Elements and Performance Criteria

This competency unit includes the processes required to weld plastic pipe, sheet and film materials to a required specification, including continuous production operations on specialised welding equipment, and often involves the use of ancillary equipment.

Materials may be from a range of thermoplastic materials in the form of pipeline systems and component parts, sheet where used in sequenced production operations including vinyl product fabrication, and film where associated with continuous production operations.

It includes the operation of hot plate (heated tool), extrusion, high frequency sound (ultrasonic), electrostatic (radio frequency) and thermal induction (heat) welding systems and production machinery designed for sequenced or continuous production operations, and all relevant ancillary equipment.

Procedures means all relevant workplace procedures, work instructions, temporary instructions and relevant industry and government codes and standards.

This competency includes tools and equipment such as:
welding equipment and machinery
hand tools as required
relevant personal protective equipment.

Typical hazards include:
fumes from overheating or poor ventilation
cuts from sharp edges on components
burns from manual handling
eye injury
welding equipment, ancillary plant, parts and attachments.

Respond to/rectify 'non-routine problems' means 'apply known solutions to a variety of predictable problems'.

Typical problems include:
component materials incompatible or not to specification
incorrect alignment or assembly in welding process
welding edge, joint, fillet, gusset or seam not suitable for welding
material feed systems not correctly sequenced (continuous production)
incorrect selection of welding process
surface moisture contacting welding or fusion points
misalignment of welding contacts or die components
sequencing problems, procedure too fast or too slow
incorrect materials selected
poor surface preparation
bonding problems, weld does not meet specification
surface and finish defects.

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

Essential knowledge and enterprise requirements:
Application of knowledge of the materials, equipment and process sufficient to recognise material and equipment conditions which may lead to out of specification production in sequenced or continuous welding of plastic pipe, sheet and film materials.
Knowledge of the enterprise's procedures and relevant regulatory requirements along with the ability to implement them within appropriate time constraints and work standards.

Competence includes the ability for the practical completion of the job to:
apply and/or explain:
different types of plastic materials and their suitability for welding operations
behaviour of different types of plastic materials in welding processes
different welding equipment and procedures and suitability for materials
identify:
control of equipment used in welding
types of welding process used
list and describe:
routine faults in products
routine problems in process
distinguish between causes of faults such as:
materials, laminates
changes to materials during the welding process
equipment - adjustments/set-up
equipment - maintenance requirements.

Critical aspects
It is essential that competence is demonstrated in the ability to:
recognise the importance of material properties and qualities
apply approved procedures
take appropriate action to resolve faults or report faults to appropriate personnel
explain and implement emergency shutdown procedures.

Consistent performance should be demonstrated. In particular look to see that:
welding production standards are met consistently
upstream and down stream communication is timely and effective
operating procedures and work instructions are read and interpreted correctly
problems are identified and appropriate action is taken (i.e., the problem is fixed or reported)
all safety procedures are followed.

Language, literacy and numeracy requirements
This unit requires the ability to read and interpret typical product specifications, job sheets and material labels as provided to operators.
Writing is required to the level of completing workplace forms.
Basic numeracy is also required to interpret specifications and make measurements.

Assessment method and context
Competence in this unit may be assessed:
on an operating plant allowing for operation under all normal and a range of abnormal conditions
by use of a suitable simulation and/or a range of case studies/scenarios
by a combination of these techniques.

In all cases it is expected that practical assessment will be combined with targeted questioning to assess the underpinning knowledge and theoretical assessment will be combined with appropriate practical/simulation or similar assessment.

Resource implications
This section should be read in conjunction with the range of variables for this unit of competency. Resources required include suitable access to an operating plant or equipment that allows for appropriate and realistic simulation. A bank of case studies/scenarios and questions will also be required to the extent that they form part of the assessment method. Questioning may take place either in the workplace, or in an adjacent, quiet facility such as an office or lunchroom. No other special resources are required.