ARSENAL produces wide range of extrusion presses.

Film is a thin material, so technology of it’s production is extremely sensitive to homogenization. Extreme growth of requirements to variation of foil tolerance distribution below 2-3 per cent makes necessary to provide fine homogeneity of viscosity and temperature of polymer melt. The range of materials used in film production grows constantly. The longer screw is used, the better result it provides. L/D ratio for film extruders went up from 20 to 34 within last 50 years. Modern screws also obligatory have spiral grooving feeding zone, soft spiral barrier and mixing elements with barrier, also spiral shaped.

Few companies in the world may afford production and delivery to the market of this expensive hardware. One of them is ARSENAL.

ARSENAL designs and manufactures wide range of modern screw presses specialized for film blowing extrusion. The extruders are retailed and optimized to customers’ needs, that is very important in order to increase output and quality and to reduce specific power consumption. So far we have to speak about hot module constituted by presses and extrusion head with spiral Mandrell, which should work in concert.

ARSENAL produces 45, 60 and 75 mm screw presses with typical output up to 70, 140 and 280 kilograms of film per hour. Together with high back-pressure extrusion head, of course.

RANGE OF MATERIALS

Hot part may process wide range of most common polymers such as: polyethylene (LDPE, HDPE, LLDPE, MDPE, metallocene, medium density, bi-modal, very low density, etc.), EVA, PP, their modifications, mixtures and combinations. There is no experience with other materials like PA, EVOH.

Some typical film types (base materials, thickness in microns, Perimeter (P) or Roll width (R) in mm):	Some typical applications
LDPE-HDPE 75 micron, P3000	Shrink film for industrial packaging
mLDPE-LDPE-LDPE 40 micron, 2xR1500	Lamination film for production of composite materials (lamination with paper, foils, other films)
LLDPE+LDPE+Cling agent, 15 to 27 micron, 8xR300, 6xR400, 4xR450, 4x500	Stretch film for manual or machine wrapping, silo film
LDPE-HDPE-LDPE, 50 to 80 micron, 2xR1500	Smooth hot sealing, glossy packaging film for high quality consumer bags
LDPE-HDPE-HDPE, 10 to 50 micron, 2xR1500	Consumer bags, Heavy duty film,
LDPE-PA-PA or LDPE-Tie-LDPE	Barrier film for packaging of meals
HDPE-PP-HDPE	Boiling resistant film for meal boiling and medical application and prefabricated food
LDPE+LLDPE 40 microns, 2x1500 mm	Deep freeze resistant film for frozen food packaging
Bimodal LDPE, LLDPE	Tear-proof  film for elastic packaging
LLDPE-EVA	Stretch hood packaging
LDPE-EVA-Anti-fog and UV-block, 80 to 120 micron, P3000 to 4500 mm	Green houses
LDPE 150 to 200 micron, perimeter 4500 to 5000 mm	Pallet heat shrink wrapping
LDPE+recycled LDPE, black, 80 microns, opened tube 3000 mm	Mulching film
LLDPE-LDPE-EVA	Pealing (protective) film
LDPE-LDPE foam-LDPE	Packaging film

OUTPUT OF HOT PART WITH 3 PRESSES 60 MM EACH
(typical, for reference only)

Material	Roll width	Thickness, microns	Output, kg  per hour	Limitation factor
LDPE	1200-1500	40-150	360	Extrusion
LDPE	1200-1500	200	300	Cooling
LDPE	1200	30	250	Winding
HDPE	1200-1500	16	160	Winding
LLDPE	1200-1500	25	200	Winding
LLDPE-HDPE-LDPE	1200-1500	50	220	Extrusion

The above output may be increased if necessary by (simple to complex) changing of winding speed by replacing gearboxes, increasing of chilling and by upgrade of extrusion modules.

Extrusion presses are most important and expensive part, “the heart” of the machine. ARSENAL soft barrier extruder presses use lau6614547_test revolutionary HELIBAR ® technology, recently developed in Germany. This technology allows best control over feeding, melting and homogenisation of polymer material.

Every press has hopper for material loading, polymer filter, geared AC motor with frequency control by inverter, set of cowlings, frame, air and water cooling system, adjustable support rolls.

Initial part of barrel has helical grooves, which provides strictly proportional RPM and feeing of melt that guarantees stable and energy-saving buildup of pressure without pulsations. This, in turn, allows use of isobaric extrusion heads with heightened backpressures and better distribution of melt flow. Thermally stabilized extruders require no outer heating, nor cooling, just fine temperature tuning. This allows precise temperature control, work at higher RPM, higher specific trough output and lower specific power consumption.

The very high ratio of screw length to the diameter (L/D ratio) is 34:1 ensures an excellent homogeneity of a polymer melt, necessary for extrusion of films with high and stable physical-mechanical properties, stability and ease of operation. Extrusion presses perfectly process complicated mixtures of polymer raw material (i.e. LDPE, LLDPE and PIB) in different proportions.

Six zones of the temperature control of every press guarantee fine adjustment and complete uniformity of polymer melt temperatures. Cooling is provided by ventilators, located to the bottom of hoods, which evacuate warm air away from sensitive bubble forming area.

