Re: [Emc-users] Single Pulse Output?
On 12 November 2012 02:18, John Kasunich jmkasun...@fastmail.fm wrote: man oneshot from the command line should get you the documentation. Or the HTML docs: http://www.linuxcnc.org/docs/html/man/man9/oneshot.9.html Note that you can set it to produce a pulse on both the rising and falling edge, so if you net-ed it to halui.machine,is-on you would get a pulse when you turned the machine on or off (F2 key in axis) You need to enable halui to get that pin: http://www.linuxcnc.org/docs/html/gui/halui.html I don't know if you get the pulse, or how long it would be, if you exit LinuxCNC without turning the machine off. Note that oneshot has the time resolution of the thread it is in. So 1mS resolution in the typical servo thread. It can't run in the base thread. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
If you want to go with the auxiliary slide idea you can often pick up short linear slides off eBay for peanuts. Bolt on your torch, add a switch and the job is done. I have some nice 100mm long THK rails here that I bought for this purpose. I have been thinking about this for some time and a while back I came up with a very different design to all of the others I have seen. First of all, you don't need or want a ball screw on Z. Z doesn't need to be hugely accurate. It needs reasonable resolution and it needs to be dirt resistant. Plasma generates a lot of very fine abrasive dust that gets everywhere and will wreck ball screws fairly quickly. My plan is to use a simple winch. Think of a drum with a coarse thread machined into it. Wind some flexible wire or heat resistant cord on the drum and control it with a stepper or servo. This is simple, dirt tolerant and provides good enough accuracy. Run the wire over a pulley at the top of the Z axis to lift the torch. The weight of the torch and slide should provide enough tension. For touch sensing, mount the pulley on a spring loaded arm with a hinge at one end and a switch at the other. As the weight comes off the cord the pulley will lift and trip the switch. Alternatively you can have a fixed pulley and a separate spring loaded pulley and switch to measure the cord tension. The main problem I can see with this setup is the possibility of the cord coming off the drum. This can happen if the cord goes slack. There are a few ways to get around this. One is to add some guides so there isn't room for the cord to lift out of the grooves. Another is to stop the machine if the touch sensing switch trips and you aren't seeking the top of the work. This is worth doing no matter what touch off mechanism you use. I have used the grooved drum setup for position measurement and have had very few problems with the cord coming off. After initial calibration they maintained surprisingly good accuaracy. I dont think your idea is a good practical idee for a production machine. The torch does touch off thousands of times and the loose nuts will wear out in no time. There is nothing wrong with a well designed floating head and in my opinion it is the best possible pactise to date. I can't see why the nut would wear. There is very little load on it when it moves on the pins. Instead of bolts you may want to use hardened pins as they can be made a better fit and will wear less. Les -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
That does sound like a lot of work when a simple acme screw and plain bearing slides do the trick. http://gnipsel.com/shop/plasma/z-axis-02.xhtml John On 11/12/2012 5:32 AM, Les Newell wrote: If you want to go with the auxiliary slide idea you can often pick up short linear slides off eBay for peanuts. Bolt on your torch, add a switch and the job is done. I have some nice 100mm long THK rails here that I bought for this purpose. I have been thinking about this for some time and a while back I came up with a very different design to all of the others I have seen. First of all, you don't need or want a ball screw on Z. Z doesn't need to be hugely accurate. It needs reasonable resolution and it needs to be dirt resistant. Plasma generates a lot of very fine abrasive dust that gets everywhere and will wreck ball screws fairly quickly. My plan is to use a simple winch. Think of a drum with a coarse thread machined into it. Wind some flexible wire or heat resistant cord on the drum and control it with a stepper or servo. This is simple, dirt tolerant and provides good enough accuracy. Run the wire over a pulley at the top of the Z axis to lift the torch. The weight of the torch and slide should provide enough tension. For touch sensing, mount the pulley on a spring loaded arm with a hinge at one end and a switch at the other. As the weight comes off the cord the pulley will lift and trip the switch. Alternatively you can have a fixed pulley and a separate spring loaded pulley and switch to measure the cord tension. The main problem I can see with this setup is the possibility of the cord coming off the drum. This can happen if the cord goes slack. There are a few ways to get around this. One is to add some guides so there isn't room for the cord to lift out of the grooves. Another is to stop the machine if the touch sensing switch trips and you aren't seeking the top of the work. This is worth doing no matter what touch off mechanism you use. I have used the grooved drum setup for position measurement and have had very few problems with the cord coming off. After initial calibration they maintained surprisingly good accuaracy. I dont think your idea is a good practical idee for a production machine. The torch does touch off thousands of times and the loose nuts will wear out in no time. There is nothing wrong with a well designed floating head and in my opinion it is the best possible pactise to date. I can't see why the nut would wear. There is very little load on it when it moves on the pins. Instead of bolts you may want to use hardened pins as they can be made a better fit and will wear less. Les -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
On 12 November 2012 11:32, Les Newell les.new...@fastmail.co.uk wrote: I have been thinking about this for some time and a while back I came up with a very different design to all of the others I have seen. First of all, you don't need or want a ball screw on Z. Z doesn't need to be hugely accurate. It needs reasonable resolution and it needs to be dirt resistant. Are double-helical racks available? It seems to me that those would give good location in a number of degrees of freedom, and allow direct stepper control. (Google) I can't find any. It would be reasonably expensive to make as an injection moulding, though relatively expensive to hob. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] running PyCAM (dev) under Windows (was: Text on rounded button.)
