This plastic mold for the bottom of water tank is the most simple one among those hundreds of complicate tanks we have ever made. As the same with other water tank, the key technology is to control the part flatness without any deform and assembly holes must be aligned perfectly. If there is any warp, the two parts could not be vibrated-welding together and water leaks. In order to solve the issue, firstly we have to run mold flow to do a pre-warp analysis so that the warp degree could be calculated and gate position decided. Mold flow is only an assistant tool in theory. Sometimes, mold flow result differs greatly with actual result. According to our years of experience in making water tank injection molds, we know where to put the gate and what size to better control the even flow of the plastic based on the reading of Mold Flow. Secondly, water line is very important. It is better to have as much cooling as possible and independent water lines for the cavity and core. It is easy to adjust the warp by changing the hot or cool water at trial stage. The mold is edge gated on the middle of the part. For the angel screwing hole, we use two slides on both sides to release the screw followed by a big angle slide to release the main hole. And there is a straight slide on cavity as well. The plastic is as thick as around 4mm and the whole part is quite strong. You won’t see sink on the part because the area where there are ribs under is designed as recessing grooves.