Re: [Emc-users] What hardware should buy to start
On Friday 04 September 2009, Youda He wrote: Thanks, that look good. Does the EMC2 tracking the actual position, assume sometimes the stepper lost a step or so, with parallel port communication, how does one feed the optical encode position info back to the computer? -- Youda Through the input pins on that same port, or if there are not enough pins available, a 2nd parport card can be added to the computer. I believe there are enough spare pins that a quadrature pair can be had for 3 axis's without the extra port being needed. However there is a potential problem with that approach. If the stepper is pushed too hard or fast, it will indeed lose steps, and that error will be fed back into emc, which will attempt to play catchup, further weakening the motors torque since steppers torque falls with increasing speeds. So the incipient stall is converted into a full blown stall by the feedback. Either way the motor will generally stall until the step rate is reduced to near zero at the far end of the move, and the part is of course wasted. In my own experiments, I have found that if the machine is well lubed and adjusted, the snappieness of movement can be sacrificed, and because the accels are reduced, then the maxvels go up quite a bit. Faster in steel than my limited spindle can cut without breaking bits because the max spindle rpm is only 2400. I end up programming steel cuts at maybe 10 thou deep and 2 to 3 thou thick chips. Any more and the spindle will stall, blow a fuse or trip its safety off, and a $14 1/4 carbide bit is made into 2 or more pieces. Hard grades of alu can be cut at faster feed speeds but requires the surface be well flooded to preserve the finish and exclude as much oxygen from the cut as is possible. That of course we all know. With steppers, it is far more preferable to stay in the bottom half of the speed envelope where the potential for a lost step and or stalls disappears. If you need more speed with steppers, throw more psu voltage at the drivers, but currents are generally more than sufficient at 2 to 2.5 amps. Or if there is torque available, change the gearing to get more speed. On Fri, Sep 4, 2009 at 6:35 PM, Gene Heskett gene.hesk...@gmail.com wrote: On Friday 04 September 2009, Youda He wrote: Thanks, it seems most computer works, especially the Intel Atom worked well. Do we have drawings to connect parallel port to step driver? We have some Allegro chip that takes pulse, direction and will do the rest of driving. That is available as a ready made unit, 3 or 4 channels(motors) wide, from xylotex, google for it. I have both a 3 axis and a 4, and within its limits (2.5 amps/motor) and 30 volts max for the psu, it works quite well. It will need active cooling, so I made a box a few inches longer than the board, and the same square as a common psu fan, one in each end of the box, one blowing in and of course the other end is sucking the warm air out. That also works well. -- Youda On Fri, Sep 4, 2009 at 12:21 PM, Peter C. Wallace p...@mesanet.com wrote: On Fri, 4 Sep 2009, Youda He wrote: Date: Fri, 4 Sep 2009 11:42:21 -0700 From: Youda He yo...@geometrysystems.com 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] What hardware should buy to start Thanks, do we need to consider what CPU performance level is needed, P4, Core2, GHz? memory size? -- Youda Probably 1 GHz or greater, 256M or more of RAM. If you are using software step generation, for example with a parallel port driving the step motors, the main issue will not be the processor speed, but be the latency of the PC. This may require some fussing about with video cards, disabling SMI, or choosing a different motherboard. The wiki lists some known good motherboards: http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Latency-Test Peter Wallace - - Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users --- --- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july
Re: [Emc-users] What hardware should buy to start
