-SQA-SCOTTISH QUALIFICATIONS AUTHORITY
HIGHER NATIONAL UNIT SPECIFICATION
GENERAL INFORMATION
-Unit Number-
2570277
-Superclass-
XE
-Title-
ADVANCED GAS SHIELDED WELDING PROCESSES
-----------------------------------------DESCRIPTIONGENERAL COMPETENCE FOR UNIT: Developing an understanding of the
principles and applications of Advanced Gas Shielded Welding Processes.
OUTCOMES
1.
explain the operating principles and equipment functions of Advanced
TAGS welding processes;
2.
explain the operating principles and equipment functions of Advanced
MAGS welding processes;
3.
explain the operating principles and equipment functions of Robotics for
MAGS and TAGS welding processes.
CREDIT VALUE:
1 HN Credit
ACCESS STATEMENT: Access to this unit is at the discretion of the centre.
However, it would be beneficial if the candidate had competence in welding and
fabrication. This may be evidenced by possession of HN Units:
2570257
2570267
Tungsten Arc Gas Shielded Welding Process
Metal Arc Gas Shielded Welding Process
or similar qualifications or experience.
-----------------------------------------
Unit No. 2570277
Continuation
For further information contact: Committee and Administration Unit, SQA,
Hanover House, 24 Douglas Street, Glasgow G2 7NQ.
Additional copies of this unit may be purchased from SQA (Sales and Despatch
section). At the time of publication, the cost is £1.50 (minimum order £5.00).
2
Unit No. 2570277
Continuation
HIGHER NATIONAL UNIT SPECIFICATION
STATEMENT OF STANDARDS
UNIT NUMBER:
2570277
UNIT TITLE:
ADVANCED GAS SHIELDED WELDING PROCESSES
Acceptable performance in this unit will be the satisfactory achievement of the
standards set out in this part of the specification. All sections of the statement of
standards are mandatory and cannot be altered without reference to SQA.
OUTCOME
1.
EXPLAIN THE OPERATING PRINCIPLES AND EQUIPMENT
FUNCTIONS OF ADVANCED TAGS WELDING PROCESSES
PERFORMANCE CRITERIA
(a)
(b)
(c)
(d)
(e)
The identification of advanced developments in the TAGS welding
processes is correct.
The identification of variables affecting the arc conditions is
correct.
The identification of equipment components and connections is
correct.
The description of functions of equipment components is correct.
The principles of advanced TAGS Welding processes are
correctly explained.
RANGE STATEMENT
Processes: plasma welding; orbital; pulsed; spot welding.
EVIDENCE REQUIREMENTS
Written evidence is required to show that the candidate can outline the principles
and equipment functions of advanced TAGS welding processes, as specified in
PCs(a) to (e).
3
Unit No. 2570277
Continuation
OUTCOME
2.
EXPLAIN THE OPERATING PRINCIPLES AND EQUIPMENT
FUNCTIONS OF ADVANCED MAGS WELDING PROCESSES
PERFORMANCE CRITERIA
(a)
(b)
(c)
(d)
(e)
The identification of advanced developments in the MAGS
welding processes is correct.
The identification of variables affecting the arc conditions is
correct.
The identification of equipment components connections is
correct.
The description of functions of equipment components is correct.
Explain the operating principles of advanced MAGS welding
processes are correctly explained.
RANGE STATEMENT
Processes: synergic; orbital; pulsed; spot welding.
EVIDENCE REQUIREMENTS
Written evidence is required to show that the candidates can outline the
principles and equipment functions of advanced MAGS welding processes, as
specified as PCs (a) to (e).
OUTCOME
3.
EXPLAIN THE OPERATING PRINCIPLES AND EQUIPMENT
FUNCTIONS OF ROBOTICS FOR MAGS AND TAGS WELDING
PROCESSES
PERFORMANCE CRITERIA
(a)
(b)
(c)
(d)
(e)
(f)
The identification of robotic configurations used for TAGS and
MAGS welding processes is correct.
