Common Sheet Metal Fabrication Techniques and Their CNC Machining Applications

Sheet metal manufacturing is a cornerstone process in automotive, electronics, aerospace and other industries, and the introduction of numerical control (CNC) technology has made sheet metal parts processing accuracy break through ±0.1mm, and productivity increase by more than 50%. In this paper, we will systematically analyse the six major sheet metal manufacturing technologies of CNC upgrade path, combined with industry cases and data comparison, to provide manufacturing enterprises with a practical guide to reduce costs and increase efficiency.

I. CNC Innovation of Six Major Sheet Metal Manufacturing Technologies

1. Laser Cutting: Subversive Upgrading of High-Precision Undercutting

Technological breakthrough:

Fiber laser cutting machine can achieve precision processing of stainless steel (0.5-30mm), aluminium alloy (0.5-25mm) and other materials, with a cutting speed of up to 40m/min and an accuracy of ±0.05mm.

Intelligent nesting software increases material utilisation by 25%, making it particularly suitable for mass production of complex contour parts such as battery trays for new energy vehicles.

Cost advantage: Compared with traditional plasma cutting, laser cutting stainless steel sheet costs 30% less per piece and requires no subsequent grinding.

2. CNC stamping: an intelligent solution for efficient hole forming

Process innovation:

Servo turret punch press supports automatic switching of 30 groups of moulds (time consuming ≤2 seconds), and can process holes with a diameter of 0.5-50mm with an accuracy of ±0.05mm.

Dynamic parameter adjustment function can automatically match the punching pressure (15 tonnes) and stroke according to the thickness of the plate (e.g. 1.2mm galvanised steel), reducing the wear and tear of the die by 40%.

Application Scenario: Micro-perforation stamping of electronic equipment heat sinks (hole diameter 0.3mm, density 200 holes/cm²) with a yield rate of 99%.

3. CNC bending: integrated forming of complex three-dimensional structures

Precision control:

The hydraulic compensated bending machine controls the angular error within ±0.1° through real-time feedback system, and the rebound compensation algorithm improves the bending consistency of the automotive bracket by 35%.

The robot bending cell achieves 24-hour continuous operation and 80% reduction of manual intervention, which is suitable for mass production of household appliance shells and other products.

Technical difficulties: High-strength steel (HSS) bending needs to be preheated to 200°C to avoid cracking and ensure that the bending radius is ≥2 times the plate thickness.

4. CNC welding: a technological revolution for high-strength connections

Process comparison:

Case: a car company used laser welding white body, welding strength increased by 25%, body weight reduction of 15%.

5. CNC spinning: thin-walled rotary parts of the mass production of tools

Technical parameters:

Double spindle spinning machine can process lampshade and missile shell with diameter ≤ 800mm, wall thickness tolerance ± 0.1mm, surface roughness Ra ≤ 0.8μm.

The multi-pass spinning process makes the production efficiency of aluminium cans up to 300 pieces/hour, and the cost is 20% lower than the stamping process.

Material adaptability: Spinning moulding of stainless steel, titanium alloy and other difficult to deform materials need to be preheated to 600-800°C.

6. CNC riveting and gluing: a reliable solution for weldless connections

Technical Advantage:

Automatic riveting machine riveting speed of 120 points / minute, auto body riveting strength is 30% higher than spot welding.

Structural adhesive robot coating thickness accuracy ± 0.05mm, curing time reduced to 10 minutes, suitable for household appliances seals.

II. CNC sheet metal processing of the four major industry practices

1. Automotive manufacturing: dual breakthroughs in lightweight and safety

Body structure: Aluminium alloy battery tray adopts laser cutting + CNC bending to reduce weight by 30%, and the processing cycle is compressed from 8 hours to 4 hours.

Core components: High-strength steel B-pillar is CNC thermoformed (heated to 950°C) with a tensile strength of 1500MPa, increasing crash safety by 20%.

2. Electronic devices: the ultimate challenge of micron-level precision

Mobile phone centre frame: The laser cutting accuracy of the stainless steel centre frame needs to be controlled to ±0.05mm to ensure a seamless fit with the screen. A brand adopts 6kW laser, cutting speed 30m/min, burr height ≤ 0.01mm.

Heat sink module: copper heat sink micro-perforation stamping (aperture 0.2mm) need to use carbide moulds, punching pressure of 20 tons, life expectancy of 500,000 times.

3. Aerospace: performance guarantee in extreme environments

Titanium alloy skin: 5-axis laser cutting machine processing aircraft skin curved surface, contour accuracy ± 0.1mm, replacing the traditional chemical milling process, weight reduction of 40%.

Fuel storage tanks: aluminium alloy spinning and forming after CNC polishing, surface roughness Ra ≤ 0.4μm, compressive strength increased to 30MPa.

4. Home appliance industry: low-cost and high-quality mass production balance

Shell production: the daily capacity of sheet metal CNC stamping line is 20,000 pieces, the defective rate is reduced from 3% to 0.5%, and the comprehensive cost is reduced by 25%.

Structural optimisation: the inner cylinder of washing machine adopts laser cutting skeleton pattern, the material utilisation rate is increased by 20%, while the noise is reduced by 5dB.

III. Future trend of CNC sheet metal processing

Process integration:

Laser cutting + stamping + bending composite machine tools to reduce material handling time by 50%, suitable for small batch multi-variety production.

AI-driven optimisation:

Machine learning algorithm real-time analysis of processing parameters (such as power, feed), automatically adjusted to the best state, so that the cost of stainless steel cutting by 15%.

Green manufacturing:

Nitrogen protection cutting technology reduces metal oxidation slag by 90% and increases scrap recycling rate to 98%.

Summary

Sheet metal manufacturing technology, as the foundation of modern industry, has achieved significant improvements in processing accuracy and efficiency through the introduction of CNC technology. From laser cutting to CNC stamping, to bending, welding, spinning and riveting, the wide application of these technologies in the automotive, electronics, home appliance and aerospace industries not only improves product quality, but also promotes the intelligence and efficiency of manufacturing.