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1018 CD, Slotting 3/8 wide, and 5/8" deep

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Houndogforever

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Oct 20, 2015
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I'm working on a fixture for some parts I run all the time. I am thinking of running them from a 12" bar of 5/8"sq. 1018 CD Steel rather than cut them into 1.5" blanks.

I need to break the blanks from the bar which means I need to mill a slot.
I'm running it on a BT30 Brother Speedio so take that into consideration on recommendations.

I guess I'm trying to figure out if a full slot thru, stepped slots thru, trochoidal mill the slot or what have you would be the fastest.
thanks for your ideas.
 
3/8" 4 flute corn-cob style rougher is how I divide parts on my BT30 machines. I use cobalt HSS cutters because for some unknown reason I ended up with about 40 of them in my toolbox from a cabinet shop auction I went to. I've been trying to burn them up for 10 years, but they seem to last forever.

I just go with book SFM, full depth, and then creep up my federate until the machine starts to complain. I am always amazed at what they will take.

Only thing that sucks is the chips are like dandruff that will end up in your sump.
 
Can you go with a 5/16? I hate slotting but maybe if you go with a stubby end mill holder, try a 4 flute carbide, two depths of around .300", 5k rpm, and 30 ipm full slot. Should take about 5 seconds. Did you get the P20 work done? How did that go?
 
The "slot" is just breaking the bar apart and distance between finished surfaces is .4330. Need to cut thru the whole 5/8 bar, minus what I face off which will be minimal.

So I can use 1/4, 5/16, 8mm, 3/8 or 10mm to break the bar into individual parts.
Initially I was thinking 3/8 dia and 2 passes, Heck I could use a 5/16 and trochoidal mill thru if you think that would be fastest / least noisy stress.

As to the P20, I'm still waiting on the metal. It is back East somewhere cutting saw cut from plate, then shipped to local warehouse and eventually brought here sometime.
 
I think your original thought of two Z passes will probably be best. Trochoidal will take too long for this. If you stepover .025" at full depth it will take about 30 passes (30 seconds?) with a lot of air cutting between. If it was the p20 or something else yes but the 1018 will probably full slot fine with z passes. No stress on the machine. Just make sure you are holding the parts well and using a short end mill holder. I usually steer people towards saw cutting blanks to near net shape but I am sure you are trying to minimize your hand loading and extending your run time between loads.
 
Can you show a picture of the strip, and the blanks that come out of it? I'm having trouble seeing why you need to cut that wide of a slot through the entire bar between each part. If I'm reading your OP correctly, you are making 7 parts out of 12" strip, with .433" between parts. Aren't you eliminating most of the depth of that .433" in the course of machining the parts, leaving a carrier that holds the parts together? Or are you fixturing a 12" strip with clamps for each of the 7 parts, then going all the way through the bar? If the latter, I should think you are money and time ahead by just clamping 1.5" saw-cut strips rather than wasting .4" of material per part.

Regards.

Mike
 
I have an application where I cut 3/8" bar through with a 3/16" carbide endmill. I do 3 passes; 2 at .170" or so each and the last pass takes out .035" and the part drops off.

I get about 100-200 pieces per tool depending on the SFM.
 
gripper.JPG

This is what the part looks like. It finishes at .590 wide and .394 at the tallest point and measures 1.457 long.

I do have an auto saw so maybe I should just keep blanking them up and just put them in the fixture that way.
 
Houndogforever said:
View attachment 284028This is what the part looks like. It finishes at .590 wide and .394 at the tallest point and measures 1.457 long.I do have an auto saw so maybe I should just keep blanking them up and just put them in the fixture that way.
Click to expand...
Actually, what I do is feed it through a Kalamazoo 5C collet chuck that is tipped sideways. I use the cut-off endmill to pull it thru b4 each cut off. If you have a decent setup and don't push the envelope you should be just fine.I found that "barfeeding" it like this is actually quite repeatable and productive. I can hold +- .005 or less. :big_grin:
 
ChipSplitter said:
Actually, what I do is feed it through a Kalamazoo 5C collet chuck that is tipped sideways. I use the cut-off endmill to pull it thru b4 each cut off. If you have a decent setup and don't push the envelope you should be just fine.I found that "barfeeding" it like this is actually quite repeatable and productive. I can hold +- .005 or less. :big_grin:
Click to expand...

If you're paranoid about breaking the endmill, and can afford the tool change, a dowel pin in a holder would work well, also.
 
TeachMePlease said:
If you're paranoid about breaking the endmill, and can afford the tool change, a dowel pin in a holder would work well, also.
Click to expand...

I've thought about it.
But I haven't broken one after 1000+ parts, so......
It's super neat running several hours like that just eating up one bar after another.
Just remember you don't have super good rigidity.
 
What kind of wall finish do you have to hit? You could use a high feed end mill. Helical has a 3/8" with 0.750" reach that you could run 9k rpm, 110ipm at a 0.015" (0.25deg) ramp down. Should be around 1 cubic inch per minute and stupid reliable. Wall finish will be okay but not like side milling will give you. Maybe you can find a 9mm high feed and leave allowance for a finish pass with a 5/16" end mill...

Otherwise ramp it with a 0.030" corner radius 5-flute like a Kyocera/SGS. Probably can get after it more but tool life is just crazy good with high feeds. Plus they add rigidity to the system since they are pushing directly up into the spindle and down into the table.
 
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