Independent-Spindle Turret for Masked Tool Changes

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Solution Overview

Problem

Current machine tool turrets for micro-mechanical parts machining face inefficiencies in tool change times, energy consumption, and risk of collisions due to complex and voluminous designs that do not effectively mask acceleration and deceleration phases, and are not suitable for micro-mechanical parts.

Innovation Solution

A turret design with independently controlled tool pins that can accelerate and decelerate in masked time, reducing tool change time to mere tenths of seconds, and featuring a rotating head with tool holders arranged to minimize collisions and energy consumption, allowing high rotation speeds and compactness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If multi-spindle turrets rotate all tools simultaneously to mask acceleration and deceleration phases, then tool change time is reduced, but energy consumption increases significantly

Engineering Contradiction:

Improvetool change timeVSAvoidenergy consumption

Core Design Contradiction:

Loss of timeVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by pre-accelerating the next tool in the sequence to its machining rotation speed while the current tool is still in use. The control system monitors the rotation speed of each spindle and prepares the subsequent tool in advance, so that when tool change is needed, the replacement tool is already at the required speed and can begin machining immediately, masking the tool change time without continuously rotating all tools at high speed.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If multi-spindle turrets use a coupling system to engage active tool spindles with drive mechanism, then tool change is enabled, but device complexity and cost increase

Engineering Contradiction:

Improvetool change capabilityVSAvoidcoupling system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the complex coupling system from the turret design. Instead of using a coupling mechanism to engage tool spindles with the drive, each spindle is equipped with its own independent drive motor. This direct-drive approach removes the coupling system entirely, simplifying the device while maintaining the ability to selectively engage and disengage spindles for tool changes.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical coupling system with an electrical control system. Each spindle has its own motor that can be independently controlled through electrical signals from the control unit. This substitution of mechanical coupling with electrical control simplifies the mechanical structure while providing precise control over each spindle's rotation and engagement state.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Loss of time

If multi-spindle turrets rotate all tools simultaneously to prepare for tool change, then tool change time is masked, but maximum rotation speed is limited due to kinematic chain

Engineering Contradiction:

Improvetool change timeVSAvoidmaximum rotation speed

Core Design Contradiction:

Loss of timeVSSpeed

Solution Approach 1:

The patent segments the drive system by providing an independent motor for each tool spindle rather than using a single drive mechanism with a kinematic chain. This segmentation allows each spindle to be driven independently at its optimal rotation speed without being constrained by the limitations of a shared mechanical transmission system. The control unit manages each spindle's speed and rotation independently, enabling higher maximum speeds while masking tool change time.

Inventive Principle:

Principle #1Segmentation

4Productivity

If multi-spindle turrets are designed with multiple tool spindles to enable tool changes, then productivity is improved, but moving masses increase generating significant moments of inertia and collision risk

Engineering Contradiction:

Improveproductivity through tool changesVSAvoidmoving masses of turret

Core Design Contradiction:

ProductivityVSWeight of moving object

Solution Approach 1:

The patent applies dynamics by implementing independent control of each spindle's rotation state. Instead of rotating all tools simultaneously (which increases moving masses and moments of inertia), the control system dynamically activates only the spindles that need to rotate. The next tool in sequence is accelerated only when needed, and other spindles remain stationary or rotate minimally, reducing the overall moving masses and moments of inertia while maintaining productivity through rapid tool change capability.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP4506091A1Turret comprising a plurality of tool-holding spindles and numerically controlled machine tool comprising such a turret

Publication Date: 2025.02.12 ETA SA MFG HORLOGERE SUISSE

Figure 1~2
Figure 3~4

AI summary

The invention relates to a turret (10) comprising a body (11) extending along an axis AA, the latter comprising at one end a base (12) for mounting to a numerically controlled machine tool (20) and at the other end a rotatable head (13), the head (13) having at least two tool-holding spindles (14, 14', 14"), each intended to receive a cutting tool (15, 15', 15"), the spindles (14, 14', 14") occupying, depending on the angular position of the head (13), a working position in which they are intended to perform a machining operation on a workpiece held in position in a fixture (21) or a standby position in which they are withdrawn from the workpiece, each of said spindles (14, 14', 14") being configured to be driven independently of the other in order to immobilize or drive rotating the cutting tool (15, 15', 15") it carries, regardless of the position it occupies.