PC-Kunststoffe haben hervorragende Eigenschaften, hohe Transparenz, gute Schlagzähigkeit, Kriechfestigkeit, großer Temperaturbereich. PC-Kunststoffe haben folgende Prozesseigenschaften
Die Empfindlichkeit der Schmelzviskosität gegenüber der Schergeschwindigkeit ist gering, aber die Temperatur ist groß, es gibt keinen offensichtlichen Schmelzpunkt, the viscosity of melt is high, the resin is easy to hydrolyze at high temperature, and the product is easy to crack. Angesichts dieser Eigenschaften, special attention should be paid to differential treatment: um die Fließfähigkeit der Schmelze zu erhöhen, 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%. In Ergänzung, 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. Was sind also heute die konkreten Probleme?, 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. Um den inneren Stress zu verhindern, die Druckhaltezeit sollte so kurz wie möglich sein. Die Schrumpfungsrate ist groß und die Größe ist stabil, aber die innere Spannung des Produkts ist groß und leicht zu knacken, 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. When the injection speed is low, the gate is easy to produce corrugations and other defects. The temperature of the radial nozzle should be controlled separately, the mold temperature should be high, and the resistance of the runner and gate should be small.
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. Beim Spritzgießen, 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, Andernfalls, 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) ausschließlich der Hilfszeit wie Formöffnung und -schließung
It can only be made after considering the shape, Größe, Formstruktur, product performance, requirements and other aspects of the product. Allgemein, when the temperature is between 270 ℃ und 320 ℃, wenn die Materialtemperatur höher ist als 340 ℃, PC wird zerfallen, the color of products will become darker, and defects such as silver wire, dunkler Streifen, schwarzer Fleck, bubble will appear on the surface, and the physical and mechanical properties will also decline significantly.
(2) Einspritzdruck
It has a certain influence on the physical and mechanical properties, innerer Stress, 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. Allgemein, the injection pressure is controlled between 80 ~ 120MPa for thin-walled, langer Prozess, 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 (120-145mpa) 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, Torgröße, wenn unsere Spritzgussfabrik ein gutes Formprodukt herstellen möchte, usw. allgemein, 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) Vorlauf des Zulaufrohres und eine höhere Temperatur am vorderen Ende des Zulaufrohres
There is no obvious effect on the performance of PC products. Außer dünnwandig, kleines Tor, Tiefloch- und lange Prozessprodukte, mittlere Geschwindigkeit oder langsame Verarbeitung wird im Allgemeinen angenommen, multi-level injection is preferred, and slow fast slow multi-level injection is generally adopted.
(5) Formtemperatur
Allgemein, 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, aber es kann die heiße Verformungstemperatur der Form nicht überschreiten.
(6) Schneckengeschwindigkeit und Gegendruck
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 / Mindest, while the back pressure should be controlled at 10% ~ 15% des Einspritzdrucks.
(7) release agent
Im Spritzgussverfahren, 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, Tor, usw.) of PC products should be no more than 70% ~ 80% of the nominal injection volume
The length diameter ratio (L / D) of the screw is 15 ~ 20, and the set compression ratio is 15 ~ 20
Über JasonMould Industrial Company Limited
Jasonmould ist ein China Formenbauer von Kunststoffformen- Spritzgussform, Druckgussformen, Kunststoffblasformen plastic, Rotationsformen, medizinisch Kunststoff-Spritzguss, zwei Schuss Kunststoff-Spritzguss, Umspritzen, Umspritzen, Metallspritzguss, Mikrospritzguss, Pulverspritzguss, Keramikspritzguss, Flüssigspritzguss, Husky-Spritzguss, Haushaltsform, Gießform, Formwerkzeug, benutzerdefinierte Formen mold, Porzellanformen, Rapid-Prototyping-Werkzeuge, Kunststoff-Prototyping-Werkzeuge, Stanzpresswerkzeuge, Matrize und Werkzeuge für Handy-/Handyteile, Autoteile, Staubsauger, wiederaufladbare Werkzeuge, Telefone, Kopierer, Computers, Multimedia-Lautsprecher, und viele andere elektronische Produkte und Haushaltsgeräte. Und auch ein Hersteller von Kunststoffprodukten, Formenhersteller China- Kunststoffteile, Wassertank aus Kunststoff, Plastikkugeln, Kunststoffbehälter, Plastikschnalle, Kunststoffanker, Kleiderbügel aus Kunststoff, Plastiklöffel, Rohrverschraubung aus Kunststoff, Plastiktrommel, Plastikgeschirr plastic, Plastiktassen, Plastikflaschen, Plastikschale, Kosmetikbehälter aus Kunststoff, Plastikbehälter, Lebensmittelbehälter aus Plastik, Plastikstühle, Plastikkappen, Verschluss aus Kunststoff, Kunststoffrohre, Wasserrohre aus Kunststoff, Kunststoffknöpfe, Kunststoffschlauch, Gebrauchskartons aus Kunststoff, Plastikregale und so weiter.
Kontakt:
Person: James Yuan
Unternehmen: JasonMould Industrial Company Limited
Hinzufügen: LongGang-Dorf,LongXi-Stadt,Bezirk BoLuo,Stadt HuiZhou,Provinz Guangdong, China
Tel: 86-752-6682869
Email: [email protected]
Seite? ˅: https://www.jasonmolding.com/custom-injection-molding/
