1. First adjust the upper roll balance mechanism of the rolling machine so that the upper roll is in a horizontal position, and raise the two lower rolls to a certain degree
2. Feed the metal sheet between the upper and lower work rolls, and then stand the sheet centering mechanism. After operating the sheet material against the sheet, align the sheet centering mechanism to make the sheet The end is parallel to the work roll axis.
3. Raise the two lower rollers at the same height, clamp the sheet material, and pay attention to whether the sheet material is placed properly, otherwise adjust it.
4. After confirming that the sheet is placed correctly, continue to raise the two lower rollers to press the sheet alternately. The amount of boost is determined by the diameter of the drum and the proficiency of the operation.
5. The work roll rotates in both directions, causing the sheet to bend and deform.
6. Repeat the above steps 4 and 5 according to the diameter of the roll until it meets the requirements.
7. Lower the lower rollers to the lower limit position alternately.
8. The return side of the dumping side hydraulic cylinder, the inverted body is dumped, and the workpiece is unloaded.
9. The inverted body is reset, and the two lower rollers are raised alternately to complete the whole rolling process.
The process of bending the end pre-bent sheet into a cylindrical workpiece on a W11H series three-roll rolling machine.As shown in Figure 1
Figure 1 The reeling process of the pre-bent sheet at the end
1. First, according to steps 1 and 2 of the A.1 roll method, level the upper roll of the rolling machine to center the sheet.
2. Lift the lower roller to clamp the sheet with the upper spokes. The lower roller on the other side plays a supporting role. At this time, the three work rollers become an asymmetrical arrangement.
3. The work roll is rotated in both directions to make the sheet bend and deform. Then check with the template. In order to get a good pre-bend at the end of the sheet, the upper and lower rollers should clamp the edge of the sheet as much as possible. , You can also appropriately raise the lower roll at the pre-bent end of the sheet to increase the amount of pressure increase until one end of the sheet reaches the required bending radius.
4. Change the position of the lower roll and pre-bend the other end of the sheet in the same way. Step: Lower the lower rolls on the pre-bent forming side of the sheet, and raise the lower rolls on the pre-bent sheet side, alternately. And make sure that the lower and upper rollers have the same lifting amount to prevent the sheet from falling off, and then rotate the work roller in both directions, until the pre-bending of the other end is completed.
5. Using the method of alternately lifting the two lower rollers, adjust the two lower rollers to a symmetrical position with the upper rollers.
6. Operate according to steps 4-9 in A.1 roll method to complete the entire bending process.
The process of feeding the pre-bent end of the sheet once and rolling it into a cylindrical workpiece is shown in Figure 2:
Figure 2 — The process of rounding the ends of the secondary pre-bent sheet
The rolling process of conical workpieces is basically the same as the rolling process of cylindrical workpieces. For a specific operation, refer to the method described in A.2, but note the following points:
1. The ability to roll conical workpieces is 50%-60% of the ability to roll cylindrical workpieces, which can be approximately understood as the maximum thickness and width of rolled conical workpieces. Only the maximum thickness of rolled cylindrical workpieces is allowed. And 1/2 to 3/5 of the width.
2. The initial sheet of the conical workpiece is fan-shaped. When feeding the sheet, the small end of the fan must be close to the friction block in the conical workpiece device to reduce the speed of the small end.
3. When the fan-shaped sheet runs back and forth in the work roll, the roller pressing line should always coincide with the bus bar of the fan-shaped blank.
4. It is required that the taper of the rolled conical workpiece is generally less than 30 degrees, and the equipment should be specially designed when the taper is large.
After the sheet material is rolled into a cylindrical shape or a cone shape by the above three methods, it is then welded. However, it is necessary to perform the rounding according to the following three steps to achieve the ideal workpiece.
a. Loading: According to experience or calculation, adjust the roller to the position of the required maximum correction curvature.
b. Rounding: Roll the roller 1 ~ 2 times under the corrected curvature (to roll the weld zone) to make the curvature of the whole circle uniform.
c. Unloading: gradually remove the load, so that the workpiece can be rolled multiple times under the condition of gradually reducing load
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