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7x22x25 slot; 22 mm wide 25 mm deep slot/ through pocket by ramping on vmc

Itzharpreet

New member
Hi there

Need to do above slot under3 minutes cycle time. Currently I am using 7 mm 4F endmill on vmc BT50 in er32 collet holder.
Problem is the endmill i have has stickout ~5d ie 33 mm to be exact so it faces wearing out very soon.(have recently tried doing one hole on each side and taking 1.2 mm plunge on either side while removing material radially; it lasted 54 pcs)

Best I achieved was going progressive ramping (or zigzag downward path 25 cycles or 50 passes)with 0.5 mm depth of cut each side with feed rate 400 mm/min and 2000 rpm with TiN coated endmill 7 mm and stickout~30mm; it lasted 250 pcs nearly but couldn’t repeat the same performance again.

I am also keen on using HSM method but not by using the software as costs would go up.

Can progressive ramping by using carbide endmill 6or7 mm help achieve desired results or some hsm method with smaller dia square endmills with 4 flutes ?
 

Milland

Active member
Chain drill (~6.8mm drill, cut the max distance, then split the remaining distance into + + +, then * * to finish the slot), then zig-zag down fast with a 7mm endmill. Obviously, use coolant, or at least air, to flush chips from the cutting area.

The + + + and * * indicates drilling such that you move over about 1.8 x drill diameter, make a hole, continue that pitch until last hole is made (still with 1.8 x diameter remaining), then go back and drill each of the .8 x diameter "webs" that are left. This leaves the bulk of the slot cut by drills (split-point stub (short) drills are best for this), and only a small amount for the endmill to clean up.

Drills are about the most efficient material removal process, and it leaves a through area for the milling chips to fall away from the work piece.
 

Itzharpreet

New member
Finish is not a problem ; as told earlier in 250 pcs activity, even visible tool marks aren’t an issue; faster material removal is the main concern
 

Itzharpreet

New member
Chain drill (~6.8mm drill, cut the max distance, then split the remaining distance into + + +, then * * to finish the slot), then zig-zag down fast with a 7mm endmill. Obviously, use coolant, or at least air, to flush chips from the cutting area.

The + + + and * * indicates drilling such that you move over about 1.8 x drill diameter, make a hole, continue that pitch until last hole is made (still with 1.8 x diameter remaining), then go back and drill each of the .8 x diameter "webs" that are left. This leaves the bulk of the slot cut by drills (split-point stub (short) drills are best for this), and only a small amount for the endmill to clean up.

Drills are about the most efficient material removal process, and it leaves a through area for the milling chips to fall away from the work piece.

This was done but much time is wasted in tool changing and making centres as it is cylindrical shaft before actual ramping and chamfering could be done
 

doug925

Active member
Drop in a Ø5mm, 4fl, variable flute, HP (SST, steel, etc) or a 3fl mill for ground / coated (aluminum, plastic)
Ramp ( zigzag) in Z to 4mm deep, slot end to end, ramp through, and slot. Then profile your slot to finish.

If ramping isn't the best option, drill a 6mm hole at the plunge point, or helix with your endmill.
 

doug925

Active member
Drills are about the most efficient material removal process, and it leaves a through area for the milling chips to fall away from the work piece.

Sawing, then drilling are the 2 fastest MMR's achievable. (to the best of my knowledge)
 

Milland

Active member
Sawing, then drilling are the 2 fastest MMR's achievable. (to the best of my knowledge)

Sure, sawing is most efficient (I was debating about mentioning it), but not for a captive volume. If you add in the time for drilling a hole, breaking a blade, threading and rewelding, then breaking the blade again it better be a pretty large amount of stock to remove before just drilling it out is slower.
 

Itzharpreet

New member
Drop in a Ø5mm, 4fl, variable flute, HP (SST, steel, etc) or a 3fl mill for ground / coated (aluminum, plastic)
Ramp ( zigzag) in Z to 4mm deep, slot end to end, ramp through, and slot. Then profile your slot to finish.

If ramping isn't the best option, drill a 6mm hole at the plunge point, or helix with your endmill.

Thanks please elaborate little 2nd and 4th sentence of yours; besides I got limited experience
 

doug925

Active member
I was attempting (and not very clearly) to describe a means to using a smaller endmill to ruff and finish your slot within 3 minutes.

(I misread your slot dimensions.)

I would use a 1/2" varifulte (style) endmill to cut the slot.
(see link -->) High-Performance Solid Carbide End Mills • VariMill™ - VariMill™

Helix the mill down to 1/2" depth, and drive the endmill down the center of the slot. (Use air blast to keep the shavings from staying in the slot. (recutting the chips will ruin tools fast.)
Then helix down to 25mm deep, and run the center of the slot again.
After that, profile your slot, leaving 0.005 on each side. Run a final profile around the slot, and your are done.

For EN8, I would guess at 500 SFM and 0.002 IPT @ 1xD=depth for slotting. (ex 1/2" endmill, 0.500 deep)

Doug
 

Itzharpreet

New member
I was attempting (and not very clearly) to describe a means to using a smaller endmill to ruff and finish your slot within 3 minutes.

(I misread your slot dimensions.)

I would use a 1/2" varifulte (style) endmill to cut the slot.
(see link -->) High-Performance Solid Carbide End Mills • VariMill™ - VariMill™

Helix the mill down to 1/2" depth, and drive the endmill down the center of the slot. (Use air blast to keep the shavings from staying in the slot. (recutting the chips will ruin tools fast.)
Then helix down to 25mm deep, and run the center of the slot again.
After that, profile your slot, leaving 0.005 on each side. Run a final profile around the slot, and your are done.

For EN8, I would guess at 500 SFM and 0.002 IPT @ 1xD=depth for slotting. (ex 1/2" endmill, 0.500 deep)

Doug
You are misreading something the slot is 7 x 22 x 25; we can use max of 7 mm endmill only; wonder where i made you read that way
 

doug925

Active member
You are misreading something the slot is 7 x 22 x 25; we can use max of 7 mm endmill only; wonder where i made you read that way


Because (I am dense. LOL) I first thought the slot was 7mm wide, 22 long and 25 deep, then re-read it again, and got confused....

Now I am back to recommending my original suggestion of: Ø5mm endmill, with driving it down the center (as opposed to a HSM path) and cleanup on the profile.

I am going to get another cup of coffee.
 








 
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