3. Sheet metal processing technology - Welding

In the design of sheet metal welding structure, the principle of "welds and welding spots shall be arranged symmetrically to avoid intersection, aggregation and overlap" shall be implemented. Secondary welds and welds can be interrupted, and primary welds and welds shall be connected. Common sheet metal welding includes arc welding, resistance welding, etc.

(1) Arc welding

There shall be enough welding space between metal plates, the maximum welding gap shall be 0.5-0.8mm, and the weld shall be uniform and smooth.

(2) Resistance welding

The welding surface shall be smooth without wrinkles and rebound.

4. Sheet metal processing technology - connection mode

This paper mainly introduces the connection methods of sheet metal in the processing process, mainly including rivet riveting, welding (as described above), reaming riveting and tox riveting.

(1) Rivet riveting: this kind of rivet is often called rivet. Riveting two plates together with rivets is called rivets. Common rivet shapes are shown in the figure:

(2) Punching riveting:

One part is a drawing hole and the other part is a counterbore, which is made into a non removable connector through a riveting die. Advantages: the drawing hole and the matched counterbore have positioning function, high riveting strength and high riveting efficiency through the die.

(3) Tox riveting:

Press the connector into the female mold through a simple male mold. Under further pressure, the material in the female die "flows" outward. In this way, a circular connection point without edges and burrs is produced, and its corrosion resistance will not be affected. Even the plate with coating or paint coating on the surface can maintain its original anti rust and anti-corrosion characteristics, because the coating and paint layer will deform and flow with it. The material is extruded to both sides and into the plate near the female die to form too.

5. Metal plate processing technology surface treatment

The treatment of sheet metal surface can play the role of anti-corrosion protection and decoration. Common sheet metal surface treatment includes powder spraying, electro galvanizing, hot-dip galvanizing, surface oxidation, surface wire drawing, screen printing, etc.

Before sheet metal surface treatment, oil stain, rust, welding slag, etc. The surface of metal plate shall be removed.

(1) Powder spraying: the surface of sheet metal is sprayed with liquid paint and powder paint. We usually use powder paint. Through powder spraying, electrostatic adsorption, high temperature baking, etc., Spraying a layer of paint of various colors on the surface of sheet metal to beautify the appearance and increase the corrosion resistance of materials is a common surface treatment method.

(2) Galvanizing and hot-dip galvanizing: galvanizing of sheet metal surface is a common surface anti-corrosion treatment method, which can beautify the appearance to a certain extent. Galvanizing can be divided into electro galvanizing and hot-dip galvanizing. The appearance of electro galvanizing is bright and flat, and the zinc coating is thin, which is commonly used. The thickness of hot-dip galvanizing layer can produce zinc iron alloy layer, and the corrosion resistance is stronger than that of electro galvanizing.

(3) Surface oxidation: mainly introduces the surface anodizing of aluminum and aluminum alloys. Moreover, the surface anodizing of aluminum and aluminum alloy can be oxidized into various colors to protect and decorate. At the same time, an anodic oxide film can be generated on the surface of the material. Anodic oxide film has high hardness and wear resistance, as well as good electrical insulation and heat insulation.

(4) Surface wire drawing: put the material between the upper and lower winding wheels of the wire drawing machine, and the winding wheel is attached with sand belt. Driven by the motor, the material pulls out traces on the material surface through the upper and lower sand belts. According to different sand belts, the thickness of traces is different, and the main function is to beautify the appearance. Generally, the surface treatment method of drawing is only considered for aluminum.

(5) Screen printing: the process of screen printing various marks on the surface of materials, generally including flat screen printing and pad printing. Plane screen printing is mainly used for general plane, but pad printing is required if there are deep pits. Screen printing requires a screen printing die.