Homing A Axis

Topics related to wrapped rotary machining in Aspire or VCarve Pro
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olf20
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Homing A Axis

Post by olf20 »

Merry Christmas / Happy New Year!!
Do any of you have a home switch on your A / Rotary
axis???
If so how did you mount and what did you use?

Thanks
olf20 / Bob

Bowber
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Re: Homing A Axis

Post by Bowber »

I converted a rotary table but I didn't bother with a home switch, it's set to home wit the other axis in mach.
I don't think a homing switch is needed either as the axis effectivly has no end.

Steve

olf20
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Re: Homing A Axis

Post by olf20 »

That's what I was thinking, but just wanted some input from some you
you guys that have thought this thru.

Thanks again!
olf20 / Bob

Greolt
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Re: Homing A Axis

Post by Greolt »

I think that when you start using the 4th axis a bit, it won't be long before you wish you had a home switch.

Just like on a linear axis, a home switch is good for re-finding zero position after an interruption, for whatever reason.

Greg

kilrabit
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Re: Homing A Axis

Post by kilrabit »

There are 2 ways to make the rotary axis home.

1. Cheap and easy way. Make a hole in the part of the rotary that rotates, make a tapered pin in the solid part that slides into the hole on the rotary, and always start from there and set your start zero. In the event something happens and the machine quits, or loss if electricity, or a breakdown, you can insert the pin and give yourself the exact starting point to go back and finish the piece.

2. With a switch, you have choices of light beam, or contact style, with an indicator on the rotary that breaks the electrical connection.

kilrabit
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Re: Homing A Axis

Post by kilrabit »

I use this interrupt switch from cnc4pc, it has a lot of uses with Mach3such as rpm, homing switch, limit switch, etc.

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metalworkz
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Re: Homing A Axis

Post by metalworkz »

Hello,
I am thinking a pin mounted near the perimeter of a disk mounted on the outboard end of the headstock spindle could trip a limit switch when the part has rotated 360º and serve as the home switch. Does this sound like a reasonable way to mount the home switch for a rotary, or is there a better way?
Best regards,
Wes
wes.spence@comcast.net
Gingery Machines:
Lathe, Horiz. Mill, Shaper, Leaf Brake

Greolt
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Re: Homing A Axis

Post by Greolt »

Wes

Looking at your part completed headstock, I gather that this will be enclosed when finished.

Photo interrupters make good home switches but are susceptible to sawdust. Mounted inside the enclosure this should not be a problem.

How about a disk on the shaft, with either a tab or a slot. You have plenty of room in there.

Greg
Attachments
RotarySpindle&Motor.jpg
H22A1,H22A2,H22A3,H22B1.jpg

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metalworkz
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Re: Homing A Axis

Post by metalworkz »

Hi Greg,
Yes, I have a cover for the top side but will need to fabricate a cover for the right side as I wasn't sure where the motor would be when I began the design. I have those photo interrupter type switches on my SX3 mill and they seem to work fine. Your idea to place the switch inside sounds like a good way to go as there is plenty of room there and then it will be enclosed in the headstock. Thanks for the suggestion, I will look into implementing it.
Best regards,
Wes
wes.spence@comcast.net
Gingery Machines:
Lathe, Horiz. Mill, Shaper, Leaf Brake

Timvmax
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Re: Homing A Axis

Post by Timvmax »

Just something to bear in mind guys..
when you home an X, Y or Z axis you'll always approach the home switch from the same direction,
so you'll always get the same position.
When you home a rotary axis it's possible to approach the switch from either side, (depending where your axis has stopped and your control software)
If you use a cam switch there'll be a big difference between one direction and the other.

kilrabit
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Re: Homing A Axis

Post by kilrabit »

My internet connection is a tethered telephone, and sometimes it is not so good. In my earlier post I had intended to post an address for a photo coupler switch which is easy to hook up and use, so here it is now..........maybe.

http://www.cnc4pc.com/Store/osc/product ... cts_id=129

Greolt
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Re: Homing A Axis

Post by Greolt »

Timvmax wrote:Just something to bear in mind guys..
when you home an X, Y or Z axis you'll always approach the home switch from the same direction,
so you'll always get the same position.
When you home a rotary axis it's possible to approach the switch from either side, (depending where your axis has stopped and your control software)
If you use a cam switch there'll be a big difference between one direction and the other.
If you are using Mach3 then homing direction is a setting, so this will not happen.

I have no experience with any other controllers.

Greg

olf20
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Re: Homing A Axis

Post by olf20 »

Well it did not take long! I hand coded a spiral / auger twist to make my grandson
a working grain auger. When cutting each pass it took a long time to return to the
start position / home.
I'm using a rotary table with a stepper, but I think if I continue with this I may have
to build my own spindle. However I want to be able to have my chuck / spindle either
horizontal or vertical.
Either way I will have to get my homing switch hooked up.

olf20 / Bob

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