Views:8 Author:Site Editor Publish Time: 2019-06-03 Origin:Site
The quality problem of laminated board is a comprehensive reflection of the quality problems of the resin, sizing and pressing processes. Although pressing is the last critical process in the manufacture of laminated board, the quality of the semi-finished products produced in the previous process will have a direct impact on the quality of the laminate. Therefore, the quality problems of the laminated board must be thoroughly analyzed in order to find the exact cause, and timely effective measures can be taken to improve the quality of the laminate.
(1) Surface burrs.This phenomenon often occurs in flakes, mainly viscous paper cloth, especially the surface material contains a small amount of glue, the content of soluble resin is low, and the fluidity of the resin is poor. Secondly, the pressure during the pressing process is not uniform. In some cases, the warm-up time is too long and the pressure is low. Therefore, in the preparation of the sheet, special attention should be paid to the fact that the content of the soluble resin of the adhesive tape is not low, and a good surface material is used, and it is preferable to press the thin plate and the thick plate together to increase the elasticity thereof.
(2) Surface unevenness and defects ,which often occur in rubber paper with high resin content and low solubility. Since the fluidity of the resin is small, the uneven glue caused by the glue is easily reflected on the surface of the laminate. It is uneven and flawed. Therefore, it is necessary to pay attention to the uniform control of the amount of glue during sizing. When preparing the material, it is important to adjust the reverse of the material to 180° to compensate for the uneven amount of glue caused by the sizing, thereby improving the surface condition.
(3) The cracking phenomenon of the laminate ,which mainly occurs in thick paper and cloth sheets, and in severe cases, cracks are generated in the laminate of 5 mm or more. The epoxy phenolic glass cloth sheet is not easily broken because of the strong adhesion of the glue. The cracking of the laminate has a great relationship with the resin adhesion. When the aged material is sandwiched between the laminates, the laminate must be broken. Therefore, the choice of the binder paper should be carried out, the aging material should be selected, and it should not be mixed into the billet. . In addition, the amount of the tape is too small and uneven, the pressure is too low or the pressure is too slow, and cracking easily occurs.
(4) The color of the middle part of the surface is dark and the periphery is white. This is mainly because the volatile material of the tape is large. When preheating, volatile substances easily escape, and the volatile substances in the middle are large, the periphery is white, and the intermediate color is deep. This test demonstrates that low molecular weight has a greater impact than water. It has been shown that the volatiles of the tape do not produce a white edge of less than 4%, and preheating of 6% or less does not produce white edges or few white edges, with white edges exceeding 6%. Big.
(5) Surface cracking.This is mainly because the resin is pressed too fast during the flow and the substrate is crushed. Therefore, when applying glue, the number and pressure of the tape should not be too high. The epoxy phenolic glass cloth plate unit pressure exceeding 7 MPa (70 kgf / cm & sup 2;) will damage the glass cloth.
(6) The thickness deviation of the laminate is large. The thickness deviation is usually thinner in the middle of the edge, which is mainly caused by the unevenness of the edge of the steel sheet. Therefore, the steel plate should be kept in a safe place and should be used after the edges are found flattened.
The above points are about the quality analysis and solution of the laminate board. In addition to laminate board, these problems are also present in other panels,such
as film faced Plywood ,fancy board ,and can also be applied to their solution to this problem.