Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: jjenks0 on May 01, 2009, 01:00:37 PM
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I have an older EMCo lathe that I am currently using Welturn on, I bought a Xylotex board to upgrade to a PC and then use Mach II. Any one done this or have ideas how to hook the board up?
Thanks.
Jack
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Hi Jack,
What is the lathe model you have in particular? I have a Compact 5 CNC and I know that this whole series had variable reluctance 72 steps/rev stepper motors. If I remember correctly they are rated at 9V. The Xylotex driver can't drive them.
Get new, modern stepper motors to replace the stock ones and you should be fine.
Daniel
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I have a compact 5 pc. What stepper motors do you recommend? do they need to be 9volt? do you have a vendor in mind? What kind of board would I get?
thanks for the info.
Jack
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What software do you use on your Emco?
Jack
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Jack,
No, they don't have to be 9V. Actually the lower the voltage the better. Since the Xylotex is 35V, and it is recommended that the drive be about 5-10 times higher voltage than the motors, I'd recommend motors rated about 2V or less. But you'll have to make sure the Xylotex will be able to handle the motor's current.
There are really lots of vendors out there. I got mine form KelingInc.net . They offer pretty good motors inexpensively.
I use Mach3 on the lathe.
Daniel
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Oh... and you might want to have a look at this manual from GeckoDrive
http://geckodrive.com/upload/Step_motor_basics.pdf
It is a pretty comprehensive manual on stepper motors.
And as a correction to my previous post - the stepper driver's voltage should be 10-25 times the stepper motor rated voltage.
Daniel
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So did you have to get a board to hook the motors to and then the board plugs into the parallel port on the computer?
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I had a Compac PC-5 which I converted to Mach. I bought motors and a Xylotex board. With the Xylotex board the machine was slower than with its old steppers. I replaced the xylotex with geckos and got acceptable performance.
I have since decided the machine was to small for my use and have sold it. Im looking aorund now for a bigger lathe for my next project
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So did you have to get a board to hook the motors to and then the board plugs into the parallel port on the computer?
Don't know what you mean by "board". My steppers are hooked to Gecko drives which in turn are hooked to a CNC4PC break out board, and this is connected to the LPT.
Ron, I think your motors where just rated too high a voltage. I think if you had 2V motors, you would have gotten acceptable performance. I have Mechatronics drive (much like the Xylotex and rated the same voltage) on my F1 mill, and the rapids are at 1400mm/min - almost twice the original rapid speed.
Daniel
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Jack,
You will probably get a lot of different opinions on what to do. So I may as well add my 2 cents worth.
You already have a Xylotex board and if i had to start from scratch that would not have been my choice
and would have went with Gecko's. For steppers why not use or buy the equivillant of 269 in-oz ones which Xylotex sells with their kit? Also take a look at their associated power supply. Download their instructions also.
I have my PC and controller on a cart since i need to move them around for use on different machines.
You didn't say what drive you bought but if it's for four axis's then the power supply should have amperage
equal to the total amperage of all the drives along with 24 to ?? voltage ( ?? check to see what you drives are
rated for ).
You should consider using MAch3.
RICH
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The stepper motors, stepper drives, and power supply need to be chosen to work together. Gecko's stepper motor guide (linked to above) is a good read, and will help you understand how to choose the parts. In short you need to start with choosing the steppers to match the job at hand ( 'bigger', more oz-in, are not always better). When you know the motors inductance you can use Geckos rule-of-thumb formula to calculate the supply voltage. Keep in mind that this calculation just gets you in the right ballpark for getting the most out of your motors. Now you'll know what current voltage range of stepper driver to look for.
I've used the Xylotex driver in the past and they work well. When the Gecko G540 came out I was blown away though. The built in optical isolation makes it a lot easier to folks to wire things up and eliminates the need for a separate break-out-board. It also has charge pump integration built right in , oh and a 0-10V output for the spindle. (So it is easier to use and less expensive too!) Here is what one looks like: http://soigeneris.com/products3.aspx, I have been redoing these pages and will get the manuals on there soon.
