Fuel Cell Polar Plate Forming With Reference-Mark Alignment
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Solution Overview
Problem
The stamping operation in the production of fuel cell polar plates causes significant deformation of the metal strip, leading to offset of centering holes and reduced quality in subsequent manufacturing steps, particularly cutting, due to the use of large-capacity presses with multiple tools.
Innovation Solution
A forming method and plant that includes a stamping press followed by a downstream press, where a reference mark is formed during the stamping step on the strip, allowing precise positioning during downstream steps using positioning members that cooperate with the reference mark to improve dimensional accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large-capacity press with multiple tools is used to perform stamping, perforation, and cutting operations, then productivity is improved, but manufacturing precision deteriorates due to significant deformation of the strip and offset of centering holes
Solution Approach 1:
The patent divides the forming process into two separate stages: a first forming process that performs only stamping operations, and a second forming process that performs perforation and cutting operations. This segmentation allows each process to be optimized independently, with the first process focusing on speed and the second process focusing on precision using the reference marks created by the first process.
Solution Approach 2:
The patent introduces a preliminary action where reference marks are formed on the strip during the first forming process before the second forming process begins. These reference marks serve as positioning references for the second process, enabling precise alignment and compensation for any deformations that occurred during stamping.
2Ease of operation
If centering holes are used to align the strip with tools, then ease of operation is improved, but manufacturing precision deteriorates due to random offset reaching 0.15 mm or more
Solution Approach 1:
The patent creates reference marks that copy the positioning function of centering holes but without the deformation problem. These reference marks are formed directly on the strip surface during the stamping process and serve as accurate positioning references for subsequent operations, eliminating the need for physical centering holes that become misaligned.
3Productivity
If the strip is advanced by a fixed pitch between press operations, then productivity is improved, but manufacturing precision deteriorates due to accumulation of positioning errors
Solution Approach 1:
The patent implements a feedback mechanism where reference marks are created during the first forming process and then used by the second forming process to detect and compensate for any positioning deviations. This closed-loop approach eliminates error accumulation by continuously referencing the actual position of features rather than relying on fixed pitch advancement alone.
Data Source
AI summary
The present method of forming a polar plate comprises:a stamping step:implemented by a stamping press, which includes a stamping tool mounted on a slider moved by vertical reciprocating movement; andduring which a network of channels for circulating fluids is stamped on the strip; anda downstream step subsequent to the stamping step and implemented by a downstream press;wherein:once the channel network is stamped on the strip, while the strip is held clamped in the stamping tool, a reference mark is formed on the strip by means of a marking tool carried by the slider; andduring the downstream step, the strip is positioned with respect to the downstream press by means of positioning members mounted on the downstream press and which cooperate with the reference mark.