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Taig mill update
As you may remember, I've been making prototype printed circuits on my Taig micro mill. I was pretty well stuck, not being able to get traces small enough. It didn't seem to matter much what my z depth was, the conical bit wouldn't cut a line that was anywhere near as narrow as its 0.1mm tip.
Then one day, it dawned on me that that the head was vibrating like a sonofabitch. I mounted a dial indicator on the bed and positioned the plunger on the head. There was +/- .003" of vibration! pretty much a killer when trying to mill lines less than 0.008" wide. I have since replaced the whole headstock with a 1.5KW 400Hz spindle motor. It runs up to 24,000 rpm and there's no detectable vibration. This is great. Of course, now that that problem is fixed, it made others more visible. I noticed that lines in the +Y direction were a different width than those in -Y. This turned out to be loose gibs, so I took apart the whole XY mechanism, tightened the nuts to remove all but 0.0005" of backlash in X&Y which I had previously compensated for in mach3, and adjusted the gibs properly. All I can say is that I wish I had taken the time to do these things from the get-go. What a difference. Next (after I get some work out of the way), I'll do the same with the Z axis. |
Taig mill update
On 3/15/2018 10:37 AM, rangerssuck wrote: As you may remember, I've been making prototype printed circuits on my Taig micro mill. I was pretty well stuck, not being able to get traces small enough. It didn't seem to matter much what my z depth was, the conical bit wouldn't cut a line that was anywhere near as narrow as its 0.1mm tip. Then one day, it dawned on me that that the head was vibrating like a sonofabitch. I mounted a dial indicator on the bed and positioned the plunger on the head. There was ± .003" of vibration! pretty much a killer when trying to mill lines less than 0.008" wide. I have since replaced the whole headstock with a 1.5KW 400Hz spindle motor. It runs up to 24,000 rpm and there's no detectable vibration. This is great. Of course, now that that problem is fixed, it made others more visible. I noticed that lines in the +Y direction were a different width than those in -Y. This turned out to be loose gibs, so I took apart the whole XY mechanism, tightened the nuts to remove all but 0.0005" of backlash in X&Y which I had previously compensated for in mach3, and adjusted the gibs properly. All I can say is that I wish I had taken the time to do these things from the get-go. What a difference. Next (after I get some work out of the way), I'll do the same with the Z axis. Hmmmm... I think somebody here might have suggested the 24K spindle on the Taig. Did you use Paul Heinreichs spindle mounts? I can tell you from experience its better to adjust out backlash to the best of your ability and ignore the Mach 3 backlash compensation. I've watched it steadily work a profile cut across the part as it gets confused before. My experience showed me a Taig mill could be adjust reliably to under ..001 backlash and run ok, but it would limit the ability to rapid without losing steps. With it loosened up to about .003 backlash overall mine would cut upto about 60IPM and rapid up to 80ipm. Of course that is also dependent on your motors and controller. Whether or not that is "good enough" depends on the type of job you are doing and how you approach the job. |
Taig mill update
On Thursday, March 15, 2018 at 5:23:54 PM UTC-4, Bob La Londe wrote:
On 3/15/2018 10:37 AM, rangerssuck wrote: As you may remember, I've been making prototype printed circuits on my Taig micro mill. I was pretty well stuck, not being able to get traces small enough. It didn't seem to matter much what my z depth was, the conical bit wouldn't cut a line that was anywhere near as narrow as its 0.1mm tip. Then one day, it dawned on me that that the head was vibrating like a sonofabitch. I mounted a dial indicator on the bed and positioned the plunger on the head. There was ± .003" of vibration! pretty much a killer when trying to mill lines less than 0.008" wide. I have since replaced the whole headstock with a 1.5KW 400Hz spindle motor. It runs up to 24,000 rpm and there's no detectable vibration. This is great. Of course, now that that problem is fixed, it made others more visible. I noticed that lines in the +Y direction were a different width than those in -Y. This turned out to be loose gibs, so I took apart the whole XY mechanism, tightened the nuts to remove all but 0.0005" of backlash in X&Y which I had previously compensated for in mach3, and adjusted the gibs properly. All I can say is that I wish I had taken the time to do these things from the get-go. What a difference. Next (after I get some