Process

Extrusion

Almost everyone is familiar with extruded semi-finished products such as pipes, windows or films, but they are often not familiar. Extrusion is a continuous process for the production of semi-finished plastic products with a wide variety of geometries. For high product quality, material, machine, process and quality assurance must be optimally coordinated in extrusion. At SKZ, the extrusion process is therefore researched holistically. For this purpose, various extruders as well as the necessary periphery for the production of pipes, films, profiles and foams are available in the processing technology center of the SKZ. The equipment is closely based on industrial plants, but is often expanded to include specific measurement technology. With the help of this equipment, existing manufacturing processes can be optimized, new processes developed and sample quantities produced. In addition to practical research and the implementation of the results obtained from this research in production applications, the focus of activities in the Extrusion Division is also on the implementation of customer-specific requirements.

An interdisciplinary team supports you in your tasks. Both the extensively equipped extrusion pilot plant and the accredited test laboratory make fast and uncomplicated processing possible. The entire range of materials can be processed, including PVC and WPC as well as high-performance polymers in addition to standard materials. Furthermore, the production of very small quantities of pipes, profiles or sheets is feasible. The processes and machines used for this purpose optimally enable the results to be scaled up to production scale.

Dipl.-Ing. Johannes Rudloff
Head of Department Material Development, Compounding and Extrusion
Würzburg
+49 931 4104-528
j.rudloff@skz.de

Services

Plant and process optimization

The continuous development of innovative materials and products as well as efforts to find economical and sustainable manufacturing processes make it necessary to optimize existing processes from these points of view. To this end, we work intensively on optimizations and improvements in our processing pilot plant in close cooperation with machine manufacturers. The equipment is closely oriented to the systems operated in industry and is available for you to work on your questions.

Characterization of materials and components
  • Physico-chemical properties
    • K-value according to DIN EN ISO 1628
    • Material density according to DIN EN ISO 1183
    • Bulk density according to DIN EN ISO 60
    • Pourability according to DIN EN ISO 6186
    • Material composition (e.g. with IR and EDX analysis, GC-MS)
    • Molar mass and distribution (GPC)
    • Shape, size and structure of PVC grains (SEM, dynamic imaging)
    • Glass transition by differential thermal analysis and/or dynamic mechanical analysis
    • Color, gloss, opacity
    • Topography determination and determination of surface roughness parameters according to DIN EN ISO 25178-2
    • Extraction resistance according to ASTM D1239
    • Water absorption according to DIN 53 495
    • Fogging according to DIN 75201 / SAE J 1756
    • Dichloromethane test according to DIN EN 580
       
  • Thermal properties
    • Dynamic thermostability (kneader measurements)
    • Plasticizing time (kneader measurements)
    • Static thermostability (DHC according to DIN EN ISO 53 381
    • Vicat softening point according to DIN EN ISO 75
    • Temperature and thermal conductivity according to DIN EN ISO 22007-4
  • Mechanical properties
    • Tensile properties according to DIN EN ISO 527 or ASTM D638
    • Charpy impact strength according to DIN EN ISO 179
    • Hardness according to DIN EN ISO 868 or ASTM D2240
    • Dynamic mechanical analysis (DMA)
    • Creep and creep rupture
    • Fatigue / endurance test
      ​​​​​​​
  • Plasticizer migration
    • Oven test
    • Plasticizer migration according to ISO 177
       
  • Aging and resistance
    • Hot, cold and climatic storage tests
    • If necessary in combination with chemical exposure
      ​​​​​​​
  • UV and weathering resistance
    • UV and xenon weathering tests, e.g. according to DIN EN ISO 48892-1/-2/-3 or DIN EN 513
    • Testing of weather fastness and weather resistance
      ​​​​​​​
  • Electrical properties
    • Volume resistivity and surface resistivity of solid, electrically insulating materials according to DIN IEC 93 or DIN 53 482
    • Determination of the comparative number and Prof number of creepage path formation on solid insulating materials under humid conditions (VDE determination) according to DIN IEC 60112
      ​​​​​​​
  • Fire behavior
    • Fire behavior according to UL94
    • Fire behavior according to DIN 13501
      ​​​​​​​
  • Characterization of various products,
    such as window profiles, foils, sheets, pipes and pipe joints, sports floors and sports products, according to national and international standards
  •  
Property determination

Part of our numerous customer and R&D activities is the production of test specimens from the various extruded components according to a wide range of standards.

