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#61
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Wow! These NEMA23 Servos are Impressive
Yesterday I loaded a program into Mach3, to simulate a peck-drilling routine of 45 equally spaced holes over the entire cutting surface of the machine. As Mach3 began it was clear the 'A-axis was not responding to directions from the controller. A brief thought came to terminate, to fix the fault and to start over, or to continue with the program and to see where the 'X-axis' motor would fail.
It was interesting to watch the one little NEMA23 servo motor drag the gantry from the first hole location to the second at 400ipm. Forty five simulated holes later still no motor fault. The motor still has not exceeded it maximum torque threshold value. At the end of the program the 'X-axis motor drove back to its Zero position with precision <0.0005 and the 'A-axis' landed back near its Zero at 0.056. Of course you could not allow the failure of one axis to continue while working a real job. But I am impressed with the performance of the one little motor dragging that heavy gantry across the table without faulting the motor. |
#62
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Good to know Bill that you have movement - any insight on the Y axis tuning method?
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#63
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Thanks for the heads up on the CS-Labs CSMIO/IP-S - 6 axis Ethernet Motion Controller. Looks like it will be my next replacement for my g540.
Cheers Tim |
#64
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tuning stuff
I know little of tuning motors. I'll share what I do know.
Other tuning documentation first: MachMotion has information regarding motor tuning and I have not heard this method before. Please refer to the following links and pages. The PDF's are easy to download and easy to read. These documents give good information for setting Acceleration and Deceleration values in Mach3. They may provide a good starting point and they make more since of tuning than I can ever do so here. So please, please look them over. http://machmotion.com/manuals/Apollo...s%20Manual.pdf page 24 and 25 http://machmotion.com/manuals/Apollo...s%20Manual.pdf pages 35,36 and 37 Bob Warfield of CNCcookbook has a great blog regarding servo tuning. This is more extensive to read, but very informative. Please give it a look over, too. http://www.cnccookbook.com/CCServoTuning.htm Now, tuning multiple drive axis that are common to some MechMates and some large gantry routers. When I tuned my 'X-axis' motor, the 'A-axis motor was installed at the other end of the gantry. The 'A' drive belt was removed to diminish drive resistance. Tuning began with the packaged software. I chose the resolution counts to use, the 'jerk' frequency setting from the available list, there were only two options, and then I hit the auto tune button. The software did the rest. When completed the tuning configuration file was downloaded for safe keeping. Next the 'A-axis', the 'Y-axis', and the 'Z-axis' motors were tuned. Later I began seeing random tracking errors faults from all the axis except the 'Y'. The 'Y-axis' ran well and never faulted. Sometimes the 'A-axis' would fault but not the 'X', and other times the 'X' would fault and not the 'A'. Then I realized, the 'SLAVE' axis must have the identical tuning profile as the master, duhh. The lesson I learned here is, if you have a good profile and all motors are alike, then share the good profile with the other motors. Also, in the case of my MechMate, there may be too much resonance in the main frame for the tuning software to affectively tune the 'X and A' axis without tracking failures. But the smoother axis, the lighter 'Y-car' axis tuned easily. So I took the 'Y-axis' tuning profile and uploaded it to the other motors. Voila, after uploading the 'Y-axis' profile to the other motors, they all work well. BillT |
#65
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Good work, Bill. Your plowing new ground!
So, have you re-run the "peck-drilling routine of 45 equally spaced holes over the entire cutting surface" since setting all the servos to the same profile? |
#66
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Great work, Bill! Could you give us a comparison in the performance differences or any other interesting differences you may have noticed after you changed over the the servos compared to running the steppers you had before? Do you feel there was enough of a difference between the two setups to justify changing out your stepper motors and BOB? I've been running the recommended OM 7.2 motors for a few years now and have been pretty happy with them but have always been drawn to the closed loop nature of servos. Thank you in advance for any input and insight you may have to offer.
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#67
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Thanks Bill for sharing your AC Servo experiences.
In time a video of your machine running with the Servo's might be very informative. Thanks Ross |
#68
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This MM is a much better machine overall than it was before. And I have more confidence it will faithfully run the tool path routine I provide without fail.
