PC 플라스틱은 우수한 특성을 가지고 있습니다., 높은 투명성, 좋은 충격 인성, 크리프 저항, 넓은 온도 범위. PC 플라스틱에는 다음과 같은 공정 특성이 있습니다.
전단 속도에 대한 용융 점도의 민감도가 작습니다., 그러나 온도가 크다, 뚜렷한 녹는점이 없다, the viscosity of melt is high, the resin is easy to hydrolyze at high temperature, and the product is easy to crack. In view of these characteristics, special attention should be paid to differential treatment: 용융물의 유동성을 증가시키기 위해, it is not achieved by increasing the injection pressure but by increasing the injection temperature. The runner and gate of the mould are required to be short and thick, so as to reduce the pressure loss of the fluid and have a higher injection pressure. The resin shall be fully dried before forming and processing to control its moisture content below 0.02%. 게다가, insulation measures shall be taken for the resin during processing to prevent moisture absorption again. It is not only necessary to design the products reasonably, but also to master the forming process correctly, such as increasing the mold temperature, post-treatment of the products and so on, which can reduce or eliminate the internal stress. Adjust the process parameters in time according to the different conditions of the products.
Process characteristics of PC: PC viscosity is large, melt temperature is high, and fluidity is poor. 이 경우, it must be injection molded at a higher temperature (270 ~ 320 ℃), relatively narrow range of material temperature adjustment, and the processibility is inferior to PMMA. The injection pressure has little effect on the fluidity, but because of the high viscosity, the injection pressure still needs to be higher. 내부 스트레스를 방지하기 위해, 압력 유지 시간은 가능한 한 짧아야 합니다.. 수축률이 크고 크기가 안정적입니다., 그러나 제품의 내부 응력이 크고 깨지기 쉽습니다., so it is better to improve the fluidity by increasing the temperature rather than the pressure, and reduce the possibility of cracking by increasing the temperature of the mold, improving the structure of the mold and post-treatment. 사출 속도가 낮을 때, the gate is easy to produce corrugations and other defects. 방사형 노즐의 온도는 별도로 제어해야 합니다., 금형 온도가 높아야 합니다., 주자와 게이트의 저항이 작아야 합니다..
Injection molding performance of PC: PC is a crystalline plastic with obvious melting point. It melts at 220 ℃ and decomposes at 350 ℃; the general processing temperature is 250-320 ℃; it absorbs water and a small amount of water can cause it to decompose at high temperature. 사출 성형 중, it must be dried, and the drying temperature can be used at 120 ℃ for 4-5h; the melting viscosity of PC material is large, so it needs a large pressure during injection molding; In the processing of PC plastics, if the conditions permit, the mold temperature can be increased by the mold temperature machine to reduce the residual stress of the product; if the product has inserts, the diameter of the inserts is less than 1-2mm, preheating can be ignored, and the larger inserts should be considered preheating, 그렇지 않으면, stress cracking will occur; The shrinkage of PC has nothing to do with the processing conditions and the wall thickness of the products. Its longitudinal and transverse shrinkage are relatively close, so it can be processed into products with high precision. Its shrinkage is 5 ‰ and the overflow value is 0.05mm.
(1) 사출 온도
It can only be made after considering the shape, 크기, 금형 구조, product performance, requirements and other aspects of the product. 일반적으로, when the temperature is between 270 ℃ and 320 ℃, if the material temperature is higher than 340 ℃, PC will decompose, the color of products will become darker, and defects such as silver wire, dark strip, 흑점, bubble will appear on the surface, and the physical and mechanical properties will also decline significantly.
(2) 사출 압력
It has a certain influence on the physical and mechanical properties, 내부 스트레스, molding shrinkage of PC plastic products, and has a great influence on the appearance and demoulding performance of products. Too low or too high injection pressure will cause some defects of products. 일반적으로, the injection pressure is controlled between 80 ~ 120MPa for thin-walled, long process, complex shape and small gate products, in order to overcome the melt flow Resistance, so that even if the mold cavity is full, a higher injection pressure (120-145안전 캡 쉘) can be selected to obtain a complete and smooth surface of the product.
