Re: [Emc-users] Planning phase for new machine, need decision support
On Fri, 9 Aug 2013 20:10:45 +0200, you wrote: Thanks Steve, that got me thinking. :) And as it happened I had some boring long term tasks at work today (load testing of a distributed retail system) and some spare time when watching the monitors and log files. So I took it further and sourced some of the heavy formula's. I didn't go to the fullest, I have added a default inertia for motor and reduction for example. But the calculations turned out to be quite interesting and fun to play with so I updated the calc sheet pretty much. Please have a look! Some goes as before, could be totally wrong (At least I tried!). http://bit.ly/16DrFdP Figures look more like what I'd expect - nice one :) Steve Blackmore -- -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
On Fri, 9 Aug 2013 01:15:41 +0200, you wrote: Anyhow, I've searched the Internet after different stepper formulas and ended with the rough estimation at the Gecko site for choosing steppers. I made a sheet out of it and played around for fun. If these figures are somewhat correct, I can go with much smaller steppers than I thought. It's here for anyone who wants to try it: http://bit.ly/16DrFdP The default values are there only to check that the calculations are correct compared to Mariss' formula found here: http://bit.ly/15SU15g If I've done the sheet correct? Heck I do' no'. But if I have a go with 3m/min, 5 mm pitch, 0.25 reduction and 2.5 Nm i end up with pretty small figures and a decent tolerance. Hi Sven - have a read of this http://www.arceurotrade.co.uk/projects/X3-CNC/X3_Article_Part_1.pdf An article by Dick Stephen about converting an SX3 mill, but this section gives a good explanation of the math required to work out what size steppers are required. Mariss formula lacks some detail ;) Steve Blackmore -- -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
2013/8/9 Steve Blackmore st...@pilotltd.net Hi Sven - have a read of this http://www.arceurotrade.co.uk/projects/X3-CNC/X3_Article_Part_1.pdf An article by Dick Stephen about converting an SX3 mill, but this section gives a good explanation of the math required to work out what size steppers are required. Mariss formula lacks some detail ;) Steve Blackmore Thanks Steve, that got me thinking. :) And as it happened I had some boring long term tasks at work today (load testing of a distributed retail system) and some spare time when watching the monitors and log files. So I took it further and sourced some of the heavy formula's. I didn't go to the fullest, I have added a default inertia for motor and reduction for example. But the calculations turned out to be quite interesting and fun to play with so I updated the calc sheet pretty much. Please have a look! Some goes as before, could be totally wrong (At least I tried!). http://bit.ly/16DrFdP /Sven -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
I think your 'Inertia Table load' is incorrect, pitch is defined as the distance the table moves with one turn of the motor (2pi), ignore the gear ratio. Bellisimo -Original Message- From: Sven Wesley [mailto:svenne.d...@gmail.com] Sent: 09 August 2013 08:11 PM To: Steve Blackmore; Enhanced Machine Controller (EMC) Subject: Re: [Emc-users] Planning phase for new machine, need decision support 2013/8/9 Steve Blackmore st...@pilotltd.net Hi Sven - have a read of this http://www.arceurotrade.co.uk/projects/X3-CNC/X3_Article_Part_1.pdf An article by Dick Stephen about converting an SX3 mill, but this section gives a good explanation of the math required to work out what size steppers are required. Mariss formula lacks some detail ;) Steve Blackmore Thanks Steve, that got me thinking. :) And as it happened I had some boring long term tasks at work today (load testing of a distributed retail system) and some spare time when watching the monitors and log files. So I took it further and sourced some of the heavy formula's. I didn't go to the fullest, I have added a default inertia for motor and reduction for example. But the calculations turned out to be quite interesting and fun to play with so I updated the calc sheet pretty much. Please have a look! Some goes as before, could be totally wrong (At least I tried!). http://bit.ly/16DrFdP /Sven -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
2013/8/9 Belli Button be...@iafrica.com I think your 'Inertia Table load' is incorrect, pitch is defined as the distance the table moves with one turn of the motor (2pi), ignore the gear ratio. Bellisimo Fixed. /S -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
Theoretically that may be true, but you can't feel slop in the middle of the step at all on these new stepper motors. They feel tight when they are being held in position.. If you grab a knob on the shaft when they are energized stationary there appears to be no slop. If you want to use steppers you need to make one step of the motor equal to a machine movement of less than the desired precision of the machine.. That dictates your motor gearing ratio to the load. Unfortunately that also dictates the max speed of the machine since steppers run out of usable torque at relatively low speeds compared to servos. But for many applications that is not a problem. I have an old Bridgeport mill with steppers and I think it was geared such that one step of the motors was equal to .001 of an inch which apparently was good enough for thousands of machines shops. On the other hand the mill I have is no speed demon during rapids with the old heavy finned motors..50-60 ipm is quite reliable. which at this point is fast enough. Dave True. Quite a large amount of machines run steppers, not only old chunks but knew ones too. Ok, they have less transport speed than I am looking for but as I see it it's a matter of putting small motors and cheap drivers in to cut the costs. I have no problem with a belt reduction in between to keep the tolerances in range of the motor movement (or to increase the movement for the motor). I can't really let the closed loop stepper setup go, it's still very cost friendly and I get brushless motors at the same time... /S -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
