Deep Hole Machining via Reference Guide Bore
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Solution Overview
Problem
Existing methods for deep hole machining, particularly in high-precision applications with thin walls and high depth-to-diameter ratios, face challenges in achieving accuracy and stability due to tool shaft bendings and vibration transmission, leading to economic losses and material waste.
Innovation Solution
A method involving the creation of a first reference hole with a predetermined spatial relationship to the deep hole, followed by the insertion of a guiding and supporting element connected to a tool shaft to maintain coaxial accuracy and stability, allowing for deep hole machining with a depth-to-diameter ratio of up to 20:1 and accurate contour finishing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the depth-to-diameter ratio of the hole is increased to achieve deeper holes, then the productivity and capability of the machining process is improved, but the risk of tool shaft bendings and vibration transmission increases, leading to decreased manufacturing precision
Solution Approach 1:
A preliminary reference hole is drilled through the workpiece before the actual deep hole machining. This reference hole serves as a guide for the tool shaft, pre-establishing the correct path and position. By performing this preparatory action, the tool shaft is guided along a predetermined trajectory during the deep hole machining, preventing bendings and vibrations that would otherwise occur when attempting to machine very deep holes directly without guidance.
2Length of moving object
If a longer tool shaft is used to reach deeper holes, then the capability to machine deep holes is improved, but the tool shaft becomes more prone to bending and vibration, worsening the manufacturing precision
Solution Approach 1:
The reference hole acts as an intermediary element between the tool shaft and the workpiece. Instead of the tool shaft directly engaging with the workpiece material over a long distance (which causes bending and vibration), the reference hole provides a guiding pathway that mediates the interaction. The tool shaft follows the reference hole as a guide, effectively using the reference hole as a mediator to maintain precision while achieving deep hole machining.
3Strength
If the tool shaft is made sturdier to prevent bending, then the structural strength is improved, but the evacuation of chips by the tool is negatively influenced, worsening the manufacturing process
Solution Approach 1:
The mechanical guidance system is replaced by using the reference hole as a natural guide. Instead of relying on a stiff tool shaft design to prevent bending, the system substitutes the mechanical rigidity requirement with a geometric guidance mechanism. The reference hole provides the necessary guidance physically, allowing the tool shaft to be less rigid while still maintaining precision, thereby preserving good chip evacuation capabilities.
Data Source
AI summary
A method for carrying out deep holes and/or bottle-boring, in particular borings, with a high ratio between final linear depth and hole diameter, higher than 14:1, comprises the steps of: carrying out a reference hole, having axis and diameter linked to the deep hole to be carried out by a predetermined spatial relationship; making a deep hole of a diameter smaller than the hole to be carried out, so that said reference hole and said first deep hole be in spatial communication; and prearranging a guiding and supporting element internal to said reference hole and connecting thereto a tool shaft and a related tool to obtain a contour internal to the deep hole and/or a deep hole of diameter and axis according to said predetermined spatial relationship.