Thanks, I am planning to cut aluminum, not the hard type, I can take when cutting, so maybe I'll cut slowly, what stepper is recommended? How big should it be? -- Youda On Fri, Sep 4, 2009 at 11:19 PM, Gene Heskett gene.hesk...@gmail.comwrote: On Friday 04 September 2009, Youda He wrote: Thanks, that look good. Does the EMC2 tracking the actual position, assume sometimes the stepper lost a step or so, with parallel port communication, how does one feed the optical encode position info back to the computer? -- Youda Through the input pins on that same port, or if there are not enough pins available, a 2nd parport card can be added to the computer. I believe there are enough spare pins that a quadrature pair can be had for 3 axis's without the extra port being needed. However there is a potential problem with that approach. If the stepper is pushed too hard or fast, it will indeed lose steps, and that error will be fed back into emc, which will attempt to play catchup, further weakening the motors torque since steppers torque falls with increasing speeds. So the incipient stall is converted into a full blown stall by the feedback. Either way the motor will generally stall until the step rate is reduced to near zero at the far end of the move, and the part is of course wasted. In my own experiments, I have found that if the machine is well lubed and adjusted, the snappieness of movement can be sacrificed, and because the accels are reduced, then the maxvels go up quite a bit. Faster in steel than my limited spindle can cut without breaking bits because the max spindle rpm is only 2400. I end up programming steel cuts at maybe 10 thou deep and 2 to 3 thou thick chips. Any more and the spindle will stall, blow a fuse or trip its safety off, and a $14 1/4 carbide bit is made into 2 or more pieces. Hard grades of alu can be cut at faster feed speeds but requires the surface be well flooded to preserve the finish and exclude as much oxygen from the cut as is possible. That of course we all know. With steppers, it is far more preferable to stay in the bottom half of the speed envelope where the potential for a lost step and or stalls disappears. If you need more speed with steppers, throw more psu voltage at the drivers, but currents are generally more than sufficient at 2 to 2.5 amps. Or if there is torque available, change the gearing to get more speed. On Fri, Sep 4, 2009 at 6:35 PM, Gene Heskett gene.hesk...@gmail.com wrote: On Friday 04 September 2009, Youda He wrote: Thanks, it seems most computer works, especially the Intel Atom worked well. Do we have drawings to connect parallel port to step driver? We have some Allegro chip that takes pulse, direction and will do the rest of driving. That is available as a ready made unit, 3 or 4 channels(motors) wide, from xylotex, google for it. I have both a 3 axis and a 4, and within its limits (2.5 amps/motor) and 30 volts max for the psu, it works quite well. It will need active cooling, so I made a box a few inches longer than the board, and the same square as a common psu fan, one in each end of the box, one blowing in and of course the other end is sucking the warm air out. That also works well. -- Youda On Fri, Sep 4, 2009 at 12:21 PM, Peter C. Wallace p...@mesanet.com wrote: On Fri, 4 Sep 2009, Youda He wrote: Date: Fri, 4 Sep 2009 11:42:21 -0700 From: Youda He yo...@geometrysystems.com 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] What hardware should buy to start Thanks, do we need to consider what CPU performance level is needed, P4, Core2, GHz? memory size? -- Youda Probably 1 GHz or greater, 256M or more of RAM. If you are using software step generation, for example with a parallel port driving the step motors, the main issue will not be the processor speed, but be the latency of the PC. This may require some fussing about with video cards, disabling SMI, or choosing a different motherboard. The wiki lists some known good motherboards: http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Latency-Test Peter Wallace - - Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Upgrading fixed the problems with ubuntu-8.04-desktop-emc2-aj12-i386.iso hm2-servo
Just in case anyone else should stumble into these waters, this further error confounded trying to start emc with a 5i20, using the demo configs: HAL: ERROR: function 'hm2_5i20.0.read' not found hm2-servo.hal:55: addf failed There was one hit on google, but the pastebin post had expired. However, performing an apt-get install emc2, to upgrade to 2.3.3, fixed that and allowed the AXIS GUI to be reached. (Shoulda done it last night, instead of just considering it.) Hey, clear road ahead! :-)) Erik -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] What hardware should buy to start
