Composite Step Drill Bit With Hard Cutting Head and Strip
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Solution Overview
Problem
Existing step drill bits are expensive to manufacture and have cutting tips and edges that wear out quickly, limiting their durability and effectiveness in drilling holes of various diameters in sheet metal or thin metal plates.
Innovation Solution
A step drill bit design featuring a body made of a less expensive material like low carbon steel, with a cutting head and elongated cutting strip composed of harder materials such as carbide, cermet, or diamond, joined using methods like brazing or mechanical connections, and manufactured using near net shape techniques like metal injection molding to reduce waste and cost, while enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the entire drill bit is made of hard material (carbide, cermet, or diamond), then the cutting life and durability are improved, but the manufacturing cost increases significantly
Solution Approach 1:
The patent applies different material properties to different parts of the drill bit: the cutting head and cutting strip are made of hard material (carbide, cermet, or diamond) for durability, while the body is made of less expensive material (low carbon steel or tool steel) for cost-effectiveness. This local differentiation of material quality resolves the contradiction between cutting life and manufacturing cost.
Solution Approach 2:
The drill bit uses composite construction by joining hard material components (cutting head and cutting strip) to a steel body through brazing or mechanical connections. This composite approach allows the drill bit to have both the durability of hard materials and the cost-effectiveness of steel, resolving the contradiction between reliability and ease of manufacture.
2Ease of manufacture
If traditional manufacturing methods are used, then the drill bit can be produced, but material waste is high and production time is long
Solution Approach 1:
The cutting head and cutting strip are pre-formed from hard material using near net shape techniques before being joined to the body. This preliminary formation reduces material waste and processing time during final assembly, resolving the contradiction between production efficiency and material waste.
Solution Approach 2:
The patent employs near net shape manufacturing techniques for forming the cutting head and cutting strip, which significantly reduce material waste compared to traditional machining methods. This parameter change in manufacturing approach resolves the contradiction between production efficiency and material waste.
3Reliability
If the cutting head and cutting strip are made of hard material, then the drill bit durability is improved, but the complexity of joining different materials increases
Solution Approach 1:
The patent uses brazing or mechanical connections as intermediary joining methods to attach the hard material cutting head and cutting strip to the steel body. These joining methods mediate between the different materials, allowing durable construction while managing the complexity of joining dissimilar materials.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The use of harder materials for the cutting head and strip increases the drill bit's life and durability, while the body's material choice reduces production costs, and near net shape manufacturing minimizes material waste and processing time, resulting in a more efficient and cost-effective drilling solution.
Implementation Method 1
a cutting tip configured to penetrate a workpiece
Implementation Method 2
The elongated cutting strip defines a cutting edge that extends along the steps in the strip
Implementation Method 3
Each of the cutting tip and the cutting strip may be joined to the body by brazing, welding, adhesive, or mechanical connection
Implementation Method 4
Each of the cutting tip and the cutting strip may be joined to the body by brazing, welding, adhesive, or mechanical connection
Implementation Method 5
Each of the cutting tip and the cutting strip may be joined to the body by brazing, welding, adhesive, or mechanical connection
Data Source
AI summary
A step drill bit includes a body with a plurality of cylindrical steps of increasing diameter from a front end toward a rear end, a flute extending from the front end toward the rear end, and cutting edges at junctions between each step and the flute. A cutting insert with a hardness greater than the hardness of the body is coupled to the front end portion and at least partially defines a cutting head portion. The cutting head portion includes a center cutting tip, a cutting edge extending radially outward from the cutting tip, a rake face extending from the cutting edge toward the rear end portion, a relief face extending from the cutting edge in a circumferential direction opposite a rotational cutting direction of the drill bit, and a chip clearing recess in communication with the flute, with the rake face facing the chip clearing recess.