Process planning for bent sheet metal parts refers to the sequential order of bending processes during manufacturing. The bending sequence must be organized based on the shape of the part, accuracy requirements, nature of the operations, and the deformation pattern of the material.
For specific bent parts, start by considering your production volume, structural design, dimensional and material accuracy, and review the feasibility of the bending process. Then, based on specific production conditions and a comprehensive analysis of influencing factors, develop a technically feasible and cost-effective bending process plan.
The bending process plan mainly includes the process analysis of the bent parts and the formulation of the bending process scheme. The general steps are as follows:
1. Analyze original design data related to bent parts
Original data includes product drawings and technical conditions of bent parts, size specifications, performance and supply status of raw materials, product production volume, condition of existing stamping equipment in the factory and other data technical.
Among these, product drawing is the most direct basis for process design, other technical data serves as reference for stamping die design, and the remaining original data is used to determine the processing method of stamped parts, Formulate the stamping process plan and choose the type of mold structure.
2. Analysis of product flexibility
Flexibility refers to the adaptability of a component to bending processes. This means evaluating whether the structure, size, precision requirements, and materials of the bent component meet the technical requirements of bend manufacturing.
Generally, components with good bendability ensure lower material consumption, fewer operations, simpler tool structure, stable product quality and low cost. It also allows for economical and sensible technical preparation and organization of production.
The objective of bendability analysis is to understand the ease or difficulty of processing the bent component, laying the foundation for developing a bending process plan.
Before analyzing product flexibility, an economic analysis of production must first be carried out. The production quantity of bent components is a critical factor in determining the reasonableness of the bending process.
Product flexibility analysis must be based on component drawings. A thorough analysis of the shape, size, accuracy requirements and flexural capacity of the material used is essential. It also involves assessing the potential for various quality problems.
Special attention should be paid to component limit dimensions (such as minimum bent edge size, minimum distance from hole edge, minimum radius of curvature), dimensional tolerances, design references, and other special requirements.
These factors significantly influence the nature, number and sequence of required operations, as well as the positioning method, bending mold structure and manufacturing accuracy.
After the above analysis, if the flexibility of the component is considered unreasonable, the product designer should be consulted.
Without compromising product usage requirements, appropriate modifications can be made to the shape, size, accuracy requirements, and material selection of the bent component.
3. Formulation of the Bending Process Plan
Based on the bending process analysis, several bending process plans are proposed. Then, by thoroughly analyzing and comparing various plans in accordance with the company's production volume and existing production conditions, the most technologically and economically optimal process plan is determined.
Generally, the formulation of a bending process plan mainly includes the following contents:
- Determine the nature, number, sequence and combination of bending operations and positioning method through analysis and calculation;
- Determine the shape and size of bending processing in each operation;
- Arrange other non-flexible auxiliary operations, etc.
In short, while satisfying the part design requirements, we strive for fewer operations, simple bending mold structure, longer service life and convenient operation.
4. Bending operation
4.1 Principles for Organizing Folding Operations
Generally, the arrangement of bending operations should follow the following principles:
1) To bend parts with simple shapes, single bend molding is adopted; To bend parts with complex shapes, two or more bending frames are adopted.
2) To bend parts with large quantities and smaller sizes, progressive dies or composite dies are preferably used.
3) For pieces bent at multiple angles, fold the outer corner first and then the inner corner. Subsequent folding must not destroy the shape of the previous folded part. The anterior fold must take into account that the posterior fold has a suitable positioning base and can be performed without problems.
4) The flexion must occur from small to large.
5) Special shapes should be folded first, followed by general shapes.
6) For bending parts with holes, holes can generally be drilled before bending to simplify the mold structure. When the hole is located in the bending deformation zone or close to the deformation zone, and the hole has high requirements with the reference surface, bending must be done before drilling the hole.
4.2 Examples of organization of the production process for typical bent parts
1) Single and single folded parts as shown in Figure 1-1.
2) Parts folded twice as shown in Figure 2-2.
a) Flat pattern
b) First curve
c) Second curve
3) Parts folded three times as shown in Figure 3-3.
- a) Flat pattern
- b) First curve
- c) Second curve
- d) Third curve
4) Parts folded four times as shown in Figure 4-4.
- a) Flat pattern
- b) First curve
- c) Second curve
- d) Third curve
- e) Fourth curve