2013/8/7 Dave e...@dc9.tzo.com ... I have an old Bridgeport mill with steppers and I think it was geared such that one step of the motors was equal to .001 of an inch which apparently was good enough for thousands of machines shops. On the other hand the mill I have is no speed demon during rapids with the old heavy finned motors..50-60 ipm is quite reliable. which at this point is fast enough. Dave I've had a nice conversation with an old guy who has long experience in building machines, he thought I was aiming too high. On the other hand he thought that about my previous machine as well but I want speed and he wants control (aka less speed). Sort of. Of course I realize I'll never reach the 2500m/s^2 acceleration I have with the servo's, but it's not that large area anyway and now there's more weight to it. Lets face it, a Tormach has pretty small steppers and they do cut steel. Anyhow, I've searched the Internet after different stepper formulas and ended with the rough estimation at the Gecko site for choosing steppers. I made a sheet out of it and played around for fun. If these figures are somewhat correct, I can go with much smaller steppers than I thought. It's here for anyone who wants to try it: http://bit.ly/16DrFdP The default values are there only to check that the calculations are correct compared to Mariss' formula found here: http://bit.ly/15SU15g If I've done the sheet correct? Heck I do' no'. But if I have a go with 3m/min, 5 mm pitch, 0.25 reduction and 2.5 Nm i end up with pretty small figures and a decent tolerance. /S -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
On Tue, 6 Aug 2013 22:11:42 -0400, you wrote: On Tue, Aug 6, 2013 at 9:13 AM, Stephen Dubovsky smdubov...@gmail.com wrote: Something to remember w/ steppers is that they produce no torque at rest. Here's what you have to remember about steppers: Zero torque at zero speed, and zero torque at maximum speed :) Old wives tale. Steve Blackmore -- -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
2013/8/6 Dave e...@dc9.tzo.com ... Here is some free motor sizing software that seems to be quite accurate. A number of Servo drive companies use this software and they brand label it.. http://visualsizer.com/ It is entirely free. I have used the Visual Sizer XP for years and it is really good but takes some effort to figure out how to run it even though it is very graphical. ... Dave i did try it out but there's something that I miss. I tried a 10 m/min calculation with a 5 mm pitch screw and it ended up with a needed RPM from motor at 60.69 RPM... /S -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
On 7 August 2013 08:24, Sven Wesley svenne.d...@gmail.com wrote: i did try it out but there's something that I miss. I tried a 10 m/min calculation with a 5 mm pitch screw and it ended up with a needed RPM from motor at 60.69 RPM... I don't know what you did there, unless you are not coupling screw to motor 1:1 10m is 2000 turns of the screw. So 10m/min is 2000 rpm. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
2013/8/7 andy pugh bodge...@gmail.com On 7 August 2013 08:24, Sven Wesley svenne.d...@gmail.com wrote: i did try it out but there's something that I miss. I tried a 10 m/min calculation with a 5 mm pitch screw and it ended up with a needed RPM from motor at 60.69 RPM... I don't know what you did there, unless you are not coupling screw to motor 1:1 10m is 2000 turns of the screw. So 10m/min is 2000 rpm. You don't have to tell me that. ;) -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
On 8/7/2013 3:24 AM, Sven Wesley wrote: 2013/8/6 Davee...@dc9.tzo.com ... Here is some free motor sizing software that seems to be quite accurate. A number of Servo drive companies use this software and they brand label it.. http://visualsizer.com/ It is entirely free. I have used the Visual Sizer XP for years and it is really good but takes some effort to figure out how to run it even though it is very graphical. ... Dave i did try it out but there's something that I miss. I tried a 10 m/min calculation with a 5 mm pitch screw and it ended up with a needed RPM from motor at 60.69 RPM... /S The software does take a little while to figure out. If you get stuck, post the configuration somewhere and I will download it and take a look at it. The workflow on how to make that application do what you want is not entirely obvious. Dave -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
On Wed, Aug 7, 2013 at 12:16 AM, Don Stanley dstanley1...@gmail.com wrote: Most stepper controllers have idle torque. Some will have full torque at idle (stopped). Most modern stepper controllers will have a selectable idle torque and some will wait a few seconds before switching from run torque to idle torque. You missed Stephen's point---yes, there's a holding current going through the stepper coils, but in the middle of the step the torque is zero. In other words, the stepper motor holds the position by having local maxima of holding torque at half step ahead and after the desired position. There's no closed loop like in a servo, where you can increase the precision by increasing the resolver resolution and/or the gain. Don't get me wrong---I actually like steppers, because they are simple and reliable, and accurate enough if engineered properly by matching their inherent accuracy to the desired movement precision. It's just that we have to understand their limitations. -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
