Plastic Strapping Manufacture.
Plastic strap is made initially from an extruded strand or sheet, and the polymeric material comprising the extrusion is then oriented, a process which increases the strength of the plastic material to approximately 10 times the unorientated strength of the material.
Pre-Extrusion Process for Treated Polyester
Crystallizing and Dehumidifying of treated PET material is absolutely indispensable for process of treated recycled PET bottle flakes into suitable condition for the production of premium quality PET straps.
The Plastic Strap Extruding Lines comprise:
Plastic strapping extruders need to be designed to provide superior melt quality, with a screw geometry that will produce a steady plasticisation and perfect homogenous melt, and therefore need to have accurate control of melt temperatures.
None-Stop Screen Changer
Available in simple continuous belt screen changer to a more sophisticated continuous flow screen changer with automatic back flush/self-cleaning feature to ensure continuous melt flow and nonstop operation during screen change. Continuous Back Flush Screen changer is strongly recommend for processing recycled material, especially for recycled PET bottle flakes.
Metering Spin Pump
Metering spin pump is indispensable for plastic strapping band extrusion, to ensure consistent polymer feeding to the die set, and give a top quality and uniformity of finished straps.
Extrusion Die Pack
A strapping die head ideally designed with bottom loading concept for easy loading and quick change of die set, to maximize uptime.
Quenching Water Bath
A quenching water bath made from stainless steel, insulated, and designed to enable smooth water circulation and consistence
water temperature. Motorized tank elevation systems allow ease height adjustment of precise water levels.
The complete extrusion line operation parameter is monitored and controlled from a central control panel. All control units are arranged
logically to optimize easy operation of the complete production line.Standardize synchronize speed ratio control system provide easier operation and accurate synchronization of entire stretching and annealing process.Besides reliably and consistently standard process control system, Central Process Monitoring & Control System incorporate a touch screen HMI can be upgrade features user-friendly operator interface with easy access to all operating setting keep all parameter on target.
STRETCHING, EMBOSSING, SETTING PROCESS
The physical characteristic of the straps, such as dimensional uniformity, tensile strength, elongation is predominantly determined by the degree of orientation. Each draw stand is precisely engineered with robust design and equipped with individual drive for precise speed control for either manual, synchronize mode, or automatic mode. Draw stand is available in 3, 5, or 7 chromium plated and/or plasma
coated godets running in cantilever concept free of slippage. Diathermic oil heated and water cooled godets are available optionally.
Plastic Strapping Embossing unit
Roller manufacture from superior quality SACM-645 material with individual drive for precise speed control. Embossing roller is adjustable and interchangeable to enable various of embossing depths and pattern.
Hot Air Pull Down Oven
Well insulated hot air stretching oven working with automatic temperature controller and adjustable circulated hot air flow is monitored and automatically controlled to ensure consistent heat distribution and precise temperature.Low energy consumption is generally assured by incorporating top grade ceramic fiber insulation material and minimizing hot air dispersion with efficient aerodynamic air flow.
Hot Air Oven and Cooling Water Bath
Final strap characteristics are set using an annealing die set, hot air oven and temperature controlled water bath to ensure strap internal stress is relieved, and to attain straight strap i.e. without camber, suitable for use in automatic strapping machines.
Winding of strap is significantly crucial to the profitability and overall operation of a strapping band extrusion line, and mechanical or PLC controlled strapping winders are available. Mechanical winders with fixed traverse cams involve change of gears for winding different strap widths, and this does mean size changeovers takel onger. PLC controlled winders are much quicker,convenient and with interchangeable mandrel and traverse guide, each unit is capable for winding various strap gauges onto every size of cardboard core.
Plastic Extruders operate with line speeds up to 150 metres/minute and convert up to 300kgs/hour.
What happens - unseen
Manufacturing plastic strap includes initially forming a molecularly oriented crystalline polyester or polyester co-polymer of uniform cross section which is many times wider than the thickness. The material is oriented by longitudinal stretching at a ratio of at least 5.0 to 1
The longitudinal stretching is carried out at raised temperatures with the material being maintained at this stressed condition until sufficient cooling has taken place. However, for strap with a combination of high strength and low brittleness, a third stretching stage should be conducted at temperatures such that the tensile strength of the strap can be significantly increased..
An outer layer of amorphous material is formed on both sides of the material. The outer layer may be imparted after the material has been extruded and oriented by stretching. This is done by heating the outside surface of the material exposing the material to heated rolls. Heating the oriented material causes the molecular structure to lose its orientation, at least in part, to a depth which depends upon the extent to which the temperature of the material is raised. To control brittleness of the core, the material may be chilled just prior to the surface treatment, and may be chilled again just after the surface treatment. The outer layer is preferably unitary and integral with the underlying high strength layer.. Strap made from material formed by the process has a high strength underlying layer which is highly oriented. The strap, when fused to itself via the outer layers, has a joint whose break strength is a function of the break strength of the high strength layer. The outer layer provides the strap with substantially improved corner strength and to resist crack initiation and propagation in the welded strap sections. Hot blade or friction weld fusing techniques can be used to provide a weld between strap sections resulting in a joint having an overall break strength approaching the break strength of at least about 80% of the underlying high strength layer.
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