The identification and operation of robot control systems is
correct.
The description of safety features built into robot welding stations
is correct.
The identification of applications of robots for welding purposes is
correct.
The description of the operation of sensors for welding operations
is correct.
The principles of the use of robotics for MAGS and TAGS Welding
processes is correct.
4
Unit No. 2570277
Continuation
RANGE STATEMENT
Robot configurations: cartesian; polar and articulated arm.
Robot Programming: lead by nose; teach pendant; off line programming.
Safety features: light beams; pressure mats; safety fence; advantages and
disadvantages of each system.
Sensors: tactile sensors; non contacting sensors; process controlled sensors.
EVIDENCE REQUIREMENTS
Written evidence is required to show that the candidates can outline principles
and equipment functions for MAGS and TAGS welding processes, as specified
in PCs(a) to (f).
MERIT To gain a pass in this unit, a candidate must meet the standards set out
in the outcomes, performance criteria, range statements and evidence
requirements.
To achieve a merit in this unit, a candidate must demonstrate a superior or more
sophisticated level of performance. This may be demonstrated by:
(i)
(ii)
successfully achieving all outcomes at the first attempt;
showing a wide knowledge and understanding of the subject by justifying
the answers to the assessment using reasoned discussion for or against
a given decision.
-----------------------------------------
ASSESSMENT
In order to achieve this unit, candidates are required to present sufficient
evidence that they have met all the performance criteria for each outcome within
the range specified. Details of these requirements are given for each outcome.
The assessment instruments used should follow the general guidance offered by
the SQA assessment model and an integrative approach to assessment is
encouraged. (See references at the end of support notes).
Accurate records should be made of the assessment instruments used showing
how evidence is generated for each outcome and giving marking schemes
and/or checklists, etc. Records of candidates’ achievements should be kept.
These records will be available for external verification.
SPECIAL NEEDS
Proposals to modify outcomes, range statements or agreed assessment
arrangements should be discussed in the first place with the external verifier.
5
Unit No. 2570277
Continuation
 Copyright SQA 1997
Please note that this publication may be reproduced in whole or in part for
educational purposes provided that:
(i)
(ii)
no profit is derived from the reproduction;
if reproduced in part, the source is acknowledged.
6
Unit No. 2570277
Continuation
HIGHER NATIONAL UNIT SPECIFICATION
SUPPORT NOTES
UNIT NUMBER:
2570277
UNIT TITLE:
ADVANCED GAS SHIELDED WELDING PROCESSES
SUPPORT NOTES: This part of the unit specification is offered as guidance.
None of the sections of the support notes is mandatory.
NOTIONAL DESIGN LENGTH: SQA allocates a notional design length to a unit
on the basis of time estimated for achievement of the stated standards by a
candidate whose starting point is as described in the access statement. The
notional design length for this unit is 40 hours. The use of notional design length
for programme design and timetabling is advisory only.
PURPOSE This unit will familiarise candidates with the principles, equipment
functions and parameters of the Advanced T.A.G.S. and M.A.G.S. Welding
process, as well as an insight into robotics. On completion of this unit
candidates will be able to identify and describe all the equipment components
and outline the principles of robotics for advanced welding processes.
CONTENT/CONTEXT Corresponding to outcomes:
Outcome 1
The candidates should be able to identify the advanced TAGS welding
processes, namely:
PLASMA WELDING: The equipment used for plasma welding. The production
of the plasma jet should be explained in detail. Gases used in plasma welding.
The mechanisation of the process should be explained along with wire feed
mechanisms for this process. MICRO plasma systems should also be explained
with the facility for welding very thin material being a priority.
ORBITAL WELDING: All aspects of the equipment set up for orbital welding
should be explained.
Advantages and limitations should be discussed.
Materials weldabability and joint set up should be discussed in detail. Shielding
gases used, inserts for uniform penetration purging gases etc should be fully
explained.