On 8/7/2013 12:23 PM, Przemek Klosowski wrote: On Wed, Aug 7, 2013 at 12:16 AM, Don Stanleydstanley1...@gmail.com wrote: Most stepper controllers have idle torque. Some will have full torque at idle (stopped). Most modern stepper controllers will have a selectable idle torque and some will wait a few seconds before switching from run torque to idle torque. You missed Stephen's point---yes, there's a holding current going through the stepper coils, but in the middle of the step the torque is zero. In other words, the stepper motor holds the position by having local maxima of holding torque at half step ahead and after the desired position. There's no closed loop like in a servo, where you can increase the precision by increasing the resolver resolution and/or the gain. Don't get me wrong---I actually like steppers, because they are simple and reliable, and accurate enough if engineered properly by matching their inherent accuracy to the desired movement precision. It's just that we have to understand their limitations. -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users Theoretically that may be true, but you can't feel slop in the middle of the step at all on these new stepper motors. They feel tight when they are being held in position.. If you grab a knob on the shaft when they are energized stationary there appears to be no slop. If you want to use steppers you need to make one step of the motor equal to a machine movement of less than the desired precision of the machine.. That dictates your motor gearing ratio to the load. Unfortunately that also dictates the max speed of the machine since steppers run out of usable torque at relatively low speeds compared to servos. But for many applications that is not a problem. I have an old Bridgeport mill with steppers and I think it was geared such that one step of the motors was equal to .001 of an inch which apparently was good enough for thousands of machines shops. On the other hand the mill I have is no speed demon during rapids with the old heavy finned motors..50-60 ipm is quite reliable. which at this point is fast enough. Dave -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
2013/8/6 Dave e...@dc9.tzo.com A lot of it depends on how much power you need from the motors..and how fast do you want your machine to move. Then also what happens if you lose position on a stepper?? Dave A well designed stepper system shouldn't loose steps, right? There are many metal working machines out there since decades with large old steppers that still runs, but they aren't fast. My steel router has small Nidec servo's running 5 m/min with no problem (with awesome acceleration), right now the computer is the threshold, I get errors if I speed up the threads. I need more outputs and a faster controller this time and it will be a Mesa card included for sure. The palette I'm going to use as a table is pretty heavy, and put a mould half on top of that. That's at least 100 kg moving parts, maybe more. And I want at least 5 m/min transport, the double would make me satisfied but that means too large motors and screws for the budget I think. Looking at the smaller cheaper machines like the Tormach they all have steppers - and a transport speed around half of my minimum requirement. I'm not sure that a stepper setup will make it, but still it's the half of the price even though I choose beefy motors. For me there's no learning curve in servo's, I'd rather say I have a learning curve when it comes to _steppers_. A five axis setup will not be cheap and this time there's a bottom in the money pocket. /S -- Get your SQL database under version control now! Version control is standard for application code, but databases havent caught up. So what steps can you take to put your SQL databases under version control? Why should you start doing it? Read more to find out. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
On Tue, 8/6/13, Sven Wesley svenne.d...@gmail.com wrote: Subject: Re: [Emc-users] Planning phase for new machine, need decision support To: Enhanced Machine Controller (EMC) emc-users@lists.sourceforge.net Date: Tuesday, August 6, 2013, 12:17 AM The palette I'm going to use as a table is pretty heavy, and put a mould half on top of that. That's at least 100 kg moving parts, maybe more. And I want at least 5 m/min transport, the double would make me satisfied but that means too large motors and screws for the budget I think. -- You need to figure out how much torque you'll need. Some people have used motors from Fisher and Paykel clothes washers and directly fit them to the table screws on milling machines. How much torque? Up to 40 Newton-meters for the Ma series, up to 50 for the MB series. http://www.fp.fisherpaykel.com/direct-drive-motors/common/pdf/4876_NZ_Motors_BRO_HR.pdf The motors on my 2400 pound Acra knee mill peak at 3 Newton-meters and use cogged belts for speed reduction. A 50 Nm motor directly coupled to the screw on such a mill would be pretty crazy. ;-) I wonder if those motors (which look to me like very overgrown 3.5 floppy drive motors) could be stacked and the windings connected in parallel for even more power? In any case those motors seem to be plentiful and cheap if you live in a country where FP is a common appliance brand. (The motors are also sought after by homebrew wind generator builders to convert into alternators.) -- Get your SQL database under version control now! Version control is standard for application code, but databases havent caught up. So what steps can you take to put your SQL databases under version control? Why should you start doing it? Read more to find out. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
2013/8/6 Sven Wesley svenne.d...@gmail.com The palette I'm going to use as a table is pretty heavy, and put a mould half on top of that. That's at least 100 kg moving parts, maybe more. And I want at least 5 m/min transport. Max acceleration is what matters most for the motor. In my router I have 7500 mm/min maxvel and 300 mm/s^2 maxaccel (it reaches max velocity in 0,4 seconds, which is fine for me). It requires 30N force to move 100 kg at 0,3 m/s^2. With a 5 mm pitch ballscrews it would require 0.023 Nm of torque applied to the screw. This calculation assumes no friction and other losses, so add 30-40% for safety and then another 50% to make sure that stepper motor is not running out of torque. It still is less than 0.1 Nm to move the machine itself around. IMHO milling forces have to be calculated to take them into account as well as that might much bigger load than these 100 kg. I definitely do like those largest Nema23 motors - SY60STH86-3008B: http://www.zappautomation.co.uk/en/attachment.php?id_attachment=140 At 60V/4.3 A and halfstepping they have something like 1.3 Nm at 1500 RPM. And 1500 RPM with 5 mm ballscrew pitch will give 7500 mm/min velocity. -- Viesturs If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Get your SQL database under version control now! Version control is standard for application code, but databases havent caught up. So what steps can you take to put your SQL databases under version control? Why should you start doing it? Read more to find out. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
