Injection Moulding Asia Moulding
Nissei upgrades its electric series
Improved cavity filling from additive
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S-based Axel Plastics has developed a proprietary process aid additive targeted at processors using PBT and PBT resin blends. The additive was developed in response to increased use of highperformance polymer blends in the automotive, transportation and electronics markets. MoldWiz INT-35PHT is said to allow more flexibility in the incorporation of filler types and loading levels as well as an easier cavity fill and release performance for the resins. In developmental extrusion testing utilising a Zenoy 5220U resin (a PC/PBT alloy by Sabic), the additive is said to have significantly decreased resin viscosity, minimised fluctuations in torque and increased output from 50 to 100%. Initial evaluations were conducted at loading levels of 0.31% and there was no reduction in the physical properties of moulded parts, says the company. A proprietary synergistic blend of modified polymers, organic fatty amides and glycerides, the product is available as a free-flowing powder or 100% active pellet (carrier and binder free), allowing for incorporation into masterbatches, gravitationally mixed or fed at the throat of a moulding machine.
Sodick’s two-stage machine will be used to demonstrate the moulding of a syringe in COC, a first for the medical industry, at the NPE exhibition
COC in medical moulding, a first
reciprocating screw system, the plasticising screw remains stationary during material transfer, minimising axial wear and ensuring each pellet has the same heat profile. The two-stage plunger injection unit provides an optimum screw size and plunger size combination (for example, 40 mm screw with 32 mm plunger injection) for an ideal recovery time and shot size. The injection unit is controlled by a closed-loop system comparing actual speed to set speed and maximum melt pressure. User selectable limits can be added on the process monitor screen. Once the exact amount of material is transferred into the injection chamber, the injection plunger that is retracted via the melt is maintained to a set position. This eliminates the need for a check valve, a primary source of material degradation and shot volume inconsistency. Prior to injection, the plasticising screw is indexed forward creating a positive shut-off (exact dosing). This action prevents any opportunity for backflow of molten material back into the melt stream.
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S injection moulding machinery maker Sodick Plustech will show its V-Line two-stage plunger system at NPE 2012 in Florida in April moulding a medical syringe made of Topas cyclic olefin copolymer (COC) from Topas Advanced Polymers in a mould from Nypro. The prototype application demonstrates the use of COC, which has improved moisture barrier and dimensional consistency, as a replacement for glass in syringes. The polymer is said to offer a nonionic, minimally reactive surface. It also does not promote adsorption, denaturation, aggregation, or precipitation. With lower leachables and extractables, the resin preserves long-term drug purity ensuring better quality at high yields and potentially lower part cost, says Topas. Sodick Plustech says its injection system utilises a two-stage V-Line method for plasticising and injection, allowing for consistent shot volumes and melt densities. Unlike a conventional in-line
apanese firm Nissei Plastic Industrial has updated its flagship Nex electric machine range. Six small and mediumsize types, ranging from 30 to 180 tonnes, are now available under the NEX-III series with an updated plasticising device (injection unit) and new controller Tact IV. The plasticising device has been designed to provide better performance by subdividing and optimising the barrel temperature control zones, thus reducing moulding defects. The newly designed nozzle and barrel permit better thermal conduction, shortening the heatup time by 25% and saving power by 8%, according to Nissei. The fluctuation of resin temperature, which occurs upon starting up a moulding machine, is also eliminated, allowing for stable plasticising of non-reinforced PBT, LCP, PA66, PP and PCTA. The two-zone controlled rear heater also shortens plasticising time. The Tact IV controller offers a larger screen, newly designed operation panel and a user-friendly software.
Nissei’s latest upgraded Nex electric machine
1 MARCH 2012
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