Spline-Connected Friction Stir Tip to Prevent Holder Binding

Solution Overview

Problem

Friction stir processing tips often bind with the holder due to axial loading, torque, lateral loads, and high temperatures, leading to premature wear and the need for both tip and holder replacement.

Innovation Solution

A friction stir processing tip with a non-threaded connecting portion using splines and lateral locating surfaces that form a sliding fit connection with the tip holder, allowing for torque transmission while preventing axial runout and binding, and enabling high-speed operation without tip holder binding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If threaded connection is used to secure the friction stir processing tip to the body, then the tip is centered and secured within the body, but the threads bind during friction stir processing operation due to axial loading, torque, lateral load, and thermal expansion

Engineering Contradiction:

Improvesecure connectionVSAvoidthread binding

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The connection interface is segmented into two distinct functional zones: a non-threaded portion with splines for torque transmission and a threaded portion for axial securing. This segmentation allows each zone to handle specific loads independently, preventing the binding that occurs when threads must simultaneously transmit torque and resist axial/lateral loads.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The torque transmission function is extracted from the threaded connection and assigned to a separate non-threaded spline connection. This removes the harmful interaction between threading and torque transmission, eliminating the binding problem while maintaining secure attachment.

Inventive Principle:

Principle #2Taking out (Extraction)

2Productivity

If high axial loading force is applied to press the friction stir processing tip against the workpieces, then friction stir processing is effective, but the axial load contributes to binding the threaded connection

Engineering Contradiction:

Improvefriction stir processing effectivenessVSAvoidconnection stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The connection interface is segmented into two distinct functional zones: a non-threaded portion with splines for torque transmission and a threaded portion for axial securing. This segmentation allows each zone to handle specific loads independently, preventing the binding that occurs when threads must simultaneously transmit torque and resist axial/lateral loads.

Inventive Principle:

Principle #1Segmentation

3Ease of repair

If the friction stir processing tip is designed to be replaceable, then tip wear can be addressed by replacement, but the threaded connection requires both tip and body replacement when binding occurs

Engineering Contradiction:

Improvetip replacementVSAvoidconnection system

Core Design Contradiction:

Ease of repairVSDevice complexity

Solution Approach 1:

The connection interface is segmented into two distinct functional zones: a non-threaded portion with splines for torque transmission and a threaded portion for axial securing. This segmentation allows each zone to handle specific loads independently, preventing the binding that occurs when threads must simultaneously transmit torque and resist axial/lateral loads.

Inventive Principle:

Principle #1Segmentation

4Speed

If high rotational speed is used to rotate the friction stir processing tip, then processing efficiency is improved, but the torque required to achieve high speeds contributes to binding the threaded connection

Engineering Contradiction:

Improverotational speedVSAvoidconnection stability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The torque transmission function is extracted from the threaded connection and assigned to a separate non-threaded spline connection. This removes the harmful interaction between threading and torque transmission, eliminating the binding problem while maintaining secure attachment.

Inventive Principle:

Principle #2Taking out (Extraction)

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 solution allows for high-speed friction stir processing without binding, extending the lifespan of the tip and potentially reducing replacement costs by allowing the tip to be replaced independently of the holder.

Implementation Method 1

The non-threaded connecting portion includes splines configured to receive a torque from the tip holder for rotating the body about the central longitudinal axis

Methodology Applied

Scientific EffectTorque transmission: Torque

Implementation Method 2

A friction stir processing tip with a non-threaded connecting portion using splines and lateral locating surfaces that form a sliding fit connection with the tip holder, allowing for torque transmission while preventing axial runout and binding

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 3

the pin and shoulder frictionally engage the two workpieces, plasticize the metallic material of the workpieces, and stir the plasticized material to form a weld between the workpieces

Methodology Applied

Scientific EffectFriction heating: Friction

Implementation Method 4

the pin and shoulder frictionally engage the two workpieces, plasticize the metallic material of the workpieces

Methodology Applied

Scientific EffectPlasticity: Plasticity

Implementation Method 5

the friction stir processing tip may reach or exceed 500 degrees Celsius during the friction stir welding operation which causes the friction stir processing tip to expand

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS11534855B2Friction stir processing tip, apparatus, and method

Publication Date: 2022.12.27 MAZAK CORP

AI summary

In one aspect of the present disclosure, a friction stir processing tip is provided for a friction stir processing device. The friction stir processing tip includes a body having a central longitudinal axis, a friction stir processing portion of the body, and a connecting portion of the body configured to connect to a tip holder of the friction stir processing device. The connecting portion includes splines configured to receive a torque from the tip holder for rotating the body about the central longitudinal axis.