2013/8/6 Viesturs Lācis viesturs.la...@gmail.com 2013/8/6 Sven Wesley svenne.d...@gmail.com The palette I'm going to use as a table is pretty heavy, and put a mould half on top of that. That's at least 100 kg moving parts, maybe more. And I want at least 5 m/min transport. Max acceleration is what matters most for the motor. In my router I have 7500 mm/min maxvel and 300 mm/s^2 maxaccel (it reaches max velocity in 0,4 seconds, which is fine for me). It requires 30N force to move 100 kg at 0,3 m/s^2. With a 5 mm pitch ballscrews it would require 0.023 Nm of torque applied to the screw. This calculation assumes no friction and other losses, so add 30-40% for safety and then another 50% to make sure that stepper motor is not running out of torque. It still is less than 0.1 Nm to move the machine itself around. IMHO milling forces have to be calculated to take them into account as well as that might much bigger load than these 100 kg. I definitely do like those largest Nema23 motors - SY60STH86-3008B: http://www.zappautomation.co.uk/en/attachment.php?id_attachment=140 At 60V/4.3 A and halfstepping they have something like 1.3 Nm at 1500 RPM. And 1500 RPM with 5 mm ballscrew pitch will give 7500 mm/min velocity. -- Viesturs Good writing Viesturs. My small Nidec servo's can keep up with the acceleration I have now and it makes the machine shake at short runs. I don't remember the acceleration config but it's just a fraction to max speed and the portal is around 80-90 kg. /S -- Get your SQL database under version control now! Version control is standard for application code, but databases havent caught up. So what steps can you take to put your SQL databases under version control? Why should you start doing it? Read more to find out. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
2013/8/6 Sven Wesley svenne.d...@gmail.com 2013/8/6 Viesturs Lācis viesturs.la...@gmail.com 2013/8/6 Sven Wesley svenne.d...@gmail.com The palette I'm going to use as a table is pretty heavy, and put a mould half on top of that. That's at least 100 kg moving parts, maybe more. And I want at least 5 m/min transport. Max acceleration is what matters most for the motor. In my router I have 7500 mm/min maxvel and 300 mm/s^2 maxaccel (it reaches max velocity in 0,4 seconds, which is fine for me). It requires 30N force to move 100 kg at 0,3 m/s^2. With a 5 mm pitch ballscrews it would require 0.023 Nm of torque applied to the screw. This calculation assumes no friction and other losses, so add 30-40% for safety and then another 50% to make sure that stepper motor is not running out of torque. It still is less than 0.1 Nm to move the machine itself around. IMHO milling forces have to be calculated to take them into account as well as that might much bigger load than these 100 kg. I definitely do like those largest Nema23 motors - SY60STH86-3008B: http://www.zappautomation.co.uk/en/attachment.php?id_attachment=140 At 60V/4.3 A and halfstepping they have something like 1.3 Nm at 1500 RPM. And 1500 RPM with 5 mm ballscrew pitch will give 7500 mm/min velocity. -- Viesturs Good writing Viesturs. My small Nidec servo's can keep up with the acceleration I have now and it makes the machine shake at short runs. I don't remember the acceleration config but it's just a fraction to max speed and the portal is around 80-90 kg. /S When checking Zapp's webshop they have hybrid closed loop steppers, it's seems to be quite easy to beef up with strong steppers at low cost... -- Get your SQL database under version control now! Version control is standard for application code, but databases havent caught up. So what steps can you take to put your SQL databases under version control? Why should you start doing it? Read more to find out. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
2013/8/6 Sven Wesley svenne.d...@gmail.com 2013/8/6 Sven Wesley svenne.d...@gmail.com 2013/8/6 Viesturs Lācis viesturs.la...@gmail.com 2013/8/6 Sven Wesley svenne.d...@gmail.com The palette I'm going to use as a table is pretty heavy, and put a mould half on top of that. That's at least 100 kg moving parts, maybe more. And I want at least 5 m/min transport. Max acceleration is what matters most for the motor. In my router I have 7500 mm/min maxvel and 300 mm/s^2 maxaccel (it reaches max velocity in 0,4 seconds, which is fine for me). It requires 30N force to move 100 kg at 0,3 m/s^2. With a 5 mm pitch ballscrews it would require 0.023 Nm of torque applied to the screw. This calculation assumes no friction and other losses, so add 30-40% for safety and then another 50% to make sure that stepper motor is not running out of torque. It still is less than 0.1 Nm to move the machine itself around. IMHO milling forces have to be calculated to take them into account as well as that might much bigger load than these 100 kg. I definitely do like those largest Nema23 motors - SY60STH86-3008B: http://www.zappautomation.co.uk/en/attachment.php?id_attachment=140 At 60V/4.3 A and halfstepping they have something like 1.3 Nm at 1500 RPM. And 1500 RPM with 5 mm ballscrew pitch will give 7500 mm/min velocity. -- Viesturs Good writing Viesturs. My small Nidec servo's can keep up with the acceleration I have now and it makes the machine shake at short runs. I don't remember the acceleration config but it's just a fraction to max speed and the portal is around 80-90 kg. When checking Zapp's webshop they have hybrid closed loop steppers, it's seems to be quite easy to beef up with strong steppers at low cost... Thanks! I build these machines for living so I should be doing some basic calculations :)) I just checked and discovered that they have also 2 phase steppers with 4 wires for the closed loop (I somehow thought that they are using _only_ 3-phase stepper motors). Here is one of their 2-phase 4-wire closedloop motors: http://www.zappautomation.co.uk/en/easy-servo-stepper-motors-closed-loop-stepper-system/882-es-m22430-3nm-holding-torque.html Based on datasheet it seems that it is Nema23, so I was wondering, if regular Nema23 stepper motor could be used instead, because there is significant price difference: http://www.zappautomation.co.uk/en/nema-23-stepper-motors/380-sy60sth88-3008bf-nema-24-stepper-motor.html -- Viesturs If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Get your SQL database under version control now! Version control is standard for application code, but databases havent caught up. So what steps can you take to put your SQL databases under version control? Why should you start doing it? Read more to find out. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