An example: Last weekend I was building up a corian spoil board and a corian tool plate to run a few parts. The spoil board was mounted to the base plate, which of course mounted to the cross bearer steel channel. The corian spoil board, 20x30 inches needed surfacing. So I built a small routine in VCarve Pro to pocket cut the surface and to leave a small shoulder on the X and Y axis for the tool plate. I chose to surface the spoil board with a 1/4" end mill. Yes, I know the 1/4" end mill is not the right tool, but I wanted a tool strategy with a long runtime. The tool path took 58.5 minutes to complete. And I ran the tool path three times, each time shaving off about 0.015. And then I mounted the 13x13" tool plate to the surface of the spoil board and surface cut the tool plate three times as well, each routine lasting 20 minutes. THE REAL TEST here was to see how well the machine would run continuously in the 105F degree Texas summer heat. The motors, the electronics, the machine ran well without any failures. I checked the motor temperatures with a digital thermometer during the run time, and the nominal temperatures ran about 10 to 13 degrees above ambient. These motors run a lot cooler than the steppers ever did. What I really like most about the new controller and motor configuration is that the cut path, whatever tool path is loaded is now repeatable and the electronics reliable. The machine will now repeat, time, and time, and time again. Cut Quality: One project in the shop to complete is to retrofit the old manual Bridgeport with CNC controls. I was cutting motor plates and I found the cutter was leaving 'chatter marks' around the long radii at the ends. This was very disappointing to say the least. Thinking the chatter problem through I realize that all the motors can be where instructed, but that the cutting material, Delrin in this case, a gummy material can actually push the cutting tip off axis, thus causing the controller to reacquire its position. Speculation on my part for sure, but better speed and feed control could help a lot. And so I realize the new controller and motors cannot heal all the ills of this machine or my understanding of its use. But still, a far better machine than it ever was before. I cannot speak to the OM motors as I have not used them. There has been much discussion of them in this forum and I believe most of the discussion regarding them to be favorable. Right before I changed the motors and controller, my friend and I completed many hours on the MM cutting form blocks, dies for aircraft bulkheads. A discussion regarding the dies and bulkheads here: http://www.mechmate.com/forums/showt...2278#post72278 thread #17 The steppers worked great while cutting the aircraft project. We had the 'feeds and the speeds' matched for the job and the cuts were good. But the 'hobby' electronics was unreliable. Sometimes during a cut routine one of the axis would quit working and from that, the part would have to be scrapped. I decided after every other part produced, the machine would be completely shut down, Windows too, and restarted. This dramatically reduced failures, but I was never able to trust the controls again. So from this experience I decided to change the controls and the motors. Would I change from stepper to servo with an existing machine? No, providing the machine and the electronic controls are in good condition. In my case, there was a failure somewhere. Was it the Windows machine, the BOB, the Smooth Stepper, or one of the Gecko's? That said, with more build or retro experience under my belt, I will never consider steppers again. The inexpensive NEMA 23's I have on the MM prove, to me at least, they are the best option for my MM and other machines moving forward. They are light weight, quiet, smart, very quick, more powerful than my old steppers, and so very precise. David, Ross, thank you for your comments. It's not that I'm some technical moron, but I really don't know how to post video to You tube. After learning CAD, 3D Modeling, CAM, and other software, etc, I really don't want to learn another software. But perhaps I should! BillT |
#69
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Photo 1: The Pattern
This photo is that of a motor plate for the Bridgeport CNC. Well, it's a failed motor plate. I made an error in CAD and scrapped this part. Anyway, I decided to have some fun so I built a cut routine in VCarve Pro to check the accuracy of the 'Z' axis. I drew 32, two inch squares to cover this part on a 30 degree angle. I programmed two routines; one routine calls for the 'Z' axis to 'Pocket Cut' the 32 squares, and the second routine calls for the 'Z' axis to 'Perimeter Cut' each square. So that means the 'Z' axis will have to extend and retract 64 times to cut the pattern on this plate. Also, because the pattern is on a 30 degree angle, all 'X and Y' moves will be simultaneous diagonal with different torque values applied for each movement. I know you can't see the surface well because of the small photo, but know that the surface is quite smooth. Photo 2 This photo shows a very smooth and accurate cover slot along the perimeter. The slot was cut with a .125 end mill at an .063 offset to the inside. I'm happy with the slot offset. Chatter marks on the end radius as described in the above post. |
#70
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Bill, thanks for laying the groundwork, very impressive! Definitely got me thinking
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#71
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Hi Bill
No problem on the video you have already done plenty. Ross |
#72
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Bill,
Nice write up of your quest. I install and use various servos and steppers where I work but they have a much higher budget to play with. You have given an option for the lower budget builders which is great. I will be waiting to hear how everything is going after 1000 hours of service. So far, everything looks promising but time is the tester of all things. I believe you will be fine but please keep us informed all things involved. |
#73
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Hi Bill,
I'm very interested in the servo approach you have taken based on the seemingly added simplicity of wiring and control. -How is your experience with the Clearpath motors and Hicon controller now that you have a few months on the kit? -Which model motor did you end up getting? Speed/torque? -If I understand correctly you are running two motors on the X-axis? Is that one on each side of the gantry? Do you think this is a requirement with the motor size you bought? -Any other wisdom learned on the upgrade? Many thanks, Brandt |
#74
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Brandt, thank you for your query.
