Compound Adjustment Screw for Extrusion Die Concentricity
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Solution Overview
Problem
Existing extrusion die assemblies face challenges in maintaining accurate concentricity between the die and tip, requiring high torque and limited sensitivity in adjustment mechanisms, which complicates the application of a consistently thick tubular layer on cylindrical products.
Innovation Solution
The introduction of a compound adjustment screw system combined with spring-loaded plungers allows for precise adjustment of the die position, reducing torque requirements and improving sensitivity by enabling movement in both x and y directions with fewer screws, and utilizing hemispherical surfaces for a universal adjustment motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple adjustment screws are used to adjust die position in x and y directions, then the die position can be adjusted, but the torque required increases and the sensitivity is limited by maximum thread density
Solution Approach 1:
The patent implements a compound adjustment screw where a fine adjustment thread is nested within a coarse adjustment thread. The fine adjustment screw (with higher thread density for greater sensitivity) is positioned inside the coarse adjustment screw, allowing both high sensitivity and reduced torque requirements through the nested configuration.
Solution Approach 2:
The adjustment mechanism is segmented into two distinct threaded components: an inner fine adjustment thread and an outer coarse adjustment thread. This segmentation allows each thread to be optimized for its specific function - the fine thread for sensitivity and the coarse thread for torque reduction - while working together in a unified adjustment system.
2Measurement precision
If standard adjustment screws are used, then the die can be adjusted radially, but the sensitivity is limited by the maximum thread density that can be machined
Solution Approach 1:
The compound adjustment screw design nests the fine adjustment thread within the coarse adjustment thread, achieving high sensitivity without proportionally increasing overall mechanism complexity. The nested structure allows both threaded components to share the same axial space, minimizing the increase in device complexity while maximizing adjustment sensitivity.
3Manufacturing precision
If adjustment screws are used to move the die radially, then position adjustment is achieved, but backlash is present and tolerance accumulation occurs in assembly
Solution Approach 1:
The die holder is pre-loaded against a stop surface by a spring mechanism before adjustment occurs. This preliminary action establishes a fixed reference point and eliminates clearance or backlash in the adjustment mechanism, ensuring that subsequent fine adjustments by the compound screw produce accurate, backlash-free positional changes with accumulated tolerance minimized.
4Adaptability or versatility
If four adjustment screws are used (one for each direction), then complete adjustment coverage is achieved, but the number of components and complexity increases
Solution Approach 1:
The patent merges the functions of multiple adjustment screws into a single compound adjustment screw assembly. The inner fine adjustment thread and outer coarse adjustment thread work together as an integrated unit, providing complete adjustment coverage in both x and y directions through the universal motion capability of the die holder, thereby reducing the total number of separate adjustment components required.
Solution Approach 2:
The compound adjustment screw mechanism is designed with universal motion capability, allowing a single adjustment assembly to provide complete adjustment coverage in multiple directions. The die holder can pivot and move radially in any direction through the coordinated action of the nested threads, making the adjustment mechanism multi-functional and eliminating the need for separate screws for each adjustment direction.
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
This solution enhances the accuracy and sensitivity of die adjustment, reducing backlash and torque needed, allowing for consistent concentric layer application with improved tolerances in extrusion processes.
Implementation Method 1
spring-loaded plungers allows for precise adjustment of the die position, reducing torque requirements and improving sensitivity
Data Source
AI summary
A device is constructed for adjusting the concentricity of a die within an extrusion die assembly. The adjustment mechanism involves a series of compound screws having multiple operating threads that employ different pitches to generate a fine adjustment motion. The compound screws are coupled to opposing spring loaded plungers that move against a bias spring in reaction to movement of the compound screws.