Numerical Control (NC) bending uses CNC bending machines equipped with molds to bend metal sheets into various geometric shapes. NC bending technology is widely used in industries such as automotive, aircraft manufacturing, light industry, shipbuilding, containers, elevators, and railway vehicles for sheet metal bending processes.
The repeat accuracy of the slide in CNC bending machines used for NC bending is ±0.0004 inches, and precise angles require such accuracy and good molds. The repeat accuracy of the slide in manual bending machines is ±0.002 inches, which can result in a deviation of ±2~3° even with suitable molds. These issues must be considered when bending many small batch parts.
To avoid errors, strict inspection of NC bending is essential. To achieve relative accuracy, the following points must be considered during inspection:
1. Confirm the viewing angle of the drawings. It is necessary to confirm whether the drawings are in the first-angle projection or the third-angle projection during inspection. After confirming, use the perspective drawing method to verify the bending direction on the tool drawing.
2. Next, compare the drawings with the actual sheet metal. Verify if the thickness of the sheet is correct and inspect various bending dimensions according to the drawings. Ensure that tolerance dimensions and distances from holes to edges are maintained during inspection.
3. During the inspection of NC bending, it is essential to check if the bending marks meet the product requirements. The A1 surface should not have any imprints, indentations, scratches, or other defects, while the B-level surface has certain restrictions on imprints, indentations, scratches, etc. Inspection should be performed according to customer requirements and the factory's standards.
4. When inspecting plated products, the material surface should not have scratches, indentations, imprints, rust, or other defects. During inspection, each product must be separated by clean and dry film and coated with clean rust-proof oil.
5. For products with untreated surfaces such as electrolytic plates, aluminum-zinc-coated sheets, and aluminum sheets, the inspection requires that the surface should not have scratches, indentations, imprints, or other defects. When stacking and arranging products processed with paper separators, it should meet operational requirements and should not be stacked too high to avoid deformation of the lower layers.
6. For aluminum products that need to be processed after drawing, the product surface should not have scratches, indentations, imprints, or other defects. To prevent workpieces from rubbing against each other during operation, protective packaging materials such as plastic bags, pearl cotton, or bubble wrap must be used during processing.
7. If there are scratches, indentations, imprints, or other defects on the surface of the workpiece, judgment should be made based on customer requirements or the factory's standards.
8. For batch processed products, to prevent batch defects caused by mold wear, loose positioning tracks, or improper positioning by operators, random inspections should be conducted at the processing site every 0.5 hours.
9. To prevent inertia thinking during inspection, which may result in the failure to detect faulty workpieces, final inspection and initial inspection personnel should be different individuals. Ideally, the same person should not perform both inspections.
The repeat accuracy of the slide in CNC bending machines used for NC bending is ±0.0004 inches, and precise angles require such accuracy and good molds. The repeat accuracy of the slide in manual bending machines is ±0.002 inches, which can result in a deviation of ±2~3° even with suitable molds. These issues must be considered when bending many small batch parts.
To avoid errors, strict inspection of NC bending is essential. To achieve relative accuracy, the following points must be considered during inspection:
1. Confirm the viewing angle of the drawings. It is necessary to confirm whether the drawings are in the first-angle projection or the third-angle projection during inspection. After confirming, use the perspective drawing method to verify the bending direction on the tool drawing.
2. Next, compare the drawings with the actual sheet metal. Verify if the thickness of the sheet is correct and inspect various bending dimensions according to the drawings. Ensure that tolerance dimensions and distances from holes to edges are maintained during inspection.
3. During the inspection of NC bending, it is essential to check if the bending marks meet the product requirements. The A1 surface should not have any imprints, indentations, scratches, or other defects, while the B-level surface has certain restrictions on imprints, indentations, scratches, etc. Inspection should be performed according to customer requirements and the factory's standards.
4. When inspecting plated products, the material surface should not have scratches, indentations, imprints, rust, or other defects. During inspection, each product must be separated by clean and dry film and coated with clean rust-proof oil.
5. For products with untreated surfaces such as electrolytic plates, aluminum-zinc-coated sheets, and aluminum sheets, the inspection requires that the surface should not have scratches, indentations, imprints, or other defects. When stacking and arranging products processed with paper separators, it should meet operational requirements and should not be stacked too high to avoid deformation of the lower layers.
6. For aluminum products that need to be processed after drawing, the product surface should not have scratches, indentations, imprints, or other defects. To prevent workpieces from rubbing against each other during operation, protective packaging materials such as plastic bags, pearl cotton, or bubble wrap must be used during processing.
7. If there are scratches, indentations, imprints, or other defects on the surface of the workpiece, judgment should be made based on customer requirements or the factory's standards.
8. For batch processed products, to prevent batch defects caused by mold wear, loose positioning tracks, or improper positioning by operators, random inspections should be conducted at the processing site every 0.5 hours.
9. To prevent inertia thinking during inspection, which may result in the failure to detect faulty workpieces, final inspection and initial inspection personnel should be different individuals. Ideally, the same person should not perform both inspections.
