Elements and Performance Criteria

This competency unit includes the extrusion and injection welding of PE, PP, ABS, HIPS and PVC plastics components using electrical and pneumatic activated welding equipment.

It also includes the operation of all relevant ancillary equipment to assemble components prior to welding.

Specifications includes national standards for materials (AS 1886), workplace specifications and instructions, and government codes and regulations.

This competency requires the use of:
electrical activated extrusion welding machines
electrical/pneumatic activated injection welding machines
measurement devices including, timers, temperature probes and callipers
cleaning fluids and spray equipment
plastics machining equipment and assembly jigs
relevant safety equipment
comprehensive work instructions.

Typical hazards include:
hazardous cleaning fluids
plastics sheet material handling
heavy stationary and moving machinery, cutting and heating components.

Routine problems include:
variable plastics sheet material grades and supplied welding rods/granules
equipment malfunction, wear and tear
variable factory and field site conditions

All operations are required to be performed in accordance with standard procedures and work instructions.

Essential knowledge and enterprise requirements:
Knowledge and understanding of PE, PP, ABS, HIPS and PVC materials and welding rods/granules as described in national standards to recognise welding compatibility and suitability.
Knowledge of detailed work instructions necessary to perform extrusion and injection welding, and the ability to implement these within required parameters to attain required quality outcomes.

Competence includes the ability to:
identify substrate and welding materials being used
identify welding conditions for individual machine types and component materials
maintain and adjust operating conditions in welding machines
set up and maintain safe working environment
operate welding machines within required conditions
assess quality of completed welded joints
identify and rectify fault causes arising from machine operation and component variability
establish and maintain quality records
as relevant for the practical completion of work required.

Critical aspects
Consistent achievement of required quality standards is critical.

Language, literacy and numeracy requirements
Read material which is sequenced for instructions, explanations, information or opinions.
Write short and simple messages about routine tasks or activities, or complete forms.
Use hands-on real-life materials and pictures/diagrams based on personal experience and prior knowledge.
Use several pieces of related mathematical information.
Read, write and speak whole numbers and money sums, recognise and interpret simple fractions, decimals and percentages, use simple data, grid references.
Uses simple grammatical forms and vocabulary to give instructions, give explanations, ask questions and express viewpoints.
Clarify intended meaning by asking for repetition when listening, and varying speed and changing tone or emphasis when speaking.
Use strategies such as providing verbal and non-verbal feedback in order to show interest or attitude.

Assessment method and context
Current competence in this unit may be assessed by the combination of:
practical workshop welding exercises
completion of a short answer questionnaire
identification and application of individual welding conditions
in-course workshop style discussions.

Resource implications
Hardware:
This section should be read in conjunction with the range of variables for this unit of competency. Resources required include suitable electrical powered and air workshop facilities, and classroom space with visual support aids, specialised electrically activated extrusion welders, electrical/pneumatic activated injection welders, measuring and monitoring control devices for time and temperature, necessary PE component samples and material ancillaries, and plastics machining facilities to cut and shape abutting ends of plastics component sheeting.

Software:
This section should be read in conjunction with the range of variables for this unit of competency. Resources required include comprehensive training resource manuals and support visual aids derived from field experience activities. Presenters require specialised training and field experience in PE, PP, ABS, HIPS and PVC materials, plastics welding technology and material testing.