The Function Of The Bottom Milling Machine For Gas Cylinder

The function of the bottom milling machine for gas cylinders
The bottom milling machine for gas cylinders (also known as milling machine, scraping machine, or boring machine) is a key equipment in the manufacturing of gas cylinders. Its core function is to remove the residual defects (such as pile-up, shrinkage cavities, etc.) on the inner wall of the bottom of the gas cylinder after the "bottom closing" process, making the inner surface of the bottle bottom smooth and flat, thereby ensuring the pressure-bearing safety of the gas cylinder and the effectiveness of subsequent inspections.
The specific functions and principles of the gas cylinder scraping machine can be understood from the following aspects:
1. Why do we need to mill the bottom?
When manufacturing seamless gas cylinders, the process first involves using high-temperature spinning and other methods to "finish the bottom" of one end of the steel pipe. However, during this high-temperature bottom-finish process, the metal material in the central area of the bottom will inevitably produce some defects due to flow:
Removing excess material and burrs: During the bottom-finish process, the excess material will form irregular "stacking" or burrs in the center area of the inner wall of the cylinder bottom, and these must be removed by milling.
Eliminating defects such as shrinkage cavities and cracking: The bottom-finish process may cause the bottom to have minor shrinkage cavities, cracks or shape defects. Milling the bottom can remove these problematic surface layers.
If these defects are not handled, they will become the starting point of stress concentration, seriously weakening the pressure-bearing capacity of the gas cylinder and affecting the accuracy of subsequent flaw detection.
2. How does the seamless gas cylinder bottom milling machine work?
The working mode of the gas cylinder bottom milling machine can be summarized as "the cylinder moves while the tool moves, precise alignment":
Fixation and positioning: The bottom-finished gas cylinder is fixed on the machine tool and the center axis of the cylinder is ensured to be precisely coincident with the axis of the rotating tool through a specialized positioning mechanism.
Rotation and feed: One end is a high-speed rotating milling head or drill, and the other end is an assembly that holds the cylinder and drives it to slowly feed towards the tool.
Precise cutting: The rotating tool extends into the cylinder interior and, according to the preset program, performs precise planar or conformal cutting on the inner surface of the cylinder bottom, removing the defective layers evenly.
Stability and protection: To prevent the long tool shaft from swinging "unbalance" during high-speed rotation, the equipment usually has auxiliary supports or internal tensioning mechanisms to ensure processing accuracy and safety.
3. Function distinction between seamless gas cylinder bottom milling machines and related equipment
To make it clearer, here is a distinction between it and the adjacent process equipment:
Bottom milling machine: Remove internal defects (stacking, shrinkage cavities) and smooth the inner surface.
Bottle mouth squarening machine: Mill a specific plane (such as square) on the outer wall of the bottle mouth for positioning and anti-rotation when installing the bottle valve.
Bottle bottom forming machine: Perform stamping or forming processing on the bottom of the cylinder's outer bottom (base).
In summary: The bottom milling machine belongs to an internal finishing equipment. Its mission is to perform a "fine repair" on the inner wall of the cylinder bottom after its formation, ensuring that the bottom is smooth and free of defects, which directly relates to whether the gas cylinder can safely withstand high pressure.