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Evidence Guide: CUVOPA09B - Use a faceting machine

Student: __________________________________________________

Signature: _________________________________________________

Tips for gathering evidence to demonstrate your skills

The important thing to remember when gathering evidence is that the more evidence the better - that is, the more evidence you gather to demonstrate your skills, the more confident an assessor can be that you have learned the skills not just at one point in time, but are continuing to apply and develop those skills (as opposed to just learning for the test!). Furthermore, one piece of evidence that you collect will not usualy demonstrate all the required criteria for a unit of competency, whereas multiple overlapping pieces of evidence will usually do the trick!

From the Wiki University

 

CUVOPA09B - Use a faceting machine

What evidence can you provide to prove your understanding of each of the following citeria?

Set up faceting equipment.

  1. Set up faceting machines to manufacturers' specifications identifying machine components and laps.
  2. Complete manufacturers' maintenance checklist.
  3. Investigate index wheels for quill and identify main and critical angles for opal.
Set up faceting machines to manufacturers' specifications identifying machine components and laps.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Complete manufacturers' maintenance checklist.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Investigate index wheels for quill and identify main and critical angles for opal.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

elect, pre-shape and dop selected opal piece.

  1. Select piece of opal suitable for faceting.
  2. Pre-shape using faceting machine or bench grinder to establish crown and pavilion.
  3. Dop stone, pavilion to be worked first (dop on crown).
Select piece of opal suitable for faceting.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Pre-shape using faceting machine or bench grinder to establish crown and pavilion.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Dop stone, pavilion to be worked first (dop on crown).

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Grind, sand and polish pavilion.

  1. Place dopped stone in quill and aligned to create girdle.
  2. Grind girdle to desired shape on medium to fine lap.
  3. Grind main facets at main angle on medium to fine lap.
  4. Grind girdle break facets at girdle break angle on fine lap.
  5. Grind culet facets at culet angle on fine or pre-polish lap.
  6. Fine lap, pre-polish and polish all pavilion facets including girdle.
Place dopped stone in quill and aligned to create girdle.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Grind girdle to desired shape on medium to fine lap.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Grind main facets at main angle on medium to fine lap.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Grind girdle break facets at girdle break angle on fine lap.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Grind culet facets at culet angle on fine or pre-polish lap.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Fine lap, pre-polish and polish all pavilion facets including girdle.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Transfer stone.

  1. Transfer stone to suitable dop.
  2. Remove crown dop and place new dop and stone in faceting quill.
Transfer stone to suitable dop.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Remove crown dop and place new dop and stone in faceting quill.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Grind, pre-polish and polish crown.

  1. Place girdle facet on lap at 90º, index setting 64 or 96 and lock quill.
  2. Grind girdle break facets at break angle establishing girdle thickness, on a medium to fine lap.
  3. Grind main facets at main angle on fine lap.
  4. Cut table facet on fine lap, to 40% of total width of stone.
  5. Pre-polish all crown facets.
  6. Grind star facets using pre-polish lap.
  7. Polish all facets.
  8. Remove stone from dop and clean.
Place girdle facet on lap at 90º, index setting 64 or 96 and lock quill.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Grind girdle break facets at break angle establishing girdle thickness, on a medium to fine lap.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Grind main facets at main angle on fine lap.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Cut table facet on fine lap, to 40% of total width of stone.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Pre-polish all crown facets.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Grind star facets using pre-polish lap.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Polish all facets.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Remove stone from dop and clean.

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Assessed

Teacher: ___________________________________ Date: _________

Signature: ________________________________________________

Comments:

 

 

 

 

 

 

 

 

Instructions to Assessors

Evidence Guide

The evidence guide provides advice on assessment and must be read in conjunction with the performance criteria, required skills and knowledge, range statement and the Assessment Guidelines for the Training Package.

Critical aspects for assessment and evidence required to demonstrate competency in this unit

To achieve competency in this unit, a person must be able to produce a faceted opal that satisfies industry standards.

The assessment must confirm the ability to select opal pieces suitable for faceting, and use faceting equipment to produce and polish a faceted opal that conforms to industry standards. All work must be done following OHS requirements for machinery and equipment procedures.

Competence in this unit must be assessed over a period of time in order to ensure consistency of performance over the range of variables and contexts applicable to the work environment.

Context of and specific resources for assessment

This unit may be assessed in a work environment, in a simulated work environment or in a combination of these situations.

Method of assessment

For valid and reliable assessment of this unit, evidence should be gathered through a range of methods to indicate consistent performance.

Assessment of this unit of competence will usually include observation of processes and procedures, oral and/or written questioning on underpinning knowledge and skills, evaluation of the final product and other methods as required.

Assessment methods should closely reflect workplace demands (e.g. literacy) and the needs of particular groups (e.g. people with disabilities, and people who may have literacy or numeracy difficulties such as speakers of languages other than English, remote communities and those with interrupted schooling).

Assessment of this competency requires access to:

a faceting machine and appropriate consumables

a qualified workplace assessor or assessment team.

Required Skills and Knowledge

Required skills:

faceting skills

grinding and polishing skills

equipment maintenance skills.

Required knowledge:

the suitability of opal pieces for faceting

opal faceting process - the equipment and consumables required

industry standards.

Range Statement

The range statement relates to the unit of competency as a whole. It allows for different work environments and situations that may affect performance. Bold italicised wording, if used in the performance criteria, is detailed below. Essential operating conditions that may be present with training and assessment (depending on the work situation needs of the candidate, accessibility of the item, and local industry and regional contexts) may also be included.

Faceting machines may include:

FACETRON (USA)

GEMMASTA (Aus)

GRAVES (USA)

Jamb-peg

Platform

POLY-METRICS (USA)

Post

RAYTECH (USA)

ULTRA TEC (USA).

Faceting machine components and laps may include:

components:

angle vernier (protractor)

coolant tank

forward/reverse switch

handpiece (quill)

height adjuster, coarse and fine

index wheel

master lap

radial vernier (cheater)

sliding post

variable speed control

laps:

angle vernier (protractor)

coolant tank

forward/reverse swit

handpiece (quill)

height adjuster, coarse and fine

index wheel

master lap

radial vernier (cheater)

sliding post

variable speed control.

Faceting laps diamond grit size may include:

coarse #80, #100, #120, #180

fine #800, #1000, #1200

medium #220, #320, #360, #400, #600

polish #14000, #50000, #10000

pre-polish #2400, #3000, #8000.

Maintenance checklist may include:

check electrics regularly for faults and water seepage

cover machine when not in use

keep all laps separate from each other

keep whole machine clean

oil and clean moving parts

read manufacturers manual and keep near machine.

Opal suitable for faceting may include:

Aus. Clear jelly opal

Aus. Electric blue opal

contra-luz

Mexican cherry opal

Mexican fire opal

any transparent opal.

Angles may include:

critical angle 43½º

crown main 43º

culet angle 44º

girdle breaks, main angle plus 6º to 15º

pavilion main 45º

star facets, main angle minus 15º

table facet 0º.