work out of the way), I'll do the same with the Z axis. Hmmmm... I think somebody here might have suggested the 24K spindle on the Taig. Did you use Paul Heinreichs spindle mounts? I can tell you from experience its better to adjust out backlash to the best of your ability and ignore the Mach 3 backlash compensation. I've watched it steadily work a profile cut across the part as it gets confused before. My experience showed me a Taig mill could be adjust reliably to under .001 backlash and run ok, but it would limit the ability to rapid without losing steps. With it loosened up to about .003 backlash overall mine would cut upto about 60IPM and rapid up to 80ipm. Of course that is also dependent on your motors and controller. Whether or not that is "good enough" depends on the type of job you are doing and how you approach the job. Yes, you did suggest the spindle. No, I did not use his mounts - he only offered me a complete set including 220V motor & VFD, radiator, water pump etc for a bit too much money. So, I bought a kit with 110V motor & VFD (easier for me) and a mount. I made a bolt-on plate that replaces the dovetail plate, and it works fine. I also have the material and tools to make a dovetail mount. I have tested the design in a plexiglass scrap and it fits fine. I still need to come up with a locking mechanism for it, and I'll get it done after I finish some "real" work. I got the backlash down to 0.001" in X&y and I have never tried to run at anything greater than 30ipm. At some point soon, I will experiment with trading looseness for speed. Also, the possibility of making delrin nuts is there. I posted something about that years ago, it involves heating two pieces of delrin and the leadscrew and squashing the delrin around the screw. Perfect fit and zero backlash. With the cad drawings available at http://medw..co.uk/fisheye/gallery/114, those should be pretty easy to make. I used those drawings to make the spindle mount as well. Also still to do is getting the VFD talking to mach3. I have the communications parts, just need to install the plugin. |
Taig mill update
On 3/16/2018 7:02 AM, rangerssuck wrote:
On Thursday, March 15, 2018 at 5:23:54 PM UTC-4, Bob La Londe wrote: On 3/15/2018 10:37 AM, rangerssuck wrote: As you may remember, I've been making prototype printed circuits on my Taig micro mill. I was pretty well stuck, not being able to get traces small enough. It didn't seem to matter much what my z depth was, the conical bit wouldn't cut a line that was anywhere near as narrow as its 0.1mm tip. Then one day, it dawned on me that that the head was vibrating like a sonofabitch. I mounted a dial indicator on the bed and positioned the plunger on the head. There was ± .003" of vibration! pretty much a killer when trying to mill lines less than 0.008" wide. I have since replaced the whole headstock with a 1.5KW 400Hz spindle motor. It runs up to 24,000 rpm and there's no detectable vibration. This is great. Of course, now that that problem is fixed, it made others more visible. I noticed that lines in the +Y direction were a different width than those in -Y. This turned out to be loose gibs, so I took apart the whole XY mechanism, tightened the nuts to remove all but 0.0005" of backlash in X&Y which I had previously compensated for in mach3, and adjusted the gibs properly. All I can say is that I wish I had taken the time to do these things from the get-go. What a difference. Next (after I get some work out of the way), I'll do the same with the Z axis. Hmmmm... I think somebody here might have suggested the 24K spindle on the Taig. Did you use Paul Heinreichs spindle mounts? I can tell you from experience its better to adjust out backlash to the best of your ability and ignore the Mach 3 backlash compensation. I've watched it steadily work a profile cut across the part as it gets confused before. My experience showed me a Taig mill could be adjust reliably to under .001 backlash and run ok, but it would limit the ability to rapid without losing steps. With it loosened up to about .003 backlash overall mine would cut upto about 60IPM and rapid up to 80ipm. Of course that is also dependent on your motors and controller. Whether or not that is "good enough" depends on the type of job you are doing and how you approach the job. Yes, you did suggest the spindle. No, I did not use his mounts - he only offered me a complete set including 220V motor & VFD, radiator, water pump etc for a bit too much money. So, I bought a kit with 110V motor & VFD (easier for me) and a mount. I made a bolt-on plate that replaces the dovetail plate, and it works fine. That's too bad. He used to sell his mounts separately on EBAY. I have two sets. One for a 65mm and one for an 80mm spindle. I also have the material and