get everything buttoned up. I'm 90% sure my problem is 'rotational clocking' of the tool arm. Because when it does drop tools, it always drops both and the other 90% of the time it works fine.

Pic. The tool arm is small and short. The tools are BT30. There are 6 bolts that go though the bottom and into the black oxide ring directly above the arm. Tightening those clamps the tapered split rings together and clamps the arm on the shaft. \

Any help is appreciated. I just want to get this back up and running. Side note, there is no manual tool change button that I can find on this machine. I've looked all over. Previous owner said the same. Didn't think much of it until the tool changer crashed, otherwise I could just run it that way.

My other, other backup plan is to possibly figure out how to change tools manually, which I could probably do with removing the arm and the correct code, but I would need to figure out how to make sure the machine know which tool is in the spindle and keeps the offsets correct. Open to suggestions for the possibility of that as way.

I'm basically open to any options or suggestions. It's what I got, It's paid for, just trying to get it making parts again.

I'd be inclined to just move it a little bit at a time and test it to see if it stops dropping tools. You will have to verify the spindle orientation, spindle height, and drawbar action as well.

You could manually change tools by removing the M6 T(tool number) from the program and just using the G43 H(tool number).

ewlsey said:

I'd be inclined to just move it a little bit at a time and test it to see if it stops dropping tools. You will have to verify the spindle orientation, spindle height, and drawbar action as well.

You could manually change tools by removing the M6 T(tool number) from the program and just using the G43 H(tool number).

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The problem is the way the arm clamps to the toolchanger spindle it’s impossible to adjust a little at a time. Has to be completely disassembled and then put back together.

Tool change alignment gauges are available.

Steep Taper 4 (BT) Tool Changer Alignment Gauge - Tool Changer Alignment Gauges

I got a quote on a set some time ago. I'm too miserable or my pockets aren't deep enough to afford them.

Its on my list of things to do, make a set. Its basically a tool holder where the Vee flange portion, has been cut away from the taper cone. And it has a bore through the centre for a plug gauge.

If you were to google "Tool Changer Alignment Tool" there should be many others. I've even thought about taking a standard tool holder, and have it wire cut split across the biggest diameter, so you have two journals the same diameter, and you should be able to feel the misalignment, like the way you do with an edge finder.

Regards.

sounds like a problem with the gripping of the fingers on the arm. if it were not clocked right then it wouldnt work at all. the only reason it would drop both tools would be if the mechenism under that little cover on the arm is no working properly.

I have a mycenter 1 that has the pin inside that arm break every 6 months or so...machines loon similar style

The "proper" way is to have a gage like machtool mentioned. That in combination with a hand crank to replace the arm drive motor allows you to position the arm under the spindle and then tweak the arm into position with the clamping screws just barely snug. When alignment is achieved then fully tighten the arm clamp screws.

The real world way since few have the gages or hand crank is to rotate the arm drive motor by hand until the arm is under the spindle. Sometimes the machine builder is so kind as to spec a motor with an extended shaft with wrench flats. Sometimes you have to pull the cover off the motor and if the fan is metal it sometimes is good enough to crank the motor with. Sometimes the fan is plastic. Then you might have to pull the fan off and turn the motor by gripping the shaft with vise-grip pliers. Combination of eyeball and maybe calipers, get the claw centerline aligned as close as you can to the spindle centerline. Tighten there.

My NTC has an M code to move the tool arm from "parked" to "tool removal position", and back

As mentioned above if this is happening randomly you might look at other than the clocking of the arm.

Have you tried running a series of tool changes (without tools) to see if the arm is not moving completely at some interval? (chipped or missing tooth in the indexing gear)
Without tools it takes some of the pucker factor out of diagnosis

I believe his tool change arm is driven by a large cam. If it's like a Kitamura, the cam controls the swing and raising and lowering the arm, as well as the drawbar.

ewlsey said:

I believe his tool change arm is driven by a large cam. If it's like a Kitamura, the cam controls the swing and raising and lowering the arm, as well as the drawbar.

Click to expand...

It's similar to this. It's a large mechanical cam system. That's why it really makes me think it's the alignment. Because when I removed the arm off of the shaft, I didn't mark the location in anyway. I was thinking it was keyed or splined somehow, but that was obviously not the case. So without getting it to the position it was when it was removed, I doubt the position of the arm is ideal. Right now it seems close enough to work 90% of the time, but that will still cause problems...

I think you will find you have to measure the vertical position of the arm at each gripper making sure it's actually straight and at the exact height to match the toolholder groove.

Also, the arm is mounted to a tube. There is shit inside that tube that slides up and down at light speed and runs the grippers. What I have often seen is that the arm is crashed and straightened and maybe the tube is sort of straightened, but nobody cares about the ID of the tube. So the rods and tapered gizmos that have to slide inside the tube don't move so hot. Make sure everything has clearance and lubrication inside the vertical tube otherwise the grippers won't lock onto the tools reliably.

On a vertical, I like to use a small bottle jack to position the arm vertically while I measure and tighten. Small machines you may be able to hold the arm, but bigger ones there's no way.