Re: [Emc-users] CAM grinder- What harware
Have you considered external offsets for this? I have had moderate success turning low lift cams with this feature. I'm preparing the retrofit of a cylindrical grinder with LinuxCNC to achieve camshaft and crankshaft grinding. With external offsets you don't need a really precise servo spindle. A normal and well reduced VFD driven spindle could be used and the X axis will follow the rotation. The obvious problem I had is that to achieve good results with the lathe I need a live tool to allow for lower spindle rpms. I'm working on that and soon I should have a live tool to mill the cams. With this approach you can use pretty simple g code and you only need a hal component to feed the external offset as the spindle turns. By the way, the cam data must be hard coded inside the component, I guess it could be fed in by some method by I didn't get there yet. Here are some tests I've been doing. https://youtu.be/KzEPyKZ6Xjo https://youtu.be/xjBXa6RHSPQ Leonardo Marsaglia El dom., 5 jul. 2020 20:24, Forums escribió: > I'm getting to the point where I need my own camshaft grinder. > > The question I have is the G-code. The grinder has 2 basic components, a > rotary operation to turn the cam and a linear movement to move the grinding > head. For simplistic sake, say the G-code is 360 deg with the > corresponding X > travel. Say we start with a blank round cam. In each revolution of the > cam, > the grinding wheel has to step in an amount till it gets to final size. > > This can be done with and If and Else statement. > > I was looking at some of the Chinese CNC controllers which are cheap and > stand > alone and as this is a simple job, would be a good option but I have not > been > able to find one that has logic in the G-Code. > > I don't think feedback is required and step and direction would be fine for > this project. It would need constant recalibration as the wheel wears. My > question is, what would be a suitable bit of hardware to run LinuxCNC. Is > the > PI up to this as yet ? > > Thanks Wallace. > > > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
Here's something that looks like the perfect thing for moving the grinder head on a CNC cam grinder. http://www.youtube.com/watch?v=9WIMscMFLAA Instead of connecting the two eccentrics to one motor and manually adjusting it, use two servo motors which would be independently controlled to continuously vary the stroke. Looks like the reaction time could be very fast, especially if both differential motor speed and reversing are used. A plain eccentric timed to the shaft rotation won't do for most camshafts. Flat tappet cams are usually egg shaped, with a rather pointy small end and a very small side to side taper around the base circle so the tappet and other valvetrain components will rotate. (The Chevy 350 smallblock V8 is a bit notorious for tappets failing to rotate then quickly chewing up themselves and the camshaft.) Roller tappet cams are usually racetrack shaped with a round end, nearly flat sides and no taper. -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
On 30 May 2013 08:42, Gregg Eshelman g_ala...@yahoo.com wrote: Here's something that looks like the perfect thing for moving the grinder head on a CNC cam grinder. http://www.youtube.com/watch?v=9WIMscMFLAA Clever, looks like fun to control. I guess that any of the steam engine valve-gear mechanisms would work too: http://en.wikipedia.org/wiki/Stephenson_valve_gear A plain eccentric timed to the shaft rotation won't do for most camshafts. Indeed, but a camshaft is a lot closer to an eccentric than to a spiral (which is what a constant-speed linear axis tries to make). The idea is to use a servo-driven eccentric to produce a heavily modified version of the basic eccentric shape by dynamically varying the phasing between the servo motor driving the eccentric and the spindle holding the cam. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
I did an interesting exercise today. I received a DXF from the cam grinder with 360 line segments. I imported into SheetCam and then exported it to GCode. I looked at the GCode and couldn't believe my eyes. It was only 7 arcs long. SheetCam must have joined the lines together and created arcs. So I plotted the arcs against the original DXF. Most of the arcs were very similar to the original and the greatest error was 15 thou. (this is on a 3 disk) Most sections were under 1 thou out. I reckon it would be almost perfect with 14 or so arcs. I have posted a similar question on SheetCams forum but does anyone have a DXF line to arc converter where I can enter the maximum error acceptable and it comes out with closest arcs? Surly the grinding head would be a lot happier and smoother with 14 or so arcs instead of 360 line segments. Cheers Wallace -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
