Conformal cooling injection mold based on 3D printing
作者:
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日期:
2016-04-01
人气:
8486
【字体:
T
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Injection molding, the life of plastic products can make a complex shape and intricate details, in maintaining the stability of the tolerance range and keep under the surface of the high quality products, to achieve mass production.
For mold manufacturers, since the quality of the mold directly decides the efficiency of injection molding production and decided to product quality, so as to determine the added value of the products. Therefore, how to in the minimum cycle time, cooling of plastic products, become with the consideration of the key in design and manufacturing of the mold with conformal cooling, and the cooling in the meantime plays an important role.
One, with the shape of the control of the cooling off the traditional way
The principle of conformal cooling is to quickly reduce the temperature of the plastic parts in a uniform and continuous manner. The injection part can not be taken out of the mold during the cooling process, until the cooling is sufficient, and then, the injection molded part is removed from the mold. Any hot spot can delay the injection cycle of the injection molding parts, which may lead to warp and sag of the injection molded parts, and may damage the quality of the surface of the plastic parts.
Rapid cooling is the passage through the coolant in the mold, the injection of heat away, the speed and uniformity of the cooling effect is determined by the fluid channel and the cooling fluid through its speed.
The traditional mold cooling channel is achieved through the two processing. Through the cross drilled, resulting in the straight line of the internal network, through the built-in fluid plug to adjust the flow velocity and direction, this method has its limitations, the shape of the waterway network is limited, so cooling channel from the mold surface far, the cooling efficiency low. Not only that, but also had to face the additional processing and assembly time, as well as the blind spot of the channel network may be blocked risk. And in complex situations, to set aside the cooling channel processing, dies also need be split into several parts to be manufactured and then spliced into a whole die, which leads to the additional manufacturing sectors, and will shorten the mould life.
The difference between the cooling mode and the traditional cooling method is that the shape of the cooling water channel changes with the shape of the injection products, and is no longer in a straight line, as shown in figure 1. The cooling water channel can solve the problem that the distance between the traditional cooling water channel and the mold cavity surface is not consistent, so that the injection products can be evenly cooled, and the cooling efficiency is higher.
Two, 3D print manufacturing
3D printing made people get rid of the restrictions of cross drilling. Now, you can design internal channel closer to the cooling surface of the die, and have a smooth corner, the faster the flow and increase the heat transfer to the efficiency of the cooling liquid; also can design different cooling circuit according to the requirements of the cooling to at a rate consistent with the heat dissipation, so as to promote the heat radiation uniformity. Coolant through the amount of the cooling rate of the mold is very important. A smooth corner must be designed to reduce the pressure loss along the channel.
Printing technology of metal powder in selective melting of 3D, also can produce a cooling passage in a small diameter of 1.4 mm. Shop manufacturing technology of powder of 3D printing a useful advantage is, powder melting brought about a slight surface texture, the texture structure increases the surface area of contact cooling, bring better heat transfer effect, so as to enhance the cooling efficiency, and the formation of small turbulent flow in the channel, so as to realize the channel self-cleaning effect.
Three, 3D printing on the added value of injection molding products
The injection mold with the shape of the 3D printing and manufacturing, can achieve up to 70% of the injection mold processing efficiency. In the example shown in Figure 2, an ice scraper of the mold, through the increasing material manufacturing methods to process, so that the injection time from 80 seconds to 40 seconds, which means that the production rate of injection parts into the original two times.
Figure 2: ice scraper with the shape of the cooling mold
By increasing material manufacturing to manufacturing with the other major advantage of the mold with conformal cooling includes: forming more uniform plastic product, make zero defect products, and avoid caused due to uneven cooling speed of sinking traces can be. In addition, in the development of new injection molding products, help to achieve through fewer iterations to complete the development of products. Of course, more advantages are also included in the manufacture of complex molds, due to the reduction of the cooling channel processing and splicing links, increasing material manufacturing method faster than the traditional way.
It should be noted that the surface of the mold is not high, it is necessary to obtain the required surface accuracy by finishing and polishing. In this aspect, the traditional machining and enhancement material manufacturing advantages to form a complementary.