Sheet Metal Aluminum Crack or Broken
The aluminum sheet metal bends very easily when it is bent. There are several cuases why the aluminum sheet metal cracks or breaks when it is bent. The hardness of the aluminum material is too high, the aluminum sheet metal is too thick, and the bending angle is too small.
- The hardness of the aluminum sheet metal has a direct impact on the bending and cracking of sheet metal aluminum. If the hardness is too high, it is very easy to crack. When designing sheet metal aluminum parts, it is very important to choose the right material. Commonly used aluminum alloys include 1 series, 3 series, 5 series, etc. There are 2 series, 6 series and 7 series with high hardness, which need to be annealed before processing to make the aluminum alloy plate in shape before bending;
- If the thickness of the aluminum sheet metal is too thick, it is not easy to bend, so a thinner aluminum alloy plate should be selected for processing;
- The larger the bending R angle, the easier it is to bend, so the bending R angle should be as large as possible;
- For aluminum alloy sheet drawing, a better processing procedure should be to bend first, and then perform drawing, which can reduce the probability of cracking.
Purpose of Heat Treatment of Sheet Metal Parts
Metal heat treatment including annealing, normalizing, quenching (solution) and tempering (aging) is one of the most important processing in the sheet metal fabrication.
When the workpiece is heated and reaches a certain temperature, different holding times are used according to the size and material of the workpiece, and then slowly cooled, which is annealing.
The main purpose of annealing is to appropriately reduce the hardness of the material, improve the plasticity of the material, facilitate subsequent processing, reduce the residual stress, and evenly distribute the composition and structure of the material.
Sheet metal processing will carry out corresponding heat treatment processes before and after the parts are processed. Its role is:
- Remove the internal stress of the blank. Mostly used for castings, forgings, welded parts;
- Improve processing conditions and make materials easy to process. Such as annealing, normalizing, etc.;
- Improve the comprehensive sheet metal processing performance of metal materials. For example, conditioning treatment;
- It can improve the hardness of the material. Such as quenching, carburizing and quenching, etc.
Therefore, in addition to the reasonable selection of materials and various forming sheet metal processing processes, heat treatment processes are often essential. Heat treatment generally does not change the shape and overall chemical composition of the workpiece, but imparts or improves the performance of the workpiece by changing the microstructure inside the workpiece or changing the chemical composition of the workpiece surface. It is characterized by improving the intrinsic quality of the workpiece, which is generally not visible to the naked eye.
Deburrs in Sheet Metal Parts
What is a burr?
Burr – refers to a kind of excess iron filings that are formed on the edge of the product when the metal material is squeezed and deformed during processing, commonly known as burrs, which are formed during cutting, grinding, milling and other similar chip processing. of. The existence of burrs has a great impact on product quality and product assembly, use, dimensional accuracy, and shape and position accuracy.
How to remove burrs?
There are two main methods for removing burrs: chemical removal and physical removal.
Chemicals are mainly used for precision core workpieces with complex shapes, deformities, high precision requirements and high cost performance.
The physical class is used for parts with rough surface and low dimensional accuracy requirements, which are easy to remove by manual operation.
The chemical deburring process is an immersion process. This process mainly uses the difference between the burr and the structure of the workpiece itself, and achieves the effect of removing the burr through the principle of vertical reaction. This process is widely used in automobile, aerospace, metal parts processing, etc. The suitable workpieces are generally auto parts, stamping parts, oil pump nozzle parts, gear parts, bearing parts, electronic components, bearing parts, transmission parts, Fasteners, CNC machining parts, etc. Compared with the traditional deburring, this process is far superior to the traditional process in terms of reliability, repeatability, stability, environmental protection, etc.; it is efficient and time-saving, improves the surface finish of the product, is safe, reliable, environmentally friendly and economical. The operation is simple, and the anti-corrosion and anti-corrosion ability of the product can be enhanced.
Physical deburring mainly includes: rough grade (hard contact) cutting, grinding, file, scraper, ordinary grade (soft contact), belt grinding, grinding, elastic grinding wheel grinding, polishing and flushing and others with different degrees of automation process. The quality of the workpieces being processed is often not guaranteed; production and personnel costs are very high.
In sheet metal processing, when choosing a deburring method, we must consider many factors, such as the material characteristics of the part, structural shape, size and precision, and especially pay attention to changes in surface roughness, dimensional tolerance, deformation, and residual stress. influence.
