Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: bowber on January 23, 2010, 09:46:53 AM

Title: Problem with the gear cutting wizards
Post by: bowber on January 23, 2010, 09:46:53 AM
Hi all, hope your all ahving a good new year so far and managing to get those extra pounds back off after christmas, I think I'm almost back to my pre christmas racing snake figure ;D

Anyway, today I'm on with cutting some gears.
Got my rotary setup and machined the blanks to size, fitted the gear cutter and fired up the new fangled wizards, selected the gear cutting one and selected the behind right (slight interferance on the left so for this A's on the right) told it the blank dia, feed clearance cut depth, etc, all in mm, I then pressed the preview code and there was nothing, no code at all.
So I rechecked, still nothing.
I then posted the code to see what came out and there was some code but no angles etc and a very bizar Y move that took the Y over the soft limits, way over the 2.28mm cut depth and no X code for the 50mm move to cut the teeth.

So just to see what it did I clicked run and got the softlimit warning and then after that I couldn't move the mill at all, I tried reset, checked the diagnostic screen and there was still communication with the limit switches.
I then shut down to restart mach and the computer locked up with a softlimit warning that just stayed there flashing with the pc speaker bipping at me.
I had to turn off the computer and it took another restart to get mach communicating with the driver.

I also tried the normal wizards with no luck and no code generated

So has anyone else had this problem with the nf wizards?

Steve
Title: Re: Problem with the gear cutting wizards
Post by: bowber on January 23, 2010, 01:40:59 PM
Hi

Now decided to use a sub to do this so I would like to know of you experts if this is right.
18 tooth gear with the A on the left of teh table and the cutter will be climb milling on the front of the blank from right to left, this part is right for how I want it to cut.
I can't check this on mach as I've got to look after the kids so can't get out to the workshop tonight.

M06 T57 G43 H57 (TOOL/MILL,gear cutter 24 dp)

O1 (tooth cut routine)
G0 Y-3
G0 X0
G0 Y-0.1
G1 Y2.28 F75
G1 X-40 F200
G0 Y-3
G0 X0
M99

G0 A0
M98 P1
G0 A20
M98 P1
G0 A40
M98 P1
G0 A60
M98 P1
G0 A80
M98 P1
G0 A100
M98 P1
G0 120
M98 P1
G0 A140
M98 P1
G0 A160
M98 P1
G0 A180
M98 P1
G0 A200
M98 P1
G0 A220
M98 P1
G0 A240
M98 P1
G0 A260
M98 P1
G0 A280
M98 P1
G0 A300
M98 P1
G0 A320
M98 P1
G0 A340
M98 P1
G0 A360
M05 M30
Title: Re: Problem with the gear cutting wizards
Post by: BClemens on January 23, 2010, 03:57:34 PM
I'm far, far from an expert but what I see looks good. (I even checked your math!)

I have a hobbing machine that I built years ago (castings from the UK) that I must show here. I use commercial hobbs found on 'that auction site' but have also attempted to make them. (ever heard of a "Eclipse" cutter relief tool?) I doubt if I will ever use the 4th axis on my NC machine to make gears....

Bill C.
Title: Re: Problem with the gear cutting wizards
Post by: bowber on January 23, 2010, 04:36:45 PM
Hi Bill

I've used the 4th axis a few times but not that much.
I've got some gears to make for a radial engine so after trying to make the cutter I ended up buying some but I've seen photo's of the eclipse tool, I think it's the eurica tool used in Ivan Law's gears and gear cutting book.

But I've seen an easier way that doesn't require a complicated machine. You form profile then offset it in a 4 jaw chuck and use the profile tool again so that nearly 1/4 is recut and then repeat for the other 3 sides. You then cut out to make 4 teeth with form relief so they can be resharpened.

Steve
Title: Re: Problem with the gear cutting wizards
Post by: BClemens on January 23, 2010, 06:18:13 PM
That sounds better than all the cams and spring action going on. Small snips in a lathe are so easy to get into trouble with, too fast, too much feed - time. You are wise to purchase cutters.

Too bad there isn't a cutter exchange or cutter borrow system. I happen to have a set of 24DP cutters that are sitting in a drawer used so little that they are still in new profile.

Yes; "THE EUREKA   A continuous form reliving tool for gear cutters  by I. R. Law". I just dug the drawings out. I must stop relying on memory for names.... Now I must look about this "Eclipes" brought up to 'refresh'.

Regards,

Bill C.
Title: Re: Problem with the gear cutting wizards
Post by: RICH on January 23, 2010, 06:24:29 PM
Steve,
I know the NFS gear cutting works since a friend has used it many times to cut gears. You need to purchase a license for the NFS wizards.

You can use a single profiled cutter in a fly cutter. If super precision is not required a  home made one will do the trick. I posted how i made gear cutters in the show and tell, but there are easier ways.I think i posted my spread sheet that calcualtes all the dimensions, then you just select the best fit end mill and shape the single cutter. My friend makes his owne gears for RC helicopters because they are better and last longer than what you buy. Beats $25 or more every time you need a cutter.
 
RICH
Title: Re: Problem with the gear cutting wizards
Post by: BClemens on January 23, 2010, 06:42:35 PM
Rich,

With most high regard and not trying to make anyone angry or attempting to pick a fight; do you know what a "THE EUREKA   A continuous form reliving tool for gear cutters  by I. R. Law" is?

