Just purchased Micro-Mill need help picking the right Stepper motor and contro
sam_sam_sam
Posts: 2,286
Hi, Everyone
I Just purchased a Harbor Freight 47158 Micro-Mill.
It will be here in Two Weeks
At this web page they show you how make it·into cnc
Here are some·
http://www.balbots.com/article_info.php?articles_id=10
This mill comes ready for hand use, with Hand-Wheels on each Axis.
What I·would like know is what type of motor i should buy when i get ready to Automate· this Micro Mill
Stepper Motors or Servo Motors and what type of Controler to use with a Basic Stamp·
But it will a·little while before·I will be able to buy the Motors and Controler
Now is the time for me to my home work on the subject so i do it right the frist time the parts are some what price
I would like to Thank Any One that can shed some light on this subject
Sam····
Post Edited (sam_sam_sam) : 12/6/2006 4:27:03 AM GMT
I Just purchased a Harbor Freight 47158 Micro-Mill.
It will be here in Two Weeks
At this web page they show you how make it·into cnc
Here are some·
http://www.balbots.com/article_info.php?articles_id=10
This mill comes ready for hand use, with Hand-Wheels on each Axis.
What I·would like know is what type of motor i should buy when i get ready to Automate· this Micro Mill
Stepper Motors or Servo Motors and what type of Controler to use with a Basic Stamp·
But it will a·little while before·I will be able to buy the Motors and Controler
Now is the time for me to my home work on the subject so i do it right the frist time the parts are some what price
I would like to Thank Any One that can shed some light on this subject
Sam····
Post Edited (sam_sam_sam) : 12/6/2006 4:27:03 AM GMT
Comments
Go to the SEARCH button above and search using "CNC" This recent thread might be most relevant to what you want:
http://forums.parallax.com/showthread.php?p=539099
As you can see, a lot of people will wish you well and would like to see how you do it when you finish... starting with me.
Luck!
kenjj
1. Hobby servos are not that heavy duty and intended for R/C use while machine works may demand quite a bit of torgue.
2. Steppers are more precise in actual steps
3. Many available CNC software packages are intended for stepper motors.
'CNC Robotics' by Williams will likely give you the best introduction to DIY design and selection for CNC.
I bought my copy used at Amazon.
I am not exactly sure that a BasicStamp would really do all that you expect.
Many people rely on a PC for actual CNC while the BasicStamp would merely interface via RS-232 and drive the three steppers that are required. [noparse][[/noparse]X,Y,and Z axis]
The Propeller could provide a lot more computational power and at about the same cost. After all, it has the kind of mathmatical capacity you may require. And interfaces video, keyboard, and mouse.
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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········
www.machsupport.com/artsoft/downloads/downloads.htm
There are numerous Cad softwares to get your Gcode ready to run on the machine. Some are cheap, others are very expensive. One that might be worth getting is calle Bobcad, you can google it up and get a demo. I think the price has come down to around 500 if I am not misataken, but get the right sales guy and they will deal.
So in order to work, you must first generate a drawing of your part, then, convert it to Gcode. You put the Gcode in the Mach3 or other machine software to run the program to cut you parts.
You can look at USdigital for a high torque nema 23 size bi polar stepper that will serve your purposes well. For $102 you can get their stepper with an encoder on it already, then the Propeller can read the encoders using the existing Rotart Encoder object. This is a bit overkill for getting started, but you might aw well start building on a foundation that you can grow with.
The stepper driver is another issue. You will need to interaface a 25pin parallel cable from your PC to the machine's driver. There are lots of options for drivers, Gecko being one of the largest, but I prefer a Propeller based controller that manages up tp 4 bipolar drivers. You can get as deep as you want into it, or stay at arms length and use existing products or even make your own PCB's etc. I recommend something in between so you can get machining faster, which is a curve unto itself. CNCzone.com is the best source for machine info and forums.
