Litho Strip Conditioning for Stable Electro-Chemical Graining
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Solution Overview
Problem
The increasing manufacturing speed in electro-chemical graining of lithostrips results in insufficient surface cleaning with sodium hydroxide pre-treatment, leading to unstable electro-chemically grained surfaces and surface defects, while reducing speed increases production costs.
Innovation Solution
A two-step conditioning method involving degreasing with a specific medium followed by pickling, either with sodium hydroxide or phosphoric acid, effectively removes subsurface oxide particles and contaminants, allowing for stable electro-chemical graining at lower charge densities and increased manufacturing speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If manufacturing speed is increased in electro-chemical graining, then productivity is improved, but surface cleaning quality deteriorates leading to unstable graining results and surface defects
Solution Approach 1:
The cleaning process is divided into two distinct steps: (1) degreasing with a specific degreasing medium to remove organic contaminants and rolling oil, and (2) pickling with a weak acid solution to remove oxide particles and inorganic contaminants. This segmentation allows each step to target specific types of contaminants effectively, ensuring high surface cleaning quality even at increased manufacturing speeds.
Solution Approach 2:
The degreasing step is performed as a preliminary action before pickling to remove organic contaminants and rolling oil that would otherwise interfere with the subsequent pickling process. This preliminary removal of hydrocarbon contaminants ensures that the weak acid pickling solution can effectively access and remove oxide particles without being hindered by organic film interference.
2Device complexity
If conventional single-step cleaning with sodium hydroxide is used, then process simplicity is maintained, but cleaning effectiveness deteriorates at high manufacturing speeds
Solution Approach 1:
The cleaning process is divided into two distinct steps: (1) degreasing with a specific degreasing medium to remove organic contaminants and rolling oil, and (2) pickling with a weak acid solution to remove oxide particles and inorganic contaminants. This segmentation allows each step to target specific types of contaminants effectively, ensuring high surface cleaning quality even at increased manufacturing speeds.
Solution Approach 2:
The invention changes the chemical parameters of the cleaning process by using a weak acid solution (pH 2-4) for pickling instead of strong base, and controls the temperature (20-80°C) and time (0.1-10 seconds) parameters to optimize the removal of oxide particles while preventing excessive aluminum dissolution. This parameter optimization ensures reliable and stable graining results.
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
The method ensures a fully grained surface with reduced charge density requirements, improved removal of rolling oil and contaminants, and enhanced mechanical features, enabling faster and more efficient electro-chemical graining processes.
Implementation Method 1
degreasing the surface of the lithostrip with a degreasing medium
Implementation Method 2
cleaning the surface of the lithostrip by pickling
Implementation Method 3
pickling comprises AC-cleaning with phosphoric acid
Implementation Method 4
pickling comprises AC-cleaning with phosphoric acid. During AC-cleaning an alternating current supports pickling process
Implementation Method 5
prior electro-chemical graining of the lithostrips
Data Source
Figure 1a~1c
AI summary
The invention relates to a method of conditioning the surface of a work piece, particularly of a strip or sheet, more particularly of a lithostrip or lithosheet, consisting of an aluminium alloy. The object of the present invention to provide a method for conditioning the surface of a work piece and a work piece consisting of an aluminium alloy enabling an increasing manufacturing speed in electro-chemically graining and maintaining at the same time a high quality of the grained surface, is solved by a conditioning method which comprises at least the two steps degreasing the surface of the work piece with a degreasing medium and subsequently cleaning the surface of the work piece by pickling.