Project Overview

• Project NameDIY Napoleon-Themed Brass Coin
• Equipment UsedHiMill D1S Desktop CNC
• Core PrinciplesHigh-Precision Brass Relief Carving + Post-Processing
• ApplicationsDesktop Collectible, Custom Accessory, Personalized Keepsake
• Difficulty Level★★★★☆ (Advanced: Requires toolpath optimization)
• Cycle TimeApprox. 4 Hours

Prep & Design

The core of coin replication lies in "detail reproduction + material stability." Planning your layout and tool selection ahead of time will double your machining efficiency.

1. Materials List (BOM)

• Brass Blank: 60 × 60 × 3.5mm solid brass plate.
• Polishing Supplies: Assorted sandpaper (400–2000 grit), brass polishing compound, and buffing pads.

2. Essential Tooling

• 2.5mm Single Flute Spiral End Mill: Dedicated to brass roughing and material clearance.
• 0.2mm Flat Bottom Engraving Bit: Used for ultra-fine relief detailing.
• 3.175mm Single Flute Spiral End Mill: Used for the final outer profile cut.

CAM Strategy & Machining Parameters

A universal parameter set adapts to both relief and profile machining. With minor tweaks for detail reproduction, even beginners can easily master this workflow.

Machining Process

The high-precision spindle and stable positioning of the HiMill D1S ensure micron-level accuracy when reproducing relief details.

1. Workholding & Calibration: Firmly secure the brass plate to the wasteboard using high-tack tape, assisted by edge stops to prevent shifting during machining.
2. Roughing (Material Removal): Use the 2.5mm single flute end mill to clear the bulk material and define the basic circular shape of the coin.
3. Relief Finishing: Swap to the 0.2mm ultra-fine flat bottom engraving bit to reproduce the Napoleon eagle crest, laurel wreaths, and lettering. The lines come out crisp and burr-free, laying a perfect foundation for polishing.
4. Outer Profile Cutoff: Finally, use the 3.175mm end mill to cut out the overall outer contour.

Post-Processing & Assembly

A standardized post-processing routine perfectly balances the historical feel with the premium metallic texture.

1. Deburring: Use 400-grit sandpaper to smooth the edges of the coin and remove machining marks. Progress to 800–1200 grit to refine the finish and eliminate sharp burrs.
2. Cleaning: Wipe the surface with alcohol to remove residual chips and cutting oils.
3. Polishing (Optional): Apply brass polishing compound with a soft cloth to buff the piece and elevate its luster.
4. Detail Refinement: Use a fine needle to clear any polishing residue trapped in the relief pockets, ensuring every letter and pattern remains crisp and three-dimensional.

Final Showcase: A Coin, A Piece of History

When a raw brass blank is reborn through precision CNC carving, the Napoleon-themed commemorative coin reveals a texture that transcends centuries:

• Eagle Crest Relief: The feather textures on the wings are clearly visible, and the lines are sharp and powerful, restoring the majesty of the imperial emblem.
• Lettering Reproduction: The depth of the edge lettering and year digits is perfectly consistent. Every character is replicated flawlessly without blurring or distortion.
• Retro Patina: The polished brass naturally emits a soft glow. Paired with a distressed finish, it carries the heft of metal while retaining the warmth of handcrafted art.
• Versatile Use Cases: It serves perfectly as a desk display, journal decor, or customized keychain. Every detail tells a historical story.

HiMill D1S Machine Review

This coin replication project once again proves the versatile capabilities of the HiMill D1S:

1. Detail Reproduction Stability: Excellent repeatability. The relief depth and line thickness remain perfectly consistent, requiring zero recalibration.
2. Machining Ceiling: From delicate feather textures to crisp lettering, the machine perfectly replicates the minutest details with high surface finish and zero blurring.
3. Limitless Creativity: As long as you can design it, the D1S can turn it into a physical brass coin. Whether it's historical themes, personal IP, or original designs, it unlocks endless possibilities!