Blow-molding mold

Figure 6.1 6 Examples of water flood cooling blow molding molds...

Basically the BM lines have an extruder with a die to form the parison or with an injection mold to form the preform. The hot parison or preform is located in a mold. Air pressure through a pin-type device expands the parison or preform to fit snugly inside the mold cavity. Blow-molded products are cooled via the water-cooling systems within mold channels. After cooling, the parts are removed from their respective molds. See blow molding mold Coca-Cola bottle bottle, beer foundry shell molding. 

The BM lines the parison or is located in a the parison or Blow molded mold channels, molds. 

In cast resin molds, vacuum holes can be provided by including greased wires in the casting for later removal. For greater detail such as graining, stitching, and relief work, cast porous aluminum molds should be considered (also used in blow molding molds). 

Before the most suitable materials can be selected, the cost, product, and process requirements must be checked out. Table 1.6 lists some of these materials used in blow molds. Molds for large volumes (> 60 L) are manufactured using either cast zinc or aluminum. For molds with a volume > 1,000 1, aluminum should be used for weight reasons. The pinch-off edge areas are mostly made from steel (for casting molds or molds from forged aluminum) to make deflashing easier or to automate it and to increase the die life. In the last 5 years, the CNC-milled production blow mold (made from aluminum) has established itself. The aluminum industry has developed new materials for this application (Table 1.6). 

Cjcolac Brand ABS—General Purpose Blow Molding Grades, Technical PubHcation SR-616, GE Plastics, Pittsfield, Mass., 1989. 

A. J. Woytek and. E. Gentilecore, "A New Blow Mol ding Process to Reduce Solvent Permeation of Polyolefin Containers," paper no. 13 presented at ddpances in Blow Molding Conference Rubber and Plastics Institute, London, Dec. 6,1977. 

As a tme thermoplastic, FEP copolymer can be melt-processed by extmsion and compression, injection, and blow molding. Films can be heat-bonded and sealed, vacuum-formed, and laminated to various substrates. Chemical inertness and corrosion resistance make FEP highly suitable for chemical services its dielectric and insulating properties favor it for electrical and electronic service and its low frictional properties, mechanical toughness, thermal stabiUty, and nonstick quaUty make it highly suitable for bearings and seals, high temperature components, and nonstick surfaces. 

Injection stretch-blow molding may be performed on a single one-stage machine in sequence or on two independent sequential two-stage machines. PET carbonated beverage botties are usually produced by injection stretch blow molding. 

This method is slow because of the multiple operations on a shuttle machine. The heat of extmsion sterilizes the bottle, which is not readily achieved after molding. Blow-mold/fill/seal systems are used commercially for beverages and for pharmaceutical packaging. 

Haemonetics Bowl Technology. Haemonetics disposable bowl technology has evolved from the original plasma separation chamber. The two principal shapes of bowls are the Latham bowl and the blow-molded bowl (Fig. 4). 

Fig. 4. Haemonetics disposable bowls (a) Latham bowl, and (b) blow-molded bowl.

Fig. 14. The H.E. IS blow-and-blow machine (85). The gob is deUvered into a blank mold, setded with compressed air, and then preformed with a counter-blow. The parison or preform is then inverted and transferred into the blow mold where it is finished by blowing.

Property Injection molded Blow molded Film UHMWPE... 

Blow-molded products represent the biggest use of HDPE resins, at around 40%. Packaging appHcations account for by far the greatest share of this market. These include such products as botties (especially for milk, juice, and soap), housewares, toys, pails, dmms, and tanks. Expected aimual average growth rates for these appHcations are about 5—6%. Injection-molding products are the second largest appHcation, with approximately 20% of the HDPE market. These products include housewares, toys, food containers, pails, crates, and cases. 

A basic dmm is often supplemented by blow-molded plastic inserts that fit closely into the interior cavity. These inserts generally are provided with molded fittings for filling and sealing. The combination, which is referred to as a composite dmm, enhances the fiber dmm for additional appHcations,... 

Fig. 15. Three stages of blow molding (a—c) A, air line B, die C, mold and D, parison. See text.

In injection blow mol ding, a parison is injection molded onto a core pin the parison is then rapidly transferred via the core pin to a blow mold, where it is blown by air into an article. This process is appHed to smad and intricate bottles. 

Soft-drink bottles made from poly(ethylene terephthalate) (PET) are usuady made by stretch-blow mol ding in a two-step process. Eirst, a test-tube-shaped preform is molded, which is then reheated to just above its glass-transition temperature, stretched, and blown. Stretching the PET produces biaxial orientation, which improves transparency, strength, and toughness of the botde (54,56). A one-step process is used for many custom containers that are injection stretch-blow molded. 

D. Rosato and D. Rosato, eds.. Blow Molding Handbook, Hanser Pubhshers, Munich, Germany, 1989. 

Some time earlier, Eastman-Kodak has been working on a novel polyester as an entry into the important polyester fiber market and had devised a new ahcychc diol, 1,4-cydohexanedimethanol [105-08-5] effectively made by exhaustive hydrogenation of dimethyl terephthalate. Reaction of the new diol with dimethyl terephthalate gave a crystalline polyester with a higher melting point than PET and it was introduced in the United States in 1954 as a new polyester fiber under the trade name Kodel (5). Much later the same polyester, now called PCT, and a cyclohexanedimethanol—terephthalate/isophthalate copolymer were introduced as mol ding resins and thermoforming materials (6). More recentiy stiU, copolymers of PET with CHDM units have been introduced for blow molded bottie resins (7). 

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