Segmented Stripper Fingers for Can Drawing Ironing
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Solution Overview
Problem
Existing stripper devices for can drawing and ironing apparatuses face challenges in removing can materials stretched over punches without damaging them, leading to buckling, cracking, and high product rejection rates, especially with laminated cans and dry molding processes.
Innovation Solution
The stripper device employs a plurality of small fingers that can elastically move in the axial direction, driven by a cam ring and rocking arms, allowing for precise engagement with the can's concave-convex shape and dispersion of compressive loads, reducing buckling and improving stability and speed of removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stripper fingers are used to remove can material from the punch, then the can material can be removed, but the can material is damaged (dented, scratched, buckled, cracked)
Solution Approach 1:
The stripper finger is divided into multiple segments (first finger segment, second finger segment, third finger segment) that can move independently relative to each other. This segmentation allows each segment to adapt to the can material surface independently, distributing the stripping force and preventing concentrated stress that causes denting and cracking.
Solution Approach 2:
The stripper finger incorporates dynamic movement capability where the first, second, and third finger segments can move relative to each other in the axial direction. This dynamic structure allows the finger to flex and adapt to the curved surface of the can material during the stripping process, preventing rigid contact that causes damage.
2Reliability
If the fingers are tightly arranged annularly along the end portion of the sleeve, then the stripping ability improves, but the fingers interfere with each other and cannot close completely
Solution Approach 1:
The stripper finger is segmented into multiple independent sections that can move relative to each other. This segmentation reduces interference between adjacent fingers while maintaining tight annular arrangement, allowing each segment to close completely without being blocked by neighboring fingers.
Solution Approach 2:
The dynamic movement capability of the finger segments allows them to adjust their positions independently during closure. This dynamic adjustment enables complete closure of all fingers even in tightly arranged configurations, preventing the interference problem that occurs with rigid structures.
3Productivity
If the fingers are percussively spread and closed by the can material, then the can material is removed from the punch, but the can material is dented and scratched
Solution Approach 1:
The segmented structure allows the stripping action to occur gradually across multiple segments rather than as a single percussive impact. This distributes the force over time and space, maintaining high productivity while preventing concentrated impact damage.
Solution Approach 2:
The dynamic flexibility of the finger segments allows them to follow the can material surface during movement, converting rigid percussive action into a more controlled flexing motion. This maintains stripping speed while eliminating the denting and scratching caused by rigid impact.
4Manufacturing precision
If the can material is stretched over the punch during ironing, then the desired can shape is formed, but the can material becomes difficult to separate from the punch
Solution Approach 1:
The segmented stripper finger structure allows for gradual engagement with the stretched can material. Each segment can independently contact and grip the material, providing sufficient holding force during ironing while enabling clean separation when needed.
Solution Approach 2:
The dynamic movement capability allows the stripper fingers to adapt to the stretched can material surface, maintaining optimal contact during ironing for precise shape formation, while enabling easy separation when the ironing is complete by reversing the motion.
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 configuration enables stable and high-speed removal of can materials without buckling or cracking, extending the service life of the device and reducing product rejection rates, even with laminated cans.
Implementation Method 1
each finger section (2) is provided with an elastic body (51) that biases the distal ends (61) of the small fingers (21) in a closing direction
Implementation Method 2
a plurality of finger sections (2) that come into contact with an opening end portion of a can material (C) stretched over a punch (P) and detach the can material (C) from the punch (P); and a drive unit that opens or closes each finger section (2)
Data Source
AI summary
A stripper device for can drawing and ironing apparatus can remove a drawn and ironed can material from a punch without causing buckling (curl and wrinkle) on the material. Each finger (2) is split into three small fingers (21), and an axial end of each small finger (21) is engaged with the lower part of a rocking arm (3) with an elastic member (24) in between. A head portion (33) of each rocking arm (3) is engaged with a cam portion (42) of a cam ring (4) to allow the finger (2) to be driven independently each other. Each rocking arm (3) is biased by an arm spring (32) in the direction of opening the small finger (21), while the small finger (21) is biased by a finger spring (22) in the direction of its closure.