(1) Insufficient glue flow;

(2) The inner circuit board or the prepreg is contaminated;

(3) Improper suppression results in air, water vapor and pollutant accumulation;

(4) The inner line is poorly blackened or the surface is polluted during blackening;

(5) Excessive glue flow - almost all the glue content in the prepreg is extruded out of the plate;

(6) During the pressing process, due to insufficient heat, too short cycle, poor quality of the prepreg, and incorrect press function, the curing degree has problems;

(7) Under the demand of no function, the inner laminates should minimize the occurrence of large copper surfaces (because the adhesion of resin to copper surface is far lower than that of resin and resin);

(8) When vacuum pressing is used, the pressure is insufficient, which will damage the glue flow and adhesive force (the residual stress of the laminated plate pressed due to low pressure is also less).