Thanks for your post i did read that post but i forgot about that post but i reread it
Kramer
Thanks for you post
The problem that i have at this point i have only done the frist few examples on the forum
and it is taking along time for me to understand the Spins codes and how to write them
I also bought the Propeller Powered HYDRA Game Console. To understand more of how to write Propeller Code
Propeller Powered HYDRA Game Console·
For beginner to intermediate coders, you need only basic programming experience in any BASIC or C-like language
I am hoping by reading this book and doing the examples i will being to learn·more about the Spin Code
·
That why i was going to start with the Basic Stamp frist
My thought was to control the Stepper Motors with a Basic Stamp and learn how do this frist
Then when i have this working then move to the Propeller
·So what ic chip· that would interface with Basice Stamp
Can it be done this way·I open to any··
Sam
Post Edited (sam_sam_sam) : 12/6/2006 5:33:26 AM GMT
A BasicStamp or a Propeller would merely provide the logic level signals.
Stepper movement is really not advanced programing. If you can get a set of 4 lights to blink sequentially, you can do a stepper.
Regarding learning SPIN, I think all of us are more fearful of the learning curve than we should be. With the color display in the IDE and books, it is probably as easy or easier than PBasic.
It just offers a lot more that you can learn with it once you get going. I think that is where the 'fear factor' comes in.
Like the Chinese say, 'A journey of a thousand miles begins with one step.'
After, the Propeller is now 'state of the art'.
Please be aware that the HYDRA is really a video learning platform and may easily distract you from CNC.
In some cases the two files overlap, but you may have to set one topic aside to get anything done with the other.
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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········
Thanks for your post
You are right that
Please be aware that
The HYDRA is really a video learning platform and may easily distract you from CNC.
In some cases the two files overlap, but you may have to set one topic aside to get anything done with the other.
What i want to learn is video platform and the keyboard platform and the mouse platform
I will take it one step at a time and one platform at a time
Sam
I read that article a few weeks ago. It certainly got my interest.
Looking forward to your project.
Best of luck.
Edit:
I did some stepper motor research a couple of weeks ago.
A few good links I've come across,
www.cs.uiowa.edu/~jones/step/
www.educypedia.be/electronics/motorstep.htm
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- - - PLJack - - -
Perfection in design is not achieved when there is nothing left to add.
It is achieved when there is nothing left to take away.
Post Edited (PLJack) : 12/7/2006 1:12:19 AM GMT
As mentioned, the Stamp is not suited to driving a 3 axis CNC machine, however, since that's where you want to start, here is one very easy solution to get started testing out bi-poplar stepper motors. It is a chip designed to take Step and Direction signals from a micro, and convert it to the actual 4 wire sequences required to turn a stepper. The mosfets to connect to the chip could be any n channel mosfet for starters. I will link some cheap mosfets as well. This way you can learn how to send steps out of the Stamp, plus a Direction pin, and see the stepper move within a matter of an hour of breadboarding. Once you get the fundamentals down from this experiment you will be able to make decisions on how to proceed with either an off the shelf 3 axis driver or build your own. The chip linked ir really a PIC disguised as a stepper controller.
Keep in mind that with this system only, there is no current limiting, so you can easily smoke some parts if you provide too much voltage and current to the motors. I will link a powerful little stepper motor as well that you can buy for $12, then just start out with around 9 volts, check the temp of the mosfets, if the system is working and no real heat, try boosting it to 12 volts etc, then 18, but at that point you are going to get some real heat, and soon the mosfets will melt, or the motor will cook first.