the line segments will give a more accurate following of the area under the curve of your cam profile. if it is an engine cam .014 could make a dramatic difference in functionality. i would want to know if you can adjust the parameters of sheet cam to out put segments at .001 resolution to get a most accurate rendition of your camshaft profile. i know nothing of sheetcam , this is a simple adjustment to mastercam resolution parameters however. the other concern is one that has been being discussed in the developers list, that is one of linuxcnc lack of infinite look ahead and jerky motion. programming by line segment allows very accurate following of nurbs splines but generates a lot of code that the controller must be able to process in a smooth manner to achieve best results. it is my understanding that lcnc has some issues with this , although i have not done much profiling in mastercam on my mill so i cannot speak from authority on this subject only to state that it is a present topic that others have an interest in seeing developed. I for one would love to see infinite look ahead and smooth motion to be able to take maximum advantage of mastercams high speed toolpath and nurbs functions. the lack of these 2 functions may well cause some undesirable tool gouge should you be requiring highly precise camshaft contours. in the production coding world programming of g2, g3 arc segments is becoming largely antiquated due to the great advancements in cad cam packages and machine accuracy . in short the cad cam packages are now so good as to be able to make accurate repeatable segments of .001 all day long allowing nearly perfect recreation of your model from cad space. Now i have the disclaimer that all of the above is not been tested by me on an lcnc machine but again has been subject to much discussion on this and the developers list . without smooth motion there is a brief stop at the end of every segment that can cause the aforementioned tool gouge . so in this case if a perfect rendition of your cam is not necessary it will be at your best advantage to program using g2 , g3 but if strict adherence to profile is necessary you will have to see how well you can get the line segment resolution and see the affect of tool gouge , if you have gouge you may even be able to reduce the resolution to get a better surface on your part . lastly what are you using to check the profile of your cam with and what type of camshaft is it? On Thu, May 30, 2013 at 5:57 AM, Marshland Engineering marshl...@marshland.co.nz wrote: I did an interesting exercise today. I received a DXF from the cam grinder with 360 line segments. I imported into SheetCam and then exported it to GCode. I looked at the GCode and couldn't believe my eyes. It was only 7 arcs long. SheetCam must have joined the lines together and created arcs. So I plotted the arcs against the original DXF. Most of the arcs were very similar to the original and the greatest error was 15 thou. (this is on a 3 disk) Most sections were under 1 thou out. I reckon it would be almost perfect with 14 or so arcs. I have posted a similar question on SheetCams forum but does anyone have a DXF line to arc converter where I can enter the maximum error acceptable and it comes out with closest arcs? Surly the grinding head would be a lot happier and smoother with 14 or so arcs instead of 360 line segments. Cheers Wallace -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- We conclude that the Second Amendment protects an individual right to keep and bear arms. That right existed prior to the formation of the new government under the Constitution and was premised on the private use of arms for activities such as hunting and self-defense, the latter being understood as resistance to either private lawlessness or the depredations of a tyrannical government. - U.S. Court of Appeals, D.C. Circuit, March 9, 2007 jeremy youngs -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net
Re: [Emc-users] Cam Grinder
That mechanism is interesting, thought non-linear. You'd need to maximize the connecting rod lengths and then probably do some linearization in software to get the output to deliver uniform incremental displacement. N. Christopher Perry On May 30, 2013, at 3:42, Gregg Eshelman g_ala...@yahoo.com wrote: Here's something that looks like the perfect thing for moving the grinder head on a CNC cam grinder. http://www.youtube.com/watch?v=9WIMscMFLAA Instead of connecting the two eccentrics to one motor and manually adjusting it, use two servo motors which would be independently controlled to continuously vary the stroke. Looks like the reaction time could be very fast, especially if both differential motor speed and reversing are used. A plain eccentric timed to the shaft rotation won't do for most camshafts. Flat tappet cams are usually egg shaped, with a rather pointy small end and a very small side to side taper around the base circle so the tappet and other valvetrain components will rotate. (The Chevy 350 smallblock V8 is a bit notorious for tappets failing to rotate then quickly chewing up themselves and the camshaft.) Roller tappet cams are usually racetrack shaped with a round end, nearly flat sides and no taper. -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
I don't see a problem with using the standard PID loops. I did something similar to this with my lathe for turning some non circular parts. I couldn't use a very high spindle speed but I'm sure it was faster than you would need while grinding. Les On 29/05/2013 12:13, Marshland Engineering wrote: Has anyone made a 4 stroke CAM grinder using LINUXCNC. Apparently positioning the head is not the way to go. From what I was told the head needs to be positioned with acceleration rather than absolute position. It sound a bit odd but apparently if you have done this before, you have an idea of what I'm talking about. Thinking about it, the grinding head will have rapid amounts of accelleration and decelleration during the CAM grinding cycle, so unless the PID loop is very fast and accurate and enough power to overcome the large inertia, it won't grind correctly. It could grind correctly and with lot less power if the control system had next move predictive option Cheers Wallace -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
