Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread andy pugh
On 9 August 2017 at 18:40, Kirk Wallace wrote: > For an absolute position sensor, I'm thinking that a section of tape from a > tape measure glued to the slide would work well in conjunction with a screw > dial or pointer. Maybe something like I found on eBay.

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread Todd Zuercher
Most of the machines I configure, I normally set them up to park close to the home switch, so that search times are relatively short. And on the occasion that it isn't, it is usually no big deal to manually jog the machine close before beginning the homing sequence. It is also why the homing

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread Kirk Wallace
On 08/09/2017 10:07 AM, Chris Albertson wrote: One use I can think of for a low precision sensor is that you should be able to home faster. The motor can run at full speed until it gets close then slow just before it hits a mechanical switch. For this use case 10% error is good enough. My

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread Dan Bloomquist
Kirk Wallace wrote: On 08/09/2017 10:07 AM, Chris Albertson wrote: One use I can think of for a low precision sensor is that you should be able to home faster. The motor can run at full speed until it gets close then slow just before it hits a mechanical switch. For this use case 10%

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread Kirk Wallace
On 08/09/2017 11:33 AM, Dan Bloomquist wrote: ... snip You made me look. :) My wheels have no markings so taped a piece of paper and made pencil mark. I mounted a .0001" dial indicator. I can't see any backlash, just my wheel is sloppy. The wheel is 6 1/2" in diameter and to get a .001" move,

[Emc-users] Excedrin headache, somewhere in 6 digit space

2017-08-09 Thread Gene Heskett
Evening All; This supposedly one ragged hole at 300 meters barrel is a P.O.S., but the final judgement will be the target of course. So far I've made 2 catheads, and I've spent the last two days hunting for the center of the bore on the butt end of the barrel, and I just now came to the

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread Gene Heskett
On Thursday 10 August 2017 00:01:38 Kirk Wallace wrote: > On 08/09/2017 11:33 AM, Dan Bloomquist wrote: > > ... snip > > > You made me look. :) My wheels have no markings so taped a piece of > > paper and made pencil mark. I mounted a .0001" dial indicator. I > > can't see any backlash, just my

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread andy pugh
On 9 August 2017 at 02:42, Dan Bloomquist wrote: > am I missing something fundamental that makes it a bad idea? If you never need to re-start a job after the machine has shut down then I think that it could be made to work. The development branch of LinuxCNC has support for

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread Mark
On 08/08/2017 09:42 PM, Dan Bloomquist wrote: I have not set homing up on my mill yet, I've been mulling it over. A switch is not satisfying unless there is a way to keep from hunting for it, can't imagine... So it occurred to me to us a laser range finder. Then lcnc would know where the

[Emc-users] Fwd: Re: Using laser time of flight sensor to home mill

2017-08-09 Thread Dan Bloomquist
re the email doesn't work so Stuart got a copy of this Stuart Stevenson wrote: Hi, What is your mill? Does it have stepper motors or servo motors? What position feedback (ie. encoder, scale...), if any, do you have? Hi Stuart, DC Servos, glass encoders at 5um/division. It is an old

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread Stuart Stevenson
Hi, What is your mill? Does it have stepper motors or servo motors? What position feedback (ie. encoder, scale...), if any, do you have? thanks Stuart On Wed, Aug 9, 2017 at 1:41 PM, Dan Bloomquist wrote: > andy pugh wrote: > >> On 9 August 2017 at 18:40, Kirk Wallace

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread Chris Albertson
One use I can think of for a low precision sensor is that you should be able to home faster. The motor can run at full speed until it gets close then slow just before it hits a mechanical switch. For this use case 10% error is good enough. On Wed, Aug 9, 2017 at 9:40 AM, Stuart Stevenson

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread Dan Bloomquist
Dan Bloomquist wrote: So it occurred to me to us a laser range finder. Then lcnc would know where the table is without having to move on boot. It does not have to be accurate like to mm as I probably never have to mill to the limit switches, and even then

