(1) After bending the metal sheet on both sides of the corner, there will be metal material protruding due to extrusion. This leads to an increase in width compared to the original size, and the protruding size depends on the thickness of the material used. The thicker the material, the larger the protruding point.
To avoid this phenomenon, a semicircle can be made in advance on both sides of the fold line. The diameter of the semicircle should preferably be 1.5 times the thickness of the material.
The same method is applied when folding leftover material.
(2) When using a press brake to bend sheet metal, it is preferable that the internal R angle is greater than or equal to 1/2 of the material thickness.
If the R angle is not made initially, the right angle will gradually disappear after several blows and the R angle will form naturally. After that, the length of one or both sides of the angle R will become slightly longer.
(3) Sheet metal is easily deformed when bent.
To prevent deformation, an appropriate amount of 45-degree reinforcing ribs can be added to the bends to increase their strength without interfering with other parts.
(4) Generally, it is difficult to maintain the straightness of a narrow and elongated sheet metal part and is prone to deformation under tension. To maintain its strength and straightness, one side can be bent into an L shape or two sides can be bent into a 冂 shape.
However, it is often not possible to connect the L and 冂 forms from beginning to end. So, what should be done if they are interrupted by some factors?
In these cases, adding an appropriate amount of ribs can help increase the strength of the sheet metal part.
(5) It is better to have narrow gaps in the bend between the flat surface and the folded surface, or the edge of the gap should be retracted after bending, otherwise burrs may occur.
The width of the opening must be at least 1.5 times greater than the thickness of the sheet.
Furthermore, it is essential to mark the corner R when creating the drawings, avoiding negligence or laziness in this aspect.
Right- or acute-angle tongue-and-groove moldings are susceptible to cracking, which can lead to additional suspension and repair expenses in the future.
(6) Unless there is a specific requirement for a 90 degree angle, process the sheet metal corner at an appropriate R angle.
A right angle on the edge of sheet metal can create sharp edges that can cut personnel.
The right angle tip of the die is prone to cracking due to stress concentration.
The top punch tip is also susceptible to cracking, causing mold repairs and production delays.
Furthermore, even if the mold does not break, over time the R angle will wear out, resulting in burrs on the product and defective items.
(7) Edge bending
There are two types of flexion: unilateral and bilateral. For greater accuracy, it is recommended to use bilateral flexion as it provides better accuracy.
It is advisable to ensure that the height of the folded edge is greater than 3mm (with T tolerance: 1.0 ~ 1.2mm), as insufficient clamping dimensions may result in unstable dimensions.
When folding the edges, make sure that the pieces on the side walls or internal projections are not too close to the bottom surface. It is recommended to maintain a distance of more than 10mm. This is because if the distance is too small, the radius of curvature of the corners below the protrusions will be greater than the radius of the left and right sides, as there will be no puncture.
This can result in an irregular shape, which affects the overall appearance. Therefore, it is crucial to maintain a consistent R angle throughout the bending process.
Solution:
A suitable length of indentation can be made at the fold line before folding, which will improve its appearance.
When folding the edges, it is important to ensure that the openings in the side walls are not too close to the bottom surface. Ideally, there should be a distance of 3mm or more between the two to avoid any deformation of the openings during the bending process.
Solution
Before bending, a long hole with a length equal to 1.5 times the thickness of the material is drilled along the bend line. The purpose of this hole is to allow easy removal of excess material without affecting the appearance of the opening.
