Sheet Metal Bending Process -Bending Hole

In this article, I will discuss the Sheet Metal Bending Process – Bending Hole, focusing on the techniques and considerations involved in creating precise bends around holes in sheet metal. Understanding how to effectively bend sheet metal while accommodating holes is crucial for achieving optimal results in fabrication. I will share my insights on the challenges we face during this process, as well as best practices to ensure accuracy and quality. Join me as we explore the intricacies of bending holes in sheet metal and how to enhance our overall production efficiency.

How to determine the size of Bending Hole?

The size of the sheet metal process bending hole depends on the position of the process hole. If the process hole is at the intersection of two lines, the process bending hole is 2 times thicker. The minimum thickness cannot be less than 1.5 times the sheet metal thickness. When bending sheet metal thick plates, taking into account the bending fillet, the process hole should be appropriately enlarged.

The disadvantages of this process hole: after bending, especially for the thick plate, the bending angle of the process hole made in this way is seriously deficient in material, and it is not beautiful and easy to weld. At this time, it is necessary to improve the manufacturing method of the process hole.

Optimization method of process hole:

It can be determined according to the situation of bending edge wrapping, considering the avoidance of plate thickness and bending fillet to determine the sheet metal process hole. See the illustration below:

The above picture shows: the thickness of sheet metal material is 3mm,the bending height of four sides is 15mm, a square sheet metal box.

Improvement plan of art hole:

Improvement of blanking method: there are two methods of sheet metal blanking, CNC blanking and laser cutting blanking. CNC blanking, the bending process holes are generally round holes, square holes or long holes are limited by the mold, difficult to achieve. The picture above is 3mm sheet metal, so laser cutting is used.

Improved process hole shape: If the process hole is made into a long shape, it can avoid aesthetic problems after bending.

How to determine the size of the rectangular process hole

The width is generally set to 1mm, which does not affect the appearance, nor does it affect the release of sheet metal bending deformation. Depth dimension calculation method: 10 mm = bending height-3 mm bending factor 5; 4 mm = sheet metal material thickness +1.

Process hole improvement effect:

After bending and forming the sheet metal part, there is only a 1 mm narrow slit. See 3D renderings:

Why avoid bending and pulling?

Harm of pulling the material:

1.Affect the bending size. During the pulling process, it takes a lot of force to forcibly tear the sheet metal thickness. The direction of the force is uncertain, which will cause the workpiece to move and cause dimensional displacement.

2.The bending mold is easy to be damaged. As mentioned before, there will be a lot of force at the sharp corners, which will exceed the bearing capacity of the mold, resulting in the phenomenon of chipping and damage.

Standard for use of bending and positioning process hole

Process hole size and form:

1 The thin plate bending positioning process hole, the opening size is 1X0.2mm root R 0.1mm, suitable for plate thickness ≤3mm.

2 Thick plate bending positioning process hole, opening size is 1X0.4mm root R 0.2mm, suitable for plate thickness> 3mm-6mm.

Use range:

1 Angle type: The bending angle is not 90 degrees, and all positioning holes are opened at the bending position, including folded edge bending;

2.Docking type: Appearance parts or butting parts with high precision requirements, all bending holes are opened with positioning holes;

3.Large size type: If the bending size is greater than 200mm, all positioning holes are opened

4.Continuous bending multi complex type: continuous bending multi complex parts, starting from the third bending to add positioning holes;

5.Bending sequence type: for parts that cannot be processed according to the normal bending sequence, all the bending positions are provided with positioning holes;

6.Repeated bending type: Due to the limitation of bending equipment, parts that need to be repeatedly bent have all positioning holes in the bending position;

7.Cannot lean against the stopper: cannot lean against the stopper type parts, bending position all open positioning holes;

8.Type of guide rail: all parts of guide rail type have positioning holes at bending positions;

9.Arc positioning holes: Positioning holes at the arc starting points at both ends of the arc;

10.Pull plate type: All positioning holes are opened at the bending position of the pull plate parts.

11.Folding edge type: Positioning holes are opened at the edge position of the edge-like parts; positioning holes are opened by the size position where the edge continues to bend.