Ultra thin injection molding technology of the hot

2022-08-07
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Ultra thin injection molding technology of UCP control system

ucp is a synonym for the injection molding technology applied to the production of ultra-thin wall plastic products by Korea Jinhe Machinery Co., Ltd. in recent years. It is a high-tech developed on the basis of traditional injection molding technology and other advanced technologies

the emergence of this new technology is in response to the ultra-thin development of today's electronic products, such as shell and battery panel plastic parts. The demand for producing small and light plastic parts of electronic products has made thin-wall injection molding the most important performance of injection molding machines. Of course, the current concept of "thin wall" is not that the wall thickness of plastic products is 1mm, but that it is less than 0.5mm or even less than 0.3mm. Due to the continuous reduction of wall thickness, the processing technology of thin-walled products needs to be changed: higher pressure and speed, shorter cooling time, so a more special injection molding machine with high-speed and high-pressure performance is required. Now people generally use the all electric injection molding machine with high-speed and high-pressure performance, which can produce plastic parts with a thickness of more than 0.4mm. Indeed, this kind of machine has its advantages, such as no leakage, low noise, high cleanliness, fast speed and so on. However, we also see that the gear belt drive and roller screw technology commonly used in all electric injection molding machines at present have restricted the development of all electric injection molding machines in some aspects due to the defects in the transmission performance of mechanical parts, the durability of ball screws, the unfavorable development of high clamping force tonnage models, and the high production cost, which are mainly reflected in the impact of mechanical transmission structure, wear, and creep in the production process, Transmission clearance and speed limit are insurmountable congenital defects. Generally, the thickness of plastic parts produced by electric injection molding machines is more than 0.4mm. However, many products, including electronic products, are becoming more and more ultra-thin. The thickness of plastic parts of general battery panels is required to be less than 0.3mm. These are impossible for electric injection molding machines. It forces us to consider developing more practical means of low-cost and high-tech to solve these problems

The injection molding technology of

ucp is developed on this basis. The precision injection molding machine manufactured by this technology is the second generation full hydraulic injection molding machine used for plastic products with high dimensional and shape accuracy and low surface roughness. The second generation full hydraulic injection molding machine using UCP technology is different from the conventional full hydraulic injection molding machine. It adopts the molding method under the conditions of high shooting speed, high shooting pressure, high material temperature and simple operation, so that the thickness of the molded product can reach 0.3mm or even thinner. The molding cycle is 1/3 shorter than that of the ordinary injection molding machine, saving 20% energy. It is a promising injection molding machine widely favored by the public

the main features of the thin-wall injection molding machine using UCP technology are introduced below, hoping to be helpful to readers

hydraulic control

this type of injection molding machine uses a synthetic proportional pump. The oil pump is the power mechanism in the hydraulic system. It is mainly used to carry out longitudinal load (tension) test on the produced bellows. Its function is to meet the energy requirements of the hydraulic actuator when driving the load. The pump forms include quantitative pump, variable displacement pump and proportional pump. We know that the curve of flow of variable displacement pump changing with pressure is difficult to realize curve change in theory, mainly because it is controlled by spring force, which changes according to linear law and has large variable impact. UCP technology adopts the world's advanced German proportional pump, which is a synthetic oil pump integrating oil pump and proportional valve. Because of its own proportional control, it can continuously and proportionally control the flow, pressure and direction of the hydraulic system according to the input electrical signal. Its output flow and pressure can not be affected by load changes, showing curve changes. It has small change impact, easy pressure control, convenient cooling, and omits many oil circuit valves, making the oil circuit simple and clean and avoiding pipeline leakage. Because of its rapid high-pressure injection, it has very high requirements for hydraulic components. First, the response of the controller. The response and opening characteristics of the hydraulic valve must be efficient. Jinhe machinery has made many tests and calculations on the selected hydraulic parts and their assembly. Now the repetition accuracy can be controlled within 0.02% and the instantaneous corresponding speed is 0.02 seconds