On 29 May 2013 12:41, Les Newell les.new...@fastmail.co.uk wrote: I don't see a problem with using the standard PID loops. I did something similar to this with my lathe for turning some non circular parts http://www.youtube.com/watch?v=FpP7iTKuWpw -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
Yup, that is pretty similar to what I did only in my case the parts were tapered and hexagonal. Les On 29/05/2013 12:48, andy pugh wrote: On 29 May 2013 12:41, Les Newell les.new...@fastmail.co.uk wrote: I don't see a problem with using the standard PID loops. I did something similar to this with my lathe for turning some non circular parts http://www.youtube.com/watch?v=FpP7iTKuWpw -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
On 29 May 2013 13:00, Les Newell les.new...@fastmail.co.uk wrote: Yup, that is pretty similar to what I did only in my case the parts were tapered and hexagonal. I have a HAL component that allows me to say how many facets I want on my polygons. It is actually in the system all the time, but is rather rarely used. Partly because my lathe can't really turn slowly enough for the X-axis to track properly. It's handy for turning parts like this: https://picasaweb.google.com/lh/photo/d4I-fmDmnUsK1nalPhVJhtMTjNZETYmyPJy0liipFm0?feat=directlink -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
I do make camshafts for living, and I'm controlling a cam grinder with LinuxCNC but only for positioning, since the grinder uses a master to make the lobes. I'm always thinking about using cnc to make the profiles and don't use the masters anymore. Because the lack of time, I couldn't even start with the tests for this but it's a feature I would really like to implement!. The first thing anyway will be the roughing of the cams using a mill, I have two old hydraulic copy lathes that are going to be used for this. If that works, it's the first step. I'm delaying this because I'm making several other projects now. Anyway I did read Andy's program and given my poor knowledge I didn't understand too much, anyway it's a matter of learning, but I think that for the roughing process with a mill there is no need to use acceleration PID, I think that using only position PID it would be ok. For the griding process it's another deal since there is no room for the error and the axis of the grinding wheel has to follow exactly the rotary axis, and obviously have the radius compensation. I think that's the trickiest part in case of doing it using acceleration instead of position. A really interesting proyect indeed. 2013/5/29 andy pugh bodge...@gmail.com On 29 May 2013 13:00, Les Newell les.new...@fastmail.co.uk wrote: Yup, that is pretty similar to what I did only in my case the parts were tapered and hexagonal. I have a HAL component that allows me to say how many facets I want on my polygons. It is actually in the system all the time, but is rather rarely used. Partly because my lathe can't really turn slowly enough for the X-axis to track properly. It's handy for turning parts like this: https://picasaweb.google.com/lh/photo/d4I-fmDmnUsK1nalPhVJhtMTjNZETYmyPJy0liipFm0?feat=directlink -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- *Leonardo Marsaglia*. -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
My HAL component used a simple lookup table that mapped spindle angle to X position. The table was generated by SheetCam so I could cut any shape I could draw. It's still on the machine but it has been so long since I last used it I can't remember how it all tied together. I also have a SheetCam post somewhere for cam grinding. It maps X,Y to X,C. It assumes you have a C axis instead of a free running spindle. SheetCam than takes care of compensating for the wheel diameter. Les On 29/05/2013 13:12, andy pugh wrote: I have a HAL component that allows me to say how many facets I want on my polygons. It is actually in the system all the time, but is rather rarely used. Partly because my lathe can't really turn slowly enough for the X-axis to track properly. It's handy for turning parts like this: https://picasaweb.google.com/lh/photo/d4I-fmDmnUsK1nalPhVJhtMTjNZETYmyPJy0liipFm0?feat=directlink -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