On Saturday 05 September 2009, Youda He wrote: Thanks, I am planning to cut aluminum, not the hard type, I can take when cutting, so maybe I'll cut slowly, what stepper is recommended? How big should it be? -- Youda Be aware that _any_ alu will have a coat of alu oxide on it, thickness dependent on how long exposed to the air, and 1/1000 of a second is sufficient to form a 50 volt thick film. alu is a _very_ reactive element in the presence of the oxygen in the air. Generally for a machining operation, this coating is responsible for 99% of the wear dulling, even on carbide tooling since alu oxide is the 2nd hardest substance in nature. There are some harder formulations between there and diamond, but neither of us can afford them, too new. You can't do anything about the surface of the raw material, but when machining, the surface should be well flooded by some relatively oxygen free fluid which will cover the cutting edge, and the freshly cut surface as quickly as possible. 2 schools of thought here, compete for how you do it. Either assumes the cut will be as deep as the spindle has power to do as that removes the unwanted material with fewer miles on the cutting edge. One is to cut an oil flooded surface very slowly so that the turning bit can remain wetted immediately behind the cutting edge, slowing the formation of the oxide. Water is comparatively useless for this as its 1/3rd oxygen. How fast you can turn the bit depends on how deep the flooding is. The other, and more commonly used method is to flood the area with a high pressure mist of oil, so everything is wet and cut as quickly as the machine has the power to do it. Again the idea is to get the job done with the least wear on the cutting edge as it plows through this rapidly forming coat of alu oxide. This will often give a better final finish as the high pressure blows away the chips so they won't get trapped by the next cutting edge and mark the surface as the chip then skids a bit before its recut again. All this needs to be taken into consideration when planning an alu machining operation. Dry, with high pressure air to clear the chips can work quite well, but its also pretty hard on the tooling, so you'll need to almost start each such part with a fresh cutting tool in the spindle. Not conducive to high profit margins. And since when am I the resident metallurgist here? I'm just an old (75 a month from now) retired television engineer. :) This gentleman Youda is obviously just getting his feet wet with this stuff, and there is a veritable encyclopedia of knowledge available on this list. In this crowd, I am _not_ a guru. So pipe right up with the stuff I'm missing guys. On Fri, Sep 4, 2009 at 11:19 PM, Gene Heskett gene.hesk...@gmail.comwrote: [...] -- Cheers, Gene There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) The NRA is offering FREE Associate memberships to anyone who wants them. https://www.nrahq.org/nrabonus/accept-membership.asp petribar: Any sun-bleached prehistoric candy that has been sitting in the window of a vending machine too long. -- Rich Hall, Sniglets -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] How to learn movements with EMC
Great ! Many thanks to everybody, there is a lot of great ideas I will explore soon ! (I have to finish the hardware first... Just operating the steppers with no machine to move is not really useful :/ ) - Matthew Ireland wyeh...@gmail.com a écrit : As the moves I need to do are very simples, (just drawing a square with the glue, in fact), I think learning moves like this will be far more easy than creating Gcode. Dude, as a person who spent years writing gcode in a text editor, all I can say is your program will be literally four g1 moves to x y coordinates. Setup and leaving moves will depend on your setup. You can write this program in one minute in Notepad. -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- (\__/) (='.'=) Ceci est un petit lapin. Copiez/collez-le dans ()_() votre signature pour l'aider à dominer le monde -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] What hardware should buy to start
Gene Heskett wrote: You can't do anything about the surface of the raw material, but when machining, the surface should be well flooded by some relatively oxygen free fluid which will cover the cutting edge, and the freshly cut surface as quickly as possible. 2 schools of thought here, compete for how you do it. Either assumes the cut will be as deep as the spindle has power to do as that removes the unwanted material with fewer miles on the cutting edge. One other thing is the direction of cut. If the material is fed against the direction of the cutting edge, noramlly called conventional milling, the cutter enters the material by scraping along the just-cut material until pressure builds enough for it to punch through. This scraping increases wear. The opposite is when the material is fed WITH the cutting edge, there the cutting tooth punches hard into the uncut material, and takes a slice that slowly decreases in thickness. This is called climb milling. This mode produces a lot less wear on the cutter, but it requires a tight machine, as this direction of feed has the cutter pulling the work, and machine table, toward it! If you have a lot of backlash in worn Acme leadscrews, this direction can cause the work to jump into the cutter, wrecking parts and breaking cutters. But, on a machine with tight screws, especially ballscrews, the results, in terms of surface finish and cutter life will be quite significant. Jon -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] What hardware should buy to start
