Vacuum compound molding technology
Vacuum compound molding technology is generally used in the plastics industry. It is used more in the automotive industry. It is commonly used in the molding process of various car door interior panels, door interior panel inserts, armrests, ceiling guards, etc.
Vacuum compound molding technology is generally used in the plastic industry, and it is used more in the automotive industry. It is commonly used in the molding process of various car door interior panels, door interior panel inserts, armrests, ceiling guards and other components. The shape of the molding surface is complex, and the molding method of mold adsorption is mostly used.
The main process is described as follows: the plastic part to be formed is clamped on the mold, and the surface is coated with bonding glue; the heated coating material is placed on the part, and the periphery is sealed with the mold joint. Under the action of the vacuum pump, the coating It is a molding technology that is evacuated to the molding die, so that the coating material is completely attached to the surface of the part to be molded in a vacuum state, and is firmly bonded to each other after cooling.
In the automotive industry, most of the parts using the vacuum composite molding process are made of ABS, because the surface of this material can be vacuum composited without polarity treatment; there are also PP parts, but the surface of the part needs to be polarized. Most of the treatment methods are flame treatment, or special adhesive for PP bonding, but the price of this type of adhesive is generally more expensive. From the perspective of cost, the price of PP is cheaper than ABS. However, one is that flame treatment is required to increase the complexity of the molding process; the other is that the glue used for bonding PP materials is more expensive, so most of them are selected. ABS.
The adhesive used in compounding is generally divided into two parts, one is the glue used for bonding, and the other is the curing agent used to cure the bonding strength between the coating and the plastic after the glue is sprayed, and the glue and curing agent are used Different colors are distinguished.
Glue can be sprayed evenly on the surface of the parts to be bonded by manual spraying. The quality of spraying should be controlled according to the composite process requirements and the instructions for use of the glue; after spraying, wait for the volatilization of the glue solvent and apply it before bonding. Perform activation processing. Generally, the glue that is not activated is not sticky, or the bonding strength does not meet the requirements of use. Activation is a simple treatment for the adhesive force of glue. Only at a certain temperature, the activity of the glue is the strongest. After bonding, a chain reaction between the coating and the substrate can occur, thereby increasing the bonding strength. .
The cladding material is mostly PVC, the thickness ranges from 0.8mm to 3.0mm, and the color is produced according to customer needs. There are also manufacturers that use other cladding materials, depending on customer requirements.
The material of the vacuum forming mold is generally made of aluminum, because aluminum is easy to process and modify, and it is light. A single composite mold has only one forming mold with a clamping frame around the structure; complex shapes are generally divided into three parts: the bottom mold is the forming mold, the upper mold is the auxiliary forming mold, and a cutter mold is attached after forming. Separate the molded part from the coating. This structure is basically unique to the automatic vacuum forming machine.
In order to save costs, many companies have changed the simpler vacuum forming process to pressure compounding. The process verification results also meet the product requirements, but the manual operation process is added, and the product qualification rate can generally be controlled above 90%. The product qualification rate of vacuum automatic forming technology, if done well, can reach more than 98%. The equipment selected for pressure forming is generally a four-column hydraulic press, and some use a cylinder structure for pressure compounding. No matter how you choose, as long as it is suitable for your company, it is the most wise to choose a product process that can meet the design and use requirements.