Packaging
Downstream of the stretch blow moulding machine from SIG Corpoplast comes the vacuum conveyor belt from GEPPERT-Band
Monday 05. May 2008 - The stretch blow moulding machine manufacturer SIG Corpoplast uses different kinds of conveyor belts for its customers in the food and chemical industries. These conveyor belts have to fulfil different functions, depending on the process and the machine.
Thus, for a certain application, oval bottles are transferred upright onto vacuum conveyor belts from GEPPERT-Band. SIG Corpoplast is aware of its special product responsibility: not only the stretch blow moulding machine must be of high quality, but also the frictionless transportation of large quantities of bottles, amongst other things.
After the spray-moulded preforms have been placed on a mandrel, they are heated to approximately 100 °C in the kiln of the stretch blow moulding machine. Due to the special oval shape of the bottle, this is referred to as preferential heating. The preform is then blown into the final shape through a combination of mechanical stretching and the simultaneous application of compressed air in the blow moulding station. Around 1,800 bottles per blow moulding station leave the stretch blow moulding machine every hour. Bottles that do not meet the high quality standards are automatically identified and rejected immediately.
After conditioning and cooling, the others are all fed into further process steps. For this, the bottles on the discharge belt have to be transported in a standing position. This is not entirely simple, as they are moving fast when they reach the belt.
In order to ensure that the lightweight plastic bottles actually stay in position after being released by the gripper, a flow is generated from inside the belt. In technical jargon this is referred to as a vacuum belt, but a genuine vacuum cannot really be created. Not all of the holes on the belt and cover frame are covered by bottles so as to be airtight.
Downstream of the guide roll, GEPPERT-Band built a suction box onto the first 1000 mm of the conveyor belt. This is fitted to the underside of the sliding surface, which is equipped with slits measuring 6 x 50 mm at intervals of 5 mm. The belt lying over this has holes with a diameter of 5 mm at intervals of 20 mm, for sucking the bottles on. The bottles are carried onwards at a uniform speed, kept upright with the aid of lateral guides, for labelling, filling and sealing. Little more than 2 minutes after the preform is placed on the mandrel, the fully finished bottles are ready to be packed into boxes.
The “vacuum belt” from GEPPERT-Band consists predominantly of standard components. The rolls, head pieces, aluminium profiles and pedestals are thus also used in other conveyor belts.
The advantages are readily apparent: quick, cost-saving production, as this is not a process of manufacturing special machinery. There are only a few parts needed that are not in stock. GEPPERT-Band did not require more than 12 days for the construction of the vacuum belt. Since the start of operations in September 2006, the band has run without interruptions, excepting wearing parts such as the belt. The situation is similar for the other 12 conveyor belts of this type that have been produced to order for SIG Corpoplast.
SIG Corpoplast
Since the introduction of PET and the development of their first small stretch blow moulding machine, SIG Corpoplast has been building plants and systems for the production of PET bottles with great success.
With the BLOMAX Series III, the company and its 260 employees are considered pioneers and technology leaders in PET stretch blow moulding systems, and with the Bottles & Shapes range, they offer their design and processing know-how for the complete plastic bottle development process.