Rapid strides in the development of plastic processing machinery in India and increased levels of sophistication has not only expanded the scope for processing of different thermoplastics, but has also opened up exciting new avenues.

The U-PVC window market has undoubtedly been the rising star of the European PVC business in the last 30 years. Modest beginnings in Germany in the 60's and 70's and then UK and other European countries in the 80's provided the platform for rapid growth during the last 20 years.

An estimated 10,00,000 tons of PVC is consumed for window profiles - accounting for 60% of the Rigid Profile market & 13% of the total PVC Market in West European Countries. Germany, UK and France account for 85% of the total PVC Profile business in Europe. Besides new construction, there is an equal demand for replacement of windows in old buildings. Parts of Eastern Europe and Turkey have also seen considerable growth in the recent years.

The demand for PVC in USA is forecasted to grow by 2.7% pa to 75,00,000 tons by 2006, 74% of which is expected to come from the construction industry. The best opportunities are anticipated in PVC Pipes and Window Profiles, both of which are becoming increasingly popular in Asian countries; with China as the leading producer.

In the wide field of processing plastics, the extrusion of profiles form a significant portion. The rising popularity of the PVC Doors and Windows is not surprising considering its advantages as compared to conventional Alumunium and Wooden Doors and Windows :
- Long life, maintenance free and termite proof
- No surface preparation & surface treatment (Painting, Polishing & Anodizing) required
- Free of rot, corrosion and rust
- Fire retardant with self extinguishing property
- Excellent Dimensional stability on prolonged exposure to moisture and sun-rays
- Ease of installations - Labour and Time saving

Market Requirements and Critical success factors
Innovative Products, Fine Quality and Cost Competitiveness acts as catalysts to the successful profile manufacturer, as these are the factors dictated by market requirements and critical to the success of the manufacturer. Machines and systems must allow cost-effective manufacturing processes. The cost-conscious processor can reduce the operative costs and get excellent quality by selecting the right extrusion machinery and increasing the extrusion speed and efficiency.
Plants for Hi-Performance Profile Extrusion
Profile extrusion means the processing of thermoplastic raw materials into profiles or products on Twin Screw Extrusion Lines. These profiles are then fabricated to end user's requirements.As prerequisites for reliable extrusion process the following basic requirements have to be met :
- Superior compounding of PVC blend in High Speed Mixer Cooler.
- Consistent material quality (bulk density , flowability, rheology & temperature)
- Low wear of processing unit, die and calibrator.
- Proper reading of melt temperature and melt pressure
- Consistent properties of the cooling water ( flow rate, temperature , purity and hardness).
Twin Screw Extruder
The Twin screw extruder, as the plasticizing unit, must comply with quality and quantity requirements of the thermoplastics with features like :
- High screw torques & melt throughputs at low screw rpm.
- Material-saving plasticization and homogenization.
- Effective degassing.
- Low-pulse conveyance.
- Low screw and barrel wear & maintenance costs.
These features ensure high performance Profile Extrusion.
Downstream Equipments
In the downstream area, the calibrating and cooling section is the stability factor for profile quality.
Dies & Calibration
Cooling or shaping of the forming channels of the calibrating Dies, as well as controlling the coolant, as a function of the extrusion speed must guarantee that no deformation occur in the thermoplastic range.
Haul Off Units
Haul Off Units pull the profile with the optimum force to provide absolute uniformity. For RPVC profile sector, Caterpillar Haul-offs in various designs are used exclusively.
Cutting Saws
Profile Saws : The operating cycle takes place from bottom to top , the profile resting on the saw table during cutting operation.
Wider width Profile saws : The operating cycle takes place across the profile and are particularly suitable for wide profiles from 350mm and above. This is suitable for Single Panel Doors.
The Twin Screw Extrusion Line fulfills the exacting demands of high performance, excellent product quality and cost efficiency by consistent application of modern techniques.

(Contributed by Mr.Jyotish Joshipura - GM (Sales), Kabra Extrusiontechnik Ltd.)