Messages

7251

Show"N"Tell ( What you have made with your CNC machine.) / SHERLINE ROTARY TABLE MOTOR MOUNTING

« on: July 06, 2008, 04:39:28 PM »

Nothing fancy. Just showing how a stepper motor was mounted to a Sherline rotary table.
The square adapter under the table allows for easy insertion into a vise and provides for centering of the table to the block.
The adapter can be remove and holes in the adapter ( can't see them ) allow for mounting to a sine and right angle plate.
The stepper motor mount was made from a scrapped assembly "save good junk". Will change out stepper with one having dual shafts so it can be used manually.
RICH

7252

General Mach Discussion / Re: im service parrellel sys- 4 mach3 setup

« on: July 06, 2008, 03:16:09 PM »

loot,
What exact kit / system did you buy? Did it include one of their controller boxes which have drives and a board?
Most of the cables you recieved should just plug into the controller and then it's a matter of configuring MACH.
Maybe MACH is already configured based on a Sherline package and associated motors.
Think folks in here would be more than happy to help you out. I would have thought that Fred would at least
waver the $60 a year IMSERVICE forum fee until you got things hooked up.
RICH 

7253

General Mach Discussion / Re: classes on g code and mach 3

« on: July 06, 2008, 10:35:01 AM »

Hi All,
Will use myself as an example.
I need enough to know how to use the MDI line to move the tables around and setup the job. Use the wizards because they just make things so easy and provides a nice place between writing code on one end and using CAD / CAM on the other end of the spectrum. The niche spot wizards provide, is you can use the CNC machine to do typical tasks and not feel it's easier or quicker to do it manually. On the CAD / CAM side you just can't beat having the code generated for complex things by a program. I could never write the code for the engraving work I have done. All the programs give you some quirky code and the ability to scroll down  / simulate the code , remove that one stupid line or lines, and know the effect is almost "mandatory".

I tend to learn what is needed to enjoy my bobby and constantly enhance as required. Remembering when I knew nothing about Gcode, just read the different definitions, played with the moves in a few programs and on paper until pacified. Got bored with that and went into using a CNC program to make chips.

When I reflect on CNC, it's not only the Gcode. CNC is quite complex, to a beginner overwhelming, computer, CAD, CAM code, controllers, wiring, machining experience, engineering expertise, etc.. Just think if your main background is only basket weaving it sure could be a challenge.
Gcode is only one part of the of the big picture. If it's your thing go for it!
RICH


 

7254

General Mach Discussion / Re: Setting up a 4th axis?

« on: July 06, 2008, 08:46:11 AM »

- What kind of backlash can I expect from the Sherline? -

Mine has approx 5 min and it varies a little. I always rotate it to take it out before indexing. You can use the backlash compensation
in MACH ( haven't tried it for a rotary table / should work fine ) and if your using a SS backlash compensation is not available yet.

I have not checked accuracy of the gearing as it's very time consuming, not worth the effort, and you need the right equipment to do it. Have done some checking of my Klinger table but that's a different story on how and why it was done.

Maybe someone will post some experience on engraving / machining around the circumference as it relates to a rotary table and what they found to be desired. It all depends on what your going to do with it.

RICH



 

7255

General Mach Discussion / Re: Setting up a 4th axis?

« on: July 05, 2008, 06:44:53 PM »

Dave,
Will post some pictures in the show and tell ( tomorrow ) with additional info so this post dosn't get off on a tangent. Three of us  have converted the manual one. Here are some angular to linear conversions which you may find usefull in relating to angular positioning:

ANGLE     PER INCH      PER 3"         PER FOOT         
1 SEC       .000005"     .000014"     .00006"
30 SEC     .00014"       .00044"      .0017"
1 MIN       .00029        .00087"      .0035"

So if you were to drill a hole out from the center 3", then index 3 min, and drill another hole, the distance you have between the holes would only be approx .003".

I use mine primarily for positioning.
RICH 

7256

General Mach Discussion / Re: Setting up a 4th axis?

« on: July 05, 2008, 04:25:42 PM »

Dave,
There are are probably 5-10 small rotary tables out there for a small mill. Three of us, over time, ended up getting the Sherline because we felt the quality was better. But only you can decide. Motors used were 100 & 125 in oz.. If you make your own base for mounting the motor you can save a bunch of $. You can mount it to a right angle plate
( maybe get one from Encho for $20-30).  Then treat yourself to a nice chuck on what you saved. I can post a picture of what i did if you wish.
RICH

7257

General Mach Discussion / Re: NOISE PROBLEMS

« on: July 05, 2008, 11:23:43 AM »

INIVATOR,
Replace the brushes on the Dremel Tool, vac out / clean the brush area, and run it off the machine for a little while giving them a
chance to seat.  No / minimum  sparking is good.

Now just for kicks, plug the dremel into the same outlet which has a TV or radio plugged into it. It'll make the picture fuzzy,
you'll get a lot of static on a radio. Post installation of new brushes try it again and you'll see a difference in the interference from the
Dremel. Now neatly coil the TV outlet wire, neatly wrapped around a tube and try again and see if there's additional  improvement.
Take the Dremel and with it plugged into  a different outlet , running ( hopefully not on the same circuit) and watch the interference. Now bring the running dremel near / around the TV and see what happens.

A coil provides an impedence to the path of the noise ( the coil / inductor can be made stronger depending on the core material ( in this case just air and the number of turns). Yes I would use shileded wire on the cables but if you don't have a problem leave them alone. You can get noise via the AC and you can also get noise traveling onto the DC switch cables since they act as a condutor of the noise.
The noise on the switch cables can really do a number since it going directly to maybe a board. Please note that i used "noise" as a general term to keep things simple.

RICH

7258

General Mach Discussion / Re: classes on g code and mach 3

« on: July 03, 2008, 09:11:39 AM »

trunkhaus,
Here's a link to a "free" course to get get you started:

http://technology.calumet.purdue.edu/met/mfet/275/coursematerial.htm

Here's a simple easy "free" program which you can just type commands and see movements :

http://www.ncplot.com/ncplotfree/ncplotfree.htm

Then maybe you can use the other posted program for more advanced stuff.
Hopefully this gives you a progressive path to follow.

7259

General Mach Discussion / Re: classes on g code and mach 3

« on: July 02, 2008, 06:14:10 PM »

Hi trunkhaus,
Here is a link to a "free" program which you may find usefull in learning G code.
I am sure there are others.

http://www.betatechnical.com/autonc.htm

RICH

7260

General Mach Discussion / Re: Power supply in parallel

« on: July 02, 2008, 03:25:05 PM »

ostie01,

Your driver board max power supply rating is 32VDC@7A, with a recomended supply of 24VDC@7A.
Now if you were to use two power supplies wired in parallel you could get 24VDC@12A which is over the driver board rating.
This is not good.

Should the filtering quality of the power supplies be inferior, a properly rated capacitor may be desired. My preference would be to provide the additional filtering and some surge capacity via the capacitor if they were parallel connected ( but that's only my opinion).

I only glanced thru the 20 pages of the power supply manual and noticed there is info on series and parallel wiring.
Pay attention to it.


With no motor curve info, which relates wiring confirguration to speed, torque @ some voltage, you can not forecast motor preformance ( it will be trial and error in finding it via tuning). The driver board info shows max individual drive fusing to be 2.5A.  This says any individaul stepper current draw will be limited to 2.5A MAX which futher defines how you would wire the steppers.
Also as a total ( three steppers with a total current draw should not exceed the 7A rating of the board ).

RICH