MECH152-L27(1.0) - 1 Design for Manufacture Manufacturing Processes Review

MECH152-L27(1.0) - 2 Handle Join Insert Fasten Inspect Manufacturing Manufacture Shape forming Handle Primary manufacturing Shape forming Inspect Shape change Handle Secondary manufacturing Machining Inspect Finish Handle Tertiary manufacturing Coating, treatment Inspect Assembly

MECH152-L27(1.0) - 3 Process Planning Given the engineering drawing: –Drawing interpretation –Material evaluation, Production volume and rate, Tolerance and surface finish, and process selection –Selection of machine and tooling –Setting process parameters –Tooling and fixtures –Selecting quality assurance methods –Costing

MECH152-L27(1.0) - 4 Combined Routing Sheet / Operation List Part No.:Part Name:Revision:Page No.: Matl.:Size:Planner:Date: No. OperationDept.M/CTooling Gauges Setup Time Cycle Time 10 Face; rough & finish turn to 36  dia. and 30  0.1 length; Face shoulder to 8  0.05 and finish turn to 45  0.05 dia. L325G8561.0h6.12m 20 Reverse: face to 120  0.1 dia. length; finish turn to 45  0.05 dia.; Drill dia. hole L3250.5h3.10m 30 Drill & Ream 3 radial holes at 9.5  0.05 dia D114F5120.3h2.50m 40 Mill 12  0.1 wide x 9.5  deep slot M240F3210.3h1.80m 50 Mill 18  0.1 wide x 9.5  deep flat M240F3220.3h1.45m

MECH152-L27(1.0) - 5 Primary Manufacturing Processes Casting Molding Powder Metallurgy

MECH152-L27(1.0) - 6 Sand Casting – Pros & Cons Pros: Produce parts with complex geometries, both internally and externally. Possible to net shape with no further manufacturing required. Large parts can be produced. Wide choice of metals. Suitable for mass production. Cons: Poor dimensional control for some processes Poor surface finish for some processes Limitation on mechanical properties Safety hazard Environmental hazard

MECH152-L27(1.0) - 7 Expendable Mold Casting - Shell Mold Pros: –Smoother surface finish than sans casting. –Surface finish of 2.5  m can be obtained. –Good dimensional accuracy  0.25 mm on small to medium size parts. –No further machining is needed. –Capability for automation lowers the cost for larger quantities. Cons: –More expensive metal pattern, especially for small batch.

MECH152-L27(1.0) - 8 Expendable Mold Casting - Vacuum Mold Sand held together by vacuum pressure. Pros: –Sand can be recovered unlike shell mold. –No chemical binder, and therefore no special treatment for the sand. –No water mixed with the sand and therefore no moisture related problems Cons: –Relative slow –Not readily adaptable to mechanization.

MECH152-L27(1.0) - 9 Expendable Mold Casting - Expanded Polystrene Mold Pros: –Pattern need not be removed. –No cope /drag is needed, all features are built into the pattern. –Possibility for automated production. Cons: –The pattern is not reusable.

MECH152-L27(1.0) - 10 Expendable Mold Casting - Investment Casting Pros: –Capability to cast parts with great complexity and intricacy. –Close dimensional control (   m tolerance). –Good surface finish. –Wax can be recovered and reuse. –Additional machining normally not required. Cons: –Normally cater for smaller parts. –Relatively expensive.

MECH152-L27(1.0) - 11 Expendable Mold Casting - Plaster Mold and Ceramic Mold Similar to sand casting in terms of process. Plaster mold is for lower temperature alloys while ceramic mold is for higher temperature alloys. Pros: –Good surface finish and dimensional control. –Capability to make thin cross sections. Cons: –Curing takes too long to render it unsuitable for volume production.

MECH152-L27(1.0) - 12 Permanent Mold Casting - Basic Permanent Mold Pros: –Good surface finish and close dimensional control. –More rapid solidification, finer grain structure, stronger castings. Cons: –Generally limited to lower melting point metals. –Simpler part geometries as mold is permanent. –Mold cost is expensive and thus cater for volume production.

MECH152-L27(1.0) - 13 Permanent Mold Casting - Die Casting Pros: –High production rates are possible. –Economical for large quantities. –Close tolerances are possible (  mm). –Good surface finish. –Thin sections are possible (down to 0.5 mm). –Rapid cooling, fine grain, high strength. Cons: –melting point of metals. –shape restriction.