tools to make a dovetail mount. I have tested the design in a plexiglass scrap and it fits fine. I still need to come up with a locking mechanism for it, and I'll get it done after I finish some "real" work. I need to break out some dovetail cutters and make some specialty tool holders for the QCTPs on my lathes. I got the backlash down to 0.001" in X&y and I have never tried to run at anything greater than 30ipm. 20-30ipm is what most folks recommend for the stock Taig V-lead setup. The newer ball screw version runs much faster. If you do not need to go faster I wouldn't mess with it to much. At some point soon, I will experiment with trading looseness for speed. Also, the possibility of making delrin nuts is there. I posted something about that years ago, it involves heating two pieces of delrin and the leadscrew and squashing the delrin around the screw. Perfect fit and zero backlash. I remember that. I have not done it, but I have tapped a few delrin nuts. On my little MaxNC5 when I converted it from crappy V-leads with split tube nuts over to acme screws I used the anti backlash nuts from Dumpster CNC. I used it pretty hard, and only greased the screws and ways. Never set it up to auto oil. With the cad drawings available at http://medw.co.uk/fisheye/gallery/114, those should be pretty easy to make. I used those drawings to make the spindle mount as well. Also still to do is getting the VFD talking to mach3. I have the communications parts, just need to install the plugin. I hope you mean hardware plugin, because there is no software plugin needed that I am aware of for VFD control. (I guess if you are using RS485 there might be.) You just need a board to convert a pulse stream over to 0-10VDC and a couple relays you can trigger with outputs off of your breakout board for forward and reverse switches. Some higher end breakout boards come with that stuff built in. I used low current trigger relays on my good breakout boards, and I used 48VDC relays from Altronix when I was still using a G540 with a 48VDC power supply. My C23 and and my C32 boards have voltage and spindle relays pre-setup and built in. The C32 did something weird with the relays though that resulted in unexpected spindle reversals. I didn't need reverse on that machine so I hooked both relays to forward on the VFD and all was good. Probably won't buy another C32 board. |
Taig mill update
On Friday, March 16, 2018 at 12:53:08 PM UTC-4, Bob La Londe wrote:
On 3/16/2018 7:02 AM, rangerssuck wrote: On Thursday, March 15, 2018 at 5:23:54 PM UTC-4, Bob La Londe wrote: On 3/15/2018 10:37 AM, rangerssuck wrote: As you may remember, I've been making prototype printed circuits on my Taig micro mill. I was pretty well stuck, not being able to get traces small enough. It didn't seem to matter much what my z depth was, the conical bit wouldn't cut a line that was anywhere near as narrow as its 0.1mm tip. Then one day, it dawned on me that that the head was vibrating like a sonofabitch. I mounted a dial indicator on the bed and positioned the plunger on the head. There was ± .003" of vibration! pretty much a killer when trying to mill lines less than 0.008" wide. I have since replaced the whole headstock with a 1.5KW 400Hz spindle motor. It runs up to 24,000 rpm and there's no detectable vibration. This is great. Of course, now that that problem is fixed, it made others more visible. I noticed that lines in the +Y direction were a different width than those in -Y. This turned out to be loose gibs, so I took apart the whole XY mechanism, tightened the nuts to remove all but 0.0005" of backlash in X&Y which I had previously compensated for in mach3, and adjusted the gibs properly. All I can say is that I wish I had taken the time to do these things from the get-go. What a difference. Next (after I get some work out of the way), I'll do the same with the Z axis. Hmmmm... I think somebody here might have suggested the 24K spindle on the Taig. Did you use Paul Heinreichs spindle mounts? I can tell you from experience its better to adjust out backlash to the best of your ability and ignore the Mach 3 backlash compensation. I've watched it steadily work a profile cut across the part as it gets confused before. My experience showed me a Taig mill could be adjust reliably to under .001 backlash and run ok, but it would limit the ability to rapid without losing steps. With it loosened up to about .003 backlash overall mine would cut upto about 60IPM and rapid up to 80ipm. Of course that is also dependent on your motors and controller. Whether or not that is "good enough" depends on the type of job you are doing and how you approach the job. Yes, you did suggest the spindle. No, I did not use his mounts - he only offered me a complete set including 220V motor & VFD, radiator, water pump etc for a bit too much money. So, I bought a kit with 110V motor & VFD (easier for me) and a mount. I made a bolt-on plate that replaces the dovetail plate, and it works fine. That's too bad. He used to sell his mounts separately on EBAY. I have two sets. One for a 65mm and one for an 80mm spindle. I also have the material and tools to make a dovetail mount. I have tested the design in a plexiglass scrap and it fits fine. I still need to come up with a locking mechanism for it, and I'll get it done after I finish some "real" work. I need to break out some dovetail cutters and make some specialty tool holders for the QCTPs on my lathes. I got the backlash down to 0.001" in X&y and I have never tried to run at anything greater than 30ipm. 20-30ipm is what most folks recommend for the stock Taig V-lead setup. The newer ball screw version runs much faster. If you do not need to go faster I wouldn't mess with it to much. At some point soon, I will experiment with trading looseness for speed. Also, the possibility of making delrin nuts is there. I posted something about that years ago, it involves heating two pieces of delrin and the leadscrew and squashing the delrin around the screw. Perfect fit and zero backlash. I remember that. I have not done it, but I have tapped a few delrin nuts. On my little MaxNC5 when I converted it from crappy V-leads with split tube nuts over to acme screws I used the anti backlash nuts from Dumpster CNC. I used it pretty hard, and only greased the screws and ways. Never set it up to auto oil. With the cad drawings available at http://medw.co.uk/fisheye/gallery/114, those should be pretty easy to make. I used those drawings to make the spindle mount as well. Also still to do is getting the VFD talking to mach3. I have the communications parts, just need to install the plugin. I hope you mean hardware plugin, because there is no software plugin needed that I am aware of for VFD control. (I guess if you are using RS485 there might be.) You just need a board to convert a pulse stream over to 0-10VDC and a couple relays you can trigger with outputs off of your breakout board for forward and reverse switches. Some higher end breakout boards come with that stuff built in. I used low current trigger relays on my good breakout boards, and I used 48VDC relays from Altronix when I was still using a G540 with a 48VDC power supply. My C23 and and my C32 boards have voltage and spindle relays pre-setup and built in. The C32 did something weird with the relays though that resulted in unexpected spindle reversals. I didn't need reverse on that machine so I hooked both relays to forward on the VFD and all was good. Probably won't buy another C32 board. I plan to hook this up with RS485 and the plugin from here https://goo.gl/3Dwf7v . This, besides setting RPM also displays actual RPM and current draw.. Only takes two wires to hook up. I also plan to hook up controls to turn the vfd, water pump and stepper drive on & off, as well as controlling the vacuum cleaner and air jet. But those things are going to wait a while, while real work gets done. |
Taig mill update
On Fri, 16 Mar 2018 07:02:48 -0700 (PDT), rangerssuck
wrote: On Thursday, March 15, 2018 at 5:23:54 PM UTC-4, Bob La Londe wrote: On 3/15/2018 10:37 AM, rangerssuck wrote: As you may remember, I've been making prototype printed circuits on my Taig micro mill. I was pretty well stuck, not being able to get traces small enough. It didn't seem to matter much what my z depth was, the conical bit wouldn't cut a line that was anywhere near as narrow as its 0.1mm tip. Then one day, it dawned on me that that the head was vibrating like a sonofabitch. I mounted a dial indicator on the bed and positioned the plunger on the head. There was ± .003" of vibration! pretty much a killer when trying to mill lines less than 0.008" wide. I have since replaced the whole headstock with a 1.5KW 400Hz spindle motor. It runs up to 24,000 rpm and there's no detectable vibration. This is great. Of course, now that that problem is fixed, it made others more visible. I noticed that lines in the +Y direction were a different width than those in -Y. This turned out to be loose gibs, so I took apart the whole XY mechanism, tightened the nuts to remove all but 0.0005" of backlash in X&Y which I had previously compensated for in mach3, and adjusted the gibs properly. All I can say is that I wish I had taken the time to do these things from the get-go. What a difference. Next (after I get some work out of the way), I'll do the same with the Z axis. Hmmmm... I think somebody here might have suggested the 24K spindle on the Taig. Did you use Paul Heinreichs spindle mounts? I can tell you from experience its better to adjust out backlash to the best of