I am very happy with the ClearPath servos and the Hicon controller. They exceed my expectations in every way. There have been failures but none under performance testing. The hardware is rock solid. Upon installing the servos and the controller, I found the Z-axis moved unexpectedly in the negative direction. I tracked this back to V-Carve tool path, specifically the following line, N150S12000M03. This line is used for spindle start/stop, and should not be relational to the Z-axis. Regardless, I don't want or use a spindle start/stop operation, so I delete this line from every tool path V-Carve builds and the Z-Axis now works as it should. But, deleting the N150 line does not address the underlying problem. To fully understand this I need to dig deeper and find solutions to the following. 1) How can I prevent VCarve Pro from writing un-needed instruction. 2) Why does the Hicon controller apply instruction to the Z-axis from this line? Any help from you guys here would be greatly appreciated!! ================================================ Yes, my MechMate has dual X- axis motor drives with one motor on each end. One motor drives clockwise while the other motor simultaneously drives counterclockwise. This is taken care of easily in the Mach3 setup. This machine has a rail center to center distance of 90 inches, 7.5 ft across the X-axis. It is impossible for this machine to maintain a perpendicular relationship between X and Y, given the weight of the three assemblies on a single mobile rail system. The three assemblies weigh in at, perhaps 100 lbs. I know for sure my machine cannot maintain perpendicularity with one driver. All it can build with one driver is parallelograms and egg shaped holes. Let's talk motor torque. I have no way to provide empirical data regarding the torque of these little servos. But I can provide two things. The manufacturers specifications listed below, and my observations. I have knocked the A-axis off line (by stupidity) a couple of times while cutting through a piece of MDF. Once, by the time I realized the A-axis was offline, I let Mach3 finish the remaining five minutes of the routine just to see how the NEMA 23 servo would perform. The tool path specifications were; 1/4" two flute carbide end mill, cutting depth .175, surface speed 75 IPM, RPM 10,000. Well, the little NEMA 23 X-axis servo kept churning along. It finished the remaining five minutes of the routine and returned to the home position like nothing was wrong. Of course the A-axis was being whipped along as the routine finished and landed about a half inch from its home position. The part was pretty ugly and I re-cut it of course, but the strength of the little NEMA 23 really impressed me. These NEMA 23 servos are far superior in every way to the NEMA 34 motors I originally installed. When you have time please watch this video. Dave provides a great description of these servos: https://www.youtube.com/watch?v=Z2kAcz-rG5s ================================================ ClearPath Servo model CPM-SDSK-2310S-RLN Motor Frame Size NEMA 23 - 59.18 mm (2.33 in) sq. Length 84.84mm (3.34 in) Peak Torque (@75 VDC) 1.57 N-m (223 oz-in) Cont. (RMS) Torque (@75 VDC) 0.32 N-m (44.9 oz-in) Max Speed 4000 RPM Rated Speed 3040 RPM Achievable Resolution 0.45 degrees Repeatability 0.03 degrees Shaft Diameter 9.525 mm (0.375 in) Weight 0.63 kg (1.38 lb) Rotor Inertia 0.077 kg-cm^2 (0.420 oz-in^2) Input (bus) Voltage Range 24-75 VDC (90 VDC max) Logic Input Voltage Range 4.0 to 28 VDC Maximum Radial Load 111.2 N (25.0 lbf) Maximum Thrust Load 22.2 N (5.0 lbf) Environmental Rating Dust & water splash resistant Ambient Temperature 0-70 deg C (derated >40C) Ambient Humidity 0-95%; non-condensing Regulatory Certifications UL recognized; CE; RoHS Country of Origin USA Warranty 3 Years |
#75
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Update: Z-Axis moves unexpectedly.
Last post I made the case that perhaps, the Z-Axis was moving because of a line of unneeded code from the VCarve tool path. Shown here: N150S12000M03.
Sure enough, that line of code causes problems with my Z-Axis since the Hicon and Clear Path servo install. The Z-Axis has never run successfully with that line of code in the file. Yesterday I had another incident with the Z-Axis runaway. However, this time there was no code posted to Mach. I was simply moving the Axis with the pendant. After such incident the workflow is the same, shutdown everything and restart again. As I pushed the shutdown button to close Windows, the Windows Search Box opened and Windows began populating the test box with all 9s. I guess this is Windows version of the same fault I just had with Mach; in Windows a runaway textbox, in Mach a runaway axis. I think it is time to look a little closer at my Dell control computer. More on this later. |
#76
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Bill..
