Plastic Processing


Technologists can process quantities from a few grams of materials to hundreds of kilos. We deliver manufacture or compound development trials. Attention to detail is always evident, for example our equipment is stripped and cleaned before use to avoid potential contamination issues. Our technologists can select the most appropriate set-up, configure the machines and develop screw profiles to suit the process requirements.

  • Counter-rotating twin screw for PVC compounding
  • Small batch mixers are available to process as little as 20g. This is ideal for early evaluation and expensive additives.
  • Single screw compounding with or without cavity transfer mixer


A range of extrusion processes are available for manufacturing and sample production. We are equipped with a range of 25, 38, 45 and 50 mm single screw extruders to produce a range of different product types.

  • Custom - Dies are often developed to make individual products. Following the successful development of dies some contracts have become part of our continuing manufacturing service.

Injection molding

Small injection molding machines are available; these are typically used for producing test samples but can also be equipped with customer moulds for trials. In addition we can offer problem solving advice and process audits.

Materials Selection and Formulation

Smithers Rapra can provide advice on the most appropriate material or formulation to satisfy client requirements for a wide range of different projects. For demanding applications Smithers Rapra can tailor individual solutions to address specific issues relating to design, performance and durability.

After establishing the right material our technicians can prepare test pieces for mechanical and chemical characterization. Existing formulations can be re-designed to enhance existing performance.

Process Development

With almost an unrivalled position of having expertise in virtually every sector of the polymer industry Smithers Rapra advises on all aspects of the process, from tool design and scale up, through to complete line layout. Smithers Rapra consultants can create custom processes or tailor existing ones to solve difficult or novel applications.

Specialist production

Smithers undertake the manufacture of specialized or niche products for various industries including medical, security and aerospace. Our technologists are experienced in designing and utilizing small scale production lines and developing novel processing technology. The highest production standards are maintained by in house auditing systems to ensure product quality and consistency.

Smithers Cavity Transfer Mixer (CTM)

Developed by Smithers Rapra, the Cavity Transfer Mixer is a cost effective solution designed to increase the distributive mixing performance of a single screw extruder. The CTM can be retrofitted to both twin and single screw extruders. The device has found successful, industry wide application in areas ranging from polymer and color blending, liquid additive incorporation, through to reactive and direct product extrusion. A variation, the By-pass CTM has been designed specifically for skin coloring applications in the pipe and cable industries.