QETA/047 Advanced turning Credit Value 10 QCF Level 3 GLH 75 Unit purpose/aims Learner pack This unit enables you to acquire the essential background knowledge relating to advanced centre lathe turning including turning techniques, tools, workholding equipment used and methods of checking turned components against specification Summary of learning outcomes You will: 47.1 Understand centre lathe and ancillary equipment construction and nomenclature 47.2 Understand lathe tool selection criteria and the ISO coding for replaceable/indexable inserts and holders 47.3 Understand the factors affecting the turning of a range of common engineering materials 47.4 Understand basic calculations required by turning operations 47.5 Understand techniques used for holding and turning eccentric/non-circular components 47.6 Understand the use of fixed and travelling steadies 47.7 Understand advanced turning techniques Assessment of the unit This unit is assessed by an internally marked multiple-choice question paper which assesses underpinning knowledge for outcomes 47.1 to 47.9 ands also two internally assessed practical assessments. Page 1 of 17
Unit 47 Learner instructions Internal assessment 47.4 and 47.5 WHY are we doing this? To demonstrate an awareness of the calculations involved when balancing an eccentric of non circular load on a face plate WHAT do we need? Calculator, paper, ruler and protractor HOW do we make a start? Observe health and safety procedures at all times. 1. Balancing a faceplate Two weights, one of 1.5kg at an angle of 135 o and a radius of 100mm, the other of 2.0kg at an angle of 30 o and radius of 80mm are to be balanced using a single mass of 3.0kg. Calculate the position in which the balancing mass is to be fixed. A 1.5kg 100mm 80mm B 2.0kg 45 o 30 o C 3.0kg Page 2 of 17
Unit 47 Solution Internal assessment 47.4 and 47.5 1. Balancing a faceplate Using a balance weight of 3kg; Vector values:- A = 100 x 1.5 = 150kg.mm @ 135 deg B = 80 x 2.0 = 160kg.mm @ 30 deg Measured values for C 189kg.mm @ 260 o For a mass of 3kg, this gives a radius of 189/3 = 63mm B (160) A (150) C Therefore the balancing mass of 3kg needs to be fixed at an angle of 260 o and a radius of 63mm. NB. Calculation gives values of 188.9kg.mm @ 260.09 o Page 3 of 17
Unit 47 Learner instructions Internal assessment 47.1, 47.2, 47.3, 47.4, 47.6, 47.7, 47.8 and 47.9 WHY are we doing this? To demonstrate that you can work safely in a machining, (turning) environment To demonstrate that you can use Centre Lathe and ancillary equipment to machine a group of components that is designed to fit and operate together To demonstrate your knowledge of the Centre Lathe and its specification, workholding equipment, cutting tools and materials, basic calculations, techniques employed for machining differing materials in a variety of conditions and the use of ancillary equipment to produce a relatively complex component WHAT do we need? Learner instructions and drawings Learner report sheet Bright drawn mild steel, brass or aluminium bar, 38mm square; bright drawn mild steel bar, 6mm diameter Centre Lathe, 3 & 4 jaw chucks, live centre, fixed steady Measuring equipment including: o Steel rule o Callipers o Tape measure o Height gauge, o Dial test indicator o Sine bar and slip gauges o Micrometers o Surface finish comparators Cutting tools: o Knife o Turn and Facing o Parting o Grooving o Boring o Threading tools o Centre drills o Drills o Reamers o Stock and Die o Taps and Wrench o Hacksaw HOW do we make a start? Observe health and safety procedures at all times. Plan each stage of the theoretical work and practical task taking particular care to foresee possible difficulties in achieving the desired results. 1. Preparation of blank Decide on workholding method, set-up procedure and tooling to be used Calculate spindle speeds, feed rates and estimate depths of cut for each tool type Fill in operation chart Select 38mm square bright drawn bar Cut off to length, (215mm minimum), either with a hacksaw or with a power saw if available Remove burrs Mount bar in 4-jaw chuck Ensure bar is running true Centre drill M4 Mount on live centre Turn outside of blank to size and length Mount fixed steady on bed of machine Apply fixed steady to workpiece Ensure workpiece runs true to centre Inspect and fill in report Continued on next page Page 4 of 17
Unit 47 Learner instructions (cont) Internal assessment 47.1, 47.2, 47.3, 47.4, 47.6, 47.7, 47.8 and 47.9 2. Piston Decide on tooling to be used Calculate spindle speeds, feed rates and estimate depths of cut for each tool type Fill in operation chart Ensure workpiece runs true to centre Rough turn outside diameter ensuring sufficient length is allowed for the piston taper and subsequent turning of the other components Finishes turn parallel section Set compound slide to required angle Finishes turn a taper using compound slide Reset compound slide and finish turn groove Withdraw centre Drill to depth in preparation of threading Face to length Thread M6 x 0.75 Part off to length leaving approximately 1mm on the length for final sizing Remove all sharp edges Final inspection and report Note: - Inspection is to include measurement of the angle of the taper using a sine-bar, slip gauges and a dial-test indicator. 3. End Cap Decide on tooling to be used Calculate spindle speeds, feed rates and estimate depths of cut where appropriate for each tool type Fill in operation chart Ensure blank is running true, adjust chuck and steady if necessary Face off end Centre drill Stage drill to 20 diameter ensuring that depth of 12mm is not exceeded Bore to 32 diameter x 12 deep Drill 5.9mm diameter Drill 7mm diameter Thread M34 x 1, 10 deep full thread Relieve thread Ream 6mm diameter Part off to length leaving approximately 1mm on the length for final sizing Remove all sharp edges Inspection and report Continued on next page Page 5 of 17
Unit 47 Learner instructions (cont) Internal assessment 47.1, 47.2, 47.3, 47.4, 47.6, 47.7, 47.8 and 47.9 4. Cylinder Body Decide on tooling to be used Calculate spindle speeds, feed rates and estimate depths of cut where appropriate for each tool type Ensure blank is running true, adjust chuck and steady if necessary Face off to length leaving approximately 1mm on the length for final sizing Centre drill Stage drill to 16mm diameter ensuring that depth of 125mm is not exceeded Drill 20mm diameter x 120mm deep Bore 24.8mm diameter x 118mm deep using a 0.4mm radius insert Ream 25mm diameter x 110mm deep External groove 2mm wide Thread M34 x 1, 10 mm full length Remove all sharp edges Final inspection and report 5. Piston Rod Decide on tooling to be used and method of workholding Thread each end of bar M6 x 0.75 6. Final Sizing to Length Decide on tooling to be used Calculate spindle speeds, feed rates and estimate depths of cut where appropriate for each tool type Decide on appropriate workholding methods for machining each component to final length, (precautions should be taken to ensure that the components are not marked by the workholder and that the holding method chosen is safe) Mount the workholder on the machine Face each component to length in turn Produce final report for each component Assemble finished cylinder Page 6 of 17
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Unit.. Learner report Internal assessment(s):-. Learner name: Date: Assessment title:- Learner no: Page.. of Report:- Assessors Comments: - Assessor Signature Date Page 13 of 17
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