Tube Bending Processing Techniques and Methods, and How Medium-Frequency Bent Pipes are Extruded:
Tube Bending Processing Techniques and Methods:
Tube bending processing is a method to further enhance the performance advantages of pipes after production. Processed pipes will have an extended lifespan and broader applications. Below are detailed explanations of the techniques and methods involved.
Techniques:
1. Roll Bending: This method involves bending pipes using three rollers, where roller 3 is the primary roller, and the other two are secondary rollers. Bending is achieved by changing the distance between the primary and secondary rollers, allowing for various radii of curvature. It is suitable for bending rings, helical fittings, and thick-walled pipes with large curvature radii.
2. Press Bending: This method uses molds on a hydraulic press to bend steel billets. It is used to create pipes or bent pipes with straight segments, among other shapes.
3. Winding Bending:
- Manual Bending: This has a low manufacturing cost, simple equipment, and easy adjustment, making it suitable for small-batch production.
- Bending Machine Bending: Depending on whether a mandrel is used, it can be classified as mandrel bending or mandrelless bending.
Methods:
1. Stamping Method: This method uses a tapered punch on a press to expand the pipe end to the required size and shape.
2. Rolling Method: A mandrel is placed inside the tube, and the outer wheel is pushed to process rounded edges.
3. Bulging Method:
- Rubber Bulging: Rubber is placed inside the pipe, and the upper part is pressed using a punch, causing the pipe to protrude and take shape.
- Hydraulic Bulging: Liquid is injected into the middle of the pipe to expand it into the desired shape. This method is commonly used in the production of corrugated pipes.
4. Rolling Method: Generally used without a mandrel and suitable for the inner edge of thick-walled pipes.
5. Forging Method: The pipe end or part is extended by a forging machine to reduce the outer diameter of the pipe. Commonly used shapes include rotating, connecting rod, and drum types.
6. Bending Forming Method: It can be divided into stretching, stamping, and roller methods. The final pipe is bent using 3-4 rollers, two fixed rollers, one adjustable roller, and adjustable roller spacing.
Bent pipes offer more functionalities than straight pipes due to their curved shape. Manufacturers often process different types of pipes to enhance their quality and meet various needs.
How Medium-Frequency Bent Pipes are Extruded:
Extrusion is a forming method, and medium-frequency bent pipes need to maintain their shape after being bent. To achieve this, they undergo an extrusion process.
1. Material Selection: The material used for extrusion in medium-frequency bent pipes typically has a melt flow index of less than 1 and a medium to wide melt flow distribution (MWD). Using low melt index (MI) materials helps achieve the appropriate melt strength. Wider MWD grades are more suitable for extrusion because they offer higher production rates, lower die pressure, and reduced melt fracture tendencies.
2. Bent Plate and Thermoforming: Thermoforming is used to create linings in many large picnic coolers, which are made of polyethylene and are known for their toughness, lightweight, and durability. Other sheet and thermoforming products include fenders, tank linings, dish shields, transport containers, and tank bodies. A rapidly growing application of sheet materials is plastic film or pool bottom villages, based on the toughness, chemical resistance, and impermeability of MDPE.
Medium-frequency bent pipes are essentially processed by further bending standard pipes. However, merely bending the pipe is not enough, and proper extrusion during the bending process enhances certain functionalities of the pipe. Effective extrusion work must be carried out during the shaping process.
Please note that "挤塑" (jǔsù) means "extrusion" in English, which is a manufacturing process used to create objects of a fixed cross-sectional profile by forcing material through a die.
