info needed

[turmite]

Can anyone explain, or better yet provide drawings on how an automatic tool change spindle works? I am wanting to build a 4-axis wood carving machine, on a budget, and would like to have an atc for it. I have found a spindle motor with the atc but it is almost $7000.

turmite

[Klox]

Did you ever heard of a Geneva Wheel? It is a very (nice?) way of indexing.
In my neighbourhood a low cast automatic toolchanger is actually an overworked, underpaid cnc-operator......
(Sorry couldn't resist pulling your leg!)
I'll see what i can find out.

Klox

[CAMmando]

Usually a tapered tool holder with some form of retention knob is used. The spindle needs to have a mechanism for "drawing" the tool holder into the spindle. Often this is a finger or collet that springs open and is mechanically drawn closed as tension is applied. Usually an air blast is blown thru the spindle to clear any debris.

Ive been toying with the idea myself (although first thinks first - get a bachine built). Im thinking that for a limited number of tools, the most echonomical arrangement would be to have a fixed "bank" of tools on the machine and have the mahine go "pick up" the tool.

[turmite]

Cammando that type of holder is called a static tool holder and that is what I was goinr to use. Thermwood has a system that they use a seperate spindle from the motor and it is driven via a belt. It still has all the tool change functions. My though was it would be a way to reduce the cost of this machine and let me get started sooner. I had all the Porter Cable I want. You have to fight bit slippage all the time with those if you use them in a production system.

turmite

[CAMmando]

Slipage between the tool and holder or the holder and spindle ? I would have dogs on the spindle.

Take a look at what Jeff (HOME CNC) did with his porter cable

http://www.cnczone.com/showthread.ph...0&pagenumber=4

[castguy2003]

Originally posted by CAMmando Slipage between the tool and holder or the holder and spindle ? I would have dogs on the spindle. Take a look at what Jeff (HOME CNC) did with his porter cable http://www.cnczone.com/showthread.ph...0&pagenumber=4

If you use a dogged system you need to be able to stop the spindle in the same place rotationally each time. That means big dollars.

[CAMmando]

I was thinking of a design where the tool holder had essentialy a face "gear" configuration on the top side of the flange. A mating arrangement would be on the spindle. The pitch would be such that no matter where the spindle was oriented, it would seat itself as it was drawn into the taper.

Patent Pending

[Klox]

Turmite, sorry i jumped to the conclusion that you wanted a indexing type tool changer. Yes i've seen static tool changer (how ever no cookin' clue how it works!).

Well there's a pending patent on CAMmando side, i'm holding thumbs!!!!

Klox

[turmite]

Hey klox I am not easily offended. Takes too much time to get over stuff. I also apologize for not replying to your first response. I have never heard of the Geneva Wheel but I know exactly what your type of atc is. As the saying goes "been there", well I am there and I really need a change! Hey I just made a joke .

turmite

[Klox]

A Geneva Wheel is a type of indexing head much like a conventional dividing head. It is used if you want to index at high speed. It is mostly used in the packaging and bottling industry where speed & accuracy is important.
I think that it could be applied as a tool changer, but it's going to take a lot of maths & a lot of head scracthing to come up with a workable concept.

Klox