Something to remember w/ steppers is that they produce no torque at rest. The maximum pullout torque is at 1/4 full step of error. W/ a typ 200 step motor thats 1/800th of a revolution. W/ a 0.2(5tpi) leadscrew like on a bridgeport that is 0.2/800= +-.00025 error depending on moving/cutting force direction. Bigger motors w/ torque reserve help but the torque curve vs displacement is sinusoidal so there is always a 'null' around the commanded location even if you oversize the motors by a factor of 100. That error can be more than acceptable in many applications (esp for ones geared down), but for high precision some other form of feedback may be necessary. Stephen On Tue, Aug 6, 2013 at 4:54 AM, Viesturs Lācis viesturs.la...@gmail.comwrote: 2013/8/6 Sven Wesley svenne.d...@gmail.com 2013/8/6 Sven Wesley svenne.d...@gmail.com 2013/8/6 Viesturs Lācis viesturs.la...@gmail.com 2013/8/6 Sven Wesley svenne.d...@gmail.com The palette I'm going to use as a table is pretty heavy, and put a mould half on top of that. That's at least 100 kg moving parts, maybe more. And I want at least 5 m/min transport. Max acceleration is what matters most for the motor. In my router I have 7500 mm/min maxvel and 300 mm/s^2 maxaccel (it reaches max velocity in 0,4 seconds, which is fine for me). It requires 30N force to move 100 kg at 0,3 m/s^2. With a 5 mm pitch ballscrews it would require 0.023 Nm of torque applied to the screw. This calculation assumes no friction and other losses, so add 30-40% for safety and then another 50% to make sure that stepper motor is not running out of torque. It still is less than 0.1 Nm to move the machine itself around. IMHO milling forces have to be calculated to take them into account as well as that might much bigger load than these 100 kg. I definitely do like those largest Nema23 motors - SY60STH86-3008B: http://www.zappautomation.co.uk/en/attachment.php?id_attachment=140 At 60V/4.3 A and halfstepping they have something like 1.3 Nm at 1500 RPM. And 1500 RPM with 5 mm ballscrew pitch will give 7500 mm/min velocity. -- Viesturs Good writing Viesturs. My small Nidec servo's can keep up with the acceleration I have now and it makes the machine shake at short runs. I don't remember the acceleration config but it's just a fraction to max speed and the portal is around 80-90 kg. When checking Zapp's webshop they have hybrid closed loop steppers, it's seems to be quite easy to beef up with strong steppers at low cost... Thanks! I build these machines for living so I should be doing some basic calculations :)) I just checked and discovered that they have also 2 phase steppers with 4 wires for the closed loop (I somehow thought that they are using _only_ 3-phase stepper motors). Here is one of their 2-phase 4-wire closedloop motors: http://www.zappautomation.co.uk/en/easy-servo-stepper-motors-closed-loop-stepper-system/882-es-m22430-3nm-holding-torque.html Based on datasheet it seems that it is Nema23, so I was wondering, if regular Nema23 stepper motor could be used instead, because there is significant price difference: http://www.zappautomation.co.uk/en/nema-23-stepper-motors/380-sy60sth88-3008bf-nema-24-stepper-motor.html -- Viesturs If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Get your SQL database under version control now! Version control is standard for application code, but databases havent caught up. So what steps can you take to put your SQL databases under version control? Why should you start doing it? Read more to find out. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Get your SQL database under version control now! Version control is standard for application code, but databases havent caught up. So what steps can you take to put your SQL databases under version control? Why should you start doing it? Read more to find out. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
On Tue, 2013-08-06 at 09:13 -0400, Stephen Dubovsky wrote: Something to remember w/ steppers is that they produce no torque at rest. The maximum pullout torque is at 1/4 full step of error. W/ a typ 200 step motor thats 1/800th of a revolution. W/ a 0.2(5tpi) leadscrew like on a bridgeport that is 0.2/800= +-.00025 error depending on moving/cutting force direction. Bigger motors w/ torque reserve help but the torque curve vs displacement is sinusoidal so there is always a 'null' around the commanded location even if you oversize the motors by a factor of 100. That error can be more than acceptable in many applications (esp for ones geared down), but for high precision some other form of feedback may be necessary. Stephen Too early in the morning and still on first cup of coffee but: if you are within the 1/4 step (null) then increased feedback of some kind won't fix it. Gearing eg. gears or timing belt with zero (?) backlash or slack will certainly help. BTW - there was an implication in an earlier email that implied that a tach would help positioning; well only in better control of velocity which makes tuning easier. The tach is a velocity loop inside the position loop. It REALLY makes it easier to tune although I've seen good tuning without it. Also alluding to an earlier email cradek tried a synthetic tach off the encoder counts and it worked rather well at speed. Of course when you get down to creeping is when the analog tach really shines. Now off to work on the coffee. ;-) Dave On Tue, Aug 6, 2013 at 4:54 AM, Viesturs Lācis viesturs.la...@gmail.comwrote: 2013/8/6 Sven Wesley svenne.d...