Extrusion Lines
The Cold Feed Pin Type Extruder
Our cold feed pin type extruders are available in all prevalent extrusion screw diameters. We design our extruders to meet profile design, component specifications and compound characteristics.
| KGS extruder | |||||
|---|---|---|---|---|---|
| KGS extruder screw dia. *** |
Ratio | Pins | Output* | Max. speed | Drive rating |
| Type | (L/D) | kg/h | rpm | kW (approx.) | |
| 90 | 16 | 7x8 | 550 | 60 | 60 |
| 120 | 16 | 8x8 | 1000 | 55 | 110 |
| 150 | 16 | 9x8 | 2000 | 45 | 240 |
| 200 | 16 | 9x12 | 3400 | 35 | 320 |
| 250 | 16 | 10x12 | 5000 | 24 | 480 |
* depends on rubber compound and profile cross section
** depends on required extrudate temperature
*** other length/diameter (L/D) ratios on request
The Locking System
Our patented locking system within the extrusion head effortlessly
absorbs the forces of the extruded compounds and reliably seals the
flow channel surfaces. Forces of up to 350 bar can be absorbed. A
safety shutdown sequence will automatically open the extrusion head
should this value ever be exceeded.
The use of hydraulic pressure and an oscillating rotation are the
hallmarks of our hammerhead locking system (1-3). The design of the
retractable locking system allows a close proximity to the flow
channels which enhances accessibility, operability and maintainability.
The MODULAR INSERT System
Important access areas can be opened individually to facilitate the change of inserts and/or compounds. This reduces changeover times and increases flexibility. Depending on the product (e.g. tread or sidewall), the system is adapted within the flow channel insert. In this case, individual lateral restrictors and humps correspond with the dimensions of the extruded product.
|
|
|
Duplex extrusion head with opened insert and compound levels |
|
Upper channel open |
Lower channel open |
System Description
The MODULAR INSERT System is Harburg-Freudenberger's concept for the
reduction of profile changeover times which is geared towards individual extrusion channels.
Configuration for MW 350 mm
Configuration for MW 650 mm
Basic insert, empty
The MODULAR INSERT System
Important access areas can be opened individually to facilitate the change of inserts and/or compounds. This reduces changeover times and increases flexibility.Depending on the product (e.g. tread or sidewall), the system is adapted within the flow channel insert. In this case, individual lateral restrictors and humps correspond with the dimensions of the extruded product.
The Feed Roller Concept
Our feed roller has been a success story for many years. Its longevity, accessibility, simple opening mechanism and maintainability are features our customers value. The slab feeder steadily guides the slab to the feed roller, which in turn guides the slab to the extrusion screw.
At our Freudenberger testing facility we test our extrusion screws
based on theoretic design methods while taking our many years of
experience into account. The results obtained determine the extrusion
screw geometry variation that will enhance the productivity of new
extrusion lines. In essence this concerns homogenization, high output
and combi screws. Our customers use the insights won through
consequential enhancement of existing extrusion screw designs to
replace traditional extrusion screws - when changing to more modern
compound, output and/or temperature requirements. In such cases we also
offer qualified test runs at our Freudenberger testing facility.
The diagram to the left shows an example of a comparison test for
extrusion screw performance. The parameters analyze the performance of
two different extrusion screw types run under identical testing
conditions. The results show that systematic extrusion screw research
work can increase productivity between 5 and 30 %.
Feed roller in maintenance position
The Upstream Equipment
The illustration shows the entire structure of the upstream equipment using a quadruplex extrusion unit with feeding devices as an example. In addition, the importance of the supporting structure needed for the pre-assembly of the extruders and the extrusion head is clearly visible.
The Downstream Equipment
The downstream equipment assembly groups are determined by the profile which is to be produced. This could be tread, sidewall or innerliner. Downstream equipment is a collective term which encompasses the assembly groups which follow the extrusion head, such as:
- shrinkage roller conveyor
- continuous scale
- camera systems
- marking devices
- calender (if requested)
- cooling line
- skiver
- winders or handbooking units
The Cooling Line Concept
Today, cooling line technology comprises immersion cooling, spray
cooling, air cooling and drum steel band cooling. Cooling lines are
designed to meet specific tasks and output profiles. The inlet and
outlet temperature as well as the compound characteristics and the
profile thickness are of special importance. The required cooling
capacity is determined by the necessary retention time and the
thickness of the profile. That is why the cooling system is usually
specified by the customer.
As every cooling system has process limits, we continuously strive
for enhancements which optimize output and economic efficiency. The two
diagrams on the left show the performance of various cooling methods;
the upper diagram - for thinner profiles - shows how our newly designed
"AirEco-Cool" decreases cooling time and why it is much better suited
to enable the shortening of cooling lines than conventional air cooling
systems. Within certain process parameters, AirEco-Cool has
considerable advantages over immersion, drum or spray cooling when it
comes to process and economic efficiency.
The lower diagram, by contrast, shows why (water) spray cooling is
still an option for thicker profiles. Harburg-Freudenberger offers
cooling lines for brand new production facilities and for retrofitting.
The Skiver
The Skiver made by Harburg-Freudenberger combines high cutting accuracy with short cutting cycles. The cutting angle can be freely adjusted with regard to the profile surface and to the direction of production. Our program includes double cross cutting action for treads.
| Description | Skiver 650 | Skiver 900 |
|---|---|---|
| Max. tread length approx. mm | 2540 | 4000 |
| Knife diameter mm | 500 | 500 |
| Tread thickness mm | 30 | 30 |
| Cutting angle to extrusion line | 70° - 90° | 70° - 90° |
| Cutting angle to tread | 20° - 40° | 20° - 40° |
| Mechanical accuracy mm | ± 0,5 | ± 0,5 |
| Number of cuts * per minute | 26 | 18 |
* The effective number of cuts (pieces per min.) is related to the line speed, depending on cutting length and width.
Process Control and Recipe Management
The process data is stored in the recipe menu as part of the customized process automatization and visualization.
Important messages which need not be continuously monitored by the
operator can be recorded and evaluated later for quality assurance
purposes. The HMI user interface with PLC background covers the
following main tasks:
- monitoring
- operating
- entering recipes
- recording faults and fault locations
- collecting machine running time data
- collecting operation data
An example of process control and recipe management for the skiver
Winding Technology for Sidewalls and Treads
All important details concerning the design and technology of the winders are discussed with the customer. The illustration to the left shows an example of winding technology as designed for a customer. Cassette winding technology is also possible for all profiles. length of treads cut offset cutting width loop sensor checkweigher speed checkweigher
Speed and Tension Control of Product Strip
Various dancer types are used for speed and tension control of the product
strip.
Usually, mechanical roller dancers, load cells and non-contact loop
controls (light curtains) are used. Angle and pressure points are
essential for stress-free operation. It goes without saying that
self-threading is optionally available for all dancer types. The dancer
is designed to enable:
- minimum tension adjustment and displacement
- adjustable pressure point
- operation data setting via recipe
- hinged roller arm at the upper limit of travel for self-threading procedures
The recipe settings and/or the HMI interface make it clear which values are possible for an individual product via angle and preset force.