What I would do is look at the factory steppers and do some googling to find out their specs. Chances are that the engineers spent a lot of time matching those motors to the machine. It will give you a good place to start looking.
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Ron, I think your motors where just rated too high a voltage. I think if you had 2V motors, you would have gotten acceptable performance.
I bought the xylotex kit, with their motors, board and power supply. When I found them to slow I replace the board with geckos and raised the power supply voltage to about 48v. That worked well.
The simple fact is that voltage equates to speed with steppers, and the Xylotex board with its 24v useful limit is just slow. With the Gecko 251s available (they were not when I started the project) I see no reason to ever buy a Xylotex board.
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Well Jack,
You asked a simple question and off we go to help you or give you more than a simple answer.
I don't like to comment on someones remarks, but, Jeff's reply is very important, also
and i would like to expand on his reply in a different way.
Let's do some design for a machine at a very high level. The motor is sized such that it will move the machines axis with enough power and at some desirable speed along with enough torque. This is true for each of the machines axis's and could be different. The power supply will need to provide the voltage and current to all of the motor drives. Motors can be wired differently to change their operation and thus their voltage and current
requirements will change. Now for each sentence above there are books upon books written.
So lets really confuse the issue of the controller box which usualy contains the power supply, drives, maybe some other boards. You can design something so that it only works within a small range of operation or you can expand the range of operation and allow for some unknown future wants or needs. Also you can be conservative in the design of the components. Cost is also something to consider and could be a deciding factor.
From a cost point of view consider the following:
- Dedicated contoller to one machine to just to get it cnc'd and fool around with to gain experience $=?
- A contoller to use for multiple machines some requiring a better power supply $=?
I would recommend the following for your consideration:
1. Make the box large enough so you can add additional drives allowing room for easy routing of the wires, access, room for other boards etc.
2. Consider a power supply / supplies , or maybe one now and addition of another such that it would take care of future needs. I have have 30 amp power supply at 36 volts, so it can take care of 4 dives easy and that allows me to address about anything at a hobby level i should need.
I just don't want you to spend money and be sorry later on. So think about it.
RICH
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Chances are that the engineers spent a lot of time matching those motors to the machine.
Jeff,
You are not familiar with this particular Emco lathe :) Saying that the engineers spent time on constructing this machine is over complementing them. Actually, for this machine, over complementing would be even saying that "engineers designed it" :D The mechanical design of this machine is so awful that it makes me wonder whether it was a dumb engineer who designed it or a warehouseman.
However, about the stepper motors in particular you might be right about this machine. They seemed to be critically suited for the job, though I didn't work much with the original setup. The factory steppers on the Compact 5 CNC were 60 Oz-in, but I think (although, as I said, they may be just powerful enough) that twice that would be more appropriate for this machine.
Just my thought.
Daniel
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The simple fact is that voltage equates to speed with steppers, and the Xylotex board with its 24v useful limit is just slow. With the Gecko 251s available (they were not when I started the project) I see no reason to ever buy a Xylotex board.
Ron,
Didn't realize the Xylotex was only 24V. Thought it had an upper limit of 35V. 24V sounds really low indeed.
Daniel
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Thanks for all of the replys. I am a shop teacher at a high school and we have quite a few cnc spectra light machines that we use. I want to upgrade the Emco because it can do longer stock. So from the replys I am getting I may be able to buy a Gecko G540 and use the motors that are on the lathe currently. Maybe just up my power supply. I am mainly interested in using an program like Mach 3 instead of the current welsoft program. When I bought the lathe it was run from a Mac. The Welsoft program up grades it to a pc and uses a 9 volt power supply.
Thanks.
jack
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Hi, Jack
Hears an article I found on the web, Should make the conversion easier for you.
Chip
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Hi Jack,
I don't think you'll be able to drive the stock motors with the G540. As far as I remember, the G540 is only 50V. Not enough for the factory motors (if they are 9V indeed, like mine were).
Daniel