Lecture 1 - PP

PROCESS PLANNING Design & Manufacture 3 B59DE  Learning Outcomes Understand what is process planning. Learn the importance of having a process plan in a manufacturing environment. Gain experience of developing and writing a process plan* ‘Engineering a Product Cycle’...

PROCESS PLANNING Design & Manufacture 3 B59DE  Learning Outcomes Understand what is process planning. Learn the importance of having a process plan in a manufacturing environment. Gain experience of developing and writing a process plan* ‘Engineering a Product Cycle’ Planning – a key activity. Good discipline…  Process planning It is a document that details the sequence of manufacturing operations for an item from the raw material to its finished drawing state. It determines the most economical method of producing a part. It outlines a sequence of instructions for operators.  Process planning package Front sheet Operation planning sheets - as many as are required; Machining times calculations sheets (if required).  HERIOT-WATT UNIVERSITY MECHANICAL ENGINEERING Front sheet SCHOOL OF ENGINEERING & PHYSICAL SCIENCES MANUFACTURING PROCESS PLANNING PACKAGE Part Number EXAMPLE 3.1 Revision 1 Part Description PLUG Material Description 50mm DIAMETER MILD STEEL BAR Material Quantity 80mm LENGTH = 1 COMPONENT Planner Details Name A. STUDENT Date 26th FEBRUARY Class MECHANICAL ENGINEERING II Project TOOLMAKER'S CLAMP Operations sheet Machining times sheet Why is a process plan needed for manufacturing?  We need to minimise the amount of 'thinking time' associated with making the product.  We need to make sure we have organised all of the tooling, raw materials and equipment to make the product. Why is a process plan needed for manufacturing?  Manufacturing time  Then we can schedule the ordering and production of all items associated with the product.  There is probably more than one operator involved in the process sequence.  Things can be determined before making a product:  The raw material requirements/sizes.  The machine tool/process requirements;  Cutting tools or other material removal/joining equipment  The operation times; Jigs/fixture requirements - these can be designed before production takes place. Factors to consider when creating a process plan Make or buy Material selection Manufacturing sequence Individual operations analysis Key factors in the make or buy decision Process available in-house Production quantity Product life Standard items Supplier reliability Alternative source  Make or Buy Suppose that the quoted price for a certain component from a vendor is £8.00 per unit for 1000 units. The same part made in the home factory would cost £9.00. The cost break-down on the make alternative is as follows: Unit material cost = £2.25 per unit Direct labor = £2.00 per unit Labor overhead cost = £3.00 per unit Equipment fixed cost = £1.75 per unit Total = £9.00 per unit Should the component be bought or made in- house?  From Vendor Equipment fixed cost: £1.75 Overhead: £3.00 Total price = £1.75+£3.00+£8.00 = £12.75 What’s the best then?  Factors to consider when creating a process plan Make or buy Material selection Manufacturing sequence Individual operations analysis  Material selection Depends on the design (overall geometry of the part and the main external and internal features). Depends on the stock available. Depends on the manufacturing process.  Material Selection BLACK BAR BRIGHT BAR TUBING HOLLOW SECTIONS FERROUS AND NON- FERROUS MATERIALS SHEET WELDED AND ASSEMBLIES/CASTINGS PLATE /FORGINGS  Factors to consider when creating a process plan Make or buy Material selection Manufacturing sequence Individual operations analysis The manufacturing sequence chosen for a particular part or assembly depends on:  the machines and processes available;  the tooling available;  the required work location (factory layout);  the type of labour （semiskilled or skilled;  the quantities to be made (batch or lot sizes);  the raw material available (e.g. a stock list).  part geometries  Individual operations analysis Select the machine. Select the cutting tools (e.g. for turning, facing, undercutting, forming…). Select speeds and feeds (machining time). Select workpiece holding (3 jaw chuck, collet, vice, clamp…). Specify inspection procedures. Facing Taper turning Contour turning Form turning Chamfering Threading Undercut/Cutoff Boring Drilling Knurling Tooling chosen depends on that available for company. You use standard tooling for turned part planning. Speeds and feed chosen as before – only facing and plain turning calculations need be done – see notes.  Turning tools Tool 06/09/2024 Workpiece holding  Case study (Coins) A video to show different processes involved. From raw material to final product.  Case study (Coins) Raw material (copper) Melting the copper in furnace (1200 °C) Cooling and pressing the copper Hot rolling and pressing Stamping and sandwiching (copper and nickel) Pattern on the coins Polishing Case Study – Mac Pro Video at the end of this live session.  Manufacturing sequence Plan summary Operation Machining Number process 10 Hydraulic impact extrusion 20 Turning 30 Polishing 40 Pre-coating 50 Milling 60 Acid etching 70 Painting  Case study Videos from Canvas Use the following path; B59DE_2024-2025_Topic 1: Process Planning & Factory Layout: Next Lecture Process planning examples