your ability and ignore the Mach 3 backlash compensation. I've watched it steadily work a profile cut across the part as it gets confused before. My experience showed me a Taig mill could be adjust reliably to under .001 backlash and run ok, but it would limit the ability to rapid without losing steps. With it loosened up to about .003 backlash overall mine would cut upto about 60IPM and rapid up to 80ipm. Of course that is also dependent on your motors and controller. Whether or not that is "good enough" depends on the type of job you are doing and how you approach the job. Yes, you did suggest the spindle. No, I did not use his mounts - he only offered me a complete set including 220V motor & VFD, radiator, water pump etc for a bit too much money. So, I bought a kit with 110V motor & VFD (easier for me) and a mount. I made a bolt-on plate that replaces the dovetail plate, and it works fine. I also have the material and tools to make a dovetail mount. I have tested the design in a plexiglass scrap and it fits fine. I still need to come up with a locking mechanism for it, and I'll get it done after I finish some "real" work. I got the backlash down to 0.001" in X&y and I have never tried to run at anything greater than 30ipm. At some point soon, I will experiment with trading looseness for speed. Also, the possibility of making delrin nuts is there. I posted something about that years ago, it involves heating two pieces of delrin and the leadscrew and squashing the delrin around the screw. Perfect fit and zero backlash. With the cad drawings available at http://medw.co.uk/fisheye/gallery/114, those should be pretty easy to make. I used those drawings to make the spindle mount as well. Also still to do is getting the VFD talking to mach3. I have the communications parts, just need to install the plugin. Be careful heating the Delrin. Formaldehyde gas is released when acetal plastics get too hot. Not only corrosive to your lungs but also to machine tools. Eric |
Taig mill update
On Monday, March 19, 2018 at 4:29:53 PM UTC-4, wrote:
On Fri, 16 Mar 2018 07:02:48 -0700 (PDT), rangerssuck wrote: On Thursday, March 15, 2018 at 5:23:54 PM UTC-4, Bob La Londe wrote: On 3/15/2018 10:37 AM, rangerssuck wrote: As you may remember, I've been making prototype printed circuits on my Taig micro mill. I was pretty well stuck, not being able to get traces small enough. It didn't seem to matter much what my z depth was, the conical bit wouldn't cut a line that was anywhere near as narrow as its 0.1mm tip. Then one day, it dawned on me that that the head was vibrating like a sonofabitch. I mounted a dial indicator on the bed and positioned the plunger on the head. There was Ä… .003" of vibration! pretty much a killer when trying to mill lines less than 0.008" wide. I have since replaced the whole headstock with a 1.5KW 400Hz spindle motor. It runs up to 24,000 rpm and there's no detectable vibration. This is great. Of course, now that that problem is fixed, it made others more visible. I noticed that lines in the +Y direction were a different width than those in -Y. This turned out to be loose gibs, so I took apart the whole XY mechanism, tightened the nuts to remove all but 0.0005" of backlash in X&Y which I had previously compensated for in mach3, and adjusted the gibs properly. All I can say is that I wish I had taken the time to do these things from the get-go. What a difference. Next (after I get some work out of the way), I'll do the same with the Z axis. Hmmmm... I think somebody here might have suggested the 24K spindle on the Taig. Did you use Paul Heinreichs spindle mounts? I can tell you from experience its better to adjust out backlash to the best of your ability and ignore the Mach 3 backlash compensation. I've watched it steadily work a profile cut across the part as it gets confused before. My experience showed me a Taig mill could be adjust reliably to under .001 backlash and run ok, but it would limit the ability to rapid without losing steps. With it loosened up to about .003 backlash overall mine would cut upto about 60IPM and rapid up to 80ipm. Of course that is also dependent on your motors and controller. Whether or not that is "good enough" depends on the type of job you are doing and how you approach the job. Yes, you did suggest the spindle. No, I did not use his mounts - he only offered me a complete set including 220V motor & VFD, radiator, water pump etc for a bit too much money. So, I bought a kit with 110V motor & VFD (easier for me) and a mount. I made a bolt-on plate that replaces the dovetail plate, and it works fine. I also have the material and tools to make a dovetail mount. I have tested the design in a plexiglass scrap and it fits fine. I still need to come up with a locking mechanism for