Tool Holder Cavities for Vibration-Damped Precision Clamping

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Solution Overview

Problem

Tool holders, particularly those using collet chucks, experience vibration issues due to reaction forces from cutting edges, leading to reduced machining performance and the need for compromised cutting speeds, which affects the system's efficiency and precision.

Innovation Solution

A tool holder design featuring a main body with a clamping portion that includes self-contained cavities within its primary shaping, providing excellent damping properties and eliminating the need for external balancing bores, while also allowing for hydraulic pressure adjustment and improved coolant supply, thereby reducing vibration and enhancing machining precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If collet chucks are used to clamp the tool shaft, then the tool can be securely held by frictional engagement, but vibration is induced due to reaction forces from cutting edges that can reach resonant ranges

Engineering Contradiction:

Improvesecure clamping of toolVSAvoidvibration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies porous materials by incorporating cavities within the collet chuck structure. These cavities create a porous-like internal structure that provides vibration damping properties, reducing the harmful resonant vibrations caused by cutting forces while maintaining the external clamping function.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent changes the physical parameters of the collet chuck by introducing cavities with specific volumes and distributions. This modifies the mass distribution and stiffness characteristics of the chuck, thereby changing its vibrational properties and moving it away from resonant frequencies.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If the tube part is widened by heating to insert the tool shaft, then the tool can be shrink-fitted into the tool holder, but the machining precision may be compromised due to vibration

Engineering Contradiction:

Improvetool insertionVSAvoidmachining precision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The cavities create a porous-like structure within the tube part that dampens vibrations during the shrink-fitting process and subsequent machining operations, thereby maintaining manufacturing precision while enabling easy tool insertion through thermal expansion.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The cavities are built into the structure beforehand to provide vibration damping cushioning during critical operations such as tool insertion and machining, preventing vibration-induced precision losses before they occur.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If conventional solid structure is used for the tool holder, then structural strength is maintained, but vibration damping properties are insufficient

Engineering Contradiction:

Improvestructural strengthVSAvoidvibration

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent introduces cavities to create a porous-like internal structure within the solid tool holder. This porous configuration provides excellent vibration damping properties while carefully maintaining sufficient structural strength for the application.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The tool holder effectively becomes a composite structure combining solid material with void spaces (cavities). This composite configuration leverages the strength of the solid material while utilizing the damping properties of the void spaces to reduce vibration.

Inventive Principle:

Principle #40Composite 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 tool holder effectively reduces vibration and maintains machining precision by utilizing internal cavities for damping and hydraulic pressure control, improving the handling and cooling efficiency of the tool holder, and allowing for easier tool removal.

Implementation Method 1

This tube part of the tool holder can be widened by heating so far in the radial direction that the cold shaft of the tool can be thrust into the tube part

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

it has been found that a cavity that is embodied as completely self-contained and completely inside a portion shaped by primary shaping has excellent damping properties

Methodology Applied

Scientific EffectVibration damping: Damping

Data Source

PatentUS11554422B2Tool holder with built-in cavities

Publication Date: 2023.01.17 FRANZ HAIMER MASCHINENBAU KG

AI summary

A tool holder having a main body for coupling the tool holder to the spindle of a machine tool and having a clamping surface connected thereto for clamping a tool, characterized in that the tool holder has at least one portion shaped in one piece by primary shaping, which in its interior has one or more cavities that form an enclave in the portion shaped by primary shaping.