Think desktop CNCs can only cut wood? That is only true if you are not using them the right way!

Today, I am using the HiMill D1S to take on a demanding metalworking project: milling a solid block of 6061 aluminum into an industrial-style ashtray with perfect "geometric steps" and a premium matte finish. From roughing strategies to sandblasted surface treatment, I am revealing the complete workflow!

Project Overview

Preparation

To create mirror-like chamfers, choosing the right tooling is the top priority.

Hardware & Materials (BOM):

• Aluminum: 6061-T6 aluminum block. It offers excellent machinability, and its chips break easily, making it suitable for CNC machining.
• Cooling/Lubrication: Industrial alcohol or cutting fluid (must be sprayed throughout the process to prevent aluminum chips from sticking to the tool and melting).
• Workholding: Vise or clamps. Recommendation: If using clamps, make sure they stay clear of the toolpath.

Recommended Tooling (The Aluminum Trio)

1. Roughing Mainstay: 3.175mm 3-Flute Spiral End Mill for metal.
   • Key Point: You must choose a tool with large chip flutes! Aluminum chips are bulky, and if they cannot evacuate, the tool may break.
2. Chamfering: 2.5mm Ball Nose End Mill for metal machining.

Design & CAM Strategy

Geometric Design

• Stepped Structure: I designed progressive interior steps, not only for aesthetics but also for convenient cigarette placement.
• Slot Design: Two U-shaped or V-shaped slots are positioned diagonally for holding cigarettes.
• Chamfers: All edges feature a [0.5mm] chamfer. This is the key to a "refined feel" and helps prevent sharp edges.

CAM Parameters (HiMill D1S Aluminum Milling Secrets)

Aluminum milling is all about "high RPM, shallow DOC (Depth of Cut), and fast feed."

1. Adaptive Clearing (Roughing):
   • Tool: 3.175mm 3-Flute Spiral End Mill for metal
   • Spindle Speed: 13,000 RPM
   • Stepdown: [0.2mm - 0.5mm] (Adjust based on machine load; shallower is safer)
   • Feed Rate: 200 mm/min
2. Finishing (Floor & Walls):
   • Stock to Leave: Leave 0.1mm during roughing for final removal.
   • Tool: 2.5mm Ball Nose for metal machining
   • Depth: 0.1mm
   • Feed Rate: Slow it down slightly to ensure a mirror-bright machined surface.

The Machining Process

As the crisp sound of cutting fills the air, silver aluminum chips pour out like a fountain.

1. Pocket Roughing: The machine mills away the aluminum in the center layer by layer, and the stepped shape begins to emerge.
   • Note: Spray alcohol frequently and use an air gun to clear aluminum chips from the deep pockets in time, preventing re-cutting.
2. Surface Finishing: The cutting sound becomes lighter as the surfaces turn flat and smooth.
3. Slot Milling: Cut the cigarette rests into the side walls.
4. Chamfering: The final step. The tool travels once around the edges, instantly outlining a bright silver border and giving the entire piece a more dimensional look.

Post-Processing: Achieving the Matte Look

Freshly machined aluminum looks bright, but it can be prone to scratches. The "Matte/Frosted" effect shown in the photos is created as follows:

• Option A (Sandblasting - Recommended): If you have a sandblaster, spray the part once with glass bead media to instantly create a premium Mac-style frosted texture.
• Option B (Manual Brushing/Stonewashing): Use a Scotch-Brite pad or 400-grit sandpaper with water, sanding in the same direction to create a brushed finish. Alternatively, place it in a vibratory tumbler for a rugged "stonewashed" vintage effect.

Final Result & Summary

On the desk, it is an ashtray; when you are not smoking, it can also serve as a minimalist paperweight or storage tray.

HiMill D1S Performance Summary:

• Metal Cutting Capability: Even when machining an aluminum part with a large amount of material removal, the D1S spindle remains stable and produces excellent sidewall verticality.
• Surface Finish: With the right parameters and alcohol cooling, a desktop CNC can produce mirror-like cut edges that require no sanding.