Screw tips

Principles of Selection of Plasticizing Barrel Assembly and Design of Injection Molding Nozzle Components

Principles of Selection of Plasticizing Barrel Assembly and Design of Injection Molding Nozzle Components Considerations: Conveying section, compression section, metering section, three-section ratio, compression ratio, depth of metering section screw groove, length-diameter ratio, number of teeth. Selection principles a.For good mixing effect, a design with a large length-diameter ratio, more teeth, high compression ratio, and shallow metering section screw groove should be used, such as PA, PE, PP, and POM. b.To prevent shear overheating, a design with a small length-diameter ratio, fewer teeth, long compression section, low compression ratio, and deeper metering section screw groove should be used, such as PC, PMMA, hard PVC, glass fiber reinforced or flame-retardant materials. c.For high plasticization rate, a design with a smaller compression ratio and deeper metering section screw groove should be used. Design of Injection Molding Nozzle Components A good check valve should have: a.Ability to stop quickly. b.Complete check function to maintain minimum plastic flow back. c.Smooth material flow without dead corners to avoid local shear heat, which can cause plastic degradation. d.Wear resistance and corrosion resistance. e.Ability to adapt to a variety of plastics.

Main factors affecting plasticizing quality

Main factors affecting plasticizing quality The main factors affecting plasticizing quality are: length-to-diameter ratio, compression ratio, back pressure, screw speed, and barrel heating temperature, etc. Length-to-diameter ratio: the ratio of the effective working length of the screw to the diameter of the screw. a.A larger length-to-diameter ratio makes feeding more uniform; b.Plastics with better thermal stability can use longer screws to improve compounding without burning, while plastics with poor thermal stability can use shorter screws or screws without threads at the end. Considering the plastic characteristics, the length-to-diameter ratio is generally as follows: 14-16 for thermosetting plastics, 17-18 for rigid PVC, high viscosity PU and other thermosensitive plastics, 18-22 for general plastics, and 22-24 for high-temperature stable plastics such as PC and POM. Compression Ratio: the ratio of the last depth of the screw in the feeding section to the first depth of the screw in the metering section. a. Considering the compressibility of the material, filling degree, backflow and other factors, the product should be compact, with good heat transfer and ventilation. b. Appropriate compression ratio can increase the density of plastic, make the binding between molecules more tight, help reduce the absorption of air, lower the temperature rise caused by pressure, and affect the difference in output. Improper compression ratio will destroy the physical properties of plastic. c. The higher the compression ratio, the higher the temperature rise of the plastic during the plasticization process in the barrel, and the better the mixing uniformity of the plastic in

Several important geometric parameters of screws

Several important geometric parameters of screws Screw diameter (D)                                                                                                                                                                                                                                                                                                         a.Related to the required injection volume                                                                                                                                                                                 

Principi di progettazione delle viti

La parte principale della vite a perno è una vite comune e il perno di bloccaggio può essere posizionato nella scanalatura della sezione di fusione o della sezione di misurazione della vite oppure sulla superficie cilindrica liscia alla fine della sezione di misurazione senza una scanalatura della vite. I perni di bloccaggio sono disposti in modo specifico con densità e quantità variabili. I perni di bloccaggio cilindrici vengono assemblati nei fori della vite, mentre i perni di bloccaggio quadrati o a forma di diamante vengono fresati direttamente sulla vite. Se questi perni di bloccaggio sono posizionati nella zona di fusione, possono schiacciare il letto solido, interrompere il flusso bifase e mescolare le fasi solida e liquida insieme, aumentando l’area di contatto tra la fase solida frammentata e il materiale già fuso, favorendo la fusione.Se i perni di bloccaggio sono posizionati nella zona di trasporto della fusione, la loro funzione principale è quella di dividere il flusso di materiale, aumentare l’interfaccia, cambiare la direzione del flusso di materiale e riorganizzare il fascio di flusso. Dividendo e fondendo ripetutamente e cambiando la direzione del flusso, i componenti e la temperatura della fusione possono essere omogeneizzati.La sezione di miscelazione è una struttura a fessura che si apre verso l’interno, posta alla fine della sezione di omogeneizzazione della vite comune, e il suo diametro esterno è uguale al diametro esterno della vite.Le scanalature sono divise in diverse gruppi e la zona di convergenza del materiale si trova tra ogni gruppo. Il materiale è diviso dalle scanalature, convergente nella zona di convergenza, per poi essere suddiviso e convergente nuovamente. Il principio è simile a quello dei perni di bloccaggio. La caratteristica di una vite separabile è che, oltre alla singola filettatura originale (chiamata vite principale), viene aggiunta una filettatura aggiuntiva (chiamata sottorosca)


The 35th International Plastics and Rubber Industry Exhibition will be held in Shenzhen, China from April 17th to April 20th. Superior Machinery will participate in this exhibition. Booth No.: 9Y59 (Hall 9) We look forward to meeting you there. ——Ningbo Superior Machinery Team  


Gentili Clienti, Grazie per la collaborazione e il supporto nel 2022. SUPERIOR continuerà a fornirti prodotti e servizi di qualità superiore. Grazie ancora! In attesa della nostra stretta collaborazione in futuro. @Ningbo Superior Machinery Team


The most important exhibition on Chinese panorama for Plastic and Rubber Industry, is coming. Superior Machinery will also attend this event from April 25th to 28th. This will be a celebration for discovering the wide-ranged screws,barrels and accessories designed for plastic processing equipment and machinery. Come and visit us at Shanghai National Convention& Exhibition Center, Booth 4.1 A07. Write to We look forward to see you in Shanghai!

Happy Holidays and a Joyful New Year

Dear Customers, another year has come to an end, we would like to thank you for the cooperation along 2021. It was a particularly difficult time for both of us due to the spread of COVID-19. Despite the inability to attend exhibitions outside of China and to meet as before, we have carried out great efforts to improve our service and guarantee the highest quality standards, always investing in innovation. The coming new year is called in China the “Tiger Year”, which means an energetic, healthy and fortunate year. That’s our wish for all of You. We sincerely wish You to have a lucky, healthy and vigorous new year in both Your life and Business! Undoubtedly, our company will keep the commitment to the continuous supply of the highest quality standard productions in the next year. Thank You again! We look forward to strengthening our close co-operation in the future! Ningbo Superior Machinery Team