In addition to the above applications for laser cutting, some miniaturized plastic molds also use laser processing to stop engraving and manufacturing. Laser engraving and the production quality is also quite high.
According to the fundamental processing method of sheet metal parts, metal laser engraving, such as cutting, bending, stretching, forming, welding. According to the different processing methods, the cutting can be divided into general punching, number punching, shearing, laser cutting, and wind cutting. Due to the different processing methods, the processing technology of the cutting is also different.
Sheet metal blanking methods are mainly digital punching and laser cutting bending
When the material is bent, the outer layer is stretched on the rounded area, and the inner layer is contracted. When the thickness of the data is fixed, the smaller the inner r, the more serious the tensile and contraction of the data; when the tensile stress of the outer corner fillet exceeds the ultimate strength of the data, cracks and breaks will occur. Design should prevent too small bending radius.
Stretching: The radius of the fillet between the bottom of the stretched part and the straight wall should be greater than the thickness of the plate, ie r1≥t. In order to make the drawing stop more smoothly, usually take r1 = (3 ~ 5) t. The radius of the large fillet should be less than or equal to 8 times the thickness of the plate, that is r1≤8t. Due to the different magnitude of the stress on the stretched parts, the thickness of the data after stretching will change.
Laser cutting processing technology is very sensitive when working, and it can stop the modification of the workpiece manufactured according to the demand and become more suitable for consumption. In Yongkang’s large-scale laser cutting process, the operator needs to pay attention to the changes in the processing size at any time.
1. The overall size of the processed product changes
This is due to the influence of the diameter of the laser focus on the incision and the width of the incision formed by the extinction area around it.
Of course, under the same conditions, the same offset compensation value can be used to ensure the accuracy of the same processed object, but the setting of the focus position depends on the feeling of the operator of the processing machine, and the role of the thermal lens will also form the focus position Changes, so it is necessary to regularly check the best offset compensation value.
2. There is a difference in dimensional error in the processing direction (local)
The dimensional accuracy of the upper part of the plate is different from the dimensional accuracy. This phenomenon has to consider two reasons. First, the roundness and intensity of the beam are not uniformly spread, and the width of the cut is different along the processing direction. The solution is to stop the optical axis adjustment or clean the optical components. Secondly, heat shrinkage of the workpiece will cause the length of the machined shape to become shorter in the longitudinal direction.
3. Changes caused by warpage
Although the dimensional accuracy is within the required range, it may cause warpage due to thermal deformation and other reasons. It is very significant when processing aluminum, copper, stainless steel, etc. It is affected by physical properties such as linear shrinkage coefficient and heat capacity. In terms of processing shape, the larger the aspect ratio, the greater the amount of warpage. Low-calorie processing conditions and processing lines are used to up and down the processing program, but the problem has not yet been fully addressed.
The residual stress of the processed board also affects the warpage and dimensional error, so we need to insist on a certain configuration direction for the processing program.
4. Pitch accuracy change
When machining many holes, the accuracy of the spacing between the holes will be biased. Since the holes are opened under heat shrinkage, the spacing becomes smaller after cooling and shrinking. We can correct the accuracy of the contraction in the program or sensitively use the shape scaling function. No matter what the situation, after the initial processing, the processing size should be measured to compensate for the error. When the distance accuracy does not change with the processing position, but deteriorates in the entire processing area, the reason is that the mechanical accuracy deteriorates.
5. Roundness change
In laser processing, the slope of the cutting surface of the hole can not be prevented. The diameter of the lower surface is larger than the diameter of the reverse surface. Generally, the roundness of the slightly smaller side of the reverse surface is evaluated.
If the size changes, it will have an impact on the quality progress of the product. There is also a problem of absorption when processing laser aluminum or copper in Zhejiang Laser Carving Factory. It is necessary to apply an absorbent on the data so that it can be better. It is also safer to improve consumption efficiency.