@gmail.com 2013/8/6 Sven Wesley svenne.d...@gmail.com 2013/8/6 Viesturs Lācis viesturs.la...@gmail.com 2013/8/6 Sven Wesley svenne.d...@gmail.com The palette I'm going to use as a table is pretty heavy, and put a mould half on top of that. That's at least 100 kg moving parts, maybe more. And I want at least 5 m/min transport. Max acceleration is what matters most for the motor. In my router I have 7500 mm/min maxvel and 300 mm/s^2 maxaccel (it reaches max velocity in 0,4 seconds, which is fine for me). It requires 30N force to move 100 kg at 0,3 m/s^2. With a 5 mm pitch ballscrews it would require 0.023 Nm of torque applied to the screw. This calculation assumes no friction and other losses, so add 30-40% for safety and then another 50% to make sure that stepper motor is not running out of torque. It still is less than 0.1 Nm to move the machine itself around. IMHO milling forces have to be calculated to take them into account as well as that might much bigger load than these 100 kg. I definitely do like those largest Nema23 motors - SY60STH86-3008B: http://www.zappautomation.co.uk/en/attachment.php?id_attachment=140 At 60V/4.3 A and halfstepping they have something like 1.3 Nm at 1500 RPM. And 1500 RPM with 5 mm ballscrew pitch will give 7500 mm/min velocity. -- Viesturs Good writing Viesturs. My small Nidec servo's can keep up with the acceleration I have now and it makes the machine shake at short runs. I don't remember the acceleration config but it's just a fraction to max speed and the portal is around 80-90 kg. When checking Zapp's webshop they have hybrid closed loop steppers, it's seems to be quite easy to beef up with strong steppers at low cost... Thanks! I build these machines for living so I should be doing some basic calculations :)) I just checked and discovered that they have also 2 phase steppers with 4 wires for the closed loop (I somehow thought that they are using _only_ 3-phase stepper motors). Here is one of their 2-phase 4-wire closedloop motors: http://www.zappautomation.co.uk/en/easy-servo-stepper-motors-closed-loop-stepper-system/882-es-m22430-3nm-holding-torque.html Based on datasheet it seems that it is Nema23, so I was wondering, if regular Nema23 stepper motor could be used instead, because there is significant price difference: http://www.zappautomation.co.uk/en/nema-23-stepper-motors/380-sy60sth88-3008bf-nema-24-stepper-motor.html -- Viesturs If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Get your SQL database under version control now! Version control is standard for application code, but databases havent caught up. So what steps can you take to put your SQL databases under version control? Why should you start doing it? Read more to find out. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
On Tue, Aug 6, 2013 at 9:41 AM, dave dengv...@charter.net wrote: Too early in the morning and still on first cup of coffee but: if you are within the 1/4 step (null) then increased feedback of some kind won't fix it. It does fix it. The feedback will cause the control loop to shift the commanded position away so that you ARE on the upslope of the torque curve. Its fundamentally how servos work. You need to develop Q(quadrature) current(flux) to get torque. The D(direct) current doesn't do any work. Technically, once you have feedback in a stepper system you can fully servo it and not require any 'holding current' if the application doesn't currently demand it. The fixed current most stepper drivers use is only because they don't know where they are in the DQ frame. So they provide a ton of D and shaft error shifts the angle to produce some Q. -- Get your SQL database under version control now! Version control is standard for application code, but databases havent caught up. So what steps can you take to put your SQL databases under version control? Why should you start doing it? Read more to find out. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
On 08/06/2013 08:17 AM, Stephen Dubovsky wrote: On Tue, Aug 6, 2013 at 9:41 AM, dave dengv...@charter.net wrote: Too early in the morning and still on first cup of coffee but: if you are within the 1/4 step (null) then increased feedback of some kind won't fix it. It does fix it. The feedback will cause the control loop to shift the commanded position away so that you ARE on the upslope of the torque curve. Its fundamentally how servos work. You need to develop Q(quadrature) current(flux) to get torque. The D(direct) current doesn't do any work. Technically, once you have feedback in a stepper system you can fully servo it and not require any 'holding current' if the application doesn't currently demand it. The fixed current most stepper drivers use is only because they don't know where they are in the DQ frame. So they provide a ton of D and shaft error shifts the angle to produce some Q. With much study, a fair amount of work and money, one 'could' get a stepper to act like a servo (except for the rapid torque fall-off at higher speeds, and resonance zones within the operating RPM range). But why bother when a real servo acts just like a servo? In my opinion, steppers fill a need for lower cost, and simplicity. If one needs to add complexity or cost to a stepper to get it to work, just use a servo. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/ -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
2013/8/6 Stephen Dubovsky smdubov...@gmail.com It does fix it. The feedback will cause the control loop to shift the commanded position away so that you ARE on the upslope of the torque curve. Its fundamentally how servos work. You need to develop Q(quadrature) current(flux) to get torque. The D(direct) current doesn't do any work. Technically, once you have feedback in a stepper system you can fully servo it and not require any 'holding current' if the application doesn't currently demand it. The fixed current most stepper drivers use is only because they don't know where they are in the DQ frame. So they provide a ton of D and shaft error shifts the angle to produce some Q. If that's the case a closed loop stepper system is still interesting. However, I've had a shorter mail discussion with Zapp about their products and the given arguments and statements out rule them totally as a provider for me. He started a debate about how bad it is to build a machine and a retrofit is much better - without knowing a thing about my engineering skills, profession or previous experience in machine construction (please find a machine which is suitable for a five axis retrofit). Right now I'm leaning towards servo's after all. -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