Another option besides individual mosfets hanging off the EDE1204 may be an L293 hbridge IC. There are circuits for each choice shown. Again, with steppers, if you provide to much juice you burn stuff up, however, to get the most torque you need to provide more voltage than the motor rating specifies. To provide more voltage you have to in turn "chop" or limit the current back down to the max rating. This can be done by numerous methods if you choose to home brew it. The ultimate chip for this is an Allegro 3986 full Hbridge with PWM current limiting features built in. This is no a hobby IC thought, it only comes in fine pitch surface packages, which soon there may a stamp version for hobbiests. Maybe Parallax should provide one one day, as it is a great solution to the DIY stepper crowd.
www.allelectronics.com/cgi-bin/item/EDE-1204/search/STEPPER_MOTOR_CONTROLLER,_BI-POLAR_.html
www.allelectronics.com/cgi-bin/item/BUZ71A/search/N-CHANNEL_POWER_MOSFET,_T0220_.html
www.allelectronics.com/cgi-bin/item/SMT-85/search/STEPPER_MOTOR,_LIN_4218L_.html
Post Edited (originator) : 12/7/2006 2:06:05 AM GMT
Fortunately, the on board Propeller is the 40pin DIP and the EEPROM isalso socketed DIP, so you could transfer everything over to another board and later repopulate the Hydra at your leisure.
BTW, Andre's text is superb. And that is the true value of the package -- the knowledge.
If the Mini-Mill didn't weight 100 plus pounds, I would order one shipped here. I fear that the shipping might cost more than the mill for me.
Before you buy any stepper motors, you need to determine how much lateral movement one 360 degree turn of the screw is equal to. Also, you need to figure some estimate of needed torque.· And finally, what your ideal operating voltage will be.· There are tons of steppers that can do the job and NEMA standard housings.· You might as well fit it all to something that is standard and easily replacible.
I suspect the mill can make the mounts for the Stepper Motors.· About the only thing you will have to buy is the linkage.
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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········
Post Edited (Kramer) : 12/7/2006 1:07:29 PM GMT
Sid
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Sid Weaver
Don't have VGA?
Newzed@aol.com
·
I have alot of home work to do at this point and I will look in all that every one·has been·post
Thank for all of your help··in matter and i will keep you posted
·
These Guys are having way to much fun··
Just· kidding······
Post Edited (sam_sam_sam) : 12/8/2006 12:48:31 AM GMT
A Mini-Mill and a HydraTM -- Santa Claus sure came early this year!!
Yes But i am going have to......Pay......................Off to work i go...................
...................This is·what my wife tell all time when i buy stuff from Parallax and for all of parts that i buy..................................
.............I tell my wife all the time that·I DO NOT want to Grow Up and i don't think that i ever·will i want to·have my Play Toys·.......
·She dose try to understand my Play Toys she says·that this is better than me going out and Drinking and·Parting
·····································
For all of the stuff that i have bought in this month it will take 4 month to pay off or so
I sure wish there·was a real Santa Claus· then i would really have Some Fun·I would be a Kid in a Candy Store If you know what i mean
The End
Sam
How would i use this with a Basic Stamp
This the data sheet for the H15S single-ended optical encoder
·is a non-contacting rotary to digital position feedback device designed for applications requiring a size 15 servo mount.
www.usdigital.com/data-sheets/H15S%20Data%20Sheet.pdf
Would be the right thing to use for what i want do
Thanks to anyone that can shed some light on this
any ·
Sam
I did some stepper motor research a couple of weeks ago.
A few good links I've come across
Thanks for those Links i readed some them already
That will help
Sam······
While they could greatly assist if you have slippage, I suspect you don't need to use them with the steppers [noparse][[/noparse]if you don't push your feed rate to extreme].
With milling there is always a balance between the hardness of material, size and shape of the cutting tool, the depth of the cut, the strength of the motor, and the rate of feed into your material.
Ultimately, one usually has to slow down or make multiple passes to cut a lot of material. If you are really concerned with speed and production time, consider a bigger mill.
The slippage can be somewhat eliminated by bigger steppers.
The optical encoders require more logic [noparse][[/noparse]because you now have 3 feedback loops to reconcile along with innate stepper positioning]
I guess what I am trying to say is that a lot of people get by without encoders, but they would assure better accuracy [noparse][[/noparse]thousands of an inch] and may help determine optimal speed for production runs [noparse][[/noparse]once you find a non-slipping balance - you can make all items with the same approach to feed, depth of cuts, and passes].