Extruders are equipped with maintenance-free asynchronous motor drives and silent gear boxes with unlimited work resource. Gear boxes have additional cooling system for hot climate conditions, unlimited service life thrust bearing. Rigid steel frame and mounting plates ensure simple alignment and excludes vibration.

Extrusion presses are most expensive and important part of the machine, so screw and barrel of ARSENAL extruders are made of aerospace grade alloys and are ion nitrated to surface hardness up to Vickers 1100 for substantial increase of endurance and durability.

Caliber of Extrusion press	45	60	75
Extruder class	High-pressure with rigid characteristic, heat stabilized
Feeding	Helical grooves
Screw type	Maillifer soft barrier screw with Gregory-Barr mixing spiral barrier, thermo balanced
Precision class	H7	H7	H7
Screw diameter, mm	Æ45	Æ60	Æ75
L/D ratio	34:1	34:1	34:1
Screw material	Crome-Moly alloy 38Cr2МoAl, hardened
Screw surface treatment and inner cylinder surface treatment	Nitration by ions treatment with mirror polishing
Cooling	Water-cooled feeding zone, air ventilators on 5 of 6 zones
Installed drive, kW	22,0	45,0	69,0
Number of temperature controlled zones in each extruders	4	6	6

EXTRUSION HEAD

The co-extrusion head is produced from high grade steel and passes thermal and galvanic treatment.

Design of the head is based on principle of the simultaneous joint of streams of melts at the expense of application of "telescopic" arrangement has allowed to maintain uniform thickness of film within each layer. The co-extrusion head is designed in Arsenal with software package Reodesigner ™ and Compuplast ™.

The software was developed in co-operation with Dubna Institute of Nuclear Physics. It allows to imitate and visualize behavior of melt trough complex channels thus optimizing residual time, pressure drop, self-cleaning ability, shear rates and other parameters to guarantee best film properties within extended range of extruded materials and outputs. Spiral Mandrel with 8 channels ensures excellent distribution of melt through every layer. The construction the extrusion head allows to reach minimum thickness of produced film. Co-extrusion heads are optimized to achieve lowest residual time and best self-cleaning ability at given tolerance variation of film thickness. We may guarantee thickness absolute variation within 7 per cent (minus 1 per cent if sigma purification is used) for every type of product and 5 per cent for most of films. In some cases (i.e. high melt index and low blow up ratios) thickness variation may be even better. The variation may be further halved by use of automatic system of thickness control.

Type of distributor	Concentric cylinders (“telescope”), with spiral Mandrell
Diameter of the die (typical range), mm	300 or 400 for low neck, 150 to 160 for high neck
Amount of temperature controlled zones:	3
Material of the head	Nickel-Chromium Alloy 40CrNi
Surface of the head and spiral channels	Chromium-plated and nitrated, polished
Feeding of cooling air	Central

The head is placed on a cart with wheels and convenient adjustments. The head has adapters with zero effect on tolerance variation, replaceable and powerful band heaters, sensors for temperature control system, gap adjusting screws.

Disassemble and cleaning is usually not necessary but it is fairly simple if necessary.

Ducts for internal cooling air are located in the best place along the central axis of the head that guarantees best distribution of temperatures along the die circumference.

The head is upgradeable for rotation and heat cartridges control of tolerance variation.

INTERNAL BUBBLE COOLING SYSTEM (IBCS)

PLC control unit of IBC continuously scan width of the bubble by thermo-corrected ultrasonic sensors. Adaptive control algorithms predict direction of corrective action in a wide range of operation factors for different kinds of production. This, in combination with modern vector control systems of air supply maintains size of bubble within 1 per cent on the wide range on used materials, thicknesses and bubble sizes.

Type	Automatic PLC controlled with ultrasonic bubble size sensors
High pressure ventilators	2 х 2,4 KW
Drives	Inverter
Type of a control system	Adaptive, with the extended range of pressure range inside the bubble
Types of air distributor	Two interchangeable designs, suitable for bubbles with short neck or long neck

CALIBRATION CAGE

The calibration/stabilizing cage has two electric drives to simplify positioning of cage along the bubble.

“Soft-touch” rollers exclude marks on surface of film.

Number of roll levels (tiers)	5
Number of combs	8
Sleeve diameter adjustment	Manual

FRAME

The three-storied frame of the line heightened rigidity ensures convenient access for operator to all parts of a line.

The height of the trestle platform ensures high efficiency of a line on all types of used polymeric raw material and standard sizes of a sleeve.

The system of a web wiring is ensured with lightweight dynamically balanced bypass rolls. Number of bypass rolls has special helicoids grooves for removal of the "folds" originating on linen along a trajectory of its movement to the winder.

The frame includes system of convenient ladders with a handrail, facilitating rise of operator to the upper levels. Fences of the trestle platform and an additional guard rod also ensure a guard from a falling. Ergonomic illumination of all floors of the trestle platform ensures necessary luminance on all sites of working space of a human controller of a line. Use of interchangeable typical members ensures fast mounting and modernizing of a line by a "designer" principle.

THICKNESS-METER FILMOSCAN

FILMOSCAN is a REAL-TIME film-measuring and gauge control system, based on a new generation of semiconductor infra-red sensors-emitters, providing precision up to HALF MICRON. This is the first and the only device of such accuracy, speed and convenience in the world today.

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