Furthermore, we offer the possibility to produce customer-specific geometries that are not yet available.

For the subsequent component characterization (mechanical, thermal, application-specific properties) a wide range of testing machines is available.

Sampling production

On our extrusion lines, we enable you to produce samples, e.g. pipes, profiles, sheets, films from a wide range of thermoplastics, including temperature-sensitive ones such as PVC. Different extruders and tools with corresponding advantages and disadvantages regarding the achievable properties of the components can be used.

In addition, we offer the possibility to carry out samples of thermoplastics as well as a comparison of the processability and properties. This also includes polymers that are still under development.

Material development and compound production

In addition to the development of customer- and product-specific materials for extrusion, we offer the production of compounds according to your requirements in order to optimally prepare the materials for the extrusion process. For this purpose, various compounding machines (co-rotating twin-screw extruders, ring extruders, planetary roller extruders, KoKneter) are available in our processing technology center.

Training and Networking

As experts in the field of plastics technology, we strive to pass on the knowledge we have acquired over decades to our customers. From material development and manufacturing processes to the application of various testing and measuring methods - in our numerous practice-oriented training courses, you as a participant will acquire the necessary knowledge in dealing with plastics as a material. This begins with the selection of the right materials and compliance with production-oriented design rules, continues with the correct handling of equipment and machines for the manufacture and processing of plastic components and ends with the correct understanding of quality criteria and the associated use of testing and measuring tools.
Bringing together people from different areas of the company as well as from different industries to exchange experiences and technical know-how is also a top priority for us, in addition to the pure transfer of knowledge. Our numerous specialist events provide the ideal venue for a free exchange of ideas. Renowned speakers from a wide range of industries and excellent technical presentations make the SKZ conferences popular meeting places within the plastics industry.

To the section education

Prototype / development tools

The extrusion die is the core component of an extrusion line. However, there are production-related restrictions that must be taken into account when designing an extrusion die. To ensure that you reliably achieve the desired result, we support you in the design of your components, from the idea to the finished component.

Process analysis

The team consists of experienced engineers and technicians. During an on-site consultation, we can support you in process analysis and optimization as well as record almost all process-relevant and quality-determining measured variables in consultation.

Process measurement technology

With our experience in process measurement technology, SKZ is able to read and process essential parameters from the machines and control the processes accordingly. For this purpose, innovative sensors such as high-resolution pressure and temperature sensors as well as terahertz and ultrasonic systems are used to facilitate operation and improve quality.

Process data analysis

Modern extrusion lines supply large quantities of process data. This data can be analyzed, interpreted and used to derive decisions that improve processes. Process models can even be used to implement dynamic data-based process control.
We help you generate added value from your data!

Contact:
Christoph Kugler | +49 931 4104-457 | c.kugler@skz.de

To the section digitalization

Non-destructive testing

Would you like to obtain information about your extrudates that is not visible to the naked eye? SKZ offers the integration and, if necessary, individual adaptation of non-destructive testing methods for inline monitoring of extrudate quality and laboratory testing. In this way, you can, for example, detect defects hidden behind the surface, such as blowholes or flow fronts, which lead to reduced product quality and, if necessary, complaints. 

For this purpose, SKZ offers a cost-neutral assessment of your inspection task and enables comparative examinations with various methods based on thermography, terahertz, microwave and ultrasound technology, among others. 

Contact:
Giovanni Schober | +49 931 4104-464 | g.schober@skz.de

To the section measurement technology

Technical equipment

Extrusion

In our extrusion pilot plant, several extrusion lines, which include both single-screw and counter-rotating twin-screw extruders with tools and calibration, are available for your task. The tools of the SKZ can be used, but also samples with customer tools can be carried out. Thanks to the extensive equipment, it is possible to process the entire range of standard thermoplastics, shear-sensitive materials such as WPC and PVC, and high-temperature thermoplastics.

