Reverse Engineering a 5-axis benchtop CNC
01 Sep 2023 20:20 - 04 Sep 2023 04:11 #279609
by drdoc
Reverse Engineering a 5-axis benchtop CNC was created by drdoc
Long story, but I'm retrofitting a 7i96 (and probably a ChinaBoB) to a VHF CAM5 S2 dental mill. TL;DR I don't have the license dongle it sold with and don't have the money to pay for the proprietary control software.
The motion part is pretty straightforward. Open loop NEMA17 steppers with ball screws, I don't expect any problem controlling the motion. I might at some point build a bigger frame but for now, I'm looking at a working envelope of about 4" x 3.5" x 3" plus I think 90 degrees on A and 360 on B.
I'm going to either forego the tool changer or re-work it as a 6 or 8 tool instead of 16. Tools with that depth-gauge circlip are way out of my budget, and I think that's integral to operating it as a 16-tool magazine. The spindle, however. It's an VHF-branded SFS 300P. Neither SFS nor VHF publish any pinout, voltage requirement, control frequency range or any useful build info. The motor control daughterboard gives me the pinout for the motor, but I don't have the electronics fu to get any farther than that.
So, my questions are:1) Does anyone here have knowledge or experience with this particular machine? A service manual or any maintenance information would be miraculous.2) Same question for the spindle assembly. I do have the pressure & flow specs for the air seal and chuck controls, but working out the input voltage and speed control are out of my depth.3) Assuming the absence of model-specific details, how should I go about reverse-engineering the motor? I have multimeters and oscilloscope.
Thanks!
Doc
The motion part is pretty straightforward. Open loop NEMA17 steppers with ball screws, I don't expect any problem controlling the motion. I might at some point build a bigger frame but for now, I'm looking at a working envelope of about 4" x 3.5" x 3" plus I think 90 degrees on A and 360 on B.
I'm going to either forego the tool changer or re-work it as a 6 or 8 tool instead of 16. Tools with that depth-gauge circlip are way out of my budget, and I think that's integral to operating it as a 16-tool magazine. The spindle, however. It's an VHF-branded SFS 300P. Neither SFS nor VHF publish any pinout, voltage requirement, control frequency range or any useful build info. The motor control daughterboard gives me the pinout for the motor, but I don't have the electronics fu to get any farther than that.
So, my questions are:1) Does anyone here have knowledge or experience with this particular machine? A service manual or any maintenance information would be miraculous.2) Same question for the spindle assembly. I do have the pressure & flow specs for the air seal and chuck controls, but working out the input voltage and speed control are out of my depth.3) Assuming the absence of model-specific details, how should I go about reverse-engineering the motor? I have multimeters and oscilloscope.
Thanks!
Doc
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01 Sep 2023 23:03 #279627
by tommylight
Replied by tommylight on topic Reverse Engineering a 5-axis benchtop CNC
I had no irrelevant and political stuff 
, but i hate using those web sites as they have all kinds of trackers, info stealers, malware and spyware, etc etc, hence my insisting on uploading pictures here on the forum.
From what i gathered through all the dust, it was a min 5 axis dental machine, has the "plate holder", use materials like titanium, zirconium, and some other stuff that are disk shaped, have NFC or RFID embedded and the machine keeps track of what has already been used, very costly, spindles are usually 50 to 60 KRPM, small tools also expensive, etc.
Fixed several of those, they are also very heavy.
I also have a full PC with PCI controller in it for one of those, probably Italian made, although the machine was bought in 2009 new.
, but i hate using those web sites as they have all kinds of trackers, info stealers, malware and spyware, etc etc, hence my insisting on uploading pictures here on the forum.From what i gathered through all the dust, it was a min 5 axis dental machine, has the "plate holder", use materials like titanium, zirconium, and some other stuff that are disk shaped, have NFC or RFID embedded and the machine keeps track of what has already been used, very costly, spindles are usually 50 to 60 KRPM, small tools also expensive, etc.
Fixed several of those, they are also very heavy.
I also have a full PC with PCI controller in it for one of those, probably Italian made, although the machine was bought in 2009 new.
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07 Sep 2023 03:08 - 07 Sep 2023 03:10 #280164
by drdoc
Replied by drdoc on topic Reverse Engineering a 5-axis benchtop CNC
Well, I tried to do some further work while tired and distracted, and smoked something in the spindle. I had hoped to avoid tearing it down and was trying to map the phases and sensors, and put 24VDC where it didn't belong.
Oscilloscope shows a nice sinusoidal back emf if I drive the motor externally, and the wiring indicates no Hall effect sensors, so I'm not sure how to drive the thing. Will a simple sensorless (back-emf controlled) BLDC circuit work?
The sensor in the second photo rides on the "dremeled" collar in the first photo
Oscilloscope shows a nice sinusoidal back emf if I drive the motor externally, and the wiring indicates no Hall effect sensors, so I'm not sure how to drive the thing. Will a simple sensorless (back-emf controlled) BLDC circuit work?
The sensor in the second photo rides on the "dremeled" collar in the first photo
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