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Topics - Zero Cool

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11
General Mach Discussion / Minnesota Mach3 Users?
« on: January 22, 2011, 11:12:27 AM »
I am curious how many Minnesota Mach3 users there are? I am looking for some help to tune my mill and would like to get in touch with some local users that would be willing to help me get the basics set up.

 It might also be fun to form a MN mach users group and get together once a month or something. any takers?


Zc

12
I was looking for a way to use the Mach3 PWM spindle motor speed control feature for my Mill that is a build in progress. So With the Help of Bill Grumble from the TC robotics Group, I built this PWM Motor controller that I thought i would share with you.

***First and foremost**** This design is connected to the AC power line and has a large capacitor that can store a deadly charge for hours after it is unplugged. THIS IS NOT FOR THE INEXPERIENCED OR FIRST TIMER! You can and will be hurt if you are not careful! build at your own risk!


with that said....

 I plan on using a modified Dremel 395 as my spindle motor. I have removed the Dremels internal Triac based speed control as the internal motor is a universal motor that will run on AC or DC. I added a IR LED and a Phototransistor to the dremel motor to send a speed pulse back to Mach3. I removed the AC power cord and added a 5pin CB radio type connector on the rear for the 2 wires for the motor and 3 for the speed sensor system(details on that later...thats next).

 next I needed a way to take the PWM signal from the printer port and control a motor with it. I was talking with Bill Grumble at a TC Robotics group meeting and he pencil sketched this basic design. I took it a bit further and worked out the details to make it run.

 The PWM signal from the PC's printer port is Optically isolated from the Motor controller through a H11L2 Optocoupler. the output from the Opto then feeds the PWM signal to a IR2109 Mosfet driver. I am only using the low side of the driver. and I choose to use a IRG4BC30S IGBT instead of a mosfet for higher current handling should the Dremel lock up. this is the basics of it. For the power supplies, I basically took apart an old switching power supply and robbed all the AC line components. the AC line enters through a fuse to an In rush limiter, then to a MOV or Zener surge suppressor. to a cap and to the bridge rectifier. the bridge converts the AC to DC and a large filter cap cleans up the ripple a bit.

 I choose a 100uf 200V cap as it is what i had on hand. this is a very small amount of capacitance and a larger cap would be better...however. there is some debate on if any benefit would be had as it seems to run perfectly fine as is.

 there is also a 12V Zener regulated supply that feeds 12V to the IC's. The mosfet really needs 15V but I choose 12V to start with. mosfets tend to die if the voltage exceeds 18-20V or so. so i choose caution to start with. you can experiment with 15V if you like. less loss through the mosfet if the mosfet is turned on all the way.

 You will not a large inductor on my PCB...this was in the original supply so i added it but its a bit overkill and really doesn't do much as it was originally part of a Pi filter. it has since been removed.

This design works well! and could be revamped to handle as large of a motor as you like! a bigger heatsink is needed if you plan on running a motor larger then 1 amp. I found with the dremel tool that the heatsink isn't even needed! the Mosfet/Igbt never even gets warm running without a load. but its a good idea to have some form of heatsinking.

 The IR2109 has a saftey lockout should the IC's voltage drop below 10V. this threw me at first. Also the rectified and filtered AC line is about 170vdc, the dremel needs to be speed limited to about 70% pwm so as not to over run the motor. you could use a 80-90vac transformer to provide 120vdc instead. would be a degree safer too.


Enjoy

13
 I was looking for a way to use the Mach3 PWM spindle motor speed control feature for my Mill that is a build in progress. So With the Help of Bill Grumble from the TC robotics Group, I built this PWM Motor controller that I thought i would share with you.

***First and foremost**** This design is connected to the AC power line and has a large capacitor that can store a deadly charge for hours after it is unplugged. THIS IS NOT FOR THE INEXPERIENCED OR FIRST TIMER! You can and will be hurt if you are not careful! build at your own risk!


with that said....

 I plan on using a modified Dremel 395 as my spindle motor. I have removed the Dremels internal Triac based speed control as the internal motor is a universal motor that will run on AC or DC. I added a IR LED and a Phototransistor to the dremel motor to send a speed pulse back to Mach3. I removed the AC power cord and added a 5pin CB radio type connector on the rear for the 2 wires for the motor and 3 for the speed sensor system(details on that later...thats next).

 next I needed a way to take the PWM signal from the printer port and control a motor with it. I was talking with Bill Grumble at a TC Robotics group meeting and he pencil sketched this basic design. I took it a bit further and worked out the details to make it run.

 The PWM signal from the PC's printer port is Optically isolated from the Motor controller through a H11L2 Optocoupler. the output from the Opto then feeds the PWM signal to a IR2109 Mosfet driver. I am only using the low side of the driver. and I choose to use a IRG4BC30S IGBT instead of a mosfet for higher current handling should the Dremel lock up. this is the basics of it. For the power supplies, I basically took apart an old switching power supply and robbed all the AC line components. the AC line enters through a fuse to an In rush limiter, then to a MOV or Zener surge suppressor. to a cap and to the bridge rectifier. the bridge converts the AC to DC and a large filter cap cleans up the ripple a bit.

