Principles of Folding Machine Operation
Folding involves fixing the upper and lower dies on the upper and lower worktables of the folding machine and using hydraulic servo motors to drive the relative movement of the worktables. Combined with the shape of the upper and lower dies, this achieves the bending and forming of the sheet metal.
Definitions and Common Knowledge of Folding
- Folding development refers to the dimensions of the product after cutting, which is the length of the compressed position or the shear size where the sheet metal undergoes deformation during the bending process without stretching.
- The formula for V-groove selection in bending: When R = 0.5, V = 5T; when R > 0.5, V = 5T + R. The folding development will vary depending on the upper and lower dies used and must be taken into consideration when changing the tooling.
- There are two types of machine motion for folding:
- Upward motion: The lower worktable remains stationary, and the pressure is applied by the descending upper slide.
- Downward motion: The upper machine bed is fixed, and the pressure is applied by the rising lower worktable.
- Process Characteristics
1. Basic principles of bending sequence: Bend from the inside to the outside; bend from small to large; bend special shapes first, then general shapes.
2. Selection of upper die for 90° bends and bends greater than 90° but less than 180°: It is generally recommended to use an upper die with a blade angle of 88° or 90° when there are no special requirements or avoidance positions specified in the standard operating procedure (SOP). This ensures better stability of the bending angle.
Calculation Methods for Folding Development Dimensions
<1> Calculation method for right-angle development
When the internal R angle is 0.5, the bending coefficient (K) = 0.4 * T, provided that the material thickness is less than 5.0mm, and the lower die is 5T.
L1 + L2 - 2T + 0.4 * T = development
<2> Calculation method for non-right-angle development
Calculation of development when R = 0.5
A + B + K = development
L1 and L2 are the dimensions of the internal intersection points.
Bending coefficient:
K = (180 - a) / 90 * 0.4T
<3> Calculation method for flattening edge development
Die selection: Use a small pointed blade with a blade angle of 30° for the upper die, and select a lower die with a V-groove angle of 30° based on the SOP and material thickness. Use the selected tooling from step 4.4.1 to bend the angle to approximately 30°-65°.
Development = L1 + L2 - 0.5T
<4> Calculation method for U-edge development: Use a small pointed blade with a blade angle of 30° for the upper die, and select a lower die with a V-groove angle of 30° based on the SOP and material thickness. Select an appropriate R upper die based on the height of the U-edge gap (choose an upper die that is closest in height to the gap). Then flatten the U-edge using a flattening die, and use a material with the same height as the gap as a spacer inside the U-edge during flattening.
When H < 2.0T, the calculation method is:
Development = L1 + L2 - 0.4T + 0.75 * H
When H ≥ 2.0T, calculate the development as a circular arc.
<5> Calculation method for segment difference: Segment difference can be divided into straight edge difference and oblique edge difference, and the processing method depends on the height of the difference.
Straight edge difference: When the height of the difference (h) is less than 3.5 times the material thickness, use a difference die or an easy mold for forming. When the height is greater than 3.5 times the material thickness, use a normal bending method with one bend in each direction to complete.
Oblique edge difference: When the length of the oblique edge (L) is less than 3.5 times the material thickness, use a difference die or an easy mold for forming. When the length is greater than 3.5 times the material thickness, use a normal bending method with one bend in each direction to complete.
For right-angle segment difference, when H ≤ 2T, use the following method. When H > 2T, calculate using a 2-bend method.
Development = L1 + L2 + T + 0.2mm
Note: 0.2 is the compensation value.
Folding involves fixing the upper and lower dies on the upper and lower worktables of the folding machine and using hydraulic servo motors to drive the relative movement of the worktables. Combined with the shape of the upper and lower dies, this achieves the bending and forming of the sheet metal.
Definitions and Common Knowledge of Folding
- Folding development refers to the dimensions of the product after cutting, which is the length of the compressed position or the shear size where the sheet metal undergoes deformation during the bending process without stretching.
- The formula for V-groove selection in bending: When R = 0.5, V = 5T; when R > 0.5, V = 5T + R. The folding development will vary depending on the upper and lower dies used and must be taken into consideration when changing the tooling.
- There are two types of machine motion for folding:
- Upward motion: The lower worktable remains stationary, and the pressure is applied by the descending upper slide.
- Downward motion: The upper machine bed is fixed, and the pressure is applied by the rising lower worktable.
- Process Characteristics
1. Basic principles of bending sequence: Bend from the inside to the outside; bend from small to large; bend special shapes first, then general shapes.
2. Selection of upper die for 90° bends and bends greater than 90° but less than 180°: It is generally recommended to use an upper die with a blade angle of 88° or 90° when there are no special requirements or avoidance positions specified in the standard operating procedure (SOP). This ensures better stability of the bending angle.
Calculation Methods for Folding Development Dimensions
<1> Calculation method for right-angle development
When the internal R angle is 0.5, the bending coefficient (K) = 0.4 * T, provided that the material thickness is less than 5.0mm, and the lower die is 5T.
L1 + L2 - 2T + 0.4 * T = development
<2> Calculation method for non-right-angle development
Calculation of development when R = 0.5
A + B + K = development
L1 and L2 are the dimensions of the internal intersection points.
Bending coefficient:
K = (180 - a) / 90 * 0.4T
<3> Calculation method for flattening edge development
Die selection: Use a small pointed blade with a blade angle of 30° for the upper die, and select a lower die with a V-groove angle of 30° based on the SOP and material thickness. Use the selected tooling from step 4.4.1 to bend the angle to approximately 30°-65°.
Development = L1 + L2 - 0.5T
<4> Calculation method for U-edge development: Use a small pointed blade with a blade angle of 30° for the upper die, and select a lower die with a V-groove angle of 30° based on the SOP and material thickness. Select an appropriate R upper die based on the height of the U-edge gap (choose an upper die that is closest in height to the gap). Then flatten the U-edge using a flattening die, and use a material with the same height as the gap as a spacer inside the U-edge during flattening.
When H < 2.0T, the calculation method is:
Development = L1 + L2 - 0.4T + 0.75 * H
When H ≥ 2.0T, calculate the development as a circular arc.
<5> Calculation method for segment difference: Segment difference can be divided into straight edge difference and oblique edge difference, and the processing method depends on the height of the difference.
Straight edge difference: When the height of the difference (h) is less than 3.5 times the material thickness, use a difference die or an easy mold for forming. When the height is greater than 3.5 times the material thickness, use a normal bending method with one bend in each direction to complete.
Oblique edge difference: When the length of the oblique edge (L) is less than 3.5 times the material thickness, use a difference die or an easy mold for forming. When the length is greater than 3.5 times the material thickness, use a normal bending method with one bend in each direction to complete.
For right-angle segment difference, when H ≤ 2T, use the following method. When H > 2T, calculate using a 2-bend method.
Development = L1 + L2 + T + 0.2mm
Note: 0.2 is the compensation value.