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread Todd Zuercher
Homing to a switch (it is an automatic probing routine.) is generally a lot faster and more accurate, than trying to manually touch off on a work piece. Granted sometimes manually touching off on a work piece is nessisary. But when it isn't or when you have a power loss, or other mishap that

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread Stuart Stevenson
Hi, Positioning the laser with magnets seems like an invitation to disaster. The laser WILL get bumped or jiggled out of position. Hopefully, the out of position would result in the machine not moving instead of moving to the wrong position. Using the laser to establish rough position (therefore

Re: [Emc-users] Fwd: Re: Using laser time of flight sensor to home mill

2017-08-09 Thread Dan Bloomquist
jeremy youngs wrote: My ignorance may land my foot in my mouth , but if it has absolute glass scales and they are being read why is there a need to home? Hi Jeremy, The glass is relative, not absolute. Yea, it would be a whole different world with absolute encoding. Best, Dan.

Re: [Emc-users] Fwd: Re: Using laser time of flight sensor to home mill

2017-08-09 Thread jeremy youngs
My ignorance may land my foot in my mouth , but if it has absolute glass scales and they are being read why is there a need to home? On Aug 9, 2017 3:09 PM, "Dan Bloomquist" wrote: > > re the email doesn't work so Stuart got a copy of this > > Stuart Stevenson wrote: >

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread Dan Bloomquist
Ok, so maybe I'm over thinking this. So I should just mount switches in the centers, make sure I'm jogged close to a known side on start up, and just home on them. I don't want to have to bounce off the limits, my X is almost a half a meter away from the center. (35" between limits). And I

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread Dan Bloomquist
andy pugh wrote: On 9 August 2017 at 18:40, Kirk Wallace wrote: For an absolute position sensor, I'm thinking that a section of tape from a tape measure glued to the slide would work well in conjunction with a screw dial or pointer. Maybe something like I found

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread Jon Elson
On 08/09/2017 10:38 AM, Dan Bloomquist wrote: I know how accurate this thing is. The idea is that I can start up without hunting switches. Why is that such a big deal? LinuxCNC now can do all axes with the press of ONE button! I really don't see the need for exotic and possibly finicky

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread Jon Elson
On 08/09/2017 12:53 PM, Dan Bloomquist wrote: Ok, so maybe I'm over thinking this. So I should just mount switches in the centers, make sure I'm jogged close to a known side on start up, and just home on them. Yup, that's how it is set up on my Bridgeport. The X trip bar is in the center, and

Re: [Emc-users] Fwd: Re: Using laser time of flight sensor to home mill

2017-08-09 Thread Jon Elson
On 08/09/2017 04:16 PM, jeremy youngs wrote: My ignorance may land my foot in my mouth , but if it has absolute glass scales and they are being read why is there a need to home? Homing gives you at least two advantages. One is that after homing, the machine limits of travel can be checked

Re: [Emc-users] Fwd: Re: Using laser time of flight sensor to home mill

2017-08-09 Thread Jon Elson
On 08/09/2017 04:31 PM, Dan Bloomquist wrote: jeremy youngs wrote: My ignorance may land my foot in my mouth , but if it has absolute glass scales and they are being read why is there a need to home? Hi Jeremy, The glass is relative, not absolute. Yea, it would be a whole different world

Re: [Emc-users] Fwd: Re: Using laser time of flight sensor to home mill

2017-08-09 Thread Stuart Stevenson
Hi, It doesn't have limit switches and home to index already set up? You should be able to move at (almost) rapid velocity to the limit switch and then slow down to search for home position. Stuart On Aug 9, 2017 4:32 PM, "Dan Bloomquist" wrote: > jeremy youngs wrote: > >> My

Re: [Emc-users] Using laser time of flight sensor to home mill

2017-08-09 Thread Gene Heskett
On Wednesday 09 August 2017 21:26:33 Jon Elson wrote: > On 08/09/2017 10:38 AM, Dan Bloomquist wrote: > > I know how accurate this thing is. The idea is that I can > > start up without hunting switches. > > Why is that such a big deal? LinuxCNC now can do all axes > with the press of ONE button!