Need Help!- Milling die cast is causing me problems!

[Micro Milling]

I'm trying to mill die cast and I am having serious problems. What seems to be happening is the die cast wraps around the end mill. When it wraps around the end mill, it will start cutting into the diecast, so it will make my whole bigger.

I'm using a mini mill, so my max speed is 2500 RPM.

Does anyone know of how to mill diecast? It seems to go through it no problem, but for some reason it shreds off and wraps around the end mill.

What are my options here?

[CNCRim]

high pressure cooling could help.

[Geof]

Diecast aluminum alloy?

These can be very awkward to machine especially if they have not been heat treated. In the as-cast form the alloy is very soft, it tends to stick to the cutting edge of the tool very badly and if it is a small tool the chips clog up the flutes and you finish up with a chunk of spinning aluminum.

Lubrication is essential and the oldest stand by for this is kerosene, just brush it on or have a little spray can to squirt it on. Varsol works just the same and ATF automatic transmission fluid is also very good. Of course regular cutting fluids work if you have access to them, but soluble coolants should be a richer mix than is normally recommended.

Tools need to be really sharp and coated carbides are not really suitable; HSS tooling is probably best on a small machine. Speed should be as high as possible, 2500 rpm is barely adequate but workable with lubrication, a shallow depth of cut and a slow feed.

[Micro Milling]

What is HHS tooling?

Do I put the oil on the end mill itself? What exactly does the oil do?

[judleroy]

High speed steel.

[Geof]

Originally Posted by Micro Milling What is HHS tooling? Do I put the oil on the end mill itself? What exactly does the oil do?

I don't know what HHS is but as mentioned already HSS is High Speed Steel.

The cutting lubricant goes on both work and tool but it is good enough to just brush or spray it on the work; brushing the tool is risky if the tool is running.

The cutting fluid is a lubricant, it prevents a build of aluminum on the tip of the cutting tool and lubricates the chip so it flows nicely through the flutes. It also provides a small amount of cooling but only a small amount.

On larger and faster machines the cutting fluids used are designed to mix with water and the mixture is called coolant; the cutting fluid content still provides the lubrication while the water provides a large amount of cooling.