How fast do you turn the cam while grinding? Les On 29/05/2013 13:23, Leonardo Marsaglia wrote: I do make camshafts for living, and I'm controlling a cam grinder with LinuxCNC but only for positioning, since the grinder uses a master to make the lobes. I'm always thinking about using cnc to make the profiles and don't use the masters anymore. Because the lack of time, I couldn't even start with the tests for this but it's a feature I would really like to implement!. The first thing anyway will be the roughing of the cams using a mill, I have two old hydraulic copy lathes that are going to be used for this. If that works, it's the first step. I'm delaying this because I'm making several other projects now. Anyway I did read Andy's program and given my poor knowledge I didn't understand too much, anyway it's a matter of learning, but I think that for the roughing process with a mill there is no need to use acceleration PID, I think that using only position PID it would be ok. For the griding process it's another deal since there is no room for the error and the axis of the grinding wheel has to follow exactly the rotary axis, and obviously have the radius compensation. I think that's the trickiest part in case of doing it using acceleration instead of position. A really interesting proyect indeed. -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
About 120 RPM for the first tenths of milimeter, and then 50 rpm for the last turns to finish it. This machine has no VFD, it uses a two speed electric motor and I use it as it was originally. I can make it go faster, but approximately that's the velocity I use to make them based on the diameters I use. 2013/5/29 Les Newell les.new...@fastmail.co.uk How fast do you turn the cam while grinding? Les On 29/05/2013 13:23, Leonardo Marsaglia wrote: I do make camshafts for living, and I'm controlling a cam grinder with LinuxCNC but only for positioning, since the grinder uses a master to make the lobes. I'm always thinking about using cnc to make the profiles and don't use the masters anymore. Because the lack of time, I couldn't even start with the tests for this but it's a feature I would really like to implement!. The first thing anyway will be the roughing of the cams using a mill, I have two old hydraulic copy lathes that are going to be used for this. If that works, it's the first step. I'm delaying this because I'm making several other projects now. Anyway I did read Andy's program and given my poor knowledge I didn't understand too much, anyway it's a matter of learning, but I think that for the roughing process with a mill there is no need to use acceleration PID, I think that using only position PID it would be ok. For the griding process it's another deal since there is no room for the error and the axis of the grinding wheel has to follow exactly the rotary axis, and obviously have the radius compensation. I think that's the trickiest part in case of doing it using acceleration instead of position. A really interesting proyect indeed. -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- *Leonardo Marsaglia*. -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
Did you just use a boring bar with your routine to do that? Very slick. How fast did you run the spindle when you did that? Dave On 5/29/2013 8:12 AM, andy pugh wrote: On 29 May 2013 13:00, Les Newellles.new...@fastmail.co.uk wrote: Yup, that is pretty similar to what I did only in my case the parts were tapered and hexagonal. I have a HAL component that allows me to say how many facets I want on my polygons. It is actually in the system all the time, but is rather rarely used. Partly because my lathe can't really turn slowly enough for the X-axis to track properly. It's handy for turning parts like this: https://picasaweb.google.com/lh/photo/d4I-fmDmnUsK1nalPhVJhtMTjNZETYmyPJy0liipFm0?feat=directlink -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
I don't see any problems with that sort of spindle speed. The normal PID loops will maintain pretty good tolerance. If your X axis is heavy you will need a reasonably powerful motor to provide the acceleration. Les On 29/05/2013 13:36, Leonardo Marsaglia wrote: About 120 RPM for the first tenths of milimeter, and then 50 rpm for the last turns to finish it. This machine has no VFD, it uses a two speed electric motor and I use it as it was originally. I can make it go faster, but approximately that's the velocity I use to make them based on the diameters I use. -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
Yes, thinking it fast I assume that a 4 kw servo motor and ballscrew will do it. Also there's the possibility of using the same hydraulic piston that the machine has but with a servo valve and a linear way. I've seen that a guy here on the list did that to a intetrior grinding machine and It worked pretty well, but this is not the same kind of movement, he only used the Z axis to make the plunge. 2013/5/29 Les Newell les.new...@fastmail.co.uk I don't see any problems with that sort of spindle speed. The normal PID loops will maintain pretty good tolerance. If your X axis is heavy you will need a reasonably powerful motor to provide the acceleration. Les On 29/05/2013 13:36, Leonardo Marsaglia wrote: About 120 RPM for the first tenths of milimeter, and then 50 rpm for the last turns to finish it. This machine has no VFD, it uses a two speed electric motor and I use it as it was originally. I can make it go faster, but approximately that's the velocity I use to make them based on the diameters I use. -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- *Leonardo Marsaglia*. -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
