seamless transparent acrylic PMMA nail art injection molding solution
PMMA is commonly known as plexiglass and acrylic. The chemical name is polymethyl methacrylate. Because PMMA has high transparency (light transmittance of more than 92%) and is not fragile, it is often used as a plastic material to replace glass products. Because the material is easy to color, it can also be injection molded into transparent handicrafts with various colors and exquisite colors. Traceless transparent acrylic PMMA nail art is a typical application case
However, due to the characteristics of high melt viscosity and fast cooling rate of acrylic materials, injection molded products are prone to internal stress cracking, thick glue level shrinkage, bubbles, bonding line depth, deformation, surface finish and transparency decline, which affect the appearance requirements and structure. Various defects. As a result, injection molding is difficult, long cycle and high cost, which is difficult to meet customer requirements.
S-TECH IV series acrylic nail art special injection molding machine is specially designed and manufactured for the application process of this product.
clamping force can be 110 tons, 140 tons, injection quantity can be 58 grams, 88 grams, 113 grams, injection speed can be 300 mm/s (ordinary ABS nail piece), 400 mm/s (pressure 3000bar, acrylic PMMA nail piece special), 1000 mm/s (special ultra-thin nail piece)
Special Injection Molding Machine:
- 1. PMMA nail tablets have high appearance requirements, and cannot have shrinkage, weld marks and flow marks. Only when the transparency is high can they be called traceless. The special injection molding machine for Echos acrylic nail art adopts V-shaped plasticizing components. Each raw material is uniformly plasticized through the screw in the whole process. The special acrylic optical screw for vehicle lamp grade is adopted. The plasticizing process is different from that of ordinary injection molding machines. When ordinary injection molding machines are plasticized, the screw retreats while melting glue, different melts pass through different screw plasticization shear length is different, can not get completely molten melt and the same quality, the use of special optical screw, no black spots, no high temperature overheating shear, to avoid the material overheating brittle and lack of transparency problems. The screw does not undertake the high-pressure injection molding function, the design of the screw groove is more free, and the screw groove can be designed to be more composite transparent sheet with high-performance plasticizing effect.
- 2. Due to the high viscosity and cooling rate of acrylic itself, multi-cavity thin-wall injection molding requires higher acceleration to ensure the filling balance of each cavity and fill each cavity at the same time. Ordinary injection molding machines adopt screw injection molding, with small screw diameter, small effective root diameter after opening the screw groove, unable to withstand high pressure, unable to enlarge injection thrust, large inertia of injection parts and low starting acceleration, therefore, the response of injection molding start-up is low and it is extremely difficult to control the process stability. The special injection molding machine for Akos acrylic nail art adopts horizontal bar plunger injection, and the starting pressure can reach 4000bar, which is more than twice that of the traditional injection molding machine. In addition, the moving parts are light in weight and the motion inertia is only 1/5 of the traditional injection molding scheme, which is one tenth of the all-electric injection molding scheme. The comprehensive acceleration performance of the special injection molding machine for Akos nail art is more than ten times that of the traditional injection molding scheme, which can fully ensure the balance of the runner and truly achieve high-speed filling, it is easier to form thin-walled products, and the internal stress is smaller, so as to obtain acrylic nail pieces with better toughness.
- 3. Acrylic nail products are small and thin in weight. To complete precision injection molding control, it is a great challenge to the traditional screw injection molding structure itself, because the traditional screw injection molding works between the two functions of plasticization and injection molding, and requires a rubber ring (also called anti-reverse ring). When melting glue, the rubber ring is passed forward, which is convenient for plasticized melt to enter the front end of the screw through the rubber ring, during injection molding, the first movement stroke of the screw is used to make the rubber ring lean against the front end surface of the screw to complete the sealing glue, prevent the melt from backflowing, and establish a pressure to inject the melt into the mold cavity at high pressure. During injection molding, a stroke of 2-5mm needs to be lost to complete the sealing glue, and then controllable filling. Due to the differences in mechanical accuracy, mechanical wear, melt viscosity, friction force, and glue injection speed, the actual sealing stroke of each mold is different, as a result, it is difficult to truly control the injection quantity. The overall injection quantity and injection time are very small. Even with high-precision all-electric injection molding, it is difficult to effectively solve this problem. However, the Echos acrylic nail molding machine adopts a plunger injection molding device without rubber ring. No sealing error affects the precision injection molding. When the injection molding starts, the melt starts the filling process, in addition, the starting acceleration itself is more than ten times that of ordinary injection molding, and the actual acceleration from comprehensive start injection molding to melt filling in this case, the comprehensive response speed reaches more than 30 times, thus realizing precise control.
- 4. Acrylic filled thin-walled products, due to their high viscosity and high cooling rate, the mold temperature is above 60-90 ℃, and the melt temperature is 245-260 ℃. During the cooling process when the melt touches the mold cavity, the viscosity temperature is non-linear. For example, there is no high-pressure follow-up during high-speed filling, resulting in low local flow rate, and it will be very difficult to continue filling in the future. Therefore, high-speed and high-pressure injection molding machine is a necessary performance index.
- 5. Accurate injection molding and rapid pressure relief-the performance requirements of high-speed and high-pressure injection molding machines do not mean high pressure holding pressure. For acrylic nail art that needs to reduce internal stress and prevent brittle products, rapid pressure relief after instantaneous high-pressure filling is a very critical machine index. In addition to the extremely low motion inertia of the V-type plunger injection mechanism of the Ecoth nail art injection molding machine, because there is no rubber ring structure, high-speed instantaneous loosening can realize high-speed pressure relief, while the traditional screw injection molding has large loosening inertia and low loosening response, and the actual pressure relief effect is poor because the rubber ring cannot be reversed after loosening and retreating.
- 6. Ultra-short loosening stroke can effectively inhibit the appearance defects of air roll and material flower in injection molding. Due to plunger structure, the movement stroke of rubber ring does not need to be considered. A small amount of loosening stroke can complete effective pressure relief and anti-casting, thus avoiding inhalation of a large amount of air at the gate after mold opening, thus making the injection molding process more stable and the appearance of products more guaranteed.
- 7. There are more special options: * Hunger feeding-reducing the incorporation of more air into raw materials during plasticization, resulting in fluid instability and oxidative degradation or hydrolysis of raw materials; * Electrostatic dust separation device-enables tiny dust in acrylic raw materials to be removed, reducing black spots, white crystals and white mist, making it possible to add more nozzle materials and reducing injection molding costs.
