• Thermoplastic Fabrication

    OVERVIEW

    “Plastic fabrications for Industry have come of age – they are the new steel, but unfortunately product and process development has far outstripped progress in terms of Design, Construction Quality Assurance and Welding Competency requirements for fabrication work which is of great concern. Improvements in these areas are needed in the immediate term to ensure that the highest possible levels of quality and safety are attained at all times and which can only be achieved by formal regulation being introduced at the highest level.........” 
    Jonathan Sykes (Managing Director, Plasweld Ltd.)

    The Industrial Fabrication process of Thermoplastics is a secondary manufacturing process which can be defined as the use and further modification of primary manufactured sheet, pipe, lining and moulded or formed profiles using compatible materials and welding methods to produce a final product or system which can be used in conjunction with or in isolation from non-thermoplastic materials in the provision of a service, facility, system or process in a diverse range of Industrial applications. 

    Typical Materials Used  

    Low Density Polyethylene LDPE
    Linear Low Density Polyethylene LLDPE
    High Density Polyethylene HDPE
    Poly Vinyl Chloride PVC
    Polypropylene Co Polymer PPc
    Polyvinylidenefluoride PVDF
        
     


    All used in the production of Primary products such as:
    THICK SHEETS & PLAQUES
    PIPES – SMALL & LARGE DIAMETER
    GEOMEMBRANE LININGS & other GEOSYNTETICS (Geotextiles, Geonets, Geogrids, Geocells, Geodrains, Drainage Composites etc)

    Plastic Tank   TYPICAL PRODUCTS PRODUCED:
    As described previously, the products which are produced are essential those born out of a Secondary manufacturing and welding process to produce:
    • Vessels and Tanks for liquid and chemical storage
    • Pipelines, branches, manifolds and knock-out pots for the water, gas and landfill Industries
    • Spray booths
    • Plastic Skids
    • Feed Troughs and Silos
    • Ductwork
    • Special Forms and Bespoke Fabrications for the aquatic, aquaculture and process industries
    • Bunds
    • Prefabricated Liner modules for water features and Ponds
    • Installed liner systems for Environmental protection in Landfills , Industrial sites and Mining.
         
     Butt Fusion Welding Machine  
    PROCESS
    The Final product or fabricated system will result from a rigorous process of Design, Polymer product selection, Manufacturing Quality assurance of primary product, welding techniques, method statement, risk assessment, Construction quality assurance, Selection criteria of welding technicians and fabricators and proof of their Competency to pre-defined standards. 
    The process of Industrial Thermoplastic Fabrication is fundamentally one which still requires a large degree of manual input and expertise, particularly in the employment of welding systems and methods and therefore such activities should be supported by experienced welding technicians and fabricators who possess the relevant qualifications supported by valid certification.
    Other than the use of machines such as CNC cutters and routers and heating and bending machines to shape and cut forms in sheets where large numbers of similarly proportioned components are required, the process of measuring, cutting, sizing, preparing and welding for assembly is essentially a manually driven exercise where the human element is crucial to the quality of the end product.
         
    Plastic welding in Industrial Fabrication
    Plastic welding requires set parameters, whether using fully automated systems or manual welding techniques. These parameters are: Temperature, Pressure and Speed/time.  
    There is also the need for cleanliness of the work piece, the weld/filler rod and the working environment, as any contamination will reduce the long term weld performance of the fabrication.  Preparation of the surface to be welded is also specific to the type of material, profile / thickness and polymer being used. 
    As manual welding processes are dependant on the expertise of the individual, it is imperative that the welding operator has successfully completed a formal and recognised Plastic Welding Training course or better still has obtained qualification by formal Examination. This will not only make the fabricator better positioned to secure critical and intricate work, but will also ensure that the highest possible level of quality and safety is achieved at all times. 

    Plasweld Ltd has recognised certain needs and deficiencies in the Industry to the extent that it has initiated the formation of an Industrial Plastic Fabrications Interest Group (IPFIG) under the auspices of the BPF. This Group will be instrumental in providing direction to the Industry in terms of introducing statutes, standards and procedures for the safe and sustainable practices involving Plastic Fabrication Materials, Personnel, and Equipment as well as representing the UK on an International basis and serving its members nationally by acting as its voice, representing their needs and exchanging and disseminating technical information through papers, seminars and technical meetings.
    Plasweld Ltd. has therefore established its key objectives to serve all facets of the fabrication Industry in not only providing a high quality fabrication service based on all elements of its Welder Training & Certification programmes, but also to provide installation and repair services using experienced and qualified staff whilst providing Training and Formal Certification in welding techniques to EN 13067 “Plastics welding personnel – Qualification testing of welders – Thermoplastics welded assemblies” which are independently assessed by Lloyd’s Register EMEA.
    The main processes in the Design, Construct and Implementation phases of Thermoplastic fabrication projects include the following key stage considerations and which, it is suggested should be regarded as Minimum requirements in the provision of any Plastic Fabrication Service:
      Extrusion Welding Fabrication

    Extrusion Welding of Internal Liner

    Welded Bespoke Fabrication
    Design 
    Assessment of operational and maintenance criteria, capacities, stored and throughput temperatures, working and standing pressures, design Life assessments, colour, weather resistance, etc.
    Who is qualified to undertake the design and to what level?

    Polymer product selection
    Based on compatibility and resistance to the stored liquids and / or gases in the long term, based on the operational needs of the final product.

    Manufacturing Quality Assurance of primary product
    Based on the products being supplied for fabrication being proven to satisfy design parameters and selected product specifications by way of batch and conformance certificates.

    Welding techniques, methods and equipment
    Based on approved welding equipment and apparatus which is fit- for purpose, suitably calibrated and carry PAT certificates.

    Method statement & Risk assessment
    As required for any standard Construction project based on accepted modus operandi and project specific assessments of risk.

    Construction Quality Assurance
    Based on project specific requirements for stated visual inspections and reports, destructive and non –destructive testing of welded samples, start up tests, use of externally certified laboratories for confirmation of weld integrity, frequency and position of tests, definition of test type and method, hydraulic testing etc.