Shenzhen Alu Rapid Prototype Precision Co., Ltd.

Drilling die-cast aluminum can be a bit "sticky" compared to drilling billet or extruded aluminum. Because die-cast parts often contain high silicon content for fluid flow during the casting process, the material can be abrasive to tools and prone to "gumming up" the drill bits.

To get a clean, precise hole without snapping a bit or ruining the part, follow these professional guidelines:

1. Tool Selection: The Right Bit

Don't just grab a standard wood or general-purpose bit.

Material: HSS (High-Speed Steel) bits are usually sufficient, but Cobalt (HSCO) bits are better because they handle the heat and abrasiveness of die-cast silicon much longer.

Geometry: Use a split-point drill bit (135-degree angle). This prevents the bit from "walking" across the smooth surface of the casting.

Flutes: High-helix (fast spiral) bits help clear out the soft, stringy chips that die-cast aluminum produces.

2. Speeds and Feeds

Aluminum likes high speeds, but die-casting requires a balance to prevent melting the metal onto the bit.

Speed (RPM): Run your drill at a relatively high speed.

Feed Rate: Maintain steady, firm pressure. If you go too slow, the bit will rub and create friction heat; if you go too fast, you risk cracking the thin walls of a casting.

Peck Drilling: This is crucial. Drill in small increments (2–3mm deep), retract the bit fully to clear the chips, and then dive back in. This prevents "chip packing."

3. Lubrication and Cooling

Never drill die-cast aluminum dry if you can avoid it. Without lubrication, the aluminum will "gall" (weld itself) to the flutes of your drill bit, causing it to seize or snap.

Best Options: Specialized aluminum cutting fluids (like WD-40 in a pinch, or AlumTap).

The Goal: The lubricant keeps the chips from sticking to the tool and flushes them out of the hole.

4. Securing the Workpiece

Die-cast parts are often thin-walled and brittle.

Support: If you are drilling through a thin section, place a "sacrificial" block of wood or aluminum directly underneath the part. This prevents blow-out (where the metal deforms or cracks as the bit exits).

Clamping: Use soft jaws or a cloth wrap in your vise to avoid marring the aesthetic finish of the casting.