What are the common problems encountered in the process of profile bending? 

Common Problems and Solutions in Profile Bending Engineering 

I. Overview 

Profile bending is a common metalworking process widely used in construction, automotive, aerospace, shipbuilding, and other fields. However, during profile bending engineering, some problems often arise. If these problems are not solved in time, they will affect product quality and production efficiency. This article will discuss in detail the common problems in profile bending engineering and their solutions. 

II. Common Problems 

1. Deviation in Profile Curvature 

Problem Description: Profile curvature refers to the degree of fit between the profile's shape after bending and the design drawing or inspection mold. If there is a deviation in profile curvature, it will affect the appearance and performance of the product. 

Cause Analysis: 

- Variation in springback of bending mold; 

- Inconsistent material properties of metallurgical extruded profiles in each batch, with local hardness variations in each piece; 

- Large changes in bending curvature radius; 

- Uneven cross-sectional area of the profile blank. 

Solutions: 

- Adjust the contour curvature of the mold by calculating the springback theoretically and correcting the mold through stretching tests. 

- Add cylinders perpendicular to the mold direction at the front end of the mold to ensure that the profile to be bent fits snugly against the mold, avoiding gaps between the bending mold and the profile being bent. 

2. Surface Defects 

Problem Description: Surface defects include cracks, shrinkage wrinkles, concave surfaces on the bend surface, and vertical marks on the side of the profile after bending. 

Cause Analysis: 

- Excessive stretching force causing cracks on the profile surface; 

- Insufficient edge finishing leading to shrinkage wrinkles; 

- Cavity profiles not filled with fillers before bending, resulting in concave surfaces on the bend surface. 

Solutions: 

- For crack issues, adjust the stretching force to solve them; 

- For shrinkage wrinkle issues, improve the profile's cross-sectional area or increase the pulling force to solve them; 

- For concave surface issues on the bend surface, fill cavity bends with fillers before bending, such as using stacked spring steel plates or adding polytetrafluoroethylene filler, or use sand filling methods. 

3. Twisting After Bending 

Problem Description: After bending, the profile exhibits twisting, affecting product appearance and performance. 

Cause Analysis: 

- Asymmetry in profile cross-sectional area; 

- Imbalance in stress between edge finishing and edge release. 

Solutions: 

- Appropriately increase stretching force during pre-stretching; 

- Add vertical push cylinders in front of the bending mold and maintain pressure for a while after bending. 

4. Verticality Deviation Beyond Tolerance Limits 

Problem Description: Verticality refers to the angle deviation between the profile's cross-sectional area perpendicular to the benchmark (perpendicular to each curvature radius of the mold) after bending and the inspection platform. If verticality exceeds tolerance limits, it will affect product performance. 

Cause Analysis: 

- Asymmetry in cross-sectional area; 

- Imbalance in stress between edge finishing and edge release. 

Solutions: 

- Improve by adjusting the curvature change of the bending mold; 

- Depending on post-correction needs, overstretch slightly, while minor deformations caused by unstable extruded profiles need to be corrected later. 

5. Profile Process Length 

Problem Description: Profile bending process length refers to the excess material length beyond the actual part length, including process lengths required for bending molds, fixtures, and equipment. If the process length is unreasonable, it will affect production efficiency and material utilization. 

Cause Analysis: 

- Inaccurate calculation of process length; 

- Poor consideration of device chuck clamping parts and device chuck extending mold rotation clearance. 

Solutions: 

- Accurately calculate the raw material length for profile bending, including part length, mold curvature extension parts, device chuck clamping parts, and device chuck extending mold rotation clearance components;  

- Add protective devices in front of the profile operation table during production, formulate corresponding rules and regulations, and train comprehensive technical operators.  

 6. Safety Production Issues  

 Problem Description: Safety issues are one of the most critical concerns in industrial production processes. During profile bending, sudden breakage may occur due to accidental factors, causing outward rebound and damaging equipment and causing personal injury.  

 Cause Analysis:  

 - Improper operation;  

 - Equipment failure;  

 - Material quality issues.  

 Solutions:  

 - Establish strict safety operation procedures;  

 - Regular maintenance and inspection of equipment;  

 - Provide safety training for operators;  

 - Add protective devices in front of the operation table to ensure safety during production.