Bill C.
Title: Re: Problem with the gear cutting wizards
Post by: RICH on January 23, 2010, 06:46:14 PM
Here is a quick how to on using the spread sheet for making a spur gear.
One advantage i have is i can take an old end mill and resharpen it to the diameter i want.
But in many cases there is no need too for model work and non critical stuff.

RICH
Title: Re: Problem with the gear cutting wizards
Post by: RICH on January 23, 2010, 06:48:43 PM
Bill,
No I do not but will take look and educate myself. In the mean time above post may be of value or interest.
 Rich
Title: Re: Problem with the gear cutting wizards
Post by: BClemens on January 23, 2010, 07:02:36 PM
Rich,

Isn't your spread sheet for making a cutter for a specific gear?
Title: Re: Problem with the gear cutting wizards
Post by: RICH on January 23, 2010, 07:09:29 PM
Yes
Title: Re: Problem with the gear cutting wizards
Post by: bowber on January 24, 2010, 05:56:41 AM
I was using 2 bobbins on a holder a set distance apart to form the cutter as per Ivan Laws book, anyway after messing on for a few evenings I had it set up and formed the 18 tooth cutter then moved onto the 12 tooth cutter, however my oil hardening steel seems to have a section of hard lumps in it just at the wrong place and it made a mess of my form tool.
So I bought some for £18 each, I was just fed up with wasting time when all I'd wanted to make was 3 gears.

I do have the licence for NF wizards and have used them no problem before for other jobs but I've never used the gear one.

Steve
Title: Re: Problem with the gear cutting wizards
Post by: BClemens on January 24, 2010, 06:50:05 AM
You've hit on the very reasons that I built this hobbing machine. Now we have CNC - !

This 'Eureka' is quite a contraption, sort-of a pain to set-up and use and s-l-o-w may not quite describe it. And unnerving to operate - sounds like three skeletons masturbating on a tin roof.

Rikity- Clackity - rickity - clickity - rickity - clackity etc, etc....

Enough about that!
Title: Re: Problem with the gear cutting wizards
Post by: Overloaded on January 24, 2010, 10:10:57 AM
Hi guys,
  Searching all over for info on this intriguing contraption and can only find a video of something similar ? ? ?
http://www.youtube.com/watch?v=kJ8kyC_bpHs   
and the patent from S. M. Balzer.   
http://www.google.com/patents?id=PblfAAAAEBAJ&pg=PA1&dq=535127&source=gbs_selected_pages&cad=1#v=onepage&q=&f=false
Found 1 other video link but it was dead.
Just out of curiosity, I wish to see a video of an original model in operation. (not the skeletons though) ;D
Know of any ?
Thanks
Title: Re: Problem with the gear cutting wizards
Post by: BClemens on January 24, 2010, 12:45:59 PM
That's it....except that he is cutting a hob. The original design was to make standard cutters using the method similar to what RICH described for the tool. Making the hob makes more sense due to the fact that you don't need to be concerned about the involute shape - it's a basic 14.5 degree acme thread pitched to the diametral pitch lead.

That's a good video - may inspire a modification to the one I built to make hobs. He used a master thread rather than the lathe lead screw.....wonder why?

Off topic again.....sorry Steve....
Title: Re: Problem with the gear cutting wizards
Post by: bowber on January 24, 2010, 01:08:09 PM
Yes that's just like it, but as Bill said they don't normally get used like that.

After a bit of messing with my subroutine I got it all working and I've cut one set so far.
I had to move the sub below the main code and I forgot to add a return at the end of the M99 so mach didn't see it and only ran through once.

Below are the results of the first run, it looks good so far, just have to see if it's the right size ;D, should be as the step is the bottom dia of the tooth and the cutter left very faint marks on it.

Steve
Title: Re: Problem with the gear cutting wizards
Post by: BClemens on January 24, 2010, 01:54:55 PM
Very good! Good photos.

Not sure why but I've always liked gears - like they are a science. Very satisfying to make a set that run sweetly together.
Title: Re: Problem with the gear cutting wizards
Post by: RICH on January 24, 2010, 03:37:23 PM
Thanks for the link interesting stuff. Though Steve was making little tiny stuff.
RICH
Title: Re: Problem with the gear cutting wizards
Post by: Overloaded on January 24, 2010, 03:59:57 PM
Yes indeed Steve, looks really good !
Sorry for the side track.
Thanks go to you and Bill for the interesting thread.
Russ

Lot of good info on your doc there Rich. I thought Steve was cutting dinky gears too. Guess he is....in a way.  :)
Title: Re: Problem with the gear cutting wizards
Post by: bowber on January 24, 2010, 08:07:40 PM
pah, can't you see that my picture was way bigger!
In fact you can see my gear hanging out of his back pockate ;-)

Because of the way my Z is driven I've had to make the blank double ended so I don't waste the material, so I just have to turn it round and true it in the 4 jaw chuck and check the centre then cut again with the other cutter for the 12 tooth gear.

And yes they may be small but their me babies so their perfect :-) (one bottle of wine and 3 bottles of cider later)

Steve
Title: Re: Problem with the gear cutting wizards
Post by: bowber on January 25, 2010, 08:24:00 AM
Oh dear!
I really shouldn't go on the computer when I'm drunk ::)
Still not as bad as my brother in law buying a trombone off eBay after he came home from the pub :)

Steve