On 8/6/2013 12:42 PM, Sven Wesley wrote: 2013/8/6 Stephen Dubovskysmdubov...@gmail.com It does fix it. The feedback will cause the control loop to shift the commanded position away so that you ARE on the upslope of the torque curve. Its fundamentally how servos work. You need to develop Q(quadrature) current(flux) to get torque. The D(direct) current doesn't do any work. Technically, once you have feedback in a stepper system you can fully servo it and not require any 'holding current' if the application doesn't currently demand it. The fixed current most stepper drivers use is only because they don't know where they are in the DQ frame. So they provide a ton of D and shaft error shifts the angle to produce some Q. If that's the case a closed loop stepper system is still interesting. However, I've had a shorter mail discussion with Zapp about their products and the given arguments and statements out rule them totally as a provider for me. He started a debate about how bad it is to build a machine and a retrofit is much better - without knowing a thing about my engineering skills, profession or previous experience in machine construction (please find a machine which is suitable for a five axis retrofit). Right now I'm leaning towards servo's after all. Sven, To really do it right and not guess, you really need to do some engineering on the motor size you need. Especially if you are making a new machine design and not replacing something that has already been running with a certain size motor. Here is some free motor sizing software that seems to be quite accurate. A number of Servo drive companies use this software and they brand label it.. http://visualsizer.com/ It is entirely free. I have used the Visual Sizer XP for years and it is really good but takes some effort to figure out how to run it even though it is very graphical. Mariss /Freimanis/ - the Gecko drive guy has stated a couple of times that the max power you can get out of a normal bipolar stepper motor/drive is about 200 watts. Keep in mind that all of the the Gecko drives run at 80 volts or less. Some other companies like Parker sell high voltage stepper drives that can deliver 200 volts or more to the motor so I think they may be able to get more than 200 watts of power out of a stepper motor due to the higher voltage which leads to higher torque at speed which equates to more power. Dave -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
On Tue, Aug 6, 2013 at 9:13 AM, Stephen Dubovsky smdubov...@gmail.com wrote: Something to remember w/ steppers is that they produce no torque at rest. Here's what you have to remember about steppers: Zero torque at zero speed, and zero torque at maximum speed :) -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
Most stepper controllers have idle torque. Some will have full torque at idle (stopped). Most modern stepper controllers will have a selectable idle torque and some will wait a few seconds before switching from run torque to idle torque. Hope this helps. On Tue, Aug 6, 2013 at 10:11 PM, Przemek Klosowski przemek.klosow...@gmail.com wrote: On Tue, Aug 6, 2013 at 9:13 AM, Stephen Dubovsky smdubov...@gmail.com wrote: Something to remember w/ steppers is that they produce no torque at rest. Here's what you have to remember about steppers: Zero torque at zero speed, and zero torque at maximum speed :) -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Get 100% visibility into Java/.NET code with AppDynamics Lite! It's a free troubleshooting tool designed for production. Get down to code-level detail for bottlenecks, with 2% overhead. Download for free and get started troubleshooting in minutes. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
On 5 August 2013 18:34, Sven Wesley svenne.d...@gmail.com wrote: As you might know (according to recent mail activity) I'm going to build a new machine. My plan is to use a mesa card setup and the machine will support 5 axis, but I will start with three... ...I think. This is where my need of decision support comes in. I have always used servo's even on smallest machines. But when I look at the stepper setups, they are like half price even if I go with beefy motors. My experience with steppers is limited, but the small NEMA 23s are quite nice, however the bigger NEMA23s became noticeably more sluggish which rather counted against the increased torque as far as performance was concerned. I can imagine that the big stepper motors continue this trend, and get stronger but more ponderous. Having built a stepper machine initially I decided on a servo machine for the second build, and have so far not regretted it. Just the repeatability of index-homing is a big plus to me. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Get your SQL database under version control now! Version control is standard for application code, but databases havent caught up. So what steps can you take to put your SQL databases under version control? Why should you start doing it? Read more to find out. http://pubads.g.doubleclick.net/gampad/clk?id=49501711iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