Ok, got pycam going on linux. A couple things.. Generate toolpath generates a flat toolpath, it requires generate all to generate the curve. MM seems to be hard coded here?? Is there a place to input retract height? Anyway, thanks for the help, I think this is going to work. And, thanks for the trouble of working on pycam. On Wed, Nov 7, 2012 at 5:57 PM, Lars Kruse li...@sumpfralle.de wrote: Hi Erik, Hacked the dll into the directory, got it going, however, whenever I click item to view, exception is thrown Gdk:ERROR:gdkgc-win32.c:748:get_impl_drawable: code shouhd not be reached I am sorry to hear that you stumbled upon this kind of ugliness! Sadly the OpenGL library that is used by PyCAM is slightly non-maintained in the Windows world. Thus I can't help you here. One or two years down the road PyCAM will switch to another OpenGL library - but this is of no help for you right now :( cheers, Lars -- LogMeIn Central: Instant, anywhere, Remote PC access and management. Stay in control, update software, and manage PCs from one command center Diagnose problems and improve visibility into emerging IT issues Automate, monitor and manage. Do more in less time with Central http://p.sf.net/sfu/logmein12331_d2d ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
Is the reason behind the floating head so there won't be damage if the head hits an object while cutting, like a warped part sticking up? I'm having trouble grasping why it's needed. Again, I have very little experience with plasma tables, being limited to the one machine my former employer had. That machine had a rigid Z axis with the plasma torch coupled with a device that used air pressure to hold the assembly in place. If the head crashed into a raised part, it would knock the 2 parts off from each other and the torch side would fall loose within the constraints of the other side of the housing and trigger an error on the control. To reset the head you had to pull it outward and lift slightly to reform the seal and the head would stick back in place. It took some tries before getting it to seal and stick, before you developed the touch. The mechanism was maybe 4 inches square, with the joining interface itself appearing to be round. A very similar machine can be seen at http://www.plasma-automation.com/mod_fabricatorHD.html and the page has a link to a slightly better image of their collision protection but they don't seem to provide many details. When the machine touched off, it appeared to use some form of conductivity to probe the surface. Holding a piece of steel off of the surface of the table and letting the head touch it wouldn't trigger the probe, until it pushed the steel down to the surface of the table. If it was strictly capacitance based, it seems it would trigger as soon as it touched, unless a human body holding onto a piece of scrap doesn't have enough capacitance to set it off. I'm sorry if I'm completely missing the point of wanting the floating head, I'm trying to comprehend the need. At first I thought the intention was for the head to just ride the surface of the workpiece and not use THC, but now I see that THC is to be implemented for cut height so I'm a little lost. Unless the float will replace the need for an electronic probing. I hope someone can clear up my confusion, and sorry if all of this is irrelevant. Jim On Mon, Nov 12, 2012 at 7:17 AM, andy pugh bodge...@gmail.com wrote: On 12 November 2012 11:32, Les Newell les.new...@fastmail.co.uk wrote: I have been thinking about this for some time and a while back I came up with a very different design to all of the others I have seen. First of all, you don't need or want a ball screw on Z. Z doesn't need to be hugely accurate. It needs reasonable resolution and it needs to be dirt resistant. Are double-helical racks available? It seems to me that those would give good location in a number of degrees of freedom, and allow direct stepper control. (Google) I can't find any. It would be reasonably expensive to make as an injection moulding, though relatively expensive to hob. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
On 12 November 2012 16:00, Jim Coleman drunkenwhip...@gmail.com wrote: Is the reason behind the floating head so there won't be damage if the head hits an object while cutting, like a warped part sticking up? I'm having trouble grasping why it's needed. While cutting you can measure the head-to-work distance using the arc voltage. However, to start cutting you need to have the head at the correct height then strike the arc. The idea is to use the head as a probe, lower to find the work, raise to the correct height, strike the arc then continue to cut while adjusting height based on arc voltage. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
