Brush Manufacturing Process Explained

Overview

Brush manufacturing transforms plastic pellets and synthetic filament into finished brushes through a series of automated processes. The complete production chain involves five core steps: injection molding (creating the handle), drilling (preparing anchor holes), tufting (implanting bristles), trimming (cutting bristles to uniform length), and flagging (rounding bristle tips for comfort). Each step uses specialized CNC machinery — and the quality of each step directly affects the quality of the finished brush.

Step 1: Injection Molding

The brush handle or body is created by injecting molten plastic into a steel mold under high pressure. PP (polypropylene) and PE (polyethylene) are the most common materials for toothbrushes and cleaning brushes. ABS and bio-plastics are used for premium brushes. The mold determines the handle shape, grip texture, and head geometry. Cycle time is typically 15–25 seconds per handle. A single molding machine can produce 2,000–3,000 handles per hour.

Step 2: Drilling

After molding, the brush head area is drilled with precisely positioned anchor holes. These holes receive the filament bundles in the tufting step. Each hole's position, angle, depth, and diameter must be exact — a deviation of even 0.1mm will show in the finished brush pattern. CNC drilling machines use high-speed spindles (24,000 RPM) and can drill 20–50 holes in 4–8 seconds per brush head. Hole patterns are programmed from CAD files or taught manually.

Step 3: Tufting

Tufting is the core process — implanting filament bundles into the drilled holes. A tufting machine picks a bundle of filaments, folds it, inserts a small metal anchor (staple), and drives the assembly into the hole. This is called staple-set tufting and is the industry standard. The machine uses 2–5 CNC axes to position each tuft precisely. Production speed: 6–10 tufts per second. A typical toothbrush has 25–40 tufts and takes 4–6 seconds to tuft completely.

Step 4: Trimming

After tufting, bristles protrude at varying lengths. A trimming machine uses a rotary blade to cut all bristles to uniform height. The cutting height is programmable with ±0.05mm repeatability. Some brush designs require contoured (scalloped) profiles — the trimming machine can follow programmed height curves for different zones of the brush head. Cycle time: ~3 seconds per brush.

Step 5: Flagging (End-Rounding)

Flagging is the mechanical end-rounding of bristle tips — critical for toothbrushes and personal care brushes. Sharp-cut bristle ends would irritate gums and skin. The flagging process uses rotating abrasive surfaces to round each bristle tip to a smooth dome. Quality standard: >95% of tips must be acceptably rounded. This step takes ~5 seconds per brush and is often integrated into the same machine station as trimming.

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