Messages

1

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: October 06, 2012, 11:51:52 AM »

Depends on the taper, but quite a lot.  A number of folks tried with R8's and it wound up taking more than they expected.  Life seems to begin at 1000 lbs or more.  Best numbers I've seen on it come with the docs for drawbar force gages if you want to Google around.  Some are 3000 lbs or more.

Best,

BW

2

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: October 06, 2012, 10:45:21 AM »

I can't believe that Rapid Changer has adequate drawbar force if it needed those cuts to mesh with the gripper balls to keep from spinning.  While the BT30 does have drive dogs as mentioned by Dan, there are plenty of taper specifications that don't.  Friction in the taper itself should prevent the spinning.  Just one more reason they need so much force.

Best,

BW

3

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: October 01, 2012, 11:45:45 AM »

Dave, here is a SCARA robot loading and unloading a lathe:

http://vimeo.com/3355086

Not my friend's setup, but similar.  The thing I like is the SCARA's have such simple geometry and construction.

Ray, yup, make the centrifugal force work for you.  Use a stronger spring in the extractor too!

I have a big collection of tool changer vids and other details I have been studying.  Eventually I will upload to CNCCookbook.  Not gonna happen until I finish a few of the giant open 55 gallon drums of worms around the shop!

Specifically, I am just putting finishing touches on installing the mill in a new Flood Enclosure and will shortly start fabricating a new head to mount my Tormach BT30 Cartridge Spindle.  Just order a Delta VFD-M and will shortly start experimenting with spindle position control.

Cheers,

BW
www.cnccookbook.com

4

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: October 01, 2012, 11:24:59 AM »

Steve, the retention mechansims being used on most VMC's for the carousel look pretty strong to me, and most are simple umbrella changes that aren't going to move as fast as the intermediate swing arm style you're building.

Check out these two videos to get a better idea:

http://www.youtube.com/watch?v=RQ4UT3IwTUg&feature=channel&list=UL

http://www.youtube.com/watch?v=aTwcBMvcqjA&feature=relmfu

And this one for a shopmade intermediate arm:

http://www.youtube.com/watch?v=KEBNB2d-syg

Tool holders are being flung hard. 

Cheers,

BW
www.cnccookbook.com

PS Dave, I'll hunt for some similar video.  My buddy never lets me video because he doesn't want customers getting irritated that their parts are showing up on the Internet.

5

General Mach Discussion / Re: BT30 spindle from scratch - with power drawbar and ATC of course

« on: September 30, 2012, 03:05:19 PM »

Lots of nice spindle and tool changer activity here.

I keep waiting for someone to set up a SCARA robot to do tool changes.  Ray's got half of an arm on his.  One more arm and the robot is ready.  It can load and unload your parts when it isn't too busy changing tools.  It can make sure the coolant nozzle is pointed at just the right spot for each tool.  Or, it can sweep the chips at the end of the day with a little brush, LOL.

Cheers,

BW
www.cnccookbook.com

PS  Mostly, joking, but a friend has a SCARA and they're remarkably simple and useful.  He uses it to move parts around on his lathe.  For example, to flip them so he can machine the part that had been chucked.

6

Promote and discuss your product / Re: *** Back to School Sale on G-Wizard Feeds and Speeds Calculator ***

« on: August 21, 2011, 11:50:53 AM »

Greg, no need to disagree, understanding is better. 

The passage you quote is accurate, but you must also apply the part I mention about the spindle to have the whole story.  The handedness of a CNC coordinate system is always relative to the spindle, not the table which is assumed to be stationary by convention.  So the diagram in the article shows the table motions we're more familiar with, precisely to make the point that it doesn't look much like a right handed system.  In fact it looks very much like a left handed system.  Looking at it from the spindle perspective is therefore key.  Whatever the table is doing, the direction is reversed when you think about it from the spindle's perspective.  So reverse those arrows and you'll find it is indeed a right handed system after all.

I added that discussion after doing a lot of research to understand why so many were saying CNC prefers a right handed system even though everything I looked at appeared to be left handed.

Here is anothe article that explains the importance of viewing the handedness from a workpiece stationary perspective:

http://www.cncexpo.com/Cartesian.aspx

Cheers,

BW

7

Promote and discuss your product / Re: *** Back to School Sale on G-Wizard Feeds and Speeds Calculator ***

« on: August 20, 2011, 11:09:08 AM »

Greg, it's accurate.  Like the caption and text says though, it is the direction of the spindle, which is reversed if the table moves.  Easy to get confused on that!

I have similar responses to the depiction of climb vs conventional in the speeds and feeds section.

In the end, you just need a way to remember what YOUR machine does, and be aware of the possibilities other machines may have.

Cheers,

BW

8

Promote and discuss your product / *** Back to School Sale on G-Wizard Feeds and Speeds Calculator ***

« on: August 18, 2011, 09:32:26 PM »

We're running a Back to School sale on the G-Wizard until the end of this month.  When you order the 3 year subscription, use the coupon code "BACK2SCHOOL" and get a 20% discount. 

That puts it at $103.20.

You can try G-Wizard for 30 days by signing up here:  http://www.cnccookbook.com/CCGWizard.html

To purchase, go to this page:  http://www.cnccookbook.com/CCBuyGWizard.html

While visiting CNCCookbook, be sure to check out our new G-Code Tutorial:

http://www.cnccookbook.com/CCCNCGCodeCourse.htm

It's free and has a lot of modules, with more to come over time.

Best Regards,

Bob Warfield
www.cnccookbook.com

9

G-Code, CAD, and CAM discussions / Re: Have you run into any Infinite Loops with g-code macros?

« on: June 30, 2011, 07:25:49 PM »

ROFL, I hate when that happens.

BW

10

G-Code, CAD, and CAM discussions / Have you run into any Infinite Loops with g-code macros?

« on: June 30, 2011, 12:49:44 PM »

I had a G-Wizard CNC Editor user contact me recently to help diagnose a problem he was having with some g-code his BobCAD CAM package had output.  He was having a hard time understanding what Mach3 was telling him:



Many of you will know what that means immediately, but many will not.  I wrote it up in an article that describes diagnosing the problem as well as some new features it prompted me to add to the G-Wizard Simulator.

The article is here:  http://www.cnccookbook.com/index.htm

Cheers,

Bob Warfield