Step Drill Bit with Deburring Recess and Depth Stop Flange
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Solution Overview
Problem
Step drill bits face challenges in efficiently drilling multiple hole sizes without enlarging or marring the workpiece, and in effectively removing burrs without increasing hole diameter, while also preventing breakthrough and protecting underlying components.
Innovation Solution
A step drill bit design featuring a shank and cutting head with progressively increasing diameter steps, conical and cylindrical portions, a depth stop flange, and a deburring recess with a sharp edge to remove burrs, which inhibits cutting and marring and prevents breakthrough by controlling the depth and diameter of holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If step drill bits are used to drill multiple hole sizes, then versatility is improved, but the risk of enlarging or marring the workpiece increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the geometry parameters of the steps, including the conical and cylindrical portions with specific taper angles and radial dimensions. Each step is designed with controlled outward angles to ensure clean cutting without enlarging the workpiece, while the progressive diameter changes enable multiple hole sizes from a single bit.
2Manufacturing precision
If deburring recesses are added to remove burrs, then surface finish is improved, but the complexity of the drill bit structure increases
Solution Approach 1:
The patent merges the deburring function with the existing step structure by integrating deburring recesses into the cylindrical portions of the steps. This combination allows the drill bit to perform both cutting and deburring operations without requiring separate components, thus improving surface finish while minimizing structural complexity.
3Reliability
If a depth stop flange is added to prevent breakthrough, then reliability is improved, but the complexity of the drill bit structure increases
Solution Approach 1:
The patent applies preliminary action by incorporating a depth stop flange that extends radially outward from the rearmost step before drilling begins. This flange pre-establishes a depth limit that prevents breakthrough and protects underlying components, ensuring reliable operation throughout the drilling process.
4Productivity
If conical and cylindrical portions are used for each step, then cutting performance is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing each step into distinct conical and cylindrical portions with specific functional characteristics. The conical portions perform the primary cutting action with controlled outward angles, while the cylindrical portions provide structural support and housing for deburring recesses, enabling efficient multi-functionality despite increased manufacturing complexity.
Data Source
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AI summary
A step drill bit includes a cutting head portion with a rear end coupled to a shank portion. The cutting head portion incudes a front cutting tip, a plurality of steps of progressively increasing diameter from the cutting head to the rear end portion. Each step includes a conical tapered portion that flares radially outward from the axis and a generally cylindrical portion that extends axially rearward from the tapered portion. A flute extends through the steps generally parallel to or helically relative to the axis. Primary and secondary cutting edges are formed at junctions between the tapered portions and the generally cylindrical portions and the flute. A depth stop flange extends radially outward from a rearmost step and has a diameter greater than the diameter of the cylindrical portion of the rearmost step. A deburring recess is disposed within or between one of the steps and includes a deburring edge at a junction between the deburring recess and the flute to remove burrs from an edge of a hole.