Some simple mods for my Tormach

[zephyr9900]

Originally Posted by BlueFin Unless I am mis-understanding you or something if the door should come open and the contactor drops then there is no decel

BlueFin, I was talking about decel of the XYZ motion under a controlled feed hold.

When the spindle door opens the contactor does drop out, but the spindle motor coasts to a stop over a longer period than when actively braked. Of course, depending on the agressiveness of the cut it can still stop pretty quickly.

I just did some experimenting--my spindle door has never come adrift on its own (forewarned is forearmed ) so I had to open it on purpose. The interlock switch drops out when the spindle door has opened less than 1/4" on my machine. The switch is a Tend TZ7311 which has a rated overtravel of 6mm, so that jives.

The Tend has a roller actuator, so instead of the door directly pushing on it, it could be rotated so that the plunger traveled in the mill's Y direction, and a flange on the door could be arranged to trip the switch with an almost arbitrary distance of overtravel--certainly allowing the door to open an inch before tripping the switch would be plenty of distance to accomodate a safety catch. The switch bracket would change, the door flange would change which would be minor costs to roll into production, the switch wouldn't change, and the main extra cost would be the added safety catch itself--possibly just a spring-steel stamping. The big paper cutter at the last place I worked had the kind I'm thinking of.

Randy

[philbur]

Why not just improve the design of the door lock mechanism.

Phil

[LeeWay]

If it were mine and I wanted to keep that door lock safety, I think I would want it to send and Estop to the whole machine rather than just the spindle.
I am considering making a Tormachish type door over the top of my mill. Right now it would be a benefit on one hand to kept my hands clear of the belts while running. Respect and common sense is so far working well for that though. On the other hand, I would have to open the door for each tool change. Not such a big deal though. I think I am leaning toward the safety factor of it all though. Plus it would dress it up cosmetically. Right now it kinda looks like a poodle with no hair or turtle with no shell. Just a bit awkward.

Nice looking mods here. Keep on posting and I'll keep watching.

[zephyr9900]

Originally Posted by philbur Why not just improve the design of the door lock mechanism.

I'm assuming there is a cost sensitivity, Phil. Personally I'd go with something like this, but seeing how cheap the latches on the stand doors and electronics cabinet are, a premium latch like the Southco is probably not an option.

I've tried tweaking/bending the strikers on the existing latches to get a better fit and less rattling with no success.

Randy

[zephyr9900]

And Len, your mods are good and useful and I apologize to you for what amounts to thread piracy on my part and I deserve for doing it.

Randy

[philbur]

Some one early on on this forum reported rebuilding the lock so that it wasn't so sloppy. It seemed like a reasonable solution. The original is somewhat on the crude side.

Phil

Edit;: or may have been on the Yahoo forum!

Originally Posted by zephyr9900 I'm assuming there is a cost sensitivity, Phil. Personally I'd go with something like this, but seeing how cheap the latches on the stand doors and electronics cabinet are, a premium latch like the Southco is probably not an option. I've tried tweaking/bending the strikers on the existing latches to get a better fit and less rattling with no success. Randy

[levelzero]

I just wanted to add my experience. The other day I cut back the shoulder on my draw bar and used a stack (3) of 7/16 washers. The top of my spindle is pretty badly grooved at this point. I was having chatter problems and the tts holders were constantly pulling out of the collet. After making the changes everything is happy again. I haven't had a reason to make any deep cuts since, but I suspect I'm getting much better clamping force on the draw bar, resulting in my holder being held a lot better.

[kevperro]

Originally Posted by levelzero I just wanted to add my experience. The other day I cut back the shoulder on my draw bar and used a stack (3) of 7/16 washers. The top of my spindle is pretty badly grooved at this point. I was having chatter problems and the tts holders were constantly pulling out of the collet. After making the changes everything is happy again. I haven't had a reason to make any deep cuts since, but I suspect I'm getting much better clamping force on the draw bar, resulting in my holder being held a lot better.

I have the same issue. I thought they had sent me a bad collet or draw bar when I first tried to use it. It was extremely difficult to thread all the way down into the collet. Even when I did get it threaded, the draw bar doesn't hold the bits with much force. I'll try adding the washers.

[LENS_CAD]

I always watch my tool holders closely when making heavy cuts (1/2" end mill in steel) because they have pulled out of the collet several times even though the drawbar is tightened as tight as I can get it with supplied wrench. I think I sometimes push the depth of cut and feed beyond what is wise for the machine.

The Tormach rubber washer heavy cut adapter seems to work well, though, because I haven't had a problem with it installed.

Len <><

[BlueFin]

How does Cat 40, or any of the other industrial ATC tool holders work? Looks like a ER collet on one end where the end mill goes (or a weldon set screw) and a huge taper on the other. Is there a flat somewhere to measure tool length offset from? Or do you drop it in some kind of matching taper socket thing that sits on a granite plate?

What I am getting at is why can't there be some kind of TTS tool holder that has a special grind that perfectly matches the R8 internal and just gets pulled up by the drawbar? You have to work the draw bar anyway to release the current TTS so I don't think it would be too much of a hassle to just need to unscrew it all the way given the fact that there would never be a tool slipage issue (other than the choice of tool holding, which seems to be working everywhere in the world currently).

As far as quick change is concerned since you would be pulling up directly on the tool holder, and the taper is doing it's thing in the spindle, and you have that little antispin alignment pin thing in the R8 you could probably do the same spring deal up on top of the spindle with an air cylider to push down to release the tool.

[philbur]

There already is it's called an R8 tool holder.

To include a "TTS" shoulder would make it a dual contact tool, which requires great precision if the taper and the shoulder are to "make up" at the same time, this is what makes them so expensive.

Phil

Originally Posted by BlueFin What I am getting at is why can't there be some kind of TTS tool holder that has a special grind that perfectly matches the R8 internal and just gets pulled up by the drawbar?

[LeeWay]

Precisely put, Phil.

The only issue with this type is they are not as accurate. They can get close, but if there is a chip anywhere, that may lock it in a different zero point that the rest. You would still need to zero out each tool each time.