Not being 100% fluent with mach code, I will ask: isn'tt that line simply a "set rpm and turn on spindle" line? If so, do you use speed control? What about a spindle on macro? |
#77
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You are correct. It is simply a line of code for the spindle and should not control any axis.
But in my system it does. I found this out by using the 'Run Single Line' feature in Mach. I ran a simple routine in Mach line by line. Every line of code ran as expected until I executed this line 'N150S12000M03', line 150. As I ran this line of code the Z axis began moving in the upward, negative direction. Again, this line should have nothing to do with the Z axis. So I'll work this out with the Hicon folks. I'm sure they'll have a solution. This MM is a manual control system and will remain so for a while. There are no home switches, limit switches, or any other electronic switches in the setup. For now, Mach is simply used as a 'Step/Direction' controller. |
#78
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Strange behavior indeed.
Just as an experiment try deleting all the code on that line apart from M3. M3 only on that line, not M03. You could edit the postprocessor to alter that line of code, or you could write a program to edit the code output from the postprocessor. |
#79
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When you run the N150S12000M03 line, are you also changing the state of the spindle? Meaning that the spindle was off, and this line starts the spindle running, or it changes the speed of the spindle?
What happens if you disable the power source to the VFD / spindle, and then run this line? Does the Z still move? If not, I'd be looking for an electrical noise problem, especially if this is happening as the spindle is accelerating from a dead stop to 12k RPM. |
#80
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Regardless, the code problems with VCarve, I'm sure that will be easy to sort out.
The last time (Sunday afternoon) the Z-Axis 'ran-away' there was no tool path posted to Mach3. Likewise, there were no motors running. I was just simply moving the Z-Axis with the pendant. Yes, the Z-Axis 'ran-away' once when I used the keyboard controls too. When I rebuilt the machine with new controller and servos I stripped all the old electronics and wiring out. Today the wiring consist of, 1) Signal wire to each motor for step and direction, and 2) DC power buss to each motor per manufacturers direction. All signal wires are shielded and appropriately grounded. Finally, the Vital System Hicon controller was chosen because 24V controllers are more immune to signal noise the their 12V cousins. |
#81
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Update questions
Bill,
It has been a couple of years since you have posted. do you have any updates, observations or reliability issues to report . Thank you for posting your work and experiences. John Higgins found me up here in WV and he pointed me to this thread. This information was exactly what I was looking for. The specific Clearpath motors being used on a Mechmate with belt drives. the simplicity of the hookup really appeals to me (simplicity = solid) also these servos are quieter than steppers (something almost never addressed) I am a bit sensitive to high frequency noise. I have seen these servos run in person and they are really quiet. Thank You archie |
#82
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Archie,
WOW! It HAS been two years.. Archie, Thank You for the query!!! The MM started out as something I was interested to build, and I had a specific purpose for it. That purpose still remain, however, I am not using the machine for the original purpose. The MM is being used to manufacture aviation parts. I'll explain briefly. A few years ago, a friend asked if the MM was capable to cut and form the die blank tooling with precision, for the ribs, bulkheads, etc, necessary to build a high performance experimental aircraft. At the time I said, 'NO', because the terrible Hobby Class controls. But I did confidently say at the time, the MM is robust enough to accomplish the task with professional controls. So I set about making the control change. I rebuilt the controls, and we went about designing parts, and cutting the tooling necessary for the airplane. The plane is still under construction and will be delivered, perhaps summer this year, 2018. Word got out to the local aviation guys about the machine, and I am now cutting aviation instrument panels for glass cockpit upgrades. So far I have redesigned and cut new panels for two Citation corporate jets, one corporate King Air twin turbo prop, and a few smaller aircraft. The guys tell me they are extremely happy with the panels the machine produces, and there are more big jobs coming. Additionally, I am using the MM to cut motor and fixture plates for my Bridgeport Knee manual mill conversion to CNC. Today, the MM spends about 80% for the time cutting aluminum. I have cut mounting brackets from 1" aluminum stock, no problem. Granted, this is not a milling machine, so you cannot take deep cuts. But it cuts 1" aluminum stock, no problem. Don't forget, the machine is driven by NEMA 23 servos. There are no plans to upgrade the servos. The servos as they are, provide more torque than tool deflection can deal with. So there will never be a reason to seek a larger ClearPath driver for this machine. I have a redesign of the gantry in drawing. This includes the replacement of the router for a spindle. Just waiting for enough money and time to implement. The machine works well as it sits. I have stripped all unnecessary controls from it. I only use hard stops for X and Y zero reference. To begin a toolpath, I manually set the machine X and Y axis against the hard stop plates. Then I reset the Zeros for both in Mach. I don't use switches. They are not accurate enough. And I use stop blocks at the ends of the table. The ClearPath servos have an automatic shutdown built into the controller should the machine strike a stop block. So there you have it. There are no switches on the machine at all, except of course the manual emergency stop, red mushroom. More info and photos later Regards, BillT |
#83
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Bill,
Great to hear from you. I told Archie that you were a no-nonsense kind of guy. Sounds like you are really getting a lot out of your MechMate. I look forward to those additional details and photos you mentioned. If you have any videos of #111 cutting aluminum, I would love to see them. |
#84
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What MechMate-111 has been up to..
