Assembly-Type Cutting Tool Threaded Connection Stability
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Solution Overview
Problem
Conventional multifunctional cutters with threaded connections suffer from loose fits, leading to wobbling of the cutter head during operation, resulting in shaky cuts, increased load on the machine tool, and reduced cutting efficiency.
Innovation Solution
The implementation of a tight fit and interference fit between the external and internal threads, combined with thermal treatment to enhance rigidity, ensures a secure radial engagement and resistance to feed loads, preventing wobbling and chatter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional threaded connection is used to connect the shank and cutter head, then the cutter can be assembled with replaceable cutter heads, but the loose fit of threads causes the cutter head to wobble during cutting operations
Solution Approach 1:
The connection structure is divided into multiple functional zones: a first threaded portion for initial engagement and assembly, and a second threaded portion for secure locking. This segmentation allows the connection to progress from easy assembly to stable fixation, resolving the contradiction between replaceability and stability.
Solution Approach 2:
The first threaded portion performs the preliminary action of engaging and positioning the cutter head on the shank. This preliminary engagement prepares the connection for the subsequent locking action of the second threaded portion, ensuring both ease of assembly and final stability.
2Ease of operation
If a loose threaded fit is used, then the cutter can be easily assembled and disassembled, but the cutter head wobbles under cutting load, causing chatter and shaky cuts
Solution Approach 1:
The threaded connection is segmented into two distinct portions with different functional characteristics. The first portion facilitates easy assembly with appropriate clearance, while the second portion provides precise locking with minimal clearance. This segmentation resolves the contradiction between ease of operation and cutting precision.
Solution Approach 2:
Different regions of the threaded connection have different quality requirements. The first threaded portion has larger clearance for easy assembly, while the second threaded portion has tighter tolerance for precision locking. This local differentiation of quality parameters resolves the contradiction between assembly ease and cutting surface quality.
3Adaptability or versatility
If the threaded connection allows movement, then the cutter can accommodate different cutter heads, but the wobble increases the load on the machine tool main shaft
Solution Approach 1:
The connection system is segmented into an assembly phase (first threaded portion) where movement is permitted for interchangeability, and a locking phase (second threaded portion) where movement is restricted to minimize main shaft load. This temporal segmentation resolves the contradiction between adaptability and force reduction.
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
This solution stabilizes the cutter head, allowing for increased cutting speed and feed, reducing the load on the machine tool by about 10% and enhancing processing efficiency.
Implementation Method 1
the tight fit and interference fit between the external thread and the internal thread help increase the extent of tight radial engagement between the shank and the cutter head
Implementation Method 2
combined with thermal treatment to enhance rigidity
Data Source
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AI summary
An assembly-type cutter (10) includes a shank (20) and a cutter head (30). The shank (20) has a hole (201) at one end. The hole (201) has a receiving portion (21), which includes an internal thread (212) and can be treated thermally for increased rigidity. The cutter head (30) has a cutting portion (32) and a connecting portion (31) at opposite ends respectively. The connecting portion (31) includes a threaded member (312) and can also be treated thermally for increased rigidity. The cutter head (30) and the shank (20) are threadedly connectable via the connecting portion (31) and the receiving portion (21). The threaded member (312) includes a body portion (3121), whose diameter is defined as a root diameter (Di), and an external thread (3122) on the body portion (3121). The body portion (3121) is slightly tapered such that a locus of the root diameter (Di) is inclined.