Cylinder Piston Synchronization in Fineblanking Presses
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Solution Overview
Problem
Fineblanking and stamping presses face challenges in synchronizing cylinder/piston units and reducing pressure peaks during high-cycle and high-speed operations, leading to undesirable deformation, quality impairment, and increased tool wear due to existing solutions' inability to independently manage pressure relief and synchronization.
Innovation Solution
The method involves maintaining cylinder/piston units at a preadjustable cushion pressure using a low-pressure source and subjecting them to a preadjustable displacement pressure from a high-pressure source, with a separate control oil quantity managing pressure peaks by discharging them into a separate tank, ensuring synchronized ejection and retraction of the press ram, independent of quantity and conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high cycle rates and speeds are used in fineblanking presses, then productivity increases, but synchronization between the main ram and counterforce ram/vee ring deteriorates due to pressure relief impairment
Solution Approach 1:
The hydraulic system is divided into two independent circuits: a low-pressure circuit with the first accumulator for cushion pressure and a high-pressure circuit with the second accumulator for displacement pressure. This segmentation allows each circuit to operate independently, enabling the cushion pressure circuit to maintain synchronization while the high-pressure circuit provides forming force, thus resolving the synchronization deterioration at high cycle rates
Solution Approach 2:
The first accumulator continuously maintains a preadjustable cushion pressure in the cylinder/piston unit before the forming operation begins. This preliminary cushion pressure is established in advance and remains constant during high-speed operations, ensuring synchronization is preserved even when the high-pressure displacement circuit operates at high cycle rates
2Productivity
If pressure relief is accelerated to maintain high cycle rates, then productivity improves, but pressure peaks during impact increase causing deformation and tool wear
Solution Approach 1:
The first accumulator continuously supplies cushion pressure to the cylinder/piston unit before the punch impacts the workpiece. This pre-established cushion pressure absorbs the pressure surge generated during impact, preventing pressure peaks from reaching harmful levels that would cause deformation or tool wear, while still allowing high cycle rates to be maintained
Solution Approach 2:
The first accumulator acts as an intermediary element between the hydraulic system and the cylinder/piston unit, mediating the pressure fluctuations during impact. It absorbs the pressure surge and maintains constant cushion pressure, protecting the system from harmful pressure peaks while enabling high-productivity operation
3Device complexity
If a single hydraulic circuit is used for both cushion pressure and displacement pressure, then device complexity is reduced, but pressure characteristics become unstable at high speeds
Solution Approach 1:
The hydraulic system is segmented into two independent circuits with separate accumulators: the first accumulator dedicated to cushion pressure and the second accumulator dedicated to displacement pressure. This segmentation allows each accumulator to be optimized for its specific function and to operate independently, ensuring stable pressure characteristics even at high cycle rates where a single circuit would become unstable
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 approach achieves synchronized movement of counterforce rams and vee rings with the press ram, reducing pressure peaks and minimizing deformation and tool wear, even at high cycle rates and speeds, while maintaining constant pressure characteristics and stable displacement pressure.
Implementation Method 1
the cylinder/piston units are continuously maintained at a preadjustable cushion pressure by means of a first accumulator supplied from a low-pressure source
Implementation Method 2
a preadjustable displacement pressure from a connectable high-pressure source, with said pressure being set to a pressure varying between cushion pressure and pressure for forming and/or blanking by supplying a separate control oil quantity to a second accumulator
Implementation Method 3
a rise in pressure caused by the impact between the tool and the workpiece is regulated, independently of quantity, from the pressure to a permissible set pressure by discharging a significant part of the pressure pulse into a separate tank
Data Source
AI summary
The cylinder/piston unit for a counterforce ram or vee ring of a fineblanking or stamping press equipped with at least one tool is continuously maintained at a preadjustable cushion pressure (P1) and is then subjected to a preadjustable displacement pressure (P2) from a connectable high-pressure source, with said pressure being set to a pressure (PU) varying between the cushion pressure (P1) and the pressure for forming or blanking by supplying a separate control oil quantity to a second accumulator via a central control unit, whereby a rise in pressure caused by the impact between the tool and the workpiece is regulated, independently of quantity of the control oil, from the pressure (P3) in the second accumulator to a permissible set pressure by discharging a significant part of the pressure pulse into a separate tank and the available cushion pressure allows ejection of the workpiece to be synchronized with retraction of the press ram.