Leonardo Marsaglia wrote: About 120 RPM for the first tenths of milimeter, and then 50 rpm for the last turns to finish it. This machine has no VFD, it uses a two speed electric motor and I use it as it was originally. I can make it go faster, but approximately that's the velocity I use to make them based on the diameters I use. I don't think you have any problem, then. At 50 RPM, it seems the grinder head could follow the typical engine cam profile just fine. You wouldn't want a 100 kg grinder head to be moved by a NEMA size 23 motor, but a proper choice of motor and drive should handle it fine. The travel should be quite a bit less than 25 mm from max to min on the cam, unless you are doing locomotive or giant marine engine parts. Jon -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
Doing that with hydraulics would be very, very expensive compared to an electric servo. You would need a constant pressure pump, accumulator, and a very expensive servo valve to get that kind of speed. Big $. Dave Cole On 5/29/2013 12:18 PM, Leonardo Marsaglia wrote: Yes, thinking it fast I assume that a 4 kw servo motor and ballscrew will do it. Also there's the possibility of using the same hydraulic piston that the machine has but with a servo valve and a linear way. I've seen that a guy here on the list did that to a intetrior grinding machine and It worked pretty well, but this is not the same kind of movement, he only used the Z axis to make the plunge. 2013/5/29 Les Newellles.new...@fastmail.co.uk I don't see any problems with that sort of spindle speed. The normal PID loops will maintain pretty good tolerance. If your X axis is heavy you will need a reasonably powerful motor to provide the acceleration. Les On 29/05/2013 13:36, Leonardo Marsaglia wrote: About 120 RPM for the first tenths of milimeter, and then 50 rpm for the last turns to finish it. This machine has no VFD, it uses a two speed electric motor and I use it as it was originally. I can make it go faster, but approximately that's the velocity I use to make them based on the diameters I use. -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
The maximum lift we are machining is about 12 mm and maximum diameter is about 45mm . And may be some eccentrics on some camshafts but nothing too big. The subject I am worried about the most is the one about how to generate the g-code, because if I want the X axis to follow the profile on the cam but with acceleration and velocity values, like the diagrams of a real cam (lobe), then it's a little tricky. For that I would need to make some programming on hal because that would be handled directly from the PID loop. Also I need to capture the exact shape of the cam, that's not that tricky. About the roughing pass, that would be much more easy since I can generate the profile in a cam software and compensate the radius of the circular mill to make the shape. About the hydraulics, yes, I think using a servo motor would be the best. Mordern landis machines use powerful linear servo motors but I think that a ballscrew that has one or two cents of a milimeter will do just fine for the job. 2013/5/29 Dave e...@dc9.tzo.com Doing that with hydraulics would be very, very expensive compared to an electric servo. You would need a constant pressure pump, accumulator, and a very expensive servo valve to get that kind of speed. Big $. Dave Cole On 5/29/2013 12:18 PM, Leonardo Marsaglia wrote: Yes, thinking it fast I assume that a 4 kw servo motor and ballscrew will do it. Also there's the possibility of using the same hydraulic piston that the machine has but with a servo valve and a linear way. I've seen that a guy here on the list did that to a intetrior grinding machine and It worked pretty well, but this is not the same kind of movement, he only used the Z axis to make the plunge. 2013/5/29 Les Newellles.new...@fastmail.co.uk I don't see any problems with that sort of spindle speed. The normal PID loops will maintain pretty good tolerance. If your X axis is heavy you will need a reasonably powerful motor to provide the acceleration. Les On 29/05/2013 13:36, Leonardo Marsaglia wrote: About 120 RPM for the first tenths of milimeter, and then 50 rpm for the last turns to finish it. This machine has no VFD, it uses a two speed electric motor and I use it as it was originally. I can make it go faster, but approximately that's the velocity I use to make them based on the diameters I use. -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- *Leonardo Marsaglia*. -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
I've done a machine with linear servos and they would be perfect for what you want to do if you can get them with a high enough force rating, but they are very expensive in longer travels. Since you have a very short movement range you may want to check on some pricing. Dave Cole On 5/29/2013 12:54 PM, Leonardo Marsaglia wrote: The maximum lift we are machining is about 12 mm and maximum diameter is about 45mm . And may be some eccentrics on some camshafts but nothing too big. The subject I am worried about the most is the one about how to generate the g-code, because if I want the X axis to follow the profile on the cam but with acceleration and velocity values, like the diagrams of a real cam (lobe), then it's a little tricky. For that I would need to make some programming on hal because that would be handled directly from the PID loop. Also I need to capture the exact shape of the cam, that's not that tricky. About the roughing pass, that would be much more easy since I can generate the profile in a cam software and compensate the radius of the circular mill to make the shape. About the hydraulics, yes, I think using a servo motor would be the best. Mordern landis machines use powerful linear servo motors but I think that a ballscrew that has one or two cents of a milimeter will do just fine for the job. 2013/5/29 Davee...