1. Using Effective Die Repair to Improve Product Flatness
Die repair is the most commonly used method domestically and internationally for addressing poor flatness in extruded materials. The advantage of this method is its wide applicability, as almost all extruded materials can use this treatment. However, its drawback is that production must be stopped, and after the die is treated, it must be reinstalled for trial extrusion, which is time-consuming and labor-intensive, and is also not conducive to energy saving and consumption reduction. Poor flatness in this type of sheet is mainly related to uneven flow rates in the die. By changing the size or angle of the flow guide pits, or by adjusting the length of the working zone, the metal flow rate can be effectively regulated to ensure uniform flow and eliminate flatness defects. This method is generally used at the initial stage of production for such sheets. Some dies can solve the flatness issue with one repair, while others may require three or more repairs to fully resolve the flatness problem. This is not only related to the die itself but also significantly associated with the skill level of the die repair workers.
2. Using offline finishing to correct the flatness of products
First, based on the specific flatness deviation characteristics of the board, reasonably configure the rollers of the offline finishing machine. Then, use a product with flatness deviation to set the rollers. By continuously adjusting the height and position of the rollers, once the flatness of this product meets the standard, fix the height and position of the rollers, and then carry out offline finishing for the batch of products. Offline finishing is generally time-consuming and labor-intensive, and it may also have some impact on the appearance of the products. Figure 3 shows an example of offline finishing for this board. The flatness condition of the board is convex on the top and concave on the bottom, with a flatness deviation. Using the roller configuration shown in the figure, as the product passes through the rollers, the middle and edges of the product are subjected to certain pressure from the rollers, which helps correct the flatness gap of the product.
3. Using Online Finishing to Correct Product Flatness
Considering that the quantity of this order is relatively large, using offline finishing would greatly reduce production efficiency and waste a lot of manpower. After a period of discussion and exploration, combined with the principles of offline finishing, the concept of online finishing was proposed, and it was decided to create a small online finishing device. If successful, it would neither affect production efficiency nor consume much manpower. The schematic diagram of the online finishing device designed for this sheet material is based on the principles of offline finishing. On the basis of the original straightening device at the extruder outlet, bearing seats and rollers are added. By adjusting the height and position of the rollers, the pressure on the product can be changed to cause a certain degree of deformation, keeping the flatness of the product within a reasonable range, thus achieving the purpose of online finishing.
