Messages

1171

General Mach Discussion / Re: Wierd X offset question/problem

« on: June 10, 2009, 11:00:18 AM »

Ah, I think I see the problem - Are the arrows indicating cutter movement, or workpiece movement?  If they show workpiece movement, then it is correct.

Regards,
Ray L.

1172

General Mach Discussion / Re: Wierd X offset question/problem

« on: June 10, 2009, 10:58:00 AM »

Yes, if you go with conventionnal machining (G42) or if you go with climb milling, go with G41

Check out the link or the attached picture, hope this help, Jeff


http://images.google.ca/imgres?imgurl=http://www.home-machine-shop.com/bits/CLIMB_MILLING_THUMB.jpg&imgrefurl=http://www.home-machine-shop.com/bits/index.htm&usg=__5HD1nU_z74D2GOZusUPOzCZTpp0=&h=421&w=450&sz=189&hl=fr&start=9&um=1&tbnid=gknMDciYjDwL4M:&tbnh=119&tbnw=127&prev=/images%3Fq%3Dclimb%2Bmilling%26hl%3Dfr%26sa%3DN%26um%3D1

Either I'm reading it wrong, or that picture is exactly bass-ackwards in it's indications of climb vs standard milling.  In standard milling, the cutting edge first contacts the work behind the cutter, so you have a thin chip that gets thicker as the tool rotates.  In climb milling, it first contact in front of the cutter, so you have a thick chip that gets thinner as the tool rotates.

Regards,
Ray L.

1173

General Mach Discussion / Re: microsteps

« on: June 09, 2009, 07:43:07 PM »

i posted earlier today about my microstepper controller having 1\2 1\4 1\8 and 1\16 settings on a dip switch,hood suggested using 8 steps.ive been playing around with the steps per unit on mach and measuring the movement until it matched the dro and found i need 640 steps per unit with my 1:1 drive and 5mm pitch screw.so i assume it must be 1\16 steps.QUESTION is ok to use 16 steps and whats the advantages and disadvantages of this.i dont want to try to alter the dip switch because i dont no what im doing.THANKS FOR ANY ADVICE.

As long as you can get the rapid speed you want, there's no real down-side to using the higher microstep rate.  It will double the step rate requirement from your PC, but if it can keep up, go for it.

Regards,
Ray L.

1174

General Mach Discussion / Re: Is this backlash or missed steps????

« on: June 09, 2009, 06:51:52 PM »

I have rack and pinion on both the X and Y axis. I am using the 1200 oz motors from keling with the 72v 20A power supply. They X axis is geared 4.875:1 and the Y axis is geared 5.143:1 using timing belts. Boths have 40 tooth 2.0 pitch diameter pinion gears on racks. Can you tell me how to calculate this. I have just been using the set axis function in Mach. Thanks

*If* I'm understanding your setup correctly:

The motor is 200 steps/rev, 4.875:1 belt reduction on X, 5.143:1 belt reduction on Y.  Both will move 2" for one rev of the pinion.  So, the steps/rev is:

X Axis: 200 * 4.875 * 1/2 = 487.5 steps/inch
Y axis: 200 * 5.143 * 1/2 = 514.3 steps/inch

If your stepper drivers do microstepping, multiply these by the number of microsteps.  So, if using Geckos, which have 10 microsteps, your steps/inch would then be 4875 and 5143.

Regards,
Ray L.

1175

General Mach Discussion / Re: XY and Z zero

« on: June 09, 2009, 04:43:08 PM »

Im building a larger router and I use the Kress spindle. I dont think there is a tool holder for Kress, but I could weld some kind of stop on all my tools and messure the lenght from there.

If there is no quick change available for your spindle (or if is stupid expensive), and your tools don't bottom in the collets (or however you hold them) you can still get a repeatable reference length by just putting a collar on each tool so that it installs in he same place each time you use it.

That will have the same effect as an end mill holder realtive to your tool change proceedure. You measure the tool once and tell Mach how long it is and then when you change tools, you just tell Mach which tool you are going to use and it looks up the length of that tool and 're-zeros' for you  . . . is one way to view it.

The tool tables and fixtures can be a big elephant to eat for a newbee, but take it a bite at a time and you'll get it. It's worth the effort and you will wonder how you every got along without it, once you figure out how convienient it is and how much time it saves.

Of course, a tool with a collar for a depth stop, inserted into a collet, will only be accurate to a couple thou, as how far the tool pulls up into the collet will depend on how tight you pull the drawbar.