@dc9.tzo.com Doing that with hydraulics would be very, very expensive compared to an electric servo. You would need a constant pressure pump, accumulator, and a very expensive servo valve to get that kind of speed. Big $. Dave Cole On 5/29/2013 12:18 PM, Leonardo Marsaglia wrote: Yes, thinking it fast I assume that a 4 kw servo motor and ballscrew will do it. Also there's the possibility of using the same hydraulic piston that the machine has but with a servo valve and a linear way. I've seen that a guy here on the list did that to a intetrior grinding machine and It worked pretty well, but this is not the same kind of movement, he only used the Z axis to make the plunge. 2013/5/29 Les Newellles.new...@fastmail.co.uk I don't see any problems with that sort of spindle speed. The normal PID loops will maintain pretty good tolerance. If your X axis is heavy you will need a reasonably powerful motor to provide the acceleration. Les On 29/05/2013 13:36, Leonardo Marsaglia wrote: About 120 RPM for the first tenths of milimeter, and then 50 rpm for the last turns to finish it. This machine has no VFD, it uses a two speed electric motor and I use it as it was originally. I can make it go faster, but approximately that's the velocity I use to make them based on the diameters I use. -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
The problem with the short travel on the machine is that, it's fine for making the camshafts, but as the wheel get's smaller because of the dressing passes I need to move the X axis closer to the workpiece. Anyway I don't see too much room for a linear motor since the machine now has a piston, I don't know if there is in existance a linear servo motor with the shape of a piston, all circular or something like that, they must exist anyway. If that exists then it could be installed, if not the best way is the ballscrew. 2013/5/29 Dave e...@dc9.tzo.com I've done a machine with linear servos and they would be perfect for what you want to do if you can get them with a high enough force rating, but they are very expensive in longer travels. Since you have a very short movement range you may want to check on some pricing. Dave Cole On 5/29/2013 12:54 PM, Leonardo Marsaglia wrote: The maximum lift we are machining is about 12 mm and maximum diameter is about 45mm . And may be some eccentrics on some camshafts but nothing too big. The subject I am worried about the most is the one about how to generate the g-code, because if I want the X axis to follow the profile on the cam but with acceleration and velocity values, like the diagrams of a real cam (lobe), then it's a little tricky. For that I would need to make some programming on hal because that would be handled directly from the PID loop. Also I need to capture the exact shape of the cam, that's not that tricky. About the roughing pass, that would be much more easy since I can generate the profile in a cam software and compensate the radius of the circular mill to make the shape. About the hydraulics, yes, I think using a servo motor would be the best. Mordern landis machines use powerful linear servo motors but I think that a ballscrew that has one or two cents of a milimeter will do just fine for the job. 2013/5/29 Davee...@dc9.tzo.com Doing that with hydraulics would be very, very expensive compared to an electric servo. You would need a constant pressure pump, accumulator, and a very expensive servo valve to get that kind of speed. Big $. Dave Cole On 5/29/2013 12:18 PM, Leonardo Marsaglia wrote: Yes, thinking it fast I assume that a 4 kw servo motor and ballscrew will do it. Also there's the possibility of using the same hydraulic piston that the machine has but with a servo valve and a linear way. I've seen that a guy here on the list did that to a intetrior grinding machine and It worked pretty well, but this is not the same kind of movement, he only used the Z axis to make the plunge. 2013/5/29 Les Newellles.new...@fastmail.co.uk I don't see any problems with that sort of spindle speed. The normal PID loops will maintain pretty good tolerance. If your X axis is heavy you will need a reasonably powerful motor to provide the acceleration. Les On 29/05/2013 13:36, Leonardo Marsaglia wrote: About 120 RPM for the first tenths of milimeter, and then 50 rpm for the last turns to finish it. This machine has no VFD, it uses a two speed electric motor and I use it as it was originally. I can make it go faster, but approximately that's the velocity I use to make them based on the diameters I use. -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users
Re: [Emc-users] Cam Grinder
On 29 May 2013 13:24, Les Newell les.new...@fastmail.co.uk wrote:
My HAL component used a simple lookup table that mapped spindle angle to
X position.
After much messing about I found the maths to be fairly simple.
Here is the comp, it goes in between the axis.0.motor-pos-cmd and the
PID/stepgen.
It needs connections to the spindle position and the current radius
and tool offset (halui holds this).
It knows how to lie about position feedback to prevent f-errors.