From the four following photos below you can see what the MM and I have been up to. Sorry for the photo size, they are as large as allowed.
Photos: 1)High performance fuselage under construction, outside view. This photo looks forward. The firewall begins as a circle, 36" in diameter and transitions slightly to elliptical shape moving to the cockpit. From the cockpit the strong elliptical shape transitions aft to the empennage. This offers a much lower drag coefficient than others. 2)High performance fuselage under construction, inside view. The camera view is two bulkhead stations behind the cockpit. It looks forward to the firewall. Shown are some 40 bulkhead pieces, others out of view, press formed, jigged and assembled as the fuselage. With the bulkheads precisely built, no shims were required as the skin was fashioned and fit. 3) A view of the Co-Pilot instrument panel. Five aluminum panels make the Main Instrument Cluster of the Cessna Citation jet. The two shown in front of the yoke, panel four and five are the Co-Pilots instruments. Many instruments from panel five were incorporated into the Garmin panel, partially in view far left. These panels are made of aviation grade 2024-T3 heat treated aluminum, 1/8". The MM cuts this material easily. 4) A motor plate for the Bridgeport CNC conversion. This is just a simple photo. It shows a ClearPath servo mounted onto a belt transmission, very similar to the ones used on the MM. The motor plates are 1/2"-6061-T6. The MM cuts this material easily. These four photos are from three projects that would not be possible without the MM. The machine and the controls work well. One final note on controls. As shown in this build thread I use the Hicon Integra. It is a six axis controller and quite expensive. Hicon has now a less expensive four axis controller; but still expensive. Over 400 bucks. Recently however, Centroid, the big daddy of all CNC controls introduced a new controller, Acorn, specifically to attract the hobby guys. Yes, I advocate professional controls and the Acorn is truly a professional controller. Centroid gives the same core CNC processor to the Acorn board found in their high end boards. So the hobby guy gets the best. You will not find a better processor for the money. Did I mention the Acorn is about 300 bucks from some vendors. It comes complete with the controller, power supply, cabling, and their light but very robust control software. Be on the lookout for a MechMate controller upgrade to Centroid. Last edited by WilliamT; Sun 14 January 2018 at 15:19.. Reason: spelling error |
#85
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I have also been reviewing the Acorn controller. I was wondering if the 23 motors needed any gear reduction. I see here that the 23's with our belt drives work great.
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#86
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Acorn
http://www.centroidcnc.com/centroid_...ontroller.html https://www.youtube.com/watch?v=6qvD5GuJUxI https://www.youtube.com/watch?v=o5KSTO8YWkE Clearpath https://www.teknic.com/model-info/CPM-SDSK-2310S-RLN/ https://www.youtube.com/watch?v=Z2kAcz-rG5s I think we may want to start a tread in Control Systems on this setup. |
#87
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Just what I needed for info THKS WilliamT !!
I'm in the....thinking & search process to upgrade from my initial & old ( but still useful) PMDX+ SS + Mach3 set up !! Wondering on & about Acorn or UCNC !?...but that's another questioning debate out of WilliamT thread @_@ !! Cheers |
#88
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Is it possible to get the resolution fine enough without gear reduction with servos?
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#89
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Hmmm, one of the main reasons to go with servos is the ability to use the encoders for feedback positioning. According to Centroid's specs, the Acorn does NOT allow for true closed loop operation:
http://www.centroidcnc.com/centroid_...d_diy_cnc.html Brian |
#90
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"Beating the dead horse again" none of the low end products close the loop at the computer there are some cards that can be put in the computer that allow closed loop at the computer. Gallile comes to mind http://www.galilmc.com/news/cnc
but the common servo's that are used with Mach3 close the loop at the drive there used to be a plug in for mach3 for the gallil card but I digress Happu Hunting archie |
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