Piston Soldering Gap Control via Wedge Geometry
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Solution Overview
Problem
The existing method for producing pistons using high-temperature soldering often results in a 'zero gap' issue, where pre-machined joining surfaces butt exactly parallel, leading to uneven solder distribution and poor material bonding between the piston top and bottom parts, causing defects and suboptimal connections.
Innovation Solution
The method introduces a defined soldering gap between the joining surfaces of the piston top and bottom parts, ensuring a reliable and process-safe soldering connection by pre-machining the surfaces to create a wedge-shaped gap, allowing for controlled capillary effect and complete wetting of the surfaces, with a gap width between 20 μm and 150 μm, and using high-temperature soldering at up to 1300°C to create a strong bond.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pre-machined joining surfaces are made parallel and flat to ensure precise alignment, then assembly precision is improved, but solder distribution becomes uneven and material bonding deteriorates due to zero gap formation
Solution Approach 1:
The joining surfaces are pre-machined with a specific wedge-shaped geometry and angular orientation before assembly. This preliminary action ensures that when the piston top and bottom parts are assembled, a defined soldering gap is automatically created, preventing the zero gap problem while maintaining precise alignment through the engineered surface geometry
Solution Approach 2:
The joining surfaces are designed with specific geometric parameters including a wedge shape and angular orientation relative to the piston axis. By changing the parameters from parallel-flat surfaces to angled-wedge surfaces, the soldering gap is controlled to be between 20-150 μm, ensuring proper solder flow and bonding while maintaining assembly precision
2Ease of manufacture
If joining surfaces are made flat and parallel for easy assembly, then ease of manufacture is improved, but solder cannot spread evenly causing defects and poor bonding
Solution Approach 1:
The joining surfaces are designed with asymmetric wedge-shaped geometry rather than symmetric flat surfaces. The angular orientation creates an asymmetric gap distribution that promotes uniform solder spread from the larger gap region toward the smaller gap region, ensuring complete wetting while maintaining ease of assembly through the simple wedge geometry
3Reliability
If a defined soldering gap of 20-150 μm is created to ensure reliable soldering, then soldered joint quality is improved, but joining surface geometry becomes more complex
Solution Approach 1:
The complexity is managed by defining specific geometric parameters for the wedge-shaped joining surfaces, including the angle relative to the piston axis and the resulting gap width of 20-150 μm. These controlled parameters ensure reliable soldering while keeping the manufacturing process straightforward through standardized wedge geometry rather than complex irregular shapes
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 prevents the 'zero gap' defects, ensures a high-quality, reliable, and loadable soldered joint, and allows for the creation of a desired solder seam geometry, enhancing the overall quality and durability of the piston.
Implementation Method 1
heating the piston body at a pressure of at 10−2 mbar maximum to a soldering temperature of 1300° C. maximum
Implementation Method 2
applying a high-temperature soldering material in the region of at least one joining surface
Implementation Method 3
a controlled utilisation of the capillary effect and also a guarantee of a complete wetting of the entire joining surfaces can be achieved
Implementation Method 4
transferring the piston body into a vacuum oven and evacuating the vacuum oven
Implementation Method 5
heating the piston body at a pressure of at 10−2 mbar maximum to a soldering temperature of 1300° C. maximum
Data Source
AI summary
A method for producing a piston may include producing a piston top part and a piston bottom part each including an inner support element having an inner joining surface and an outer support element having an outer joining surface. At least one of the joining surfaces may include a solder depository. The method may also include pre-machining at least one of the joining surfaces and introducing a high-temperature soldering material in at least one solder depository. The method may further include assembling the piston top part and the piston bottom part to form a piston body via creating at least one of circular contact and linear contact between the joining surfaces such that a gap width is 20 μm to 150 μm. The method may also include transferring the piston body into a soldering oven, melting the high-temperature soldering material via heating the piston body, and cooling the piston body.