On Mon, 2013-08-05 at 19:42 +0100, andy pugh wrote: On 5 August 2013 18:34, Sven Wesley svenne.d...@gmail.com wrote: As you might know (according to recent mail activity) I'm going to build a new machine. My plan is to use a mesa card setup and the machine will support 5 axis, but I will start with three... ...I think. This is where my need of decision support comes in. I have always used servo's even on smallest machines. But when I look at the stepper setups, they are like half price even if I go with beefy motors. My experience with steppers is limited, but the small NEMA 23s are quite nice, however the bigger NEMA23s became noticeably more sluggish which rather counted against the increased torque as far as performance was concerned. I can imagine that the big stepper motors continue this trend, and get stronger but more ponderous. Having built a stepper machine initially I decided on a servo machine for the second build, and have so far not regretted it. Just the repeatability of index-homing is a big plus to me. Eh? however the bigger NEMA23s became noticeably more sluggish Maybe NEMA43's . I've been wanting to say this for years: If steppers were to suddenly disappear then this list would be surprising quiet. Most traffic comes for problems with steppers. I do think there is an initial learning curve with servos but once you get by that you tend to have less problems. Certainly if money is a problem then entry into servos may more phased but 10-12 years ago STG and Jon's PPMC were basically the only options. STG is ISA so pretty much out of the picture. Jon's PPMC is a high-end control (who else has 16 bits?) but there are much less expensive alternatives available today (12 bit) however I'm not aware of any in with 16 bit resolution. just my tuppence (not adjusted for inflation) Dave -- Get your SQL database under version control now! Version control is standard for application code, but databases havent caught up. So what steps can you take to put your SQL databases under version control? Why should you start doing it? Read more to find out. http://pubads.g.doubleclick.net/gampad/clk?id=49501711iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
On Mon, 5 Aug 2013 19:42:48 +0100, you wrote: On 5 August 2013 18:34, Sven Wesley svenne.d...@gmail.com wrote: As you might know (according to recent mail activity) I'm going to build a new machine. My plan is to use a mesa card setup and the machine will support 5 axis, but I will start with three... ...I think. This is where my need of decision support comes in. I have always used servo's even on smallest machines. But when I look at the stepper setups, they are like half price even if I go with beefy motors. My experience with steppers is limited, but the small NEMA 23s are quite nice, however the bigger NEMA23s became noticeably more sluggish which rather counted against the increased torque as far as performance was concerned. I can imagine that the big stepper motors continue this trend, and get stronger but more ponderous. Bigger motors generally are more coggy and at low rpm they want to bump from step to step rather than rotating smoothly, but not all bigger motors are sluggish - many will do 2000 rpm or more. Most poor performing stepper systems seem to be low voltage machines running crappy Xylotex or similar drives at 24-30V. If you run the same steppers at 60-80V with decent drives the difference can be amazing. The new DM range Leadshine drives are very good with software tuning and a lot of programmable parameters. Have a look at the manual for the DM856 http://www.zappautomation.co.uk/en/attachment.php?id_attachment=144 I'm not a fan of Gecko drives. They all seem to suffer from DIR problems, including the latest G320X servo drives! Having built a stepper machine initially I decided on a servo machine for the second build, and have so far not regretted it. Just the repeatability of index-homing is a big plus to me. There are closed loop stepper systems too :) I saw a large closed loop stepper driven router/vinyl cutter recently that was being made for a sign company, it's performance was outstanding. I honestly thought it was a servo system when I saw it under test. It had two heads, they could be vinyl knives or high speed spindles and took about a minute to change. Price wise - steppers are cheaper than servos, and if chosen carefully they can perform well. My router is stepper driven, direct drive to 4mm pitch ballscrews, it will run at 5m/min+ if required. I normally run it in the 3 to 4m/min range and I can honestly say I've never suffered from lost steps or lack of torque and it's right on the performance range I designed it for. Steve Blackmore -- -- Get your SQL database under version control now! Version control is standard for application code, but databases havent caught up. So what steps can you take to put your SQL databases under version control? Why should you start doing it? Read more to find out. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Planning phase for new machine, need decision support
A lot of it depends on how much power you need from the motors..and how fast do you want your machine to move. Then also what happens if you lose position on a stepper?? Dave On 8/5/2013 1:34 PM, Sven Wesley wrote: As you might know (according to recent mail activity) I'm going to build a new machine. My plan is to use a mesa card setup and the machine will support 5 axis, but I will start with three... ...I think. This is where my need of decision support comes in. I have always used servo's even on smallest machines. But when I look at the stepper setups, they are like half price even if I go with beefy motors. Should I cut the costs and use steppers, or should I bit the apple and pay for a servo setup this time too? FYI, this is the base of my machine. I have two of these Deckel palettes. http://bit.ly/16Y5o8y I've been using motors and drives from http://cncdrive.com with great success in the past and their drives are really stable with some nice security features. /S -- Get your SQL database under version control now! Version control is standard for application code, but databases havent caught up. So what steps can you take to put your SQL databases under version control? Why should you start doing it? Read more to find out. http://pubads.g.doubleclick.net/gampad/clk?id=49501711iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Get your SQL database under version control now! Version control is standard for application code, but databases havent caught up. So what steps can you take to put your SQL databases under version control? Why should you start doing it? Read more to find out. http://pubads.g.doubleclick.net/gampad/clk?id=48897031iu=/4140/ostg.clktrk ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