it, and I'll get it done after I finish some "real" work. I got the backlash down to 0.001" in X&y and I have never tried to run at anything greater than 30ipm. At some point soon, I will experiment with trading looseness for speed. Also, the possibility of making delrin nuts is there. I posted something about that years ago, it involves heating two pieces of delrin and the leadscrew and squashing the delrin around the screw. Perfect fit and zero backlash. With the cad drawings available at http://medw.co.uk/fisheye/gallery/114, those should be pretty easy to make. I used those drawings to make the spindle mount as well. Also still to do is getting the VFD talking to mach3. I have the communications parts, just need to install the plugin. Be careful heating the Delrin. Formaldehyde gas is released when acetal plastics get too hot. Not only corrosive to your lungs but also to machine tools. Eric Thanks for the tip. Any idea how hot is "too" hot? It really just needs to soften enough to mold around the screw. |
Taig mill update
On Mon, 19 Mar 2018 14:30:04 -0700 (PDT), rangerssuck
wrote: On Monday, March 19, 2018 at 4:29:53 PM UTC-4, wrote: On Fri, 16 Mar 2018 07:02:48 -0700 (PDT), rangerssuck wrote: On Thursday, March 15, 2018 at 5:23:54 PM UTC-4, Bob La Londe wrote: On 3/15/2018 10:37 AM, rangerssuck wrote: As you may remember, I've been making prototype printed circuits on my Taig micro mill. I was pretty well stuck, not being able to get traces small enough. It didn't seem to matter much what my z depth was, the conical bit wouldn't cut a line that was anywhere near as narrow as its 0.1mm tip. Then one day, it dawned on me that that the head was vibrating like a sonofabitch. I mounted a dial indicator on the bed and positioned the plunger on the head. There was ? .003" of vibration! pretty much a killer when trying to mill lines less than 0.008" wide. I have since replaced the whole headstock with a 1.5KW 400Hz spindle motor. It runs up to 24,000 rpm and there's no detectable vibration. This is great. Of course, now that that problem is fixed, it made others more visible. I noticed that lines in the +Y direction were a different width than those in -Y. This turned out to be loose gibs, so I took apart the whole XY mechanism, tightened the nuts to remove all but 0.0005" of backlash in X&Y which I had previously compensated for in mach3, and adjusted the gibs properly. All I can say is that I wish I had taken the time to do these things from the get-go. What a difference. Next (after I get some work out of the way), I'll do the same with the Z axis. Hmmmm... I think somebody here might have suggested the 24K spindle on the Taig. Did you use Paul Heinreichs spindle mounts? I can tell you from experience its better to adjust out backlash to the best of your ability and ignore the Mach 3 backlash compensation. I've watched it steadily work a profile cut across the part as it gets confused before. My experience showed me a Taig mill could be adjust reliably to under .001 backlash and run ok, but it would limit the ability to rapid without losing steps. With it loosened up to about .003 backlash overall mine would cut upto about 60IPM and rapid up to 80ipm. Of course that is also dependent on your motors and controller. Whether or not that is "good enough" depends on the type of job you are doing and how you approach the job. Yes, you did suggest the spindle. No, I did not use his mounts - he only offered me a complete set including 220V motor & VFD, radiator, water pump etc for a bit too much money. So, I bought a kit with 110V motor & VFD (easier for me) and a mount. I made a bolt-on plate that replaces the dovetail plate, and it works fine. I also have the material and tools to make a dovetail mount. I have tested the design in a plexiglass scrap and it fits fine. I still need to come up with a locking mechanism for it, and I'll get it done after I finish some "real" work. I got the backlash down to 0.001" in X&y and I have never tried to run at anything greater than 30ipm. At some point soon, I will experiment with trading looseness for speed. Also, the possibility of making delrin nuts is there. I posted something about that years ago, it involves heating two pieces of delrin and the leadscrew and squashing the delrin around the screw. Perfect fit and zero backlash. With the cad drawings available at http://medw.co.uk/fisheye/gallery/114, those should be pretty easy to make. I used those drawings to make the spindle mount as well. Also still to do is getting the VFD talking to mach3. I have the communications parts, just need to install the plugin. Be careful heating the Delrin. Formaldehyde gas is released when acetal plastics get too hot. Not only corrosive to your lungs but also to machine tools. Eric Thanks for the tip. Any idea how hot is "too" hot? It really just needs to soften enough to mold around the screw. When machining it if I take a heavy cut without coolant I can smell the formaldehyde. Drilling fast I can smell it too. Eric |