How I would do it: Use a trapezoidal screw and a delrin nut. Allow the nut to float axially in its housing, with a microswitch to detect when it has moved. Normally the head hangs on the nut. When the head touches then the nut slides down in its housing, operating the microswitch. (Use the probe G-code) back off to the required height + the known actuation distance and start the arc. I think I would use a leaf-spring suspension to supply the required angular constraint on the nut. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
Ok so I should have re-read the first message in this thread before sending that. I now see the OP is looking for a way to handle the overtravel from decel on the Z axis after the probe has touched. I'm guessing that just probing slow enough to be able to stop quickly is less than desirable because of the amount of time it will take for probing before every cut. How far will the head overshoot at probing speed once the probe event occurs? Is the machine too rigid to just handle the flexing while the axis decelerates? Do people regularly use automated probing on a mill to set tool length to work surface, or is it only done on a special pad to absorb any overshoot? When I worked running Haas and Fadal machines we just jogged by hand while sliding a gauge block back and forth until it hit snug to set length offsets, and the Hitachi-Seiki had a special tool setter that was set on the table and the machine probed down to it's surface. I would guess there was some give to the surface on that device. Jim On Mon, Nov 12, 2012 at 11:00 AM, Jim Coleman drunkenwhip...@gmail.comwrote: Is the reason behind the floating head so there won't be damage if the head hits an object while cutting, like a warped part sticking up? I'm having trouble grasping why it's needed. Again, I have very little experience with plasma tables, being limited to the one machine my former employer had. That machine had a rigid Z axis with the plasma torch coupled with a device that used air pressure to hold the assembly in place. If the head crashed into a raised part, it would knock the 2 parts off from each other and the torch side would fall loose within the constraints of the other side of the housing and trigger an error on the control. To reset the head you had to pull it outward and lift slightly to reform the seal and the head would stick back in place. It took some tries before getting it to seal and stick, before you developed the touch. The mechanism was maybe 4 inches square, with the joining interface itself appearing to be round. A very similar machine can be seen at http://www.plasma-automation.com/mod_fabricatorHD.html and the page has a link to a slightly better image of their collision protection but they don't seem to provide many details. When the machine touched off, it appeared to use some form of conductivity to probe the surface. Holding a piece of steel off of the surface of the table and letting the head touch it wouldn't trigger the probe, until it pushed the steel down to the surface of the table. If it was strictly capacitance based, it seems it would trigger as soon as it touched, unless a human body holding onto a piece of scrap doesn't have enough capacitance to set it off. I'm sorry if I'm completely missing the point of wanting the floating head, I'm trying to comprehend the need. At first I thought the intention was for the head to just ride the surface of the workpiece and not use THC, but now I see that THC is to be implemented for cut height so I'm a little lost. Unless the float will replace the need for an electronic probing. I hope someone can clear up my confusion, and sorry if all of this is irrelevant. Jim On Mon, Nov 12, 2012 at 7:17 AM, andy pugh bodge...@gmail.com wrote: On 12 November 2012 11:32, Les Newell les.new...@fastmail.co.uk wrote: I have been thinking about this for some time and a while back I came up with a very different design to all of the others I have seen. First of all, you don't need or want a ball screw on Z. Z doesn't need to be hugely accurate. It needs reasonable resolution and it needs to be dirt resistant. Are double-helical racks available? It seems to me that those would give good location in a number of degrees of freedom, and allow direct stepper control. (Google) I can't find any. It would be reasonably expensive to make as an injection moulding, though relatively expensive to hob. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
