Aluminum CNC Parts by Type

Enclosures and housings

A machined enclosure is a block with most of its inside removed, so the cost follows the volume of chips and the depth of the pocket. 6061-T6 plate is the default. 6082-T6 is the common European equivalent and 6063 gives a more even cosmetic anodize where the box is a visible product.

Typical walls are 1.5 to 3 mm; below about 1 mm the wall chatters and moves as material comes out. Keep pocket depth under about four times the corner tool diameter and give inside corners a radius a little larger than that tool. If the lid seals with a gasket, put a flatness callout on the sealing face, typically 0.05 to 0.1 mm over the face, and machine it last. The thin-wall guide covers distortion, and the enclosure guide goes through a full housing.

Heat sinks and cold plates

Thermal conductivity is the reason to pick the alloy. Typical published values: 1100 about 220 W/m·K, 6063-T5/T6 about 200 W/m·K, 6061-T6 about 167 W/m·K, 7075-T6 about 130 W/m·K. 6063 is mostly sold as extrusion, so a machined sink is often an extruded profile cut to length and finished, while a skived or fully milled sink starts from 6061 plate.

The fin height to gap ratio sets the machining limit: about 10:1 is a practical ceiling for milled fins, more needs slitting saws or skiving. The base must be flat where the device sits, typically 0.05 mm or better, and that face is left bare or chem filmed because anodize is an insulator. Cold plates with internal channels add a leak test and a sealing method (O-ring lid, brazed or friction-stir-welded cover) to the RFQ. See the heat sink guide.

Brackets and mounts

The simplest family and the most common. 6061-T6 covers most of them; 7075-T6 (yield about 500 MPa against 276 MPa for 6061-T6) and 2024-T351 come in where the bracket is stress or fatigue limited. Neither is weldable in practice, and 7075 resists corrosion less well, so it is normally anodized.

Price follows the number of setups: every face with a feature on it is another clamping unless the shop runs 4 or 5 axes. Hole positions to ±0.05 mm are routine, tighter needs a reason. Threads in aluminum strip before steel screws do, so give them engagement of at least 1.5 to 2 × D or use inserts; see threads and inserts.

Manifolds and valve blocks

A hydraulic or pneumatic manifold is mostly drilled holes meeting inside a block. 6061-T6 suits low and medium pressure; 2024-T351 or 7075-T651 is used at higher pressure. Hard anodize (Type III) on the outside protects against wear and corrosion.

Three things to state in the RFQ: the port thread standard (SAE J1926 O-ring boss, ISO 6149 metric or BSPP to ISO 228-1 with ISO 1179 ports), the working and test pressure, and how intersecting holes are deburred and checked, since a burr inside a cross hole cannot be seen from outside. Drill depth over about 10 × D slows the job and needs gun drilling or peck cycles. The manifold guide covers the drawing details.

Fixtures and tooling plates

Flatness and stability come first, strength second. Cast tooling plate (MIC-6 class, see the profile) is ground or fly-cut flat by the mill and carries almost no residual stress, so it stays flat after heavy pocketing. Stress-relieved 6061-T651 is the stronger option; 5083 is used for large plates that must not distort.

Typical callouts are a flatness of 0.025 to 0.05 mm over the working area, dowel holes reamed to H7 and a hole grid with a positional tolerance from a datum corner. Wear faces that see clamping get Type III. The fixture plate guide walks through a grid plate.

Robot links, grippers and end effectors

Every gram on an arm costs payload, so these parts are pocketed hard and 7075-T6/T651 is common. Because stiffness is the same across alloys, a link that bends too much needs a deeper section, not a stronger grade. Bearing seats are bored to a fit, typically H7 for a housing bore, with a cylindricity callout when two bearings share a shaft. Type III anodize protects wear faces; leave bearing bores masked or bore them after anodize.

Optical and sensor mounts

The part must hold position over time, so residual stress matters more than strength. Use stress-relieved T651 plate or cast tooling plate, rough, rest, then finish. Black Type II anodize cuts stray reflections. Flatness of the mounting face and perpendicularity of the bore are the usual critical callouts; the optical mount guide has the detail.

Where these parts end up

The alloy and finish follow the part, not the industry. These are the fields that send most aluminum RFQs, the parts they ask for, and what to add to the request so the shop prices the right job.

Design notes that apply to every family

• Inside corners: give a radius at least a little larger than the cutter you expect, about R1 to R3 mm on most pockets. A sharp inside corner needs EDM.
• General tolerance: ISO 2768-m on the title block covers non-critical features. Tolerance only what fits or seals; read the tolerance guide.
• Anodize growth: Type III adds roughly 25 to 50 µm in total, about half outward. Run the anodize growth calculator on every fit before releasing the drawing.
• Material certificate: ask for a mill certificate to EN 10204 3.1 when the alloy and temper must be traceable.
• Surface finish: Ra 3.2 µm is a normal machined face, Ra 1.6 µm is achievable with a finishing pass, below Ra 0.8 µm costs extra time.