(3) Pressure maintaining pressure and time
The magnitude and duration of holding pressure have great influence on the internal stress of PC products. Too small holding pressure, small feeding effect, easy to appear vacuum bubble or surface shrinkage; too large holding pressure, easy to produce large internal stress around the gate. In actual processing, the method of high material temperature and low holding pressure is often used to solve this problem. The selection of holding time depends on the thickness of products, 게이트 크기, 금형 온도, 기타. 일반적으로, small and thin products do not need a long holding time; on the contrary, large and thick products should have a long holding time. The length of holding time can be determined by the test of gate sealing time.
(4) 사출 속도
There is no obvious effect on the performance of PC products. Except for thin-walled, small gate, deep hole and long process products, medium speed or slow processing is generally adopted, multi-level injection is preferred, and slow fast slow multi-level injection is generally adopted.
(5) 금형 온도
일반적으로, it can be controlled at 80-100 ℃, and it can also be increased to 100-120 ℃ for products with complex shape, thinner and higher requirements, but it can not exceed the hot deformation temperature of the mold.
(6) 나사 속도 및 배압
Due to the high viscosity of PC melt, the requirement of screw speed should not be too high to prevent the screw from being overloaded, which is favorable for the maintenance of plasticizing, exhausting and injection molding machine. It is generally suitable to control the screw speed at 30 ~ 60R / 분, while the back pressure should be controlled at 10% ~ 15% 사출 압력.
(7) release agent
사출 성형 과정에서, the use of release agent should be strictly controlled, and the use of recycled material should not exceed three times, and the use amount should be about 20%.
(8) It is required that the maximum injection volume (including flow channel, 문, 등.) of PC products should be no more than 70% ~ 80% of the nominal injection volume
The length diameter ratio (L / 디) of the screw is 15 ~ 20, and the set compression ratio is 15 ~ 20
JasonMould Industrial Company Limited 정보
Jasonmould는 중국 금형 제작자 플라스틱 금형- 사출 금형, 다이 캐스팅 금형, 플라스틱 블로우 성형, 회전 성형, 의료 플라스틱 사출 성형, 투샷 플라스틱 사출 성형, 인서트 몰딩, 오버 몰딩, 금속 사출 성형, 마이크로 사출 성형, 분말 사출 성형, 세라믹 사출 성형, 액체 사출 성형, 허스키 사출 성형, 가정용 곰팡이, 주조 금형, 금형 도구 다이, 맞춤 금형, 중국 금형, 신속한 프로토 타이핑 도구, 플라스틱 프로토 타이핑 툴링, 펀치 프레스 툴링, 모바일 / 휴대폰 부품 용 다이 및 툴링, 자동차 부품, 진공 청소기, 충전식 도구, 전화기, 복사기, 컴퓨터, 멀티미디어 스피커, 및 기타 많은 전자 제품 및 가전 제품. 또한 플라스틱 제품 제조업체, 금형 제조업체 중국– 플라스틱 부품, 플라스틱 물 탱크, 플라스틱 공, 플라스틱 용기, 플라스틱 버클, 플라스틱 앵커, 플라스틱 걸이, 플라스틱 숟가락, 플라스틱 파이프 피팅, 플라스틱 텀블, 플라스틱 식기, 플라스틱 컵들, 플라스틱 병, 플라스틱 쟁반, 플라스틱 화장품 용기, 플라스틱 케이스, 플라스틱 식품 용기, 플라스틱 의자, 플라스틱 캡, 플라스틱 캡 폐쇄, 플라스틱 튜브, 플라스틱 수도관, 플라스틱 손잡이, 플라스틱 튜브, 플라스틱 유틸리티 박스, 플라스틱 선반 등.
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