Explanation of high-precision sheet metal processing technology

Course content:

  • 1. Definition
  • 2. Introducing process flow
  • 3. Introduction of treatment method
  • 4. Introduction of industrial processing capacity

Sheet metal processing flowchart

Definition of sheet metal processing

Sheet metal processing is a comprehensive cold working process for metal plates (usually 6 mm or less), including shearing, blanking, bending, welding, riveting, molding and surface treatment. Its feature is the uniform thickness of the same parts. According to different processing methods, they are generally divided into two categories.

1. Non-mold processing:

Machining tools for sheet metal processing techniques such as NCTs (CNC punching machines), lasers (laser cutting machines), CNC bending machine tools, and rivets commonly used for rapid prototyping add cost.

2. Mold processing:

The mold is fixed and the metal plate is machined. Generally, there are punching dies and molding dies that are mainly used for mass production and have low cost.

Introduced a general processing method.

  • 1. NCT (Cnc Machine) processing
  • 2. Laser (laser cutting) processing
  • 3.Folding machine
  • 4. Pliers
  • 5. Mold processing
  • 6. Surface treatment
  • 7. Sheet metal connection

Machining principle of CNC machine tools

CNC machine tools are flexible automatic machine tools that can adapt to frequent product changes. The various movements and steps required for the machining process and the relative displacement between the tool and the workpiece are represented by digitized codes. Digital information is sent to a dedicated or general purpose computer via a control medium (such as tape or disk) that processes and calculates input information. Various commands are issued to allow the machine to automatically process the required workpieces or products to control the machine’s servo system or other actuators.

General applications of CNC machine tools

Unloading, punching mesh, punching flange, trimming, bulge, ribbing, pressing, punching.

(The crimping line is post-pressed for all post-pressing methods such as hot stamping, bumping, embossing, lamination, pressing, pasting and cutting. The minimum distance between two pressure lines is usually 3mm, but it is machined. It depends on the object to be made.) CNC machine machining accuracy: +/- 0.1mm

NCT (CNC Punching Machine) Processing Technology and Precautionary Measures:

  • 1. If the edge distance is less than the thickness of the material, the punch will raise the edge. Square holes are larger and more prominent, usually considering laser (laser cutting) twice.
  • 2. Make sure the distance between the holes in the NCT punch is not too small. The tolerances are shown in Table 1. Table 2 shows the minimum aperture values ​​for NCT punching.
    Minimum aperture for NCT punching
  • 3. Pull-out hole:The minimum distance from the edge of the NCT pull hole is 3T. The minimum distance between the two wire lead holes is 6T. The minimum safe distance from the stamped edge (inside) is 3T + R. If it is too small, it should be treated with a pressure line.
  • 4. After the field test, the height of the NCT semi-shear protrusion does not exceed 0.6T, and if it exceeds 0.6T, it easily falls off.
  • 5. T above indicates the thickness of the plate.

Laser Machining Principle

LASER is abbreviated as a prefix for optical amplification of stimulated emission radiation. Generally converted to a laser. Laser cutting uses electron emission as an energy source, uses a mixed gas of He, N 2, and CO 2 as an excitation medium, and generates a laser beam by a group of reflectors to cut the material. Driven by a programmed servomotor, the cutting head moves along a predetermined path to cut workpieces of various shapes.

Commonly used laser machines: punching, cutting shape, secondary cutting, cutting line, cutting hole

Laser machining accuracy: ± 0.1mm

Laser Machining Technology and Precautionary Measures

  • 1. When cutting the bottom hole of a metal part, it is necessary to increase by 0.05 mm. Because there are small dots at the beginning and midpoint of the cut.For example, the bottom hole φ5.4 must be cut to φ5.45.Note: The holes in the bottom of metal parts are usually machined by NCT ​​or mold to ensure machining accuracy.
  • 2. The width of the machined hole is generally larger than 0.5mm, the smaller the burr, the more obvious.
  • 3. For a secondary cut from flat to convex, the speed must be very slow, which is actually similar to cutting thick material.
  • 4. The laser is hot-worked to heat the cutting net and thin material, making it easier to deform the workpiece.
  • 5. Unless there are special requirements for sharp angles on all workpieces, they must be rounded to R0.5mm during laser machining.

Principle of bending

The upper and lower dies are fixed to the upper and lower worktables of the folding bed, respectively, and the relative movement of the workbench is driven by a hydraulic drive. Bending and bending of the sheet is achieved by combining the shapes of the upper and lower dies.

It is usually divided into up and down movements. Basic Principle of Bending Sequence: Bending from inside to outside. Bending from small to large.

First fold the special shape and then the general shape.

After the formation of the previous process, it does not interfere with subsequent processes.

Bending accuracy:

  • One bend: ± 0.1mm
  • Two bends: +/- 0.2mm
  • 3 bends: +/- 0.3mm
  • Bending machine General folding knife and V-groove shape

In the image above, the size is the distance from the hole to the inner edge. If the distance is exceeded, the hole will be deformed. In this case, the problem of deformation can be solved by other processing methods. Laser cutting, cut line processing, or direct mold production after the first bending process will increase the processing cost.

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