What about, instead of it actually floating, if you were to soften the structure a little so it could handle the impact of hitting on the probe operation? I'm envisioning the torch mounted on rubber standoffs resembling the body mounts to a car. I'd think they could allow enough flex to keep from breaking stuff, but be rigid enough for accurate cutting, as accurate as plasma can be. Again I'm not all that familiar with plasma tables and their results, I know that the one I ran occasionally and bent parts from every day, would be doing great to give 1/16 inch repeatability cutting 13g steel. Jim On Mon, Nov 12, 2012 at 11:14 AM, andy pugh bodge...@gmail.com wrote: How I would do it: Use a trapezoidal screw and a delrin nut. Allow the nut to float axially in its housing, with a microswitch to detect when it has moved. Normally the head hangs on the nut. When the head touches then the nut slides down in its housing, operating the microswitch. (Use the probe G-code) back off to the required height + the known actuation distance and start the arc. I think I would use a leaf-spring suspension to supply the required angular constraint on the nut. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
I concur with Andy. Some of us use plasma cutter on a daily basis in production and some of us (Me) do consultation to sort out machine problems on a daily basis. From experience and seeing many good and many bad machines, the best production solution is a floating head that will detach when run into a job. I have seen many alternative solutions that all end up being scraped and redone to floating head. It is my opinion that the only good and maybe better alternative is the capacitive sensing THC system. The simpler the solution the lesser the troubles:) On 2012/11/12 06:08 PM, andy pugh wrote: On 12 November 2012 16:00, Jim Coleman drunkenwhip...@gmail.com wrote: Is the reason behind the floating head so there won't be damage if the head hits an object while cutting, like a warped part sticking up? I'm having trouble grasping why it's needed. While cutting you can measure the head-to-work distance using the arc voltage. However, to start cutting you need to have the head at the correct height then strike the arc. The idea is to use the head as a probe, lower to find the work, raise to the correct height, strike the arc then continue to cut while adjusting height based on arc voltage. -- Regards / Groete Marius D. Liebenberg MasterCut cc Cel: +27 82 698 3251 Tel: +27 12 743 6064 Fax: +27 86 551 8029 Skype: marius_d.liebenberg Skype Me^(TM)! skype:marius_d.liebenberg?call Get Skype http://www.skype.com/go/download and call me for free. --- avast! Antivirus: Outbound message clean. Virus Database (VPS): 121112-0, 2012/11/12 Tested on: 2012/11/12 07:06:25 PM avast! - copyright (c) 1988-2012 AVAST Software. http://www.avast.com -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
I like it when pros weigh in. The machine I used (it was in a production environment) didn't have any floating mechanism that I could see, but then again I wasn't at all impressed by that machine. It's homing sequence would get you within a repeatability of 2 inches or so in both X and Y, resuming a stopped cut was a headache of rehoming over and over till it chose the right spot. I do wish I had experience with a machine of higher quality, I'd probably think better of plasma tables. I developed a disdain for it, having to bend the parts and keep holes located consistently relative to a bends, and keep overall part widths consistent while bending with opposite sides of the burnt parts against the press' stops. Jim On Mon, Nov 12, 2012 at 12:06 PM, Marius Liebenberg mar...@mastercut.co.zawrote: I concur with Andy. Some of us use plasma cutter on a daily basis in production and some of us (Me) do consultation to sort out machine problems on a daily basis. From experience and seeing many good and many bad machines, the best production solution is a floating head that will detach when run into a job. I have seen many alternative solutions that all end up being scraped and redone to floating head. It is my opinion that the only good and maybe better alternative is the capacitive sensing THC system. The simpler the solution the lesser the troubles:) On 2012/11/12 06:08 PM, andy pugh wrote: On 12 November 2012 16:00, Jim Coleman drunkenwhip...@gmail.com wrote: Is the reason behind the floating head so there won't be damage if the head hits an object while cutting, like a warped part sticking up? I'm having trouble grasping why it's needed. While cutting you can measure the head-to-work distance using the arc voltage. However, to start cutting you need to have the head at the correct height then strike the arc. The idea is to use the head as a probe, lower to find the work, raise to the correct height, strike the arc then continue to cut while adjusting height based on arc voltage. -- Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
Controlling arc distance has been used as an example of one of the hardest things to put in a control loop. The interaction is non linear and chaotic. For cutting most sheet material, I would set it up to start at some sane distance and have a long, filtering time constant in the loop with some dead-band hysterisis - might want to throw away out of range samples. Trying to do a lot of fancy math to linearize the loop will lead to frustration. Karl Schmidt EMail k...@xtronics.com Transtronics, Inc. WEB http://secure.transtronics.com 3209 West 9th Street Ph (785) 841-3089 Lawrence, KS 66049 FAX (785) 841-0434 True wisdom is knowing what we don't know; There are many things that we can be certain of if we are willing to think, but true maturity is being comfortable with the idea that there are unknowable things. -KPS -- Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
