Gas Assisted Moulding Animation and process
The main two applications of Gas Assisted Moulding are to either inject the gas into the component cavity (internal gas injection), or to use the gas on the outside surface, but still within the mould cavity, to consolidate the component (external gas injection).
Internal Gas Injection - Most widely used process
External Gas Injection - used for enhanced surface definition
A number of variants of gas use are incorporated into the Internal gas injection process:
Full Shot Internal Gas Assisted Moulding Short Shot Internal Gas Assisted Moulding Plastic Expulsion Process … PEP Moving Core Gas Assisted Moulding Gas Cool for Internal and External Gas MouldingEach variant has its uses and benefits. For more information, click here (Cinpres Web Page)
Why Gas Injection Moulding?
Techniques have been developed whereby inert gas nitrogen is injected into the still molten plastic in the mould cavity. Acting from within the component shape, the gas inflates the component and counteracts the effects of the material shrinkage. The effect is to keep an internal pressure on the material until it solidifies and skins at the mould cavity surface. This is independent of any gate freezing.
Internal Gas Injection - Most widely used process
External Gas Injection - used for enhanced surface definition
Wednesday, June 11, 2008
gas-assist injection molding
Nitrogen is Cheaper Than PlasticGas assist improves cosmetics — and cuts costsDesign News Staff -- Design News, September 4, 2006
With resin costs running through the roof, it's a good time to take another look at gas-assist injection molding.
You remember gas assist. It's a process that uses an inert gas, particularly nitrogen to create one or more hollow channels within an injection-molded plastic part. At the end of the filling stage, nitrogen is injected into the still-liquid core of the molding. The gas follows the path of the least resistance and replaces plastic, usually in thick sections, with gas-filled channels. Gas pressure subsequently packs the plastic against the mold cavity surface. The gas is vented to atmosphere or recycled.
It's not brand new. But acceptance was weak because of concerns over patents, rights and royalty fees. Many of those original patents have expired, and there is less acrimony in the gas-assist field. There are still many opportunities to convert current aluminum and steel applications in automotive as well as other industrial applications to gas assist. Many designers have used gas assist to achieve an excellent surface finish on a cosmetic part. You can also create larger, more complex parts with fewer injection gates than is possible with conventional injection molding.
The three examples here are winners from the recent design competition held by the Alliance of Plastics Processors.
With resin costs running through the roof, it's a good time to take another look at gas-assist injection molding.
You remember gas assist. It's a process that uses an inert gas, particularly nitrogen to create one or more hollow channels within an injection-molded plastic part. At the end of the filling stage, nitrogen is injected into the still-liquid core of the molding. The gas follows the path of the least resistance and replaces plastic, usually in thick sections, with gas-filled channels. Gas pressure subsequently packs the plastic against the mold cavity surface. The gas is vented to atmosphere or recycled.
It's not brand new. But acceptance was weak because of concerns over patents, rights and royalty fees. Many of those original patents have expired, and there is less acrimony in the gas-assist field. There are still many opportunities to convert current aluminum and steel applications in automotive as well as other industrial applications to gas assist. Many designers have used gas assist to achieve an excellent surface finish on a cosmetic part. You can also create larger, more complex parts with fewer injection gates than is possible with conventional injection molding.
The three examples here are winners from the recent design competition held by the Alliance of Plastics Processors.
Gas injection pin mechanism for plastic injection molding systems
Gas injection pin mechanism for plastic injection molding systems
A gas injection pin mechanism for introducing pressurized gas into a mold cavity or melt stream. A stationary pin member is positioned directly in a bore or opening in a mold member without a sleeve member. The pin member is an elongated body member with a first end facing a mold cavity and a first gas passageway through the pin member connected to a second passageway that is traverse to the first gas passageway. The second gas passageway has an opening on an exterior lateral surface of the pin member and gas through the second gas passageway is introduced into the cavity in annular space between the pin member and the mold opening.
Plastic Moulding ExpertsDesign, tooling and moulding fast For all your plastic product needswww.rgegroup.comInjection Molding MachineFull line of vetical insert molding machines, shuttles or rotaryswww.gluco.comFlexPen®FlexPen® is superior to SoloStar® in dose accuracywww.NovoNordisk.comStorage of CoilsCoilstorage systems made of high quality plasticwww.lankhorst-mouldings.comExpert Vacuum ConsultingUltra/High Vacuum System Design, Hardware and Analysis. World Widewww.VACCLimited.comDrierite DesiccantsDesiccants and drying equipment -100 deg. F dewpointwww.drierite.comInjection Molding FilterOil Filtration on plastic injection molder. Fewer stops, longer life.www.cjc.dk/plastic_injection/filter
A gas injection pin mechanism for introducing pressurized gas into a mold cavity or melt stream. A stationary pin member is positioned directly in a bore or opening in a mold member without a sleeve member. The pin member is an elongated body member with a first end facing a mold cavity and a first gas passageway through the pin member connected to a second passageway that is traverse to the first gas passageway. The second gas passageway has an opening on an exterior lateral surface of the pin member and gas through the second gas passageway is introduced into the cavity in annular space between the pin member and the mold opening.
Plastic Moulding ExpertsDesign, tooling and moulding fast For all your plastic product needswww.rgegroup.comInjection Molding MachineFull line of vetical insert molding machines, shuttles or rotaryswww.gluco.comFlexPen®FlexPen® is superior to SoloStar® in dose accuracywww.NovoNordisk.comStorage of CoilsCoilstorage systems made of high quality plasticwww.lankhorst-mouldings.comExpert Vacuum ConsultingUltra/High Vacuum System Design, Hardware and Analysis. World Widewww.VACCLimited.comDrierite DesiccantsDesiccants and drying equipment -100 deg. F dewpointwww.drierite.comInjection Molding FilterOil Filtration on plastic injection molder. Fewer stops, longer life.www.cjc.dk/plastic_injection/filter
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