Why is the problem of demolding difficult?
1) There are grooves in the mold;
2) Insufficient demoulding slope;
3) The mold finish is not high.
Failures caused by insufficient drafting slope are very common. When designing products, the drafting slope must be marked on the drawing. The drafting slope is usually in the range of 1 to 2 degrees. It is better to be as large as possible, and it is also allowed to be more than 0.5 degrees in special occasions.
If the injection pressure is too high, the product is too close to the mold, and demolding becomes difficult. In order to smoothly release the product from the mold, generalists use a release agent containing silicone oil, but when using the release agent, only a very thin layer can be applied. If the spray is too thick, it is difficult to wipe off. In addition, due to the action of the release agent, the secondary processing such as printing marks on the product becomes very bad. Once the release agent coated on the mold is attached to the product, it is quite difficult to wipe it off.
Based on the above root cause, come up with a solution:
1. Immediately: reduce the injection pressure, shorten the pressure holding time, reduce the mold temperature, reduce the demolding speed, spray the mold release agent
2. Short term: Improve the finish of the mold cavity
3. Long-term: increase the demoulding slope and increase the number of demolding pins
For heavy and hard materials, such as GPPS, it is common for products to break due to insufficient lift off. For both sticky and soft materials, such as PE, it is possible to cut off the product in several pieces. The PVC drain pipe is mainly used for water supply, and the diameter of the drain pipe is generally 50-75-110-160 and so on.
The PVC drainage pipe is made of sanitary polyvinyl chloride (PVC) resin as the main raw material, adding an appropriate amount of stabilizers, lubricants, fillers, color enhancers, etc., through extrusion molding by plastic extruder and injection molding by injection molding machine. Curing, shaping, inspection, packaging and other processes to complete the production of pipes and fittings.
PVC drainage pipe is an alternative to traditional drainage pipes and has better physical and chemical properties. It has a smooth inner wall and lower frictional resistance than conventional drainage materials, so the installation slope of the transverse pipe is smaller, which can improve the indoor clear height of the building. At the same time, the PVC drainage pipe is light in weight, one-fifth of the cast iron pipe, easy to transport and operate; it adopts adhesive connection, which is convenient for installation and maintenance; the price is lower than that of conventional drainage pipes, which greatly reduces the project cost; strong corrosion resistance, It is widely used in construction sewage and rainwater pipeline systems. In addition, the widespread use of PVC drainage pipes is conducive to saving steel, which is of great significance for alleviating the shortage of steel in our country.