Problems and solutions that easily occur in the SMC molding process

The problems that are likely to occur in the SMC molding process are: blistering and internal bulging on the surface of the product; warpage and deformation of the product; cracks in the product after a period of time, and partial fiber exposure of the product. The reasons for the related phenomena and the disposal measures are as follows:

1. Foaming on the surface or bulging inside the product
The cause of this phenomenon may be that the content of moisture and volatile matter in the material is too high; the mold temperature is too high or too low; the pressure is insufficient and the holding time is too short; the heating of the material is uneven Evenly. The solution is to strictly control the volatile content in the material, appropriately adjust the mold temperature, and reasonably control the molding pressure and holding time. Improve the heating device so that the material is heated evenly.
2. Product deformation and warpage
This phenomenon may be caused by incomplete curing of FRP/SMC, low molding temperature and insufficient holding time; uneven thickness of the product, resulting in uneven shrinkage.
The solution is to strictly control the curing temperature and holding time; select the molded material with a small shrinkage rate; under the premise of meeting the requirements of the product, the structure of the product is appropriately changed to make the thickness of the product as uniform as possible or smooth transition.
3. Cracks
This phenomenon mostly occurs in products with inserts. The reason may be. The structure of the inserts in the product is unreasonable; the number of inserts is too much; the demoulding method is unreasonable, and the thickness of each part of the product is too different. The solution is to change the structure of the product under permitted conditions, and the insert must meet the requirements of molding; reasonably design the demoulding mechanism to ensure the average ejection force.
4. The product is under pressure, local lack of glue
The reason for this phenomenon may be insufficient pressure; excessive fluidity of the material and insufficient feeding amount; too high temperature, so that part of the molded material solidifies prematurely.
The solution is to strictly control the molding temperature, pressure and press timing; ensure sufficient materials and no shortage of materials.

5.  Product sticking mold
Sometimes the product sticks to the mold and is not easy to release, which seriously damages the appearance of the product. The reason may be that the internal release agent is missing in the material; the mold is not cleaned and the release agent is forgotten; the surface of the mold is damaged. The solution is to strictly control the quality of materials, carefully operate, and repair mold damage in time to achieve the required mold finish.
6. The waste edge of the product is too thick
The reason for this phenomenon may be unreasonable mold design; too much material added, etc. The solution is to carry out a reasonable mold design; strictly control the feeding amount.
7. The product size is unqualified
The reason for this phenomenon may be that the quality of the material does not meet the requirements; the feeding is not strict; the mold is worn; the mold design size is not accurate, etc. The solution is to strictly control the quality of the materials and accurately feed the materials. The size of the mold design must be accurate. Damaged molds must not be used.
The problems of products during the molding process are not limited to the above. In the production process, sum up experience, continuous improvement, and improve quality.