How to deep slot on a speedio?

[Houndogforever]

I have an aluminum 6061-t6 part. It is 1-1/2" x 3" and 8-1/2" long.

Standing on edge, I mill the part to 2.875 tall, then mill a 1" step down across most of it.
At the bottom of that step is a 3/4" wide slot going down from the edge of the tall square end to the opposite end.
This requires a 1" stick out PLUS the 1-3/4" depth of slot leaving me with a tool hanging 2-3/4" +.
I've been running this is a Fadal with a long 5/8 3 flute hog mill taking steps down but I'm not too sure of running a long 5/8 endmill in old speedy.

So how would you guys rough out the big slot?

 

[F35Machinist]

You could remove most of the material with a flat bottom drill and then clean up the sides with a 1/2" long neck end mill. You could also use a high feed mill and that might be a bit faster. You could also use the same 5/8 tool and just go slower.

I use 1/2" end mills with 4" stick out sometimes on my speedios and haven't run into issues yet, but obviously I'm not full slotting with them.

 

[mhajicek]

Option 1: Perforate the slot with a drill just a little smaller than the slot.
Option 2: Use a high feed endmill to ramp contour leaving a little for a finish pass.

Aluminum

www.helicaltool.com

 

[gkoenig]

This slot is roughly the same size as yours. 2.375" deep, narrowing to .66 at that little pinch point.
I went with a .5" Swift Carb Ramp Mill in a 2.5" LOC and the TSC option. All 16k, .05" engage, 120IPM, full depth and a pre-drilled 15mm entrance hole (right at the pinch point to avoid collapsing the trochoidal path). Total cycle of about 45 seconds.

This was a test cut for a customer and cycle time was critical. TSC is definitely something you want for these applications, as is Big+. Moving to a relieved neck end mill would be absolutely workable if you don't have those two options, but you're reaching the machine's comfortable performance envelope.

 

[Houndogforever]

TSC and Big+ are things I don't have yet.
The 5/8 long 3 flute hog mill ramping about .200 deep at a time at 3700 rpm and 42IPM in the Fadal.
Do you think speedy will be ok with that?
I am using a necked and extended endmill to finish the inside of the slot, just trying to figure out a roughing method.

 

[DavidScott]

1/2" coarse tooth corncob mill would be my pick to rough with in a Maritool stubby sidelock holder, pretty sure the tool will break before causing real damage with that much stickout. Clearing the chips will be the hard part but at least you can get your coolant nozzles close to the cut. Full DOC for the mill with adaptive clearing paths and play with % of engagement if you are doing a few.

 

[gkoenig]

TSC and Big+ are things I don't have yet.
The 5/8 long 3 flute hog mill ramping about .200 deep at a time at 3700 rpm and 42IPM in the Fadal.
Do you think speedy will be ok with that?
I am using a necked and extended endmill to finish the inside of the slot, just trying to figure out a roughing method.

HSM says that is an under 1hp cut, so I think your Speedy can probably handle it just fine. This is going to be tooling limited, not machine power or anything, but HSM is just giving me a sense of what we're looking at.

Try it on a big test chunk of 6061 first.

 

[Mtndew]

So how would you guys rough out the big slot?

I'd just grab a 1/2" necked 3 flute and ramp it. No need to do a .200 ramp, you can do a .05" ramp and kick up the speeds and feeds and be just as fast if not faster.
Then take a full depth cut around the perimeter for a finish pass.

 

[GiroDyno]

How many are you making?
1? Just ramp with whatever you used before.
100? Get a drill and chain down the slot; Z axis is your friend and the drill will clear chips out of the pocket easily. Then a couple lightning fast loops around to clean up the cusps with a reduced neck tool and some well aimed flood coolant.

 

[Houndogforever]

I've been making the part for 30+ years, but I only make about 6-10 a year.

In the past, I do one side, flip it, do the other side, flip it 90* and mill the top and slot, then flip it over and tap a couple holes on the bottom.
I'm hoping to reduce this to one or two positions on a trunnion.

Thanks for all your ideas.

 

[DavidScott]

Something like this is what I would try, I might even get a 3/8" version to try too. 2 each so you're not too afraid of breaking one finding out how hard you can push it. I bet your limitation will be chip evacuation. Full DOC and HSM paths with a predrilled hole.

 

[hi-fly-cnc]

If it's only a few parts, then it's so fast to drill holes that I would just drill a bunch to give the chips somewhere to go. The Speedio excels at rapid moves, so adaptive it with high speed repositioning moves like suggested above? Tune the speeds by using the same tool to cut out the upper slot on some sample stock, plenty of room for the chips to leave, so you can focus on finding a good chipload/speed

I keep a 16mm YG-1 37 degree HPC on my machine. It's left with 52mm (2") of stickout for reach. Most recent job was 16k RPM, 16mm deep, stepover of 12.5% 0.44mm/flute. I think I also played with doing an inner pocket at 25% stepover, 0.35mm/flute. I can't say that it sounded like it was struggling? This with collect holder and Big+ spindle. It's about a 60-100KG cut according to HSMadvisor (2" out)

Actually, I think I ramped into the inner pocket on that at 0.35mm/flute. So that's a 70% ish step over temporarily.

My guess is that if you drilled a few holes, then did an adaptive with a 1/2" tool it would be done easily? Perhaps buy some more loc-line to point the flood right into the hole?