Single screw extruder

  • KME 1-45-30 B, KraussMaffei, München
  • KMBE 1-30-25 D, KraussMaffei, München
  • ZE45, Maschinenfabrik Weber, Kronach

 

    counter-rotating twin screw extruders

    • DS7.22, Maschinenfabrik Weber
    • CE3, Maschinenfabrik Weber
    • KMKK 40, KraussMaffei, München

    Extrusion tools

    Profile tools

    • Box profile - large
      Geometry: 100 x 50 mm
      Wall thickness: 2; 3; 4 mm
      Profile type: hollow chamber profile
      Material: PVC, PE, PP, WPC (e.g. PVC up to 50 % wood content)
      Coextrusion: yes
      Manufacturer: Gargiulo Extrusionstechnik
       
    • Box profile - small
      Geometry: 40 x 40 mm
      Wall thickness: 2; 4 mm
      Profile type: hollow chamber profile
      Material: PLA, WPC (e.g. PVC up to 50 % wood content)
      Coextrusion: yes
      Manufacturer: Beologic n. v.
       
    • Window profile
      Geometry: 70 mm wide
      Wall thickness: 3 mm (area for sampling
      Profile type: hollow chamber profile
      Material: WPC (e.g. PVC up to 50 % wood content)
      Coextrusion: yes
      Manufacturer: Technoplast
       
    • Shaft
      Geometry: 145 x 21 mm
      Wall thickness: 7 mm
      Profile type: solid profile
      Material: WPC (PE, PP, ≥ 70 % wood content)
      Coextrusion: no
      Manufacturer: Beologic n. v.
       
    • Wall panel
      Geometry: 140 x 16 mm
      wall thickness: 4 mm
      Profile type: hollow chamber profile
      Material: WPC (PP, PE, ≥ 70 % wood content).
      Coextrusion: yes
      Manufacturer: Beologic n. v.
       
    • Solid bar
      Geometry: Ø 48 x 1000 mm
      Profile type: solid profile
      Material: highly filled PP
      Coextrusion: no
      Manufacturer: SKZ
       

    Pipeheads

    • KM RKW33 PO
      Type: Spiral mandrel distributor
      Diameter: 32; 50; 75; 110; 160 mm
      Material: PE, PE-Xb,c, PP, PVDF, ABS, PA12
      Coextrusion: Outer jacket or color stripes
      Manufacturer: KraussMaffei

    • KM 3L-RKW30 PEX
      Type: spiral mandrel distributor
      Diameter: 32 mm
      Material: PE, PE-Xb,c, PP, adhesion promoter, EVOH
      Coextrusion: 3 layers
      Manufacturer: KraussMaffei

    • PVC pipehead
      Type:mandrel holder
      Diameter: 16; 32 mm
      Material: PVC
      Coextrusion: no
      Manufacturer: G&G Extrusionstechnik

    Foil nozzles

    • Wide slot die BD35 F.o.S LAB
      width: 350 mm
      Thickness: 0.1 to 4.0 mm
      Material: biopolymers
      Multilayer: no
      Manufacturer: Kuhne GmbH

    • Foil nozzle - large
      width: 350 mm
      Thickness: 0,2 to 4,0 mm
      Material: PE, PP, PS, PA, PC, TPE, (natural fiber) compounds
      Multilayer: no
      Manufacturer: Extrusion Dies Inc.

    • Foil die - small
      width: 100 mm
      Thickness: 0,1 to 0,5 mm
      Material: PVC-P, PET, PA, PS, PC
      multilayer: no
      Manufacturer: COLLIN Lab & Pilot Solutions GmbH / SKZ

    • Foil nozzle - small (PE-X)
      width: 100 mm
      Thickness: up to 1,0 mm
      Material: PEXa,b,c
      multilayer: no
      Manufacturer: SKZ
       

    Milling

    In plastics compounding, many materials are used in powder form for simplified handling or more efficient action. For the preparation of premixes, precise dosing of starting materials or better dispersion in the plastic matrix, the raw materials are often converted into powder form before processing. Grinding technology is used for this purpose.
     

