In November WM Wrapping Machinery SA from Stabio (Switzerland) completed the successful testing of a complete line for the production of two-colour disposable cups made of multi-layer polypropylene.
The plant destination is a leading extra European manufacturer of disposables items, to whom is currently being delivered another WM complete in line system dedicated to the production of plates made of co-extruded polystyrene HIPS.
The line subjected to testing and named by the Swiss company INTEC FT 900/3 consists of a unit for the automatic dosing and feeding of the raw material in granules, including a system of management and recycling of the ground line waste.
An extrusion group, provided always by WM Wrapping Machinery Sa and including a main extruder with a screw diameter of 120 mm and two co-extruders with a diameter of 80 mm. The total extrusion capacity of the group is 1,096 kg/h.
The flat die head of the extrusion feeds a vertical laminating calender with three rolls creating a sheet with a width of 930 mm and a thickness ranging from 0.2 to 2 mm.
The extruded sheet is then sent in line to the transport system with toothed chains of the thermoforming machine model FT 900, with a tilting lower platen and a servo-assisted plugging unit. The forming tool can accommodate moulds with a maximum size of 880×520 mm and has a clamping force of 75,000 DaN. The tilting system of the movable lower platen is based on an innovative double DESMODROMIC system of cams and levers operated by a servomotor.
The mould has 51 cavities for the production of cups with a finished border diameter of 73 mm and a height of 95 mm.
Once thermoformed and cut (an operation that occurs simultaneously in the same mould) the cups are removed from the bottom half-mould which tilts at 75 degrees by a plate with aspirating spindles and automatically transported to a collection cage, which automatically unloads the various rows of stacked cups on a conveyor belt and continuously feeds a rimming unit (a WM production) with three rotating screws. This turns up the upper edge of the cups and then send the rods to the accessory counting and packing units.
The waste or the residual perforated polypropylene sheet from which the cups are made, is sent in line to a soundproof grinding mill, which reduces the scrap to flakes and, by means of a blower group, sends it to the dosing/mixing unit located above the extrusion unit. This creates a closed loop from the raw material to the finished product, with the direct in line recycling of waste materials.
The INTEC 900/3 system can produce up to 120,000 pcs of 200 cc cups per hour, minimising energy consumption and significantly reducing necessary personnel.
As mentioned, WM Wrapping Machinery SA designs and manufactures INLINE systems dedicated to the production of disposable plates made of co-extruded polystyrene as well as systems for yogurt, butter, margarine and ice cream containers, made of polypropylene, polystyrene or a multi-layer barrier.