Taig mill update
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On Mon, 19 Mar 2018 14:30:04 -0700 (PDT), rangerssuck wrote: On Monday, March 19, 2018 at 4:29:53 PM UTC-4, wrote: On Fri, 16 Mar 2018 07:02:48 -0700 (PDT), rangerssuck wrote: On Thursday, March 15, 2018 at 5:23:54 PM UTC-4, Bob La Londe wrote: On 3/15/2018 10:37 AM, rangerssuck wrote: As you may remember, I've been making prototype printed circuits on my Taig micro mill. I was pretty well stuck, not being able to get traces small enough. It didn't seem to matter much what my z depth was, the conical bit wouldn't cut a line that was anywhere near as narrow as its 0.1mm tip. Then one day, it dawned on me that that the head was vibrating like a sonofabitch. I mounted a dial indicator on the bed and positioned the plunger on the head. There was ? .003" of vibration! pretty much a killer when trying to mill lines less than 0.008" wide. I have since replaced the whole headstock with a 1.5KW 400Hz spindle motor. It runs up to 24,000 rpm and there's no detectable vibration. This is great. Of course, now that that problem is fixed, it made others more visible. I noticed that lines in the +Y direction were a different width than those in -Y. This turned out to be loose gibs, so I took apart the whole XY mechanism, tightened the nuts to remove all but 0.0005" of backlash in X&Y which I had previously compensated for in mach3, and adjusted the gibs properly. All I can say is that I wish I had taken the time to do these things from the get-go. What a difference. Next (after I get some work out of the way), I'll do the same with the Z axis. Hmmmm... I think somebody here might have suggested the 24K spindle on the Taig. Did you use Paul Heinreichs spindle mounts? I can tell you from experience its better to adjust out backlash to the best of your ability and ignore the Mach 3 backlash compensation. I've watched it steadily work a profile cut across the part as it gets confused before. My experience showed me a Taig mill could be adjust reliably to under .001 backlash and run ok, but it would limit the ability to rapid without losing steps. With it loosened up to about .003 backlash overall mine would cut upto about 60IPM and rapid up to 80ipm. Of course that is also dependent on your motors and controller. Whether or not that is "good enough" depends on the type of job you are doing and how you approach the job. Yes, you did suggest the spindle. No, I did not use his mounts - he only offered me a complete set including 220V motor & VFD, radiator, water pump etc for a bit too much money. So, I bought a kit with 110V motor & VFD (easier for me) and a mount. I made a bolt-on plate that replaces the dovetail plate, and it works fine. I also have the material and tools to make a dovetail mount. I have tested the design in a plexiglass scrap and it fits fine. I still need to come up with a locking mechanism for it, and I'll get it done after I finish some "real" work. I got the backlash down to 0.001" in X&y and I have never tried to run at anything greater than 30ipm. At some point soon, I will experiment with trading looseness for speed. Also, the possibility of making delrin nuts is there. I posted something about that years ago, it involves heating two pieces of delrin and the leadscrew and squashing the delrin around the screw. Perfect fit and zero backlash. With the cad drawings available at http://medw.co.uk/fisheye/gallery/114, those should be pretty easy to make. I used those drawings to make the spindle mount as well. Also still to do is getting the VFD talking to mach3. I have the communications parts, just need to install the plugin. Be careful heating the Delrin. Formaldehyde gas is released when acetal plastics get too hot. Not only corrosive to your lungs but also to machine tools. Eric Thanks for the tip. Any idea how hot is "too" hot? It really just needs to soften enough to mold around the screw. When machining it if I take a heavy cut without coolant I can smell the formaldehyde. Drilling fast I can smell it too. Eric ================================================== ============= Wikipedia gives 352F as the melting point and there to 410F as the range for extrusion and injection molding, depending I guess on how low you need the viscosity. Also say the annealing temperature is 310F so I would assume you will need to be between there and 350F for your hot press forming of the nuts. They don't mention a decomposition temperature. -- Regards, Carl Ijames |
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