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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········
I took look at this web page this just what i am looking for it is a little price
I am going to try some Stepper Motor Control Chip at this wed page
allegromicro.com· frist then when i learn how to write the code to control it
then i will move on to the next step
http://www.usdigital.com/data-sheets/MS23C%20Data%20Sheet.pdf
Now at www.usdigital.com they also have a stepper motor contoler at
http://www.usdigital.com/products/md2s/·there are two models they have
I·am not sure with one i would need to use with a Basic Stamp or Propeller
I will a few month before i can even think about buying anything else
This is the time for me to my home work and to learn how to do this
Thanks for this web site this has given me alot to think about
Sam
Kramer
This # one reason why want to use a Optical Encoder
You can make all items with the same approach to feed, depth of cuts, and passes].
The ot·reason i want to use a Optical encoders are positon feedback devices
(1) I want to know where the Start and Stop Postion for each part that i make on the same board
·where the next Start and Stop Postion and so on
And for these two reason· is why i want to use a Optical encoders are positon feedback devices
Thanks your input this·has really has help alot
·Sam
I· want Thank Every One·that given me thing to think about and Web Pages to go to
············ ·
·Sam
Post Edited (sam_sam_sam) : 12/8/2006 6:13:45 AM GMT
Not everyone has the funds. They certainly will add to more consistent production runs.
Consider how the optical encoders need to mount before purchasing your steppers. You may have to have shafts coming out of both ends of the stepper, rather than one. Or you may require a longer shaft.
Either way, it is very important to consider the optical encoders mounting before buying anything or you might have wasted money. Try to stick with NEMA standard stepper housings as they will always be replacible if you burn one up or want to change to a different electrical configuration [noparse][[/noparse]higher or lower voltage, etc.]. They do come with various shaft configurations.
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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········
I am going to produce a batch of Propeller 4 axis controller boards soon that will read 4 Step and Direction inputs plus 4 encoders, then it compares the two and outputs a signal in the event of X missed steps on the encoder. The signal is sent back up the parallel port so you can set your software(Mach3 or other) to pause or shut down on errors. Usually you will only get an error at really high speeds, or when you bind up your end mill or drill bit in a part. At slow speeds, the 4 amp US digital bi polars are like bulldozers, it takes a lot to stop them or miss a pulse. The Prop controller board has outputs to up to 4 3986 driver boards, and all the driver boards have individual input current sense resistors with individual comparators that can be set to send a signal back to the Popeller at a threashold. In my case I have 4 separate 4 amp supplies, one to each motor. After a while you get an idea of the typical load on a motor and can set the current sense accordingly. The Prop can take a current sense overlimit from any motor, send a pause or quit back to your software. For CNC this is not so critical, but the boards are used for various projects beside CNC machine, and the current trip can be set extremely sensitive, so even grabbing the stepper shaft with a few fingers will trip it. On the controller boards are two extra mosfets for spindle control and flood for example.
Anyways, it sounds like you are getting there rapidly. Keep at it.
--Below are the almost finished boards, one more revision next week including solder mask and screening will have them mostly dialed in. I was going to produce an entire motion system for those that didn't want the headache and learning curve, the system would consist of Prop controller, 1-4 driver boards, 4 motors with or without encoders. The Prop controller will run off USB to serial as well using another program which accepts position data and controls the motors directly. This is not ideal for CNC machining. I could help you with some code when you get to that point.
Post Edited (originator) : 12/8/2006 6:29:01 PM GMT
How do you greate your G-code?
I am running SolidWorks and am looking at SolidCAM. My understanding is that the 3-D CAD program makes the part, the CAM program makes the tool path and the post-processor writes the code for the machine. Waht are you suing to do all that?