PULSED TAGS: The power sources and ancillary equipment for pulsed TAGS
welding should be fully explained. Conventional TAGS and Pulsed TAGS
welding processes should be compared with regard to cost, speed of operation,
materials weldability etc.
7
Unit No. 2570277
Continuation
SPOT WELDING: The uses of TAGS welding equipment for spot welding should
be fully explained. Type of ancillary equipment required eg. timer, special
nozzles etc. Material thickness and types of material weldability should be
discussed.
In all these processes advantages and limitations should be discussed.
Equipment costs, portability etc should also be considered.
Outcome 2
The candidates should be able to identify the advanced MAGS welding
processes namely:
Synergic MAGS: All aspects of the synergic process should be fully explained.
Shielding gases used, torch types etc should be discussed. The advantages of
‘ONE KNOB’ control in synergic machines should be discussed.
Pulsed Spot Orbital: All aspects of these processes should be discussed as for
support notes for Outcome 1.
Outcome 3
The three types of robot operating characteristics should be fully explained ie.
Polar co-ordinate, Cartesian co-ordinate and articulated arm robot systems. The
advantages and limitations of each should be discussed.
Control systems for manipulators and robots should be fully discussed including
computer control, teach pendant control, lead by nose.
It is not envisaged that actual programming techniques are taught but an insight
into the types of control systems only be taught.
Automatic wire feed for TAGS robot systems to be discussed with limitations of
use pointed out.
A comparison between TAGS and MAGS robotic systems should be made with
regard to initial cost, speed, metals weldable, flexibility of processes etc. Safety
considerations for a robot welding station should be covered to include type of
accident that can happen, safety features built into robots ie. dead man’s handle,
programmed cut outs etc, braking systems, speed controls, fixed wire mesh
guarding, pressure pads or matting, infra red curtains, electro magnetic field
safety barriers.
The use of sensor devices used in robot welding operations should be fully
discussed. These Tactile (contact) sensors, non contacting sensors and process
controlled sensor devices.
TACTILE: feeler pins, rollers, slide sensors.
NON CONTACT: capacitive sensors, inductive sensors, ultrasonic sensors, laser
distance sensors, laser scanning sensors, video electronic sensors.
PROCESS CONTROLLED:
plasma deflection (magnetic), welding head
deflection (mechanical), double wire technique.
8
Unit No. 2570277
Continuation
Advantages and limitations of each sensoring method should be discussed.
APPROACHES TO GENERATING EVIDENCE
corresponding to outcomes.
As contained in context/context
ASSESSMENT PROCEDURES
Centres may use the Instruments of
Assessment which are considered to be the most appropriate.
Examples of Instruments of Assessment that could be used are as follows:
Outcome 1 PC(a) Written questions identifying advanced developments in
T.A.G.S. welding.
PC(b) Written question asking for an explanation of variables affecting arc
conditions and the reasons for these effects.
PC(c) Possibly a line drawing of Advanced T.A.G.S. set up asking for equipment
and connections to be identified.
PC(d) Written question asking for a description and use of three named
components.
PC(e) Written question asking for the principles of operations of an Advanced
T.A.G.S. welding process.
Outcome 2 As for outcome 1 but for Advanced M.A.G.S.
Outcome 3 Sufficient written questions to fully cover the range statement.
PROGRESSION
Successful completion of this unit would lead a fuller
understanding of more in depth robotics units.
REFERENCES
1.
2.
3.
4.
Guide to unit writing.
For a fuller discussion on assessment issues, please refer to SQA’s
Guide to Assessment.
Information for centres on SQA’s operating procedures is contained in
SQA’s Guide to Procedures.
For details of other SQA publications, please consult SQA’s publications
list.
 Copyright SQA 1997
Please note that this publication may be reproduced in whole or in part for
educational purposes provided that:
(i)
(ii)
no profit is derived from the reproduction;
if reproduced in part, the source is acknowledged.
9