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Evidence Guide: CUVOPA403A - 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

 

CUVOPA403A - 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:

 

 

 

 

 

 

 

Select, 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 and work on pavilion first
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 and work on pavilion first

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Grind, sand and polish pavilion

  1. Place dopped stone in quill and align 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 align 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.

Overview of assessment

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

Evidence of the ability to:

select opal pieces suitable for faceting

use faceting equipment to produce and polish a faceted opal that conforms to industry standards

follow all OHS requirements for machinery and equipment procedures.

Context of and specific resources for assessment

Assessment must ensure access to:

a faceting machine

appropriate consumables.

Method of assessment

A range of assessment methods should be used to assess practical skills and knowledge. The following examples are appropriate for this unit:

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

review of portfolios of evidence

review of third-party workplace reports of on-the-job performance by candidate.

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).

Guidance information for assessment

Holistic assessment with other units relevant to the industry sector workplace and job role is recommended.

Required Skills and Knowledge

Required skills

critical thinking and analytical skills to select appropriate opal pieces

problem-solving skills to deal with contingencies and OHS issues

numeracy skills to use numerical features of machinery

technical skills to:

facet, grind and polish stones and maintain equipment

set up equipment to manufacturer specifications.

Required knowledge

suitability of opal pieces for faceting

equipment and consumables required for opal faceting process

industry standards for faceting.

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).

Machine components may include:

angle vernier (protractor)

coarse and fine height adjuster

coolant tank

forward and reverse switch

handpiece (quill)

index wheel

master lap

radial vernier (cheater)

sliding post

variable speed control.

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 manufacturer manual and keep near machine.

Opal suitable for faceting may include:

Australian clear jelly opal

Australian 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.