If the facets pin is 2 it tries to make a polygon. Handy for those
home-made pentagonal allen keys and matching bolts :-)
component polygon Add a spindle-position related offset to an axis
for polygon turning;
pin in float encoder-pos encoder position, should be scaled 0-1;
pin in float pos-in the input (motor position);
pin in float pos-relative The commanded position, used for calcs.
halui.axis.N.pos-relative;
pin in float tool-offset;
pin in float facets = 0 the number of facets required;
pin out float pos-out the modified position request;
pin in float fb-in position feedback from joint;
pin out float fb-out position feedback to motion;
function _ ;
license GPL;
author Andy Pugh;
;;
#include rtapi_math.h
FUNCTION(_) {
float f, d;
if (facets 3) {
pos_out = pos_in;
fb_out = fb_in;
return;
}
f = encoder_pos - floor(encoder_pos * facets)/facets - (1 / (2 * facets));
d = (pos_relative - tool_offset) * (1 / cos(6.28318530717959 * f) - 1);
pos_out = pos_in + d;
fb_out = fb_in - d;
}
--
atp
If you can't fix it, you don't own it.
http://www.ifixit.com/Manifesto
--
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Re: [Emc-users] Cam Grinder
On 29 May 2013 18:49, Leonardo Marsaglia leonardomarsagli...@gmail.com wrote: Anyway I don't see too much room for a linear motor since the machine now has a piston, I don't know if there is in existance a linear servo motor with the shape of a piston, all circular or something like that, they must exist anyway. There are voice-coil servos, but I doubt they have enough force. I would actually be tempted to try a servo motor and crank on top of a conventional X-axis. In a rare move away from CNC, the crank throw would probably need to be manually adjusted to suit the total cam lift. For a simple eccentric this would only need to rotate at constant speed in exact phase with the spindle. As your cam profile deviates from the simple eccentric, then the relationship between the angular position of the two motors needs to be modified. Here is a HAL component that could apply this modification: http://www.linuxcnc.org/docs/devel/html/man/man9/lincurve.9.html It isn't ideal as it stands, it would need to be able to read cam profiles in from a data file. I think that mechanically this is a lot less challenging for the servo and controllers, the motor never changes direction, it just slows down and speeds up relative to the spindle. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
do you have a master cam? if so you could just build a cam duplicator On Wed, May 29, 2013 at 2:24 PM, andy pugh bodge...@gmail.com wrote: On 29 May 2013 18:49, Leonardo Marsaglia leonardomarsagli...@gmail.com wrote: Anyway I don't see too much room for a linear motor since the machine now has a piston, I don't know if there is in existance a linear servo motor with the shape of a piston, all circular or something like that, they must exist anyway. There are voice-coil servos, but I doubt they have enough force. I would actually be tempted to try a servo motor and crank on top of a conventional X-axis. In a rare move away from CNC, the crank throw would probably need to be manually adjusted to suit the total cam lift. For a simple eccentric this would only need to rotate at constant speed in exact phase with the spindle. As your cam profile deviates from the simple eccentric, then the relationship between the angular position of the two motors needs to be modified. Here is a HAL component that could apply this modification: http://www.linuxcnc.org/docs/devel/html/man/man9/lincurve.9.html It isn't ideal as it stands, it would need to be able to read cam profiles in from a data file. I think that mechanically this is a lot less challenging for the servo and controllers, the motor never changes direction, it just slows down and speeds up relative to the spindle. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- We conclude that the Second Amendment protects an individual right to keep and bear arms. That right existed prior to the formation of the new government under the Constitution and was premised on the private use of arms for activities such as hunting and self-defense, the latter being understood as resistance to either private lawlessness or the depredations of a tyrannical government. - U.S. Court of Appeals, D.C. Circuit, March 9, 2007 jeremy youngs -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
http://www.youtube.com/watch?v=88CgdUkrk3s here like this . if you set ti up to use a master lobe you can machine the lobe on a cnc mill then machine it off the master lobe and produce any cam you want On Wed, May 29, 2013 at 3:38 PM, jeremy youngs jcyoung...@gmail.com wrote: do you have a master cam? if so you could just build a cam duplicator On Wed, May 29, 2013 at 2:24 PM, andy pugh bodge...@gmail.com wrote: On 29 May 2013 18:49, Leonardo Marsaglia leonardomarsagli...@gmail.com wrote: Anyway I don't see too much room for a linear motor since the machine now has a piston, I don't know if there is in existance a linear servo motor with the shape of a piston, all circular or something like that, they must exist anyway. There are voice-coil servos, but I doubt they have enough force. I would actually be tempted to try a servo motor and crank on top of a conventional X-axis. In a rare move away from CNC, the crank throw would probably need to be manually adjusted to suit the total cam lift. For a simple eccentric this would only need to rotate at constant speed in exact phase with the spindle. As your cam profile deviates from the simple eccentric, then the relationship between the angular position of the two motors needs to be modified. Here is a HAL component that could apply this modification: http://www.linuxcnc.org/docs/devel/html/man/man9/lincurve.9.html It isn't ideal as it stands, it would need to be able to read cam profiles in from a data file. I think that mechanically this is a lot less challenging for the servo and controllers, the motor never changes direction, it just slows down and speeds up relative to the spindle. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- We conclude that the Second Amendment protects an individual right to keep and bear arms. That right existed prior to the formation of the new government under the Constitution and was premised on the private use of arms for activities such as hunting and self-defense, the latter being understood as resistance to either private lawlessness or the depredations of a tyrannical government. - U.S. Court of Appeals, D.C. Circuit, March 9, 2007 jeremy youngs -- We conclude that the Second Amendment protects an individual right to keep and bear arms. That right existed prior to the formation of the new government under the Constitution and was premised on the private use of arms for activities such as hunting and self-defense, the latter being understood as resistance to either private lawlessness or the depredations of a tyrannical government. - U.S. Court of Appeals, D.C. Circuit, March 9, 2007 jeremy youngs -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Cam Grinder
I make the master cams (lobes) with one of my machines since it's built for the purpose too. Then I use the same masters on the other machines. The pivot lenght is practically the same, I think the worst case is 1 or 2 mm of difference between machines. Also, I use the same range in diameter for the grinding wheels in all machines, so there is no difference between the original camshaft, and the ones that we build. If I want to digitally capture the function of the cam (lobe) I would preffer to make a little device for that purpose. One thing to study there is the way the follower in that device changes it's tangential point with the cam (lobe). This I think the most complex part in capturing the function, but with that resolved, you can capture almost any lobe. I suppose that the component to make the change in position based on acceleration would have to use certain control points and between those points fill the curve with a smooth path, so it would be a spline. That's were I don't know how to start, because it's a little advanced for me, but really interesting. Doable I think, since Linuxcnc proved to handle very well things that seem more complicated. Leonardo. 2013/5/29 jeremy youngs jcyoung...@gmail.com http://www.youtube.com/watch?v=88CgdUkrk3s here like this . if you set ti up to use a master lobe you can machine the lobe on a cnc mill then machine it off the master lobe and produce any cam you want On Wed, May 29, 2013 at 3:38 PM, jeremy youngs jcyoung...@gmail.com wrote: do you have a master cam? if so you could just build a cam duplicator On Wed, May 29, 2013 at 2:24 PM, andy pugh bodge...@gmail.com wrote: On 29 May 2013 18:49, Leonardo Marsaglia leonardomarsagli...@gmail.com wrote: Anyway I don't see too much room for a linear motor since the machine now has a piston, I don't know if there is in existance a linear servo motor with the shape of a piston, all circular or something like that, they must exist anyway. There are voice-coil servos, but I doubt they have enough force. I would actually be tempted to try a servo motor and crank on top of a conventional X-axis. In a rare move away from CNC, the crank throw would probably need to be manually adjusted to suit the total cam lift. For a simple eccentric this would only need to rotate at constant speed in exact phase with the spindle. As your cam profile deviates from the simple eccentric, then the relationship between the angular position of the two motors needs to be modified. Here is a HAL component that could apply this modification: http://www.linuxcnc.org/docs/devel/html/man/man9/lincurve.9.html It isn't ideal as it stands, it would need to be able to read cam profiles in from a data file. I think that mechanically this is a lot less challenging for the servo and controllers, the motor never changes direction, it just slows down and speeds up relative to the spindle. -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users -- We conclude that the Second Amendment protects an individual right to keep and bear arms. That right existed prior to the formation of the new government under the Constitution and was premised on the private use of arms for activities such as hunting and self-defense, the latter being understood as resistance to either private lawlessness or the depredations of a tyrannical government. - U.S. Court of Appeals, D.C. Circuit, March 9, 2007 jeremy youngs -- We conclude that the Second Amendment protects an individual right to keep and bear arms. That right existed prior to the formation of the new government under the Constitution and was premised on the private use of arms for activities such as hunting and self-defense, the latter being understood as resistance to either private lawlessness or the depredations of a tyrannical government. - U.S. Court of Appeals, D.C. Circuit, March 9, 2007 jeremy youngs -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes.
Re: [Emc-users] Cam Grinder
Looks like you chaps were busy chatting while is was sleeping piecefully and waking to a nice first this morning. The CAM grinder was a discussion I had with my local CAM grinder yesterday and from the replies, it looks like LinuxCNC will be able to create working solution. Thanks for the replies. It's on the back burner at the moment but definatly workable. Thanks Wallace. -- Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with 2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