Regards,
Ray L.

1176

General Mach Discussion / Re: XY zero

« on: June 06, 2009, 10:22:02 AM »

Thanks again.

Is it possible to make some kind of Offset from my "job Zero point" to a location where I always be changing tools? That will be the best way to do it but I don`t know how.

Adam

Ps. Simpson36 - its in the Yahoo Groups. Look at Mach support window.

It's certainly possible - you can do almost anythig with macros.  But I don't understand exactly what it is you're proposing.  Ordinarily you touch off on the part to establish your zero point, then use fixtures if you want to offset from there.

Regards,
Ray L.

1177

General Mach Discussion / Re: M9 doesnt turn off coolant

« on: June 05, 2009, 11:24:28 PM »

That's pretty odd....  No macros required.  Sounds like maybe your install got whacked?

Regards,
Ray L.

1178

General Mach Discussion / Re: XY zero

« on: June 05, 2009, 02:45:03 PM »

I can`t thank you enough Ray - it`s working :-)

But the Vise X - why does it touch the same side of my material twice? There is only 1 zero point.

Edge Finder:  http://www.youtube.com/watch?v=XwOuTb0O1_Y&feature=channel_page

Vise X:    http://www.youtube.com/watch?v=4rtn5gTvzeU

Center finder:   http://www.youtube.com/watch?v=-UUwVK6FYN0&feature=channel_page


Adam

Adam,

It's for aligning the vise to a machine axis.  For instance, if you're setting the vise so the fixed jaw is parallel to the X axis, it first locates the left-front corner of the fixed jaw in both X and Y, and zeroes to the DROs to that corner.  Then it goes to the far right-hand end of the fixed jaw, and checks where it is in Y relative to the first end.  The status line displays how far out of alignment the jaw is.  So, if it indicates the mis-alignment is +0.010", that means the right-hand end of the vise is 0.010" further back (towards the column) than the left-hand end.

If you've completely milled away the top face of the part, then you can re-zero to the new surface, and either adjust your code for this new zero datum, or, after letting the macro zero to the new top surface, manually re-set the Z DRO to the true Z dimension (for instance, -0.010" if you had removed 10 thou).  It's also sometimes handy to set your zero reference to the bottom of the part instead, so it doesn't move if you face the entire top surface.

Regards,
Ray L.

1179

General Mach Discussion / Re: XY zero

« on: June 05, 2009, 10:06:33 AM »

Thank you Ray

Something is moving on Mach 3 screen on my home PC - without the router. Now I go to try it with my router.

I`m a metric user, and I saw you wrote something about inches - do I have to modify something, somewhere?

This PCB I use or a piece of a metal pipe as the Z zero and edge finder tool - is it enough to conect it to port 15 and have some wire connected to GND and my router bit, and mark it as a Probe in config menu?

Adam

BTW - Make sure you configure the PROBE input as active LOW.

1180

General Mach Discussion / Re: XY zero

« on: June 05, 2009, 10:05:39 AM »

Thank you Ray

Something is moving on Mach 3 screen on my home PC - without the router. Now I go to try it with my router.

I`m a metric user, and I saw you wrote something about inches - do I have to modify something, somewhere?

This PCB I use or a piece of a metal pipe as the Z zero and edge finder tool - is it enough to conect it to port 15 and have some wire connected to GND and my router bit, and mark it as a Probe in config menu?

Adam

Adam,

You do need to set Mach3 to operate in metric, but it has no effect on the macros - they use whatever units Mach is using. 

For the tool length setting, all you need is a piece of PCB material with a wire soldered to the top side, and connected to the PROBE input of your BOB.  You *might* need to put a pull-up resistor on the BOB end of the wire, if the BOB does not already have pullups.  The tool will be grounded, so when it touches the plate, the PROBE input gets yanked low.

For edge finding, you can use the same piece of PCB material, slipped in between the tool and the part, but in that case you'd need to set the "probe diameter" DRO to the radius of the tool plus the thickness of the PCB material.  This will work fine, but will sometimes be hard to get the PCB material in the right position to get an accurate reading.  I use a Fowler electronic edge finder (about $30 from Enco, etc. - see Enco P/N 307-3436) that I've modified by removing the "guts", and connecting a wire to the probe tip.  I made the wire short (about 6"), and put an alligator clip on it.  I have the piece of PCB material permannently connect to my probe input.  When I use the edge finder, I just clip the alligator clip to the piece of PCB and go to work.

Regards,
Ray L.