Help me make my endmillls last longer

[Rstewart]

Using harvey tools 1/16" coated, .01 CR, stub flute length endmills.  Having to finish a very shallow slot up against a .09" tall wall. 

 

I'm only allotted .0005" taper on the wall and they seem to be wearing prematurely.  I'm holding the tool in a MX-06 mini chuck and I measure about .0003" runout at the tip.

 

I've tried the High speed approach (light, fast, and air blast) and the slow and steady with coolant.  The material (4130) is hardened to 45Rc.   I've been cutting full depth with a .0002 finish pass and start to get taper after just a few parts (maybe 60" of cutting).

 

I have tried Harvey's speeds and feeds...   

 

I can Message someone the file if anyone would like to take a crack at it....  Simple geo, just dunno if I can attack it another way.

 

 

Thanks in advance

[YoDoug®]

In the past in harder materials requiring very little wall taper I have run a spring pass or very light finish pass in conventional cut direction. 

[gcode]

Use 2 endmills, one for roughing, one for finish

[crazy^millman]

4130 is the worse about work hardening as you are cutting. Rough and Finish tools are going to be your best bet. 60" of cut at that RC is decent.

[dstryr]

Rough and finish. I'd be tempted to try to "ramp" the finish shape to help keep the tool from deflecting as opposed to just using the side of it.

[jeff]

Can you use air blast instead of coolant? 

[absolute technologies]

I would use 3 end mills, 1 for roughing, 1 for finishing using climb cut and another finisher that conventional cuts, it will take the taper out but you want this end mill to just dust the previous end mill, you don't want the conventional pass taking too much stock. If the endmill toolpath is doing arcs make sure you adjust your federate for advance per tooth at the periphery of the cut, not the same federate at centerline for a linear move.

 

Good Luck

Len Dye

[Rstewart]

Thank you guys!!

 

G: I am using a rough and finisher (both same type Harvey endmill).

 

Jeff:  I can use either

 

I think I may try the 3 endmill approach!  How does leaving .002" for the semi-finisher, and .0005" for the conventional finish sound?

 

 

I will report back tomorrow

 

 

 

Edit:   This ain't on no Haas

[absolute technologies]

Thank you guys!!

 

G: I am using a rough and finisher (both same type Harvey endmill).

 

Jeff:  I can use either

 

I think I may try the 3 endmill approach!  How does leaving .002" for the semi-finisher, and .0005" for the conventional finish sound?

 

 

I will report back tomorrow

 

 

 

Edit:   This ain't on no Haas

yeah maybe rough to +.001-.002 stock per side and maybe only a .0001-.0002 per side for the conventional cut, but .0005 isn't going to kill it. I usually program the climb and conventional cut right to finish net and just use the CDC so the last endmill just dust the surface. We recently did a .040 slot +/-.001 on size and location that was 8xD with Harvey end mills on heat treated S.S. and worked like a champ. Anytime I can use a drill to remove as much of the slot as I can I will do that as well.

 

Cheers!

Len Dye

[Rstewart]

The 3 endmill approach is working Great

 

Why does the conventional finish cut so much straighter in hardened materials?

[duckdogers]

The 3 endmill approach is working Great

 

Why does the conventional finish cut so much straighter in hardened materials?

not sure,climb milling should always cut straighter because it pulls the cutter into the material

[absolute technologies]

The 3 endmill approach is working Great

 

Why does the conventional finish cut so much straighter in hardened materials?

deflection is a direct function of length to diameter ratio of how far the end mill sticks out of the holder and hardness of the material, with climb cut the deflection will push away from the side and with conventional cut the deflection will suck it into the surface, the trick is to not let the conventional pass cut too much material so that it doesn't suck in but rather just dust the surface and take the taper out from the climb cut.  The sharper the end mill the better as well, sometimes when replacing the end mills I only replace the conventional cut end mill and use the used end mill for the climb cut tool or the rougher to get a lil more economics out of it. Obviously with carbide being 6X more stiff than HSS you want to use carbide. 

 

glad it worked out for you!

 

Cheers!

Len Dye