One of the most outstanding advantages of UCP technology is that it can make up for some hydraulic system functions that cannot be realized by electric injection molding machine. For example, most plastic molds do not use hot runner molds because of their fast updating speed. If non hot runner molds are used, the injection pressure maintaining function should be considered. Pressure maintaining is very important for gate products, because the material flow in the mold cavity can be better fused through pressure maintaining, so that the plastic entering the mold cavity can be fused into one, and the shrinkage of the plastic due to cooling can be supplemented, so as to obtain products with high density, small shrinkage, high accuracy and good mechanical properties. In addition, many current plastic part molds still need to have the function of ejection and core pulling, so the hydraulic parting and core pulling mechanism must exist. UCP has conducted repeated experiments on salt particle size, compounding mode and proportion, printing temperature, printing rate and other parameters. The technology is to develop the main characteristic functions of the electric injection molding machine from the hydraulic control system, while retaining some important functions that the electric injection molding machine does not have

injection device

during injection molding, it is very important to select the injection pressure and injection speed, which are related to plastic performance, plasticizing mode, plasticizing temperature, mold temperature, flow resistance, product shape and product accuracy

speed is one of the key factors for successful thin-wall injection molding. The shorter the injection time is, the higher the speed is required. We generally use the method of increasing the screw speed. Rapid mold filling and high pressure can inject molten thermoplastic material into the mold cavity at high speed, thus preventing cold solidification of the gate. If a standard part is filled within two seconds, the thickness will be reduced by 25%, and the filling time may be reduced by 50%, just one second. Therefore, it is necessary to design the screw and barrel that meet these conditions

generally, the injection volume of ordinary injection molding machines is 40%-70% of the barrel capacity. Considering that the total molding cycle of thin-walled products is greatly shortened, the UCP technology adopts an injection device that accurately controls the small injection volume in the injection system, so that the minimum injection volume is reduced to 20%-30% of the barrel capacity

in order to improve the injection pressure and speed, it uses a high-strength, high wear-resistant, thin and short special screw. The screw diameter is generally mm, which is smaller than that of similar models. It greatly shortens the residence time of the resin in the barrel and avoids the decomposition caused by the resin staying too long, so that the injection speed can be controlled at about 240mm/s and the pressure can reach about 3000kg/cm2. It is completely suitable for precision molding

for some special users, for example, to produce plastic products with a thickness of 0.25mm, energy accumulators can be used to replace electric energy to realize the high-pressure hydraulic system. Through the automatic energy storage and release during the forming process, high-pressure and high-speed can be achieved and energy consumption can be greatly reduced

clamping device

clamping force reflects the ability of injection molding machine to process products to a certain extent, but the author believes that it is not the main factor here. In fact, the clamping force has generally decreased in recent years. This is due to the use of UCP molding technology to improve the structural design of the injection screw to improve the plasticizing quality, to accurately control the injection volume, to improve the injection speed, and to implement program control. The clamping device is improved to improve the manufacturing accuracy of the die and screw. When the wall thickness decreases and the injection pressure increases, the high-speed five point mold locking structure adopted by UCP injection molding machine helps to reduce the bending deformation of the template. The ratio of pull rod to template thickness of injection molding machine for thin-wall products is 2:1 or less. The condition of realizing super wide and super large die thickness and relatively reducing clamping force is to ensure the parallelism error and position error accuracy of the template. Generally, UCP injection molding machines technically ensure that the template movement position error is within 1mm, and the template unevenness is controlled within 0.05m. Advanced high molecular materials enterprises account for 30% of the number of new materials enterprises

control system

the control system adopted by UCP is the PC system, which is the current development trend of the injection molding machine. Its operation screen is in Chinese and can display the whole process of injection molding. The graphical operation interface that makes the operator clear at a glance is simple and easy to use, and has become a prominent selling point of plastic machinery. It will greatly improve the use level of the machine and significantly shorten the training time of operators. This is its practical function. More importantly, we can use computer precision control to improve the control accuracy, so that the response time of the system can reach 0.1ms. The PID temperature control error is within ± 1 ℃. The effective control of temperature and pressure can make the shape and position tolerance accuracy of the product less than 5mm. When producing thin-walled parts, the closed-loop control of injection speed, pressure and other processing parameters is helpful to control mold filling and pressure maintaining under high pressure and high speed

from the above analysis, the performance of the full hydraulic injection molding machine adopting UCP technology is completely comparable to that of the electric injection molding machine, but its manufacturing cost is far lower than that of the electric injection molding machine. It is believed that as this technology is recognized and mastered by more and more people and continuously improved, it will be welcomed and adopted by more and more customers. UCP technology will open up a new field with broad development in injection molding machine manufacturing

ucp injection molding machine will surely write a new chapter in the field of injection molding machine

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