 I choose a 100uf 200V cap as it is what i had on hand. this is a very small amount of capacitance and a larger cap would be better...however. there is some debate on if any benefit would be had as it seems to run perfectly fine as is.

 there is also a 12V Zener regulated supply that feeds 12V to the IC's. The mosfet really needs 15V but I choose 12V to start with. mosfets tend to die if the voltage exceeds 18-20V or so. so i choose caution to start with. you can experiment with 15V if you like. less loss through the mosfet if the mosfet is turned on all the way.

 You will not a large inductor on my PCB...this was in the original supply so i added it but its a bit overkill and really doesn't do much as it was originally part of a Pi filter. it has since been removed.

This design works well! and could be revamped to handle as large of a motor as you like! a bigger heatsink is needed if you plan on running a motor larger then 1 amp. I found with the dremel tool that the heatsink isn't even needed! the Mosfet/Igbt never even gets warm running without a load. but its a good idea to have some form of heatsinking.

 The IR2109 has a saftey lockout should the IC's voltage drop below 10V. this threw me at first. Also the rectified and filtered AC line is about 170vdc, the dremel needs to be speed limited to about 70% pwm so as not to over run the motor. you could use a 80-90vac transformer to provide 120vdc instead. would be a degree safer too.


Enjoy

14
General Mach Discussion / Dremel Aluminum cutting bits?
« on: July 25, 2010, 11:11:21 AM »
Anyone have suggestions or tips for milling aluminum using a Dremel tool as the spindle motor? I want to be able to do light engraving as well as some through hole panel cuts on 1/8" aluminum. I have some carbide buts but they have a fine tooth pattern and seem to clog easily.

 any good web stores with a variety of bits??

and what about spindle speeds?

15
General Mach Discussion / Hobby CNC Spindle Motor Choices
« on: July 25, 2010, 11:09:12 AM »
Im curious if there are other choices out there for Hobby type CNC Mills other than a Dremel or a Laminate trim type router. something reasonably priced. I have seen some liquid cooled $1000 small spindle motors and those are out of the question. I am talking something in the sub $100 range or possibly a bit more but that ball park anyway.

 And what Laminate trim routers work well? any that enable easy mounting etc?

Right now I am using a Dremel 395 to get my machine running and I plan to do PCB milling, some aluminum panel engraving but also some aluminum panel cut outs. where the panels maybe 1/8" thick. I would assume through hole cut outs would need to be done in many steps, a little bit at a time of course. My machine isn't real powerful or anything. but i am wondering what alternate choices there are. it would be nice if one day i could do 1/2" thick aluminum panels but that may be pushing it with this machines capabilities.

16
I am building a new motor controller box and I am looking for suggestions for what front panel controls, buttons, meters etc would be important to have for use with mach3

 I have a nice rack mount aluminum box large enough to hold the internals and I know for sure I am putting a power switch and E-stop buttons on the front. I have been considering either a joystick for X & Y axis or a 6 button arraignment for X,Y & Z axis's.

Being new to mach3 and CNC in general what other buttons would be important to have on the front panel? is there anything that is simply a must have?

 I plan to build a custom pendant later. But I don't mind duplicating functions.

17
*****VIDEOS***** / First run of my Shibaura Roibot
« on: July 04, 2010, 05:37:16 PM »
The first run of my Shibaura Roibot. I had just gotten control of the motors. no tuning had been done yet and i only had control of 3 directions due to a bad motor controller opto. but it was a major step to get this thing running. Not much to look for you "Pro's" but for a newb like me with ZERO knowledge of CNC and limited Stepper knowledge this was major!

http://www.youtube.com/watch?v=RdyetgERBR4

18
General Mach Discussion / ANY MN Mach users?
« on: June 30, 2010, 11:33:55 PM »
Any users here from Minnesota? would like to meet local people with mills running Mach for local assistance etc.



Zc

19
General Mach Discussion / Mach3 and win XP setup and tweaks??
« on: June 29, 2010, 11:47:20 PM »
I just re-purposed a nice 3ghz SFF PC for use with mach3, I have 2gb of ram, 40gig drive, and running winXP pro. I am keeping the machine stripped down and trying to keep it as clean as possible.

 I have Mach3 demo currently installed and running. I'm new to Mach3 so im learning but thus far i have watched the first video tutorials and have been able to get manual control of my motors. so far so good.

I am looking for tips and tweaks, do's and don't for setting up winXp for smooth running of my mill. are there any gotcha's? things to avoid etc?

 I will be adding a 2nd parallel port card to the machine at a later date for additional I/O

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