On Tue, Nov 13, 2012 at 1:06 AM, Marius Liebenberg mar...@mastercut.co.zawrote: I have seen many alternative solutions that all end up being scraped and redone to floating head. It is my opinion that the only good and maybe better alternative is the capacitive sensing THC system. The simpler the solution the lesser the troubles:) The plasma head we worked with is rigid type. We use the torque feedback of the Z-axis servo motor to decide if it is hitting the plate. We called it analog probing. It is useful for underwater plasma cutting. Here's the video: http://youtu.be/amnozqEhRYE -Yishin -- Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
On Nov 12, 2012, at 5:56 PM, Yishin Li wrote: On Tue, Nov 13, 2012 at 1:06 AM, Marius Liebenberg mar...@mastercut.co.zawrote: I have seen many alternative solutions that all end up being scraped and redone to floating head. It is my opinion that the only good and maybe better alternative is the capacitive sensing THC system. The simpler the solution the lesser the troubles:) The plasma head we worked with is rigid type. We use the torque feedback of the Z-axis servo motor to decide if it is hitting the plate. We called it analog probing. It is useful for underwater plasma cutting. Here's the video: http://youtu.be/amnozqEhRYE Very nice. This is a feature of Granite servo drives (http://granitedevices.com/index.php?q=servo-drive-vsd-e). It is called homing to a hard stop. We use it on our plasma machine to home the X and Y axes which are driven by Granite VSD-E drives . We have it torque limit the servo motors and slow the velocity until the axis runs into a door stop (literally) that we placed at the end of travel. When the ferror reaches a settable max it then backs up to the index pulse of the encoders. Very accurate homing, no switches/wiring required. I never thought of using it to do touch off for the torch, but why not? -Tom -- Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
On Mon, 12 Nov 2012, Tom Easterday wrote: Date: Mon, 12 Nov 2012 19:13:15 -0500 From: Tom Easterday tom-...@bgp.nu Reply-To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Floating plasma torch - asking to share experience On Nov 12, 2012, at 5:56 PM, Yishin Li wrote: On Tue, Nov 13, 2012 at 1:06 AM, Marius Liebenberg mar...@mastercut.co.zawrote: I have seen many alternative solutions that all end up being scraped and redone to floating head. It is my opinion that the only good and maybe better alternative is the capacitive sensing THC system. The simpler the solution the lesser the troubles:) The plasma head we worked with is rigid type. We use the torque feedback of the Z-axis servo motor to decide if it is hitting the plate. We called it analog probing. It is useful for underwater plasma cutting. Here's the video: http://youtu.be/amnozqEhRYE Very nice. This is a feature of Granite servo drives (http://granitedevices.com/index.php?q=servo-drive-vsd-e). It is called homing to a hard stop. We use it on our plasma machine to home the X and Y axes which are driven by Granite VSD-E drives . We have it torque limit the servo motors and slow the velocity until the axis runs into a door stop (literally) that we placed at the end of travel. When the ferror reaches a settable max it then backs up to the index pulse of the encoders. Very accurate homing, no switches/wiring required. I never thought of using it to do touch off for the torch, but why not? -Tom It should be noted that this should be possible with any torque mode servo and some HAL magic. Peter Wallace Mesa Electronics -- Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
But not practical for touch off on thin material... On 11/12/2012 6:30 PM, Peter C. Wallace wrote: On Mon, 12 Nov 2012, Tom Easterday wrote: Date: Mon, 12 Nov 2012 19:13:15 -0500 From: Tom Easterday tom-...@bgp.nu Reply-To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Floating plasma torch - asking to share experience On Nov 12, 2012, at 5:56 PM, Yishin Li wrote: On Tue, Nov 13, 2012 at 1:06 AM, Marius Liebenberg mar...