The mold is the main equipment for forming FRP products. According to the material, the mold can be divided into steel, aluminum, cement, rubber, paraffin, FRP and other types. Glass fiber reinforced plastic molds have become the most commonly used molds for hand lay-up glass fiber reinforced plastics due to their characteristics of easy molding, easy availability of raw materials, low cost, short manufacturing cycle and easy maintenance.
The surface requirements of FRP molds and other plastic molds are the same, usually the surface of the mold is one grade higher than the surface finish of the product. The better the mold surface, the shorter the molding time and post-processing time of the product, and the better the surface quality of the product, the longer the service life of the mold. After the mold is delivered for use, in order to maintain the surface quality of the mold, the mold must be well maintained. The maintenance of the mold includes: cleaning the surface of the mold, cleaning the mold, repairing the damaged parts, and polishing the mold. The timely and effective maintenance of the mold is the final starting point of the mold maintenance. In addition, the correct maintenance method of the mold is the key. The following table shows the different maintenance methods and corresponding maintenance results.
Different maintenance methods for different molds are as follows
① New molds or molds that have not been used for a long time
First, clean and inspect the surface of the mold, and perform necessary repairs on the damaged mold and unreasonable structure. Secondly, use a solvent to clean the surface of the mold. After drying, polish the surface of the mold one or two times with a polishing machine and polishing paste. Finish waxing and polishing three times in a row, then wax again, and polish again before use.
②Mould in use
First of all, ensure that the mold is waxed and polished every three times, and the vulnerable and difficult to demold parts should be waxed and polished before each use. Secondly, a layer of foreign objects (probably polyphenylene or wax) that is prone to appear on the surface of the mold for a long time must be cleaned in time. The cleaning method is: use cotton cloth items dipped in acetone or special mold cleaner to scrub (the thick part can be used Scrape off gently), and the part after scrubbing will be demoulded according to the new mold.
③ In the broken mold
For molds that cannot be repaired in time, you can use wax blocks and other materials that are easily deformed and do not affect the solidification of the gel coat to fill and protect the damaged parts of the mold and continue to use. For those that can be repaired in time, the damaged area must be repaired first. The repaired area should be cured by at least 4 people (at 25℃). The repaired area must be polished and demoulded before being put into use.
The normal and correct maintenance of the mold surface determines the service life of the mold, the stability of the product surface quality, and the stability of production, so there must be a good habit of mold maintenance.
In short, by improving materials and processes and improving the surface quality of the mold, the surface quality of hand lay-up products will be significantly improved.