Rotary Tool - Epilog Homemade

[Pete Simmons]

Would someone measure and send me the diameters of the pulleys and rotor on the Epilog tool? Maybe even a picture of the power end of the tool.

If Epilog will sell me the stepper motor for not a huge number of $$$ I would like to build my own chuck based rotary tool.

[Shane Gould]

Please keep us informed on this project, prices etc. I may be interested in doing something like this as well.

Thanks,

[Doug Fennell]

Pete, no need to go through Epilog for a motor - it's just a vexta 2-phase 6 wire motor. No need to even use the vexta brand for that matter.
Model number is PH-265m-33-C9 (when you do a search, just search for PH-265m-33).

Specs are 24V (not even critical for this application)
.21A (per phase)
.9deg per step

Pacific Scientific makes similar specd motors, and Ebay is a great source for steppers in general.

Should be an easy project. I'll measure the rotors tomorrow. The rotation angle per step will be critical, but the way of getting there is open for debate - in other words, you could do a worm drive if you'd like.

Made several of these for CNC mills in the past, the one for the Epilog shouldn't be an issue.

As for parts, I'd consider the 3 jaw chuck from a Taig mini lathe - they're inexpensive and top quality. Perfectly suited for this app.

As for the drive, easiest will be to use a bronze spur gear and worm. Best will be to hob your own on a lathe. For this app, I wouldn't even bother with hobbing a gear, I'd just use bronze.

[Doug Fennell]

You know, on second thought it'd be even easier to just use a belt drive - there's really no torsional force so no need for a gear drive unless you just wanted to. It's gonna come down to the mass of the chuck you choose to go with - lighter the better.

[Kim Vellore]

The rotary fixture is quite simple to build and will work better if custom built for your application.
Epilog has gone from Vexta to Lin Engineering motor (lot cheaper). The motors are cheap Just make sure it is unipolar and rated for minimum of 24V, Doug is right in saying 24V not critical, I would agree for most application and when I made mine I used a 12V motor but it almost got burnt. Here is the reason: Epilog uses the chip LMD18245, it is a full bridge motor driver to drive the rotary stepper motor. The problem is way Epilog drives this motor, it is driven at full power no PWM, or current limit or cutback at idle, The motor sees ~50V DC at the coils all the time, even the 24V motor I used gets pretty hot.

Most steppers are rated at low voltages and are driven at 3-25 times the rated voltage that is OK if the driver limits the current. In the Epilog driver there is no current limit. I had to look hard to find some 24V motors, I found some at a surplus store for $3.95.
Dont worry about the torque, this motor is over driven and can turn a gorilla.
Kim

[Justin Harrington]

I would be very interested to find out is anyone has managed to make a chuck type rotary fixture for the Epilog. I recentley lost out on a very luctrative deal to laser engrave telescope eye rings due to the fact that there was no way of holding the part on the current rotary and achieving accurate spacings as the part was prone to slip on the wheel arrangement. If anyone out there is planning or has the capability to make one I'd be interested.

Thanks
JUSTIN

[Pete Simmons]

Let me describe how I think some of this works and see if I can get aggreement or be corrected.


Rotary tool - for the moment lets forget the drive ratio from the stepper motor to the drive wheels. Lets just look at the drive wheels.

Since you set vertical page size to the cercumfernce of the item you want to engrave - if your item was the same diameter as the drive wheel then the drive wheel should make exactly 1 revolution - Correct??

Example - engrave a line around a rod the diameter of the drive wheel. Set the vert page size correct and it should make 1 rev.

[Doug Fennell]

Well, you can't seperate the two. A stepping motor works by by sending a pulse train of on/offs to it and it steps (in this case) 9deg per step - assuming that Epilog is not microstepping the drive. I doubt they aremicrostepping, there would be no reason to for this application.

In other words, it the piece you are working on is the same diameter of the drive wheel, the drive wheel will make 1 revolution if it's driving in a 1:1 ratio and your engraving the entire circumfrence. If the piece you are working on is 10 times the diameter of the wheel, or 100X or even 100000X, the drive wheel will still make 1 revolution if you're engraving the entire circumfrence of the object.

Clear as mud? :-)

The bottom line is your drive ratio must mimic the epilog's unit, regardless of the mechanism used to drive.

Here's the easiest way to make what you're after...

Order a Taig lathe headstock spindle and 3 jaw chuck.
Mount a drive wheel the diameter required to mimic the final drive ratio of the Epilog rotary on the rear of the headstock.
Drive with a belt dirrectly off of the stepper output shaft.

Do a search for Nick Carter and Taig on google, you'll come up with his page - he sells everything you'd need to put it together on the cheap.

[Richard Rumancik]

Just a word or warning, though, about home-built rotary fixtures. If you choose to select a surplus motor that seems "about the same" as the Epilog motor, and you damage the driver, you are on your own. If my laser was under warranty, I would only buy the motor from Epilog. If it was off warranty, I would probably use whatever motor Epilog uses, regardless of where I got it.

I have considered building a rotary for my Mercury, but if I do, I will be very careful to match their motor. On the Mercury, the motor drivers are on the mainboard (I don't particularly like this configuration) but if you blow the driver, the mainboard needs to be repaired. Don't know whether the Epilog and ULS do the same thing. Some people would not be comfortable replacing the drivers on the board. And troubleshooting without schematics can be a problem.

[Alan Young]

Just wondering if the motors for the mercury are servo or stepper for the rotary. Seem like an intriguing project since I do not have a rotary. Any idea where to get the pin out of the mercury connection?

Alan

[Pete Simmons]

Just got this answer to an inquiry to the manufacturer


Peter
Thank you for contacting Oriental Motor.
The motor part number you mentioned is a proprietary motor,
and it has specail modification from the standard motor.
The best replacement is to contact the machine manifacturer for the replacement.
Oriental Motor USA
Technical Support
www.orientalmotor.com

> Vexta PH265M-33-C9 <

[Mike Hood]

Just wondering if the motors for the mercury are servo or stepper for the rotary. Seem like an intriguing project since I do not have a rotary. Any idea where to get the pin out of the mercury connection?

Alan

Servo is made by SOHO with two part numbers labeled:

T1MO051858 and 7Q3360-19110B-18Y

I took mine apart and shot some pics. Hope they help with the ideas. It would be VERY easy to add a chuck to a LaserPro laser.

[Doug Fennell]

Here's the basic idea - just replace the worm drive with belt.

http://members.shaw.ca/mryankey/4th%20axis.htm

As an alternative if you'd rather not tackle the job yourself, have Paul Jones build it for you. He caters to the DIY CNC community and would have no problem building the entire rig for you. Here's his webpage -

http://www.cnconabudget.com/

[Doug Fennell]

Mike, that unit would be super easy to retrofit a chuck to. It's actually a very nice design.

[Richard Rumancik]

. . . Thank you for contacting Oriental Motor. The motor part number you mentioned is a proprietary motor,
and it has specail modification from the standard motor.

It is hard to say offhand what the special mod is. Sometimes it is something simple like the connector style. Othertimes it might be the OEMs choice of encoder. Or an extra ground wire. Or special bearings. In any event they do not want to rock the boat with their OEM customers by selling "spare parts" thereby undercutting their primary customers.

If you can decipher the part number code then that can shed some light on it. For example, -C9 could be a connector style (just a guess/example).

They might sell an off-the-shelf version but keep in mind they are used to selling many motors at a time.