    • Ultra Centrifugal Mill ZM 200
      Grinding principle: Rotor mill
      Achievable fineness: medium particle size adjustable
      (ring sieves from 6 mm up to 80 µm)
      Batch size: 10 g to 10 kg
      Cooling: nitrogen or dry ice (manual addition)
      Manufacturer: Retsch
       
    • Impact Disc Mill PU 180
      Grinding principle: Impact disk mill
      Achievable fineness: average particle size approx. 500 µm
      Batch size: up to 25 kg
      Manufacturer: Herbold Meckesheim
    Mixing

    The blending of different substances in a specific ratio is often used as preparation for extrusion. Especially in the preparation and processing of PVC-based formulations, the production of blends, the so-called dryblend, is essential.
     

    • Container mixer CM 80-H
      Container volume: 80 l
      Speed: up to 1000 min-1
      Batch: up to 40 kg
      Other features: Temperature control, mobile containers
      Manufacturer: Mixaco
    • Heating/cooling mixer FML 10 - KM23
      Heating mixer: volume 10 l, speed up to 4200 min-1
      Cooling mixer: volume 23 l, speed up to 500 min-1
      Batch: up to 3 kg
      Further features: possibility to add liquid components
      Manufacturer: Zeppelin Reimelt
    Pressing
    • Testing press P 300 P
      Available area: 297 x 297 mm
      Max. Temperature: 300 °C
      Max. Clamping force: 300 kN
      Manufacturer: COLLIN Lab & Pilot Solutions GmbH

    Other features:

    • Heating and cooling ramps as well as pressure ramps programmable
    • reproducible production of test specimens (foils and plates)
    • lamination of polymer masses with e.g. foils, metals, fibrous materials
       

    Selection of special processes

    Direct extrusion

    Direct processing combines preparation and processing. In this way, a finished product is created from individual formulation components in just one processing step. Due to the very gentle processing in "one heat", this process is ideally suited for temperature- and shear-sensitive materials. Another advantage of this process is the economic aspect. In addition to material selection and formulation development, process development and process optimization are also the focus of activities. Thanks to the experience gained from various research projects in the field of direct extrusion, SKZ is a competent partner for industry.

    Foam extrusion

    SKZ has been working on the foaming of thermoplastics in the extrusion process (chemical and physical foaming) for several years and can provide you with competent advice and support for your questions.
     

    • Gas dosing unit type Z400
      Throughput range: 10 - 500 g/h
      Manufacturer: Promix Solutions 

    • Cooling mixer type P1
      Manufacturer: Promix Solutions

    • Wide slot nozzle for physically foamed films and sheets.
      width: 350 mm
      thickness: 0,1 to 4,0 mm
      Manufacturer: Kuhne GmbH
    • Foam nozzle with different capillaries
      diameter: 1,8 to 5 mm
      Manufacturer: SKZ
       
    Processing of shear sensitive materials

    SKZ offers complete support in the development of products made of shear-sensitive plastics, such as PVC. Through many years of know-how and numerous facilities, SKZ is a competent partner for their questions and supports in different development stages of the product.

    Preparation and processing of dryblends and granules

    • Heating/cooling mixer type FML10 - KM23, Zeppelin Reimelt
    • Container mixer type CM 80-H, Mixaco
    • Press type P 300 P, COLLIN Lab & Pilot Solutions GmbH
    • Laboratory kneader of type Plasticorder PL200, Brabender
    • Rolling mill type Polystat 110, Schwabenthan
    • Single screw extruder type ZE45, Maschinenfabrik Weber
    • Counter-rotating twin screw extruder type DS 7.22, Maschinenfabrik Weber
    • Counter-rotating twin-screw extruders of type CE3, Maschinenfabrik Weber
    • Planetary roller extruder type TP-WE 70/800 M2, Entex, Bochum, Germany
    • Twin screw extruder type Teach-Line ZK25T, COLLIN Lab & Pilot Solutions GmbH
    • Various extrusion dies Profile dies, film dies, pipeheads

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