Frame Manufacturing Processes
1、 Feed:
Most of the factories hook the head tube of the frame behind the wire tube reinforcement piece and other accessories, which are outsourced, because there is a factory that makes these small parts separately. Like the motorcycle industry in Chongqing, many small parts of the motorcycle frame factory are purchased from outside. The bicycle factory feeds pipes.
2、 Material preparation: (The premise of material preparation is that all drawing data shall prevail)
After the pipes come in, they shall be classified, placed and identified according to the length and diameter of each pipe required by the frame drawing
Material preparation generally refers to two departments, one in the front triangle and the other in the back triangle. Each department should take its own responsibility.
For example, the material preparation of the front triangle is used to process the pipe shape according to the drawing requirements (such as flattening and bending). If there is arc punching, it is weld crater processing. This process is more important and technical. Because it involves mold debugging, it is impossible for ordinary employees to do this work. It is all done by professional technicians. In addition, the quality of the weld junction directly affects the quality of the welding process. There is also butt welding. Look at the wire tube on the frame we ride. It is also completed during the material preparation process. After the butt welding, the oxygen welding group will strengthen the wire tube through oxygen welding (including the nut of the kettle). Wire conduits are also welded. The same is true for the rear triangle. During these work processes, inspectors will inspect each process.
3、 Front triangle assembly
The front triangle assembly is equipped with a special assembly platform, which can be adjusted at will according to the shape of the frame. After the assembly mold is debugged, a sample will be spot welded. First, the angle and data will be compared according to the drawings, and then the center line will be tested on the platform. If the deviation is not within the tolerance range, the assembly mold will be adjusted until the standard. Some factories will inspect the front triangle of each assembly to reduce the occurrence of defective products. (If defective products are found after welding, the entire front triangle will be basically scrapped)
4、 Front triangle welding
After the front triangle is assembled, the front triangle is welded. Generally, 5-6 people are used as an assembly line, and each welding process is of the same level. If one of the welders is out of order, products will accumulate and the flow process will not be smooth.
After the front triangle is welded, the inspector will inspect its welding quality, such as what the weld bead is not smooth, missing welding, false welding, etc.
5、 After the inspection, the front triangle is corrected.
Speaking separately, I think that correction is an important link
On the alignment platform, the frame alignment is based on the five way joint (including the alignment of the whole frame), and the center line of the five way joint is the center line. It is required that the whole frame, regardless of the rear fork gear of the upper tube, the lower tube and the middle tube, should be on the same center line on a parallel basis. It is troublesome to correct the rear fork, including tire alignment (symmetry of the rear upper and lower forks on the centerline) and correction of the opening and verticality of the rear fork hook.
If the tire misalignment is not corrected properly, it may occur when we assemble the vehicle: if the centerline of our wheel set is OK, the centerline of the rear fork shift is OK. After installing the wheel set, we find that the distance from the tire edge to the left and right of the rear upper and lower forks is different. If it is a V brake, we can feel that the V brake is completely biased to one side. If such a situation occurs, it is mostly a correction problem of tire misalignment.
If the center line of the rear fork is not corrected properly (the symmetry of the left and right rear forks on the center line), the installed rear wheels and front wheels are completely not on the same center line.
If the rear fork opening gear and tire alignment are corrected, but the perpendicularity of the bottom of the fork hook is not corrected, it will occur: when the wheel set is completely standard, after the wheel set is installed, the tires are at the center of the rear upper and lower forks, and one end of the hub of the flower drum will not fully contact the bottom of the rear fork hook. If the hub of the flower drum is completely in contact with the bottom of the rear fork hook, Then the tire will deviate from the center line of the rear upper and lower forks (this problem is also obvious for the V brake). This is the impact of frame alignment on the frame.
6、 After the front triangle is corrected, the rear triangle is assembled. This process is similar to that of the front triangle, except that there is an additional front triangle. The welder feels a little heavy when taking the frame, hehe. After the whole frame is welded, it is necessary to calibrate the whole frame (saving has been mentioned previously).
7、 After the whole frame is welded, the brake seat is spot welded (there is no such process for the disc brake). Why should the brake seat be processed in this process? Because the brake seat is welded when the symmetry of the rear upper fork of the frame is not corrected, and there is no way to operate when the rear brake seat is corrected.
8、 After the brake seat is welded and calibrated, it is necessary to make the reamed hole of the middle pipe of the frame. Because the inner wall of the frame pipe itself has burrs, plus the heating deformation and penetration welding during the welding process, our seat pipe cannot be installed. Therefore, it is necessary to use a reamer to clean the inner diameter of the middle pipe (the size of the reamer varies with the diameter of the middle pipe).