@mastercut.co.zawrote: I have seen many alternative solutions that all end up being scraped and redone to floating head. It is my opinion that the only good and maybe better alternative is the capacitive sensing THC system. The simpler the solution the lesser the troubles:) The plasma head we worked with is rigid type. We use the torque feedback of the Z-axis servo motor to decide if it is hitting the plate. We called it analog probing. It is useful for underwater plasma cutting. Here's the video: http://youtu.be/amnozqEhRYE Very nice. This is a feature of Granite servo drives (http://granitedevices.com/index.php?q=servo-drive-vsd-e). It is called homing to a hard stop. We use it on our plasma machine to home the X and Y axes which are driven by Granite VSD-E drives . We have it torque limit the servo motors and slow the velocity until the axis runs into a door stop (literally) that we placed at the end of travel. When the ferror reaches a settable max it then backs up to the index pulse of the encoders. Very accurate homing, no switches/wiring required. I never thought of using it to do touch off for the torch, but why not? -Tom It should be noted that this should be possible with any torque mode servo and some HAL magic. Peter Wallace Mesa Electronics -- Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
I think it would work fine, you can set the torque and velocity quite low. I think I could touch off on cardboard if I had to :-) -Tom On Nov 12, 2012, at 8:14 PM, John Thornton wrote: But not practical for touch off on thin material... On 11/12/2012 6:30 PM, Peter C. Wallace wrote: On Mon, 12 Nov 2012, Tom Easterday wrote: Date: Mon, 12 Nov 2012 19:13:15 -0500 From: Tom Easterday tom-...@bgp.nu Reply-To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Subject: Re: [Emc-users] Floating plasma torch - asking to share experience On Nov 12, 2012, at 5:56 PM, Yishin Li wrote: On Tue, Nov 13, 2012 at 1:06 AM, Marius Liebenberg mar...@mastercut.co.zawrote: I have seen many alternative solutions that all end up being scraped and redone to floating head. It is my opinion that the only good and maybe better alternative is the capacitive sensing THC system. The simpler the solution the lesser the troubles:) The plasma head we worked with is rigid type. We use the torque feedback of the Z-axis servo motor to decide if it is hitting the plate. We called it analog probing. It is useful for underwater plasma cutting. Here's the video: http://youtu.be/amnozqEhRYE Very nice. This is a feature of Granite servo drives (http://granitedevices.com/index.php?q=servo-drive-vsd-e). It is called homing to a hard stop. We use it on our plasma machine to home the X and Y axes which are driven by Granite VSD-E drives . We have it torque limit the servo motors and slow the velocity until the axis runs into a door stop (literally) that we placed at the end of travel. When the ferror reaches a settable max it then backs up to the index pulse of the encoders. Very accurate homing, no switches/wiring required. I never thought of using it to do touch off for the torch, but why not? -Tom It should be noted that this should be possible with any torque mode servo and some HAL magic. Peter Wallace Mesa Electronics -- Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
On Tue, Nov 13, 2012 at 9:14 AM, John Thornton bjt...@gmail.com wrote: But not practical for touch off on thin material... There's a digital probe signal attached to the plasma head. For thin material or dry plasma cut, we use digital probe. -Yishin -- Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Floating plasma torch - asking to share experience
Karl Most good THC equipment give you three signals of importance. 1: The Arc good signal - tells you that the system has pierced and is ready to move 2: Torch up - tells you the torch is too low 3: Torch down - tells yo the torch is to high Simple bit of logic will sort out the THC loop I think. On 2012/11/13 12:34 AM, Karl Schmidt wrote: Controlling arc distance has been used as an example of one of the hardest things to put in a control loop. The interaction is non linear and chaotic. For cutting most sheet material, I would set it up to start at some sane distance and have a long, filtering time constant in the loop with some dead-band hysterisis - might want to throw away out of range samples. Trying to do a lot of fancy math to linearize the loop will lead to frustration. Karl Schmidt EMail k...@xtronics.com Transtronics, Inc. WEB http://secure.transtronics.com 3209 West 9th Street Ph (785) 841-3089 Lawrence, KS 66049 FAX (785) 841-0434 True wisdom is knowing what we don't know; There are many things that we can be certain of if we are willing to think, but true maturity is being comfortable with the idea that there are unknowable things. -KPS -- Regards / Groete Marius D. Liebenberg MasterCut cc Cel: +27 82 698 3251 Tel: +27 12 743 6064 Fax: +27 86 551 8029 Skype: marius_d.liebenberg Skype Me^(TM)! skype:marius_d.liebenberg?call Get Skype http://www.skype.com/go/download and call me for free. --- avast! Antivirus: Outbound message clean. Virus Database (VPS): 121112-1, 2012/11/12 Tested on: 2012/11/13 07:27:23 AM avast! - copyright (c) 1988-2012 AVAST Software. http://www.avast.com -- Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
