Anchor Bolt Roll-Forming Defect Relocation
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Solution Overview
Problem
Current expansion anchor manufacturing methods lack efficiency in producing high-quality anchors with minimal surface defects and effective diameter expansion, often resulting in defects being located at the anchor's end, which can affect loading and setting processes.
Innovation Solution
A method involving roll-forming a rod-shaped workpiece using wedge-shaped tools to create tapered and conical portions, with optional use of a flat-shaped tool to generate voids and reshape the workpiece, allowing for increased diameter and surface quality while relocating defects to non-critical areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional rolling methods are used to increase anchor diameter, then manufacturing efficiency is improved, but surface defects occur at critical load-bearing areas
Solution Approach 1:
The rolling process is divided into multiple sequential stages: initial rolling to create tapered portions, followed by a second rolling pass to create conical portions. This segmentation allows surface defects from the first pass to be relocated to non-critical areas while the final surface is formed in the second pass, ensuring load-bearing areas have high surface quality.
Solution Approach 2:
Surface defects that naturally occur during the rolling process are strategically relocated by the forming geometry to the anchor's end portion, which is explicitly identified as non-load-bearing. This converts the harmful effect of surface defects into a beneficial outcome where defects exist but do not compromise structural integrity or installation performance.
2Shape
If aggressive rolling is used to achieve sufficient diameter expansion, then anchor performance is improved, but surface defects are generated
Solution Approach 1:
Different regions of the anchor are given different quality requirements: the conical and tapered portions have smooth surfaces suitable for load-bearing, while the end portion accepts surface defects. The rolling process is designed to deliver appropriate surface quality to each region based on its functional requirements.
Solution Approach 2:
The problem is solved by adding the dimensional aspect of defect location to the analysis. Instead of merely reducing defect quantity, the process redistributes defects along the anchor's length, placing them in the end portion dimension while maintaining surface quality in the load-bearing conical and tapered regions.
3Manufacturing precision
If defects are located at the anchor end, then non-critical area quality is maintained, but diameter expansion may be insufficient
Solution Approach 1:
The preliminary rolling pass creates the tapered portions and intentionally generates surface defects in areas that will become the anchor end. This preliminary action prepares the material distribution and defect pattern before the final rolling pass creates the smooth conical portions, ensuring both adequate diameter expansion and proper defect location.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively rolls-shapes anchors with increased diameter and improved surface quality, relocating defects to non-load bearing areas, enhancing the anchor's performance and reliability during installation.
Implementation Method 1
material of the workpiece is displaced by the wedge-shaped tools towards the plane
Implementation Method 2
The material of the non-circular shape is subdue to large stress and will relax by forming a void along the axis
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The inventive method of forming anchor bolts comprises following steps. A rod-shaped workpiece (26) is roll-formed by penetrating the rod-shaped workpiece (26) with two wedge-shaped tools (34,35) at two points (46,47). The two points (46,47) are arranged on opposite sides and axially separated of a plane (33) perpendicular to an axis of the rod-shaped workpiece (26). The two wedge-shaped tools (34,35) are axially approaching to the plane (33) while the rod-shaped workpiece (26) is revolved around the axis (38). The roll-formed workpiece (26) is separated along the plane (33) for forming two bolts. A sleeve is applied around the anchor bolts.