If you want to make PCB's, you can export directly from Eagle using a ULP called PCBgcode which you can google up, or get off cadsoftusa.com. You then can either run the code directly from Mach3, or import it into your cadcam app and tweak it, which is what I always do.
Post Edited (originator) : 12/8/2006 8:04:21 PM GMT
I did just did call them and they are very help full
If you use nema 23 which is adequate for the mill you have, then the US digital stepper with built in encoder is $102(4 amp bi-polar high torque), already assembled and ready to go. They have a wiring harness for it for $10. You shouldn't try to add your own encoders, let the factory do it. US digital only has one nema 23 high torque stepper motor with your choice of encoders, MS233c-E5-200(motor and encoder assembly) is what I use $102.95. Just call and ask for tech help if you have any questions, they are very helpful.
I Going to buy MS233c-E5-200 for 102 each and some other thing that the tech was telling about
The person that was helping says that there will some learning to do and he is very right
It will be a few months before i will have the money to buy all of the parts that i need
I have alot of reading to do and lot of learning to do
originator and Kramer and PLJack and Newzed
Thanks for all of your help in this matter so far you give me alot to think about
I already have learned a few thing already
I could help you with some code when you get to that point.
originator
I would like to take you up on your offer when i get to that point
Sam
I had just order the Stepper Motor IC Chips last week i just got them yesterday i will order the Stepper Motors and the Mosfet on Monday
Thanks for your help
Sam
Seems to be headed toward the cost of a Sherline Packaged deal.
Actually I need to peek in on them and compare.
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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········
But I am wondering how you are going to reconnect the handles with Encoders on the motors.
The double shaft usually is used to provide for the handles [noparse][[/noparse]w/o the encoders].
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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········
But I am wondering how you are going to reconnect the handles with Encoders on the motors.
The double shaft usually is used to provide for the handles [noparse][[/noparse]w/o the encoders].
Kramer
I was thinking the same thing the only thing i though of was ether use a motor with a double shaft· and add a encoders
the only problem with is how to keep all dirt out of the encoders
Or use a motor with the encoders in them and have a manul way to move the table to where you need to have it
I also looked at their web page and they cost more than i want to spend
I do not know which way that i will go with this yet with the motors and the encoders
I have some time to make up my mind which way to go
I want to thank you all of your input and all of your thoughts·in this project
··
If the table and Z framing material is steel, you can make the motor mounts from steel and weld it on, then tap the holes in the mounting plate for the motor and bolton the motors.
Here is a small mill to show you what I mean. This is a $2500 fairly popular machine, note that all motor mount with only 2 bolts.
If in fact you had a error corection in the code, it could attempt to correct a missed step, then continue if successful.
If i had ·error on the table i would· want an corection to slow down the table until the error was cleared and leave it at that speed
and i also would want it that after slow down if still has an error after so many steps or NO steps then stop everything· then you have clear the problrm then restart unit
But, at low RPM's if one of those steppers stalls, you have bigger problems, that usually means your end mill/bit is bound up or that you have hit something, in which case, you don't want the machine trying to autocorrect,you want it to shut everything down, including the spindle, to avoid burning everything up
You are complely right if you are not getting any steps in one second then· STOP EVERY THING IN ONE SECOND
And this the reason why· i want to use an· Encoder to do just that if there is a problem i want it to stop every thing in it tracks
i would not use as an auto speed controler as far as speeding thing up
If i was going to use auto speed it would be base on·on the amps to the stepper motor and the· Encoder
·I might do that if i can thing of away to do it
i work with automation where i work so i have worked·with it before
Thanks for posting this it dose give me some thing to think about
Sam
I say this advice, but then I use encoders on everything [noparse]:)[/noparse] When you are ready, I have the code already done for reading the encoders and reading the step in from your PC, comparing and outputting on missed steps. I literally just finished hooking up 4 motors and drivers, and am now plugging in the encoder wires.