Plastiblow electric blowing machine for the production of laboratory flasks

A new interesting experience in the medical sector

The continuous research aimed at the use of new materials in the extrusion blow molding process is the trait of Plastiblow, a leading company in the sector with over twenty years of experience in the manufacture of electric blow molding machines. These machines are particularly suitable for medical and hospital applications, as they avoid contamination deriving from the use of hydraulic oil (in the past indispensable for the operation of mechanical components), as well as limiting energy consumption, noise level and the use of consumable parts.

The volumetric measurement of liquids is one of the routine tasks in laboratory analyses. Measuring instruments such as volumetric flasks, calibrated and graduated pipettes, graduated cylinders and burettes are used in chemical laboratories for the accurate dosage of liquids in experimental tests and can be produced in both glass and plastic.

There is no universal material that can satisfy all needs: the choice to use glass or plastic depends on the application and design of the product, as well as the specific properties of each material and economic aspects.

Volumetric plastic instruments are characterized by high breaking strength, low weight, lower sensitivity than glass to thermal changes. Among the most suitable materials there are: PP (Polypropylene), PMP (Polymethylpentene), PFA (Perfluoroalkoxy).

Volumetric instruments can be produced in PP, which in terms of precision fall within the error limits of class B (DIN EN ISO1042), while PMP and PFA are also used for measuring instruments with an error limit corresponding to class A.

Plastiblow has recently supplied a blow molding machine suitable for the production of 1000ml, 250ml and 100ml flasks. For the realization of these containers, a crystalline polyolefin (TPX) produced by MITSUI CHEMICALS was used, a particularly light, transparent, unbreakable material, with high heat resistance (melting point between 220 - 240 ° C) which allows sterilization in autoclave.

The high quantity of cutting perimeter, resulting from the shape of the flasks, required a careful evaluation in the choice of the most suitable model of blowing machine in terms of closing force, just as the particular material to be processed required a specific study of the extrusion head and the most suitable screw profile for correctly plasticising this type of polymer.

The choice fell on the Plastiblow full electric single station blow molding machine model PB12ES 430 with a closing force of 12 tons, equipped with a 70 mm diameter extruder and a double cardioid single head with a 100 mm diameter die.

The main technical measures adopted to manage the high working temperatures are the use of ceramic heater-bands in the extruder, of low expansion steels for the construction of the head and the addition of a pressurized water temperature control unit for the molds.

The project, not without difficulties and unknowns, given the peculiarity of the chosen material, was tackled with particular commitment by the Plastiblow technical team and brilliantly completed: a new interesting experience in the production of medical items.