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All-Electric FlexBlow Machine Offers Wide Flexibility and Quick Changeovers
Time: 2018-01-23
If you are interested in an attractively priced stretch-blow machine to produce a wide range of sizes and shapes of PET or PP bottles in low volumes with frequent changeovers, then take a look at the all-electric FlexBlow machine from Terekas UAB.
What makes these machines different is their wide range of versatility, said to be unprecedented for a two-stage (reheat) system. Normally, such flexibility is associated with one-stage machines that require higher investment, especially for tooling. For example, a two-cavity FlexBlow 2 model can mold neck sizes from 18 to 110 mm, bottle sizes from 50 ml to 2L (or up to 6L in one cavity) at outputs around 1600 bph. It can produce oval or asymmetric bottles and hot-fill containers (to 93 C/200 F), and it guarantees alignment of neck detail to the container body. A complete format changeover, including restart time to produce good bottles, is only 20-30 min, beating the competition by a wide margin, according to Gytis Sirvinskas, market-development manager.
Terekas calls its FlexBlow machines “the smallest universal blow molder” with the “highest flexibility on the two-stage market” and “the fastest complete changeover the industry.” A FlexBlow 2 (two-cavity) measures 1.7 × 2.8 m (5.6 × 9.2 ft). Output of the newest models is up to 1600 bph per cavity. The standard FlexBlow models employ intermittent preform feeding, which sacrifices some speed in return for maximum flexibility, as shown by the wide range of neck and bottle sizes.
The FlexBlow Hybrid models combine rotary and linear motions and have larger numbers of cavities for higher speed, though with somewhat less range in neck-size flexibility, but they retain fast mold changes. The largest model, FlexBlow Multi, is essentially two eight-cavity Hybrid models linked to one infeed system; it’s designed to compete with high-output rotary systems. 
For the U.S. market, Sirvinskas sees two- to six-cavity machines as the most attractive models. He says they fill a gap in the custom bottle market for highly variable production batches as small as 10,000 to 20,000 bottles at a time. Features include Siemens color touchscreens with easy-to-use, intuitive programming. Air-recovery systems take exhaust high- pressure blowing air and return it to the low-pressure system. FlexBlow machines can use molds from competing systems (KHS, Sidel, etc.).
The company is particularly proud of its proprietary preform heating technology. Preferential heating to produce oval or asymmetric bottles uses eight lamps arranged horizontally—rather than vertically as in other machines. These lamps, 30 cm long, are arranged on two sides of the preform, which stops spinning for 5-7 sec to soak up the heat. Multiple lamps allow creation of different heat zones along the length of the preform body.
FlexBlow machines also boast special protections against neck overheating. First, the preforms are heated with the neck down, rather than neck up as in most machines. This protects the neck from rising hot air from the body heaters, and also traps heat inside the preform for greater efficiency. Preform neck-support rings are cooled while the body is heated. Keeping the preform neck cold and the body hot allows for optimum material distribution and maximum design freedom for lightest preform weight.
Competitive cost is another edge for the FlexBlow line. Two- to six-cavity FlexBlow machines are entering the U.S. market for producing a wide range of custom bottles in batches as low as 10,000 to 20,000 units.
Source: Plastics Technology