The basic process of SMC molding procedure is to put a certain amount of preprocessed molding compound to the die, put high pressure on the compound and make it fill in the die cavity. Under predetermined temperature, molding compound will solidify in the die cavity, and the SMC product can be taken out from the die, and one can get the final product with necessary auxiliary processing. The specific steps are as follows:
1. Cutting
The shape and size of the sheet are determined by the structural shape of the product, feeding position, flow path, and then one can make the sample cutting material. The shape of the sheet is usually square or round; the size is about 40%-80% of the projected area of the product surface. In order to prevent the contamination from impurities outside, the upper and lower film of the sheet molding compound is torn off before feeding.
2. Weighing
Confirm the feeding amount
3. Cleaning the molds
The molds need to be thoroughly cleaned before pressing and painted with mold release agent; the mold release agent should be wiped evenly with clean gauze before feeding to avoid affecting the appearance quality of the product; the new molds need to be degreased before being used
4. Placing material
The position and method of the SMC material will directly affect the appearance, strength and directional property of the product. Under normal conditions, the position of the material is in the middle of the die cavity. For asymmetric complicated products, the feeding position should guarantee that the material flows reach the ends of each die cavity. The material placing method should be beneficial for venting. When multi-layer of sheets overlap, it is better to place the material like a pagoda with the bottom bigger than the upper. In addition, it would be better if the material blocks are placed on the die simultaneously, or there will be internal porosity and welding areas, which will result in a reduction in strength.
5. Pressing
The press machine will go down fast when the material blocks enter the die cavity. When the upper and lower molds fit with each other, the needed molding pressure should be put slowly. After the material is solidified, the molding of the product is completed. During the molding process, one should select the various molding process parameters and press operating conditions reasonably.
6. Demolding
The setting time (or holding time) of SMC under molding temperature is related to its properties and curing system, molding temperature, the thickness of the product colors and so on.
7. Taking out the formed product
8. Checking
Check whether the product has any flaws and whether it's qualified.
9. Processing: secondary processing
10. Finished products
PHP is specialized in making SMC hydraulic press and we have become the supplier of many clients home and abroad. If you have any questions, please reach us at cindy@wuxipd.com or call us at +86 0510 83394311.
Publication Date: 13 May, 2020
Category: Compression Molding Process
