[How do I?] Aluminium Chip Control

[cascao]

I've regrinded a HSS aluminium tool trying to improve chip control.
It worked very nice at the start than....starter to be not good.
Looked for some aluminium sticked in the tip but notning....
6160 at 600rpm diameters around 1/2"...
Feel that i'm close but missed something.

Se the tool in action and what I said...
https://flic.kr/p/Dgbp2L

The angle of the chip changes!?!?!

 

[Wreck™Wreck]

Higher feed rate, the chip will not break if it is to thin also if the chip is to hot it will soften and not break, try flood coolant.

 

[kingmt01]

6061 cuts like picking at bubble gum for me. It looked really good for a while then a chunk comes out or a chip gets in front of the cutter & it get pressed into the finnish. I usually just use steel but I still use 6061 when weight is a concern because that is the easiest stuff to find but I really hate working it.

 

[janvanruth]

you dont see it but there is build up on the cutting edge
migh want to use a lubricant

 

[aametalmaster]

Something I am not good at either...Bob

 

[cascao]

Im using kerosene....

 

[rick9345]

any heat in 6061/tool and it will get gummy,stringy
faster feed to get ahead of the heat

 

[eugene13]

6061 cuts like picking at bubble gum for me. It looked really good for a while then a chunk comes out or a chip gets in front of the cutter & it get pressed into the finnish. I usually just use steel but I still use 6061 when weight is a concern because that is the easiest stuff to find but I really hate working it.

Make sure the insert is tight in the holder

boy did i screw this up, still learning, guys and girls

 

[mattthemuppet2]

fiddle around with speeds'n'feeds. For 1/2in alu and HSS I would be working up above 1000rpm. Rough rule of thumb for cutting speed: steel = (100sfm x 4)/work diameter; alu = (200sfm x 4)/work diameter. So 1/2in alu should be 800/0.5 = 1600rpm as a start point up or down. High degree of top/back rake can also help, the swarf will curl and be unsupported, so it'll break periodically.

 

[mikey]

I agree with the others that feed and speed make a big difference, as depth of cut and the use of cutting fluid. However, I wonder about your tool geometry as well. From the pics it looks like you have decent back rake but your side rake looks to be negative? Can you post better pics?

Aluminum likes a lot of side rake in order to flow the chip out of the cut. By a lot, I mean 35-40 degrees. This helps reduce cutting temperatures and avoids the "gummy" issue caused by high localized temps. If your side rake is negative then you are building heat and that may be why you start off okay and then the chip changes - the heat in the part may be building. Not sure this is the case, however, since Al. likes to come of stringy if your DOC is too shallow and your feed is too slow. Post pics and that will help.