Rotary Press Upper Ram Ejection Control
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Solution Overview
Problem
In rotary presses, materials tend to adhere to the pressing surfaces of the rams during the return travel, affecting the quality of the compact and subsequent compression processes, especially when the compact is not circular.
Innovation Solution
The upper ram is pre-loaded downward by its own weight and remains on top of the compact during ejection, with a stripper engaging the compact between the pressing surfaces after a certain distance, ensuring the upper ram is lifted off before contact with the stripper, and the lower ram's control cam extends horizontally to minimize the compact's height above the die-plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the upper ram is rotated during return travel to eliminate adhesion, then material adhesion is reduced, but the mechanism becomes more complex and requires additional rotational drive mechanisms
Solution Approach 1:
Instead of rotating the ram during return travel as in prior art, this invention inverts the approach by keeping the ram stationary and non-rotating. The stripping action is achieved through the relative motion between the stationary ram and the moving compact, eliminating the need for complex rotational mechanisms while still preventing adhesion.
Solution Approach 2:
The invention extracts the rotation function from the ram itself and separates it into a dedicated stripping mechanism. The ram performs only its primary compression function without rotation, while the stripper component handles the adhesion prevention through relative motion, simplifying the overall system.
2Object-affected harmful factors
If the upper ram is seized by the cam portion before the stripper pushes the compact away, then the upper ram is prevented from contacting the stripper, but the control mechanism becomes more complex
Solution Approach 1:
The invention merges the control functions into a single integrated cam mechanism that simultaneously performs multiple tasks: guiding the ram's vertical motion, controlling the timing of ram seizure, and coordinating the stripper action. This consolidation achieves the desired protection without requiring separate complex control systems.
Solution Approach 2:
The cam mechanism is designed as a multi-functional component that performs several control functions: it guides the ram during compression, seizes the ram at the appropriate moment, and coordinates the stripper operation. This universal control element simplifies the overall system by eliminating the need for multiple specialized control mechanisms.
3Object-generated harmful factors
If the compact is pushed away between the pressing surfaces over a certain distance, then material adhesion is prevented, but the ejection distance and cycle time increase
Solution Approach 1:
The invention applies partial action by pushing the compact away only over a minimal necessary distance (at least 0.5 mm) rather than completely ejecting it from the die cavity. This partial ejection is sufficient to prevent adhesion to the pressing surfaces while minimizing the time required for the ejection cycle.
Solution Approach 2:
The stripping action is performed rapidly over a short distance, rushing through the essential motion needed to prevent adhesion without completing the full ejection sequence. This allows the process to quickly pass through the critical adhesion-prevention phase and return to compression more efficiently.
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 method prevents material adhesion to the rams' surfaces, ensuring continuous production and eliminating the need for cleaning, allowing for the compaction of problematic mixtures that were previously impossible.
Implementation Method 1
the upper ram will rest on the compact as before because of its own weight
Implementation Method 2
the compact is ejected from the die by means of the lower ram
Data Source
AI summary
A method for operating a rotary press, comprising a rotor rotatably driven about a vertical axis that has a die-plate and upper and lower rams which, while being guided vertically in guides of the rotor, interact with holes of dies in the die-plate wherein at least one compression station is provided and has an upper and a lower pressing roller past which the presser rams run along and by which they are moved towards the die-bore for the purpose of compacting the material in the die-hole, wherein the upper and lower rams are lifted subsequent to the compression procedure, causing the lower ram to eject a compact from the die and the compact to be stripped by a stripper in the direction of a discharge chute, characterized in that while an compact ejection procedure is under way the upper ram stands upright on top of the compact and is lifted therewith and the stripper seizes the compact laterally while the upper ram is still standing upright on top of the compact.