Aluminum CNC Routing for Flat and Profiled Parts

Routing spins a rotating cutter and moves it along a programmed path in X, Y and Z. On aluminum sheet, that path usually comes from CAD geometry converted into G-code. The cutter enters from the top of the blank, travels the profile, and exits. A vacuum table or a fixture holds the workpiece down while the tool loads the edge.

The cutting action differs from milling in one practical way. Routed parts are normally held flat and cut through the thickness, so the tool spends most of its time in profile passes rather than in deep axial cuts. That keeps side loads low and lets a 6 mm cutter run at high feed rates without chattering.

Heat is the main constraint. Aluminum conducts heat away from the cut quickly, so the chip carries most of it. Run too light a feed and the edge rubs instead of shearing. The result is built-up edge, poor finish, and a tool that dulls in minutes. Feed per tooth matters more than spindle speed here.

Most routing work in our shop runs on 6061 and 6061-T6. The alloy machines cleanly, holds a sharp edge, and takes anodizing without blotching. Sheet from 1 mm to 12 mm thick is common, and plate up to 25 mm works if the part is not too thin in section.

5052 and 5083 are gummy compared with 6061. They form chips that weld to the cutter if feeds are conservative. Routed 5052 is still common for enclosures and brackets because it bends and welds well, but expect a rougher as-machined surface and more deburring time.

2024 and 7075 route fast and hold tight tolerances, which makes them useful for aerospace ribs and tooling plates. Both are more notch-sensitive and less corrosion-resistant than 6061. If the part sees weather or washdown, plan a finish and avoid sharp internal corners.

6063 is usually extruded, not routed, but it does appear in frames and heat sinks. ADC12 is a die-casting alloy, so it belongs in casting, not routing. If your drawing calls for ADC12 and the part is flat, that is a sign the process should change.

A cutter needs room to enter. Minimum internal corner radius equals the cutter radius, so a 6 mm tool leaves a 3 mm radius. If the drawing calls for a sharp inside corner, someone has to add a relief or accept a radius. State the radius you can live with.

Thin walls deflect. On a routed panel, a 1 mm wall between two pockets will chatter and may bow. We keep unsupported walls above 1.5 mm where possible, and above 2 mm for parts longer than 300 mm. Below that, ask whether the wall is structural or just a spacer.

Pocket depth is limited by tool reach. A 6 mm cutter with 20 mm flute length cannot safely cut a 40 mm deep pocket. Reach more than three times the diameter and the tool starts to flex, which shows up as tapered walls and a bad floor finish.

Through-holes and slots are easy. Tapped holes are not, because routing does not index the part for a tap. If the part needs threads, plan a second operation on a mill or add a threaded insert.

Routing wins on flat parts with a large footprint. A 2,000 mm panel with cutouts, slots and a shallow pocket is faster on a router than on a mill, because the table holds the whole blank and the tool never has to reposition the part. Setup time drops, and so does the risk of a fixture shifting mid-cut.

Milling wins when the part has features on several faces, deep pockets, or tight angular relationships. A five-axis mill can reach five sides in one setup. A router cannot, so a multi-face part on a router becomes several operations with more tolerance stack-up.

If a part is flat but needs a mirror finish or a precise bore, think again. Bores on a router are interpolated, not bored, and the roundness suffers. The same applies to faces that must be flat within 0.01 mm over 500 mm.

For prototypes, routing is often the cheapest way to get a flat part in hand within days. For production runs above a few thousand identical flat parts, stamping or extrusion may beat routing on unit cost. Routing sits in the middle, and that middle is wide.

Send STEP or native CAD for the part, and DXF if the part is cut from sheet. Include a 2D drawing with tolerances, alloy, thickness, finish, and any notes about burrs or edge condition. If only one dimension is critical, say which one.

Tell us the quantity and whether the part is a prototype or a production run. A single unit and a 10,000 part run take different setups, and the quote will reflect that. Free DFM analysis comes back with the quotation, usually within 12 hours.

Mark the surfaces that show. Anodizing, bead blasting and laser marking all change the surface, and a scratch that is fine on a hidden face is a reject on a visible one. Laser marking holds a minimum character height of 1.5 mm.

Uploads stay confidential. An NDA is available on request, and we do not share drawings outside the production team.