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Evidence Guide: CUVOPA404A - Cut opal spheres and beads

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

 

CUVOPA404A - Cut opal spheres and beads

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

Set up machinery and equipment

  1. Set up bead mill, sphere-making equipment and drills to manufacturers’ specifications
  2. Identify the maintenance areas and complete the required maintenance routine
  3. Investigate other methods of making spheres and beads if commercial equipment is not available
Set up bead mill, sphere-making equipment and drills to manufacturers’ specifications

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Identify the maintenance areas and complete the required maintenance routine

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Investigate other methods of making spheres and beads if commercial equipment is not available

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Select and pre-form material

  1. Select materials suitable for making spheres or beads
  2. Preform opal using saw or grinder to produce required shape
  3. Grind shape corners to establish rounded form
Select materials suitable for making spheres or beads

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Preform opal using saw or grinder to produce required shape

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Grind shape corners to establish rounded form

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Produce opal bead

  1. Fill holder template with pre-formed beads (range of shapes)
  2. Grind pre-formed beads in bead mill using #120 silicon carbide powder until they are rounded
  3. Change the holder template to a small size if necessary
  4. Remove faulty or broken opal from the bead mill
  5. Remove beads from the bead mill and clean
Fill holder template with pre-formed beads (range of shapes)

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Grind pre-formed beads in bead mill using #120 silicon carbide powder until they are rounded

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Change the holder template to a small size if necessary

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Remove faulty or broken opal from the bead mill

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Remove beads from the bead mill and clean

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Drill beads

  1. Select beads for drilling
  2. Place bead in bead vice, drill half way into the bead, turn over, check alignment and drill the other half ensuring a cut hole through the bead
Select beads for drilling

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Place bead in bead vice, drill half way into the bead, turn over, check alignment and drill the other half ensuring a cut hole through the bead

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Polish beads

  1. Place cleaned beads in tumble polisher with increasingly fine grinding medium
  2. Clean tumbler and beads at every change over
  3. Clean beads thoroughly after the final grind, place in the tumbler with polishing medium and tumble to a high lustre
  4. Clean finished beads thoroughly with water
Place cleaned beads in tumble polisher with increasingly fine grinding medium

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Clean tumbler and beads at every change over

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Clean beads thoroughly after the final grind, place in the tumbler with polishing medium and tumble to a high lustre

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Clean finished beads thoroughly with water

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Produce opal spheres

  1. Select opals to make spheres and pre-form the spheres
  2. Grind the spheres in a sphere maker with water and increasingly fine grinding medium
  3. Clean spheres thoroughly at each change over
  4. Polish cleaned sphere with polishing medium and water using leather sphere cups to desired polish
Select opals to make spheres and pre-form the spheres

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Grind the spheres in a sphere maker with water and increasingly fine grinding medium

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Clean spheres thoroughly at each change over

Completed
Date:

Teacher:		 Evidence:

 

 

 

 

 

 

 

Polish cleaned sphere with polishing medium and water using leather sphere cups to desired polish

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:

identify and safely use machinery and equipment to cut and polish opal beads and spheres to meet the requirements of industry.

Context of and specific resources for assessment

Assessment must ensure access to:

machinery, equipment and consumables required to produce opal beads and spheres.

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 finished product

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 investigate other methods of making spheres and beads where commercial equipment isn’t available

planning and organising skills to organise required materials

problem-solving skills to deal with contingencies

numeracy skills to use numerical features of machinery

technical skills to:

use appropriate machinery and equipment

select appropriate material for beads and spheres.

Required knowledge

suitability of rough for production of beads and spheres, taking into account the level of wastage and cost

equipment and consumables needed for the process

industry standards for opal beads and spheres

OHS issues related to machinery.

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.

Bead mill, sphere making equipment and drills may include:

Arrowhead Gemcraft (USA) Sphere Machine

E & J Adams Lapidary (USA) Sphere Machine

home-made equipment

Mahashi (Japan) Bead Mill

Richardson’s (USA) Sphere Machine.

Maintenance areas may include:

bead mill:

all bearings

all electrics

bead holders and wear factor

bottom rotating disc and wear factor

rubber pad on top rotating disc

sphere makers:

all electrics

assorted sphere cups

polishing pads

reduction boxes.

Materials suitable for making spheres and beads may include:

any opal material, taking into account a yield factor or recovery rate of only 10% to 15% from a given ounce of rough opal

beads of a variety of regular or free form shapes

spheres cut from any opal material, with consideration of yield factor.

Grinding mediums may include:

diamond powder #80 through to #1200

silicon carbide grit #80 through to #1200.

Polishing mediums may include:

cerium or tin oxide

diamond powder #3000 through to #100,000.