Cutting A Ten Tooth Spline On Vmc With 4th Axis

[rrrrrgh]

ANY SUGGESTIONS FOR PROGRAMING THE ROOT RADIUS GEOMETRY ON A TEN TOOTH SPLINE . USING A OKUMA VMC AND ROTARY TABLE.SPLINE LENGHT IS 4.5 LONG X 3.0 DIA.I AM USING A SLOT MILL AND ROTATING THE 4HT AXIS TO CREATE FACETS ALONG THE ROOT RADIUS.

[wisp]

when you say spline, are you meaning helix? I need more info to program it. Is it 10 teeth over 4.5" or 10 teeth per inch?

[HuFlungDung]

I made up a little sketch in OneCNC to see how I would attack this problem. If using a 1/4" endmill, you can see from the diagram, if you start with the cutter on center over the centerline of the rotary table, that the half angle of rotation of the work will be 7.5 degrees, by the time the corner of the spline tooth has become vertical. Since the cutter must gradually shift off-center by its own radius in order to not interfere, this would be a travel of .125".

So if you wanted to index the part by .75 degree for each pass, this would take 10 passes, so each pass would require a side shift (in Y) for your tool of .125/10 = .0125"

You could do one half of each toothspace this way, then run it again, but shifting the tool to the other side of the centerline as you index in the opposite rotation.

BTW, this is only to show how you'd clean out the tooth space, the actual milling of the tooth width I'll assume you can handle

[rrrrrgh]

THATS WHAT I AM DOING. JUST LOOKING FOR ANY FRESH IDEAS! THANKS FOR YOUR REPLY. SCOTT

[rustyolddo]

Don't know if this will help but maybe it will give you an idea.

We acquired an old B&S 2A mill that was missing the silent chain. It wasn't worth the cost of replacing the chain so it was decided to replace the chain with a timing belt instead. I was charged with the task of making the top gear. I determined the radius neccessary to match the belt and took the original gear and turned all the teeth off of it. I ground a .5" toolbit in the surface grinder to the precise profile required of the tooth. I mounted the toolbit in a fabricated flycutter that held the toolbit horizontal instead of at an angle. The tool was mounted in the mill, the gear was mounted to the indexing head on a plate that I had fabricated. I cut each tooth in a total of 3 passes. Yes it took a while and it was slow but hey, no CNC. (Armstrong CNC?) It came out perfect, I did have to chamfer each edge of the teeth using a metric radiusing endmill that I reground for clearance.

Another thought is having a custom endmill ground for your spline profile.

Hope this sparks a few ideas.

[Bear]

Hello all,
I cut lots of splines , different jobs , projects etc.Use both horiz./vert. machines
using slotting cutters. Center cutter & part,offset cutter thickness+half slot thickness
cut length,offset oppiset direction,cut again,mill out middle.
Bear