Stretching parts are components made by stretching process (using molds to cause plastic deformation of sheet metal or billet, forming open hollow parts), widely used in fields such as machinery, automobiles, electronics, home appliances, aerospace, etc. Its core role can be summarized from three aspects: function, structure, and process:

1、Functional level: Achieving specific physical performance or work requirements

1. Load bearing and force transmission

  Case: Stretching parts of automobile engine brackets (such as engine suspension brackets) need to withstand the weight and vibration load of the engine, and the strength and fatigue resistance are improved through the curved structure formed by stretching.

  Principle: Using stretching technology to evenly distribute material thickness and avoid stress concentration, such as the bottom arc transition design of cup-shaped stretching parts, can enhance compressive strength.

2. Accommodation and sealing

   Case: Pressure vessel heads (such as elliptical heads for storage tanks and reaction vessels) are formed into curved structures through stretching, providing larger internal space and meeting sealing requirements.

  Application: Stretch parts such as washing machine inner tubes and rice cooker inner liners in the home appliance field use cylindrical structures to achieve large capacity storage, while edge flanging technology can enhance sealing and safety.

3. Guidance and positioning

  Case: A mechanical guide slider stretching component that forms a groove or protrusion structure through stretching, providing guidance for moving parts (such as the slider of a machine tool linear guide).

  Features: The verticality and dimensional accuracy of the side walls of the stretching parts (with a tolerance of up to ± 0.1mm) can meet the requirements of precision assembly and reduce the amount of subsequent mechanical processing.

2、Structural level: Optimize part shape and assembly efficiency

1. Simplify complex structures

  Case: Irregular pipe fittings in the aerospace field (such as bends in rocket fuel delivery pipes) are formed in one go through a stretching and bulging composite process, replacing traditional multi piece welding structures and reducing stress concentration points.

  Advantages: Complex curved stretching parts (such as parabolic and conical parts) can be processed in one go through molds, avoiding material waste and process complexity in casting or cutting.

2. Reduce the number of parts

  Case: Automotive fuel tank stretching parts are formed into upper and lower shells through integral stretching, replacing traditional multi panel splicing structures, reducing the number of welds, and improving sealing and impact resistance.

   Data: After adopting stretching technology for the fuel tank of a certain vehicle model, the number of parts was reduced from 12 to 2, the assembly efficiency was improved by 50%, and the risk of leakage was reduced by 80%.

3. Easy to integrate functions

  Case: The stretching parts of electronic device casings (such as laptop body frames) are synchronously formed and installed with protrusions, heat dissipation holes, buckles, and other structures during the stretching process, without the need for additional drilling or riveting.

  Process: Through progressive die stretching (multi station continuous forming), multiple functional structures can be achieved on a single part, such as the integrated pole ear connection groove and explosion-proof valve pre cut of the mobile phone battery case stretching part.

3、Process level: Improve manufacturing efficiency and cost advantages

1. High material utilization rate

  Principle: The stretching process is mainly based on plastic deformation, and the material has basically no cutting loss, with a utilization rate of over 90% (traditional cutting processing is only 50%~70%).

  Case: Aluminum alloy stretching parts for beverage cans (can body+can bottom integrated forming), with material thickness stretched from 0.3mm to 0.1mm, reducing weight by 40% and material cost by 30%.

2. High production efficiency

  Case: Using high-speed stretching molds (with a stroke speed of up to 200 times/minute) to produce motor end caps, a single device can produce up to 100000 pieces per day, suitable for large-scale production (such as household appliances and automotive parts).

  Automation: The stretching process can be integrated with stamping, edge cutting, punching and other processes in a fully automated production line, achieving unmanned continuous operation (such as automotive cover stretching production line).

3. Controllable surface quality and accuracy

  Case: Medical device stretching parts (such as syringe shells), with precision molds controlling the stretching gap (tolerance ± 0.02mm), have a surface roughness of Ra ≤ 1.6 μ m, meeting the hygiene requirements for direct contact with the human body.

  Subsequent processing: Stretch parts can be directly subjected to surface treatments such as electroplating and spraying, without the need for additional polishing (such as chrome plated stretch parts for bathroom hardware).