Try a conventional cut for the finish pass on steel and see if you don't like the finish better. Sent via BlackBerry from T-Mobile -Original Message- From: Jon Elson el...@pico-systems.com Date: Sat, 05 Sep 2009 13:41:39 To: Enhanced Machine Controller (EMC)emc-users@lists.sourceforge.net Subject: Re: [Emc-users] What hardware should buy to start Gene Heskett wrote: You can't do anything about the surface of the raw material, but when machining, the surface should be well flooded by some relatively oxygen free fluid which will cover the cutting edge, and the freshly cut surface as quickly as possible. 2 schools of thought here, compete for how you do it. Either assumes the cut will be as deep as the spindle has power to do as that removes the unwanted material with fewer miles on the cutting edge. One other thing is the direction of cut. If the material is fed against the direction of the cutting edge, noramlly called conventional milling, the cutter enters the material by scraping along the just-cut material until pressure builds enough for it to punch through. This scraping increases wear. The opposite is when the material is fed WITH the cutting edge, there the cutting tooth punches hard into the uncut material, and takes a slice that slowly decreases in thickness. This is called climb milling. This mode produces a lot less wear on the cutter, but it requires a tight machine, as this direction of feed has the cutter pulling the work, and machine table, toward it! If you have a lot of backlash in worn Acme leadscrews, this direction can cause the work to jump into the cutter, wrecking parts and breaking cutters. But, on a machine with tight screws, especially ballscrews, the results, in terms of surface finish and cutter life will be quite significant. Jon -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] What hardware should buy to start
On Saturday 05 September 2009, Jon Elson wrote: Gene Heskett wrote: You can't do anything about the surface of the raw material, but when machining, the surface should be well flooded by some relatively oxygen free fluid which will cover the cutting edge, and the freshly cut surface as quickly as possible. 2 schools of thought here, compete for how you do it. Either assumes the cut will be as deep as the spindle has power to do as that removes the unwanted material with fewer miles on the cutting edge. One other thing is the direction of cut. If the material is fed against the direction of the cutting edge, noramlly called conventional milling, the cutter enters the material by scraping along the just-cut material until pressure builds enough for it to punch through. This scraping increases wear. The opposite is when the material is fed WITH the cutting edge, there the cutting tooth punches hard into the uncut material, and takes a slice that slowly decreases in thickness. This is called climb milling. This mode produces a lot less wear on the cutter, but it requires a tight machine, as this direction of feed has the cutter pulling the work, and machine table, toward it! If you have a lot of backlash in worn Acme leadscrews, this direction can cause the work to jump into the cutter, wrecking parts and breaking cutters. But, on a machine with tight screws, especially ballscrews, the results, in terms of surface finish and cutter life will be quite significant. Jon Also very well said, thanks Jon, for plugging a hole I missed. And I can testify about the sloppy screws bit as I have 2 to 3 thou of backlash in my setup. I have tried climb cutting, but in my case I have to take a really large increment in order to get the entry angle of the cutter steep enough that it doesn't pull the table and attack. With a .010 z increment, I have to feed the y about .1 per x pass. Because I don't have enough spindle power to take a .010 cut per flute, the bit wear seems to be a wash here, either is pretty darned hard on bits. I really would like to get an X3 put in ball screws, but as a hobby, I can't justify that big an outlay for no more time than I have left to enjoy it, darnit. -- Cheers, Gene There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order. -Ed Howdershelt (Author) The NRA is offering FREE Associate memberships to anyone who wants them. https://www.nrahq.org/nrabonus/accept-membership.asp It is impossible to enjoy idling thoroughly unless one has plenty of work to do. -- Jerome Klapka Jerome -- Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
