Consultancy

RK- Lineartechnik Abfüllanlage

The new dimension in PET bottle production

Considering the huge quantities of PET bottles that are manufactured, a 3% reduction in material used represents an enormous saving. If, at the same time, precision is improved and setup time reduced, then it can be fairly described as a new dimension in PET bottle production. KHS Corpoplast, based in Hamburg, is a technological market leader and innovative supplier of stretch-blow moulding systems (www.khscorpoplast.com). The company relies on suppliers with outstanding project expertise, such as RK Rose + Krieger GmbH, who have contributed specially designed stretching system linear units for the new InnoPET Blomax Series IV.



When KHS plans a new development, it usually means a large-scale project. And the new InnoPET Blomax Series IV, which produces up to 72,000 PET bottles every hour, is no exception. At a speed the naked eye cannot follow, the PET preforms are heated to around 95°C and positioned in their moulds. They are then "stretch-moulded" into PET bottles under high pressure and with the aid of specially developed linear stretching systems. The extremely high dynamic performance demands the movement of extremely small masses in order to minimize the cycle times and to achieve maximum service life. On the basis of the established RK Duoline, RK Rose+Krieger developed a linear axis with an exceptionally high resistance to the forces and torques acting on it. At the heart of the device is an aluminium profile, specially developed for this application, which can resist the high torsional stresses required. A high-precision ball-screw spindle with a high pitch permits the breathtaking acceleration figures needed to achieve the cycle time.

The RK DuoLine, like many other linear units from well-known manufacturers, underwent a comprehensive stress test. Realistic service conditions were simulated, involving double cycles in the tens of millions, accelerations of up to 42 m/s², vmax. up to 2.3 m/s and a constant counteracting force of 800 N.

 

The torque loads resulting from the movement of the mould carousel were also built into the test. A particular challenge was presented by the level of precision required, made more difficult by the continuous, high-speed rotation of the carousel with simultaneous linear movement, controlled by individual cam plate profiles. By the end of the tests, only the RK DuoLine satisfactorily reached the required performance figures, with a calculated service life of 5 years.

In addition to the test figures, KHS also took other factors into account. Suppliers had to provide proof of their reliability in system partnership and must have relevant project experience. Here again, RK Rose+Krieger impressed the decision-makers, and were finally awarded the contract for series production.

The torque loads resulting from the movement of the mould carousel were also built into the test. A particular challenge was presented by the level of precision required, made more difficult by the continuous, high-speed rotation of the carousel with simultaneous linear movement, controlled by individual cam plate profiles. By the end of the tests, only the RK DuoLine satisfactorily reached the required performance figures, with a calculated service life of 5 years.

In addition to the test figures, KHS also took other factors into account. Suppliers had to provide proof of their reliability in system partnership and must have relevant project experience. Here again, RK Rose+Krieger impressed the decision-makers, and were finally awarded the contract for series production.


 

RK DuoLine