Back-Tapered Web Deep-Hole Drill for Chip Evacuation

The patent applies parameter changes by transitioning from stepped web thickness variations to continuous back-tapered web thickness reduction. The web thickness is gradually reduced from the distal end toward the proximal end according to a continuous tapering profile, eliminating abrupt step changes while maintaining manufacturability through controlled gradual material removal.

Instead of increasing web thickness toward the distal end (conventional approach), the patent inverts the approach by reducing web thickness toward the distal end through back-tapering. This reverse configuration optimizes chip evacuation by creating a gradual expansion of the flute cross-sectional area in the direction of chip flow, preventing chip packing while maintaining structural integrity.

The patent changes the web thickness parameter continuously along the axial direction through back-tapering, creating a gradient structure that optimizes both strength and chip evacuation. The continuous parameter variation allows the drill to maintain adequate web thickness for strength while progressively reducing it toward the distal end to enhance chip flow, enabling high-speed drilling without breakage.

The patent applies local quality by varying the web thickness locally along the axial direction. The proximal end maintains greater web thickness for structural support, while the distal end features reduced web thickness for optimal chip evacuation. This localized differentiation of properties allows the single drill structure to simultaneously satisfy both strength and chip removal requirements at different locations.