Plastic Twisting Die for Low-Friction Threaded Ties and Rods
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Solution Overview
Problem
Existing twisting-dies for manufacturing helically-shaped members are multi-segment machined metal components, which are intricate, expensive, and prone to friction and buckling due to high pressure, leading to inefficiencies and material damage.
Innovation Solution
A plastic twisting die with self-lubricating properties and a single-piece design, featuring helical grooves, reduces friction and allows for efficient twisting of profiled feed-wires into helical shapes, overcoming the limitations of traditional metal dies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multi-segment machined metal twisting-dies are used, then the die can be assembled to form a hollow die with internal helical troughs, but the machining, assembly and use is problematic, intricate, slow and expensive
Solution Approach 1:
The die is divided into multiple segments that can be assembled together to form the complete hollow die with internal helical troughs. Each segment can be manufactured separately and then joined to form the final complex shape, simplifying the manufacturing process while maintaining the required functional complexity.
Solution Approach 2:
Multiple die segments are assembled together to form the complete hollow die structure. The segments are joined using appropriate connection methods to create a unified tool that can perform the twisting operation, combining simpler manufactured parts into a complex functional whole.
2Productivity
If flange-profiled feed-wire is pushed through the steel die, then helical twisting can be achieved, but the wire becomes predisposed to buckling due to substantial force required and extreme pressure squeezing out lubrication
Solution Approach 1:
A lubrication system is introduced as an intermediary between the steel wire and steel die surfaces. Lubricant is supplied to the interface to reduce friction and prevent the extreme pressure conditions that cause buckling, enabling reliable high-speed twisting operations.
Solution Approach 2:
The friction conditions at the wire-die interface are changed by introducing lubrication. This parameter change reduces the coefficient of friction, allowing the wire to be pushed through the die at higher velocities without buckling, thereby increasing productivity while maintaining reliability.
3Productivity
If higher velocity is introduced into the twisting process, then commercially viable production rates can be achieved, but the pressure, heat and coefficient of friction at the twisting interface will increase
Solution Approach 1:
Lubricant is introduced as a thermal intermediary at the wire-die interface. It serves to reduce both friction and heat generation, enabling high-velocity twisting operations without excessive temperature rise that would damage the materials or tooling.
Solution Approach 2:
The direct metal-to-metal contact mechanism is replaced with a lubricated contact system. This substitution reduces the mechanical friction and associated heat generation, allowing commercially viable production rates to be achieved without the harmful thermal effects.
4Productivity
If flange-profiled feed-wire is advanced from the reel, then continuous production can be maintained, but the curvatures in two dimensions prevent the leading end being advanced directly into and through the die
Solution Approach 1:
The wire is pre-straightened or pre-formed at the reel before entering the die. This preliminary action removes the two-dimensional curvatures that would prevent proper engagement with the die, allowing continuous production to proceed without interruption while maintaining the required wire geometry.
Solution Approach 2:
The wire feeding system is designed to dynamically manage the wire's transition from coiled storage form to straight feeding form. The system accommodates the shape change from curved to straight as the wire is paid out and guided into the die, enabling continuous operation.
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 plastic die enables efficient production of high-tensile helical members with improved wear resistance and reduced friction, allowing for mass production of helical ties and rods with enhanced mechanical interlock properties.
Implementation Method 1
A plastic twisting die with self-lubricating properties and a single-piece design, featuring helical grooves, reduces friction and allows for efficient twisting of profiled feed-wires into helical shapes
Data Source
Figure 1~3D
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AI summary
Method and means of manufacturing ties, fasteners and rods (15) having a plurality of longitudinal threads by forcing a coil of roll-profiled feed-wire made of steel (11) through a twisting-die made of plastic (1). Also described is: a twisting-die made of plastic (1) that is suitable for twisting profiled feed-wire (11) made of steel; a method of forming a plastic twisting die (1) using an axially driven tap (31) in the form of a twisted rod (15); and a helically-shaped member (15) having lead measurements (X) along the length of the helical thread that vary less than pitch measurements (Y) along the lengths of the helical threads.