MECH152-L27(1.0) - 14 Casting

MECH152-L27(1.0) - 15 Molding Tolerances

MECH152-L27(1.0) - 16 Powder Metallurgy - Pros Net shape manufacturing Minimum wastage of material Production of porous parts, typically for self-lubricating applications Produce parts from material difficult to process Produce parts with special alloying content Good dimensional control Can be automated for economic production

MECH152-L27(1.0) - 17 Powder Metallurgy - Cons High tooling and equipment cost. Expensive raw material. Difficulty with storing and handling of powder. Limiting in geometry as the powder does not flow readily in die. Inhomogeneity of produced part.

MECH152-L27(1.0) - 18 Powder Metallurgy Design Considerations Large batch size to make it cost effective, typically over 10,000. Controlled porosity parts. Special alloying elements parts. Limited geometry to allow die opening. Built-in chamfers and radii. Minimum wall thickness of 1.5 mm and minimum hole diameter of 1.5 mm.

MECH152-L27(1.0) - 19 Secondary Manufacturing Processes Machining Turning, Boring Drilling Reaming Milling Shaping Broaching Sawing

MECH152-L27(1.0) - 20

MECH152-L27(1.0) - 21

MECH152-L27(1.0) - 22 Tertiary Manufacturing Processes Grinding and Abrasive Processes –Grinding –Honing, Lapping, Super-finishing, Polishing and Buffing Non-traditional Machining and Thermal Cutting Processes –Mechanical Energy Processes –Electrochemical Machining Processes –Thermal Energy Processes –Chemical Machining

MECH152-L27(1.0) - 23 Surface Roughness Values

MECH152-L27(1.0) - 24 Tertiary Manufacturing Processes Application Considerations Very small holes below mm diameter. (Laser beam machining, LBM) Holes with large depth-to-diameter ratio, d/D>20. (ECM or EDM) Holes that are not round (ECM or EDM) Narrow slots in slabs or plates (ECM, LBM, EDM, water jet, abrasive jet) Micromachining (PCM, LBM, EBM) Shallow pockets and surface details in flat parts (Chemical machining) Special contoured shapes for mold and die applications (EDM or ECM)

MECH152-L27(1.0) - 25 Special shapes for which the non traditional processes are appropriate (a) very small diameter holes, (b) holes with large depth-to-diameter ratios, (c) nonround holes, (d) narrow, non-straight slots, (e) pockets, and (f) die sinking Tertiary Manufacturing Processes Application Considerations

MECH152-L27(1.0) - 26 Tertiary Manufacturing Processes Materials Consideration

MECH152-L27(1.0) - 27 Tertiary Manufacturing Processes Machining Characteristics

MECH152-L27(1.0) - 28 Case Study

MECH152-L27(1.0) - 29 Product Specification Final product specification will be issued after: –Prototyped is designed, fabricated, and tested –Cost analysis after trail batch es Dimension – specified in the drawing Material – Grey cast iron Maintenance – the bolting arrangement should incorporate standard parts.

MECH152-L27(1.0) - 30 Product Specification

MECH152-L27(1.0) - 31 Product Specification

MECH152-L27(1.0) - 32 Drawing Interpretation Review the part drawing to determine the primary manufacturing process: casting or forming –Casting – tooling fabrication –Forming – tooling fabrication or direct stock purchase Secondary manufacturing process: machining –Overall stock size and material –Tolerance & surface finish requirements

MECH152-L27(1.0) - 33 Material Evaluation Light weight Hard with good wearing resistance Low cost Good casting properties Good machinability Batch size - 350

MECH152-L27(1.0) - 34 Manufacturing Considerations the 100 mm and 50 mm bores cannot deviate from the nominal size by more than 0.01mm; the 100 mm diameter bore must also be perpendicular to the flange face within 0.1 mm tolerance zone; the 100 mm and 50 mm bores must be machined to a surface finish of 0.1m; the flange face and centreline of the 12 mm hole must be parallel to each other to within a tolerance zone of 0.1mm; the flange face must be machined to a surface finish of 0.8m; the 12 mm hole must be perpendicular to the component centreline within a 0.01 mm tolerance zone; all holes must not deviate by more than 0.1 mm of the nominal size; all holes must have a surface finish of 1.6m; all spotfaces must not deviate by more than 0.1 mm of the nominal size; all spotfaces must have a surface finish of 0.8m; all fillets are R7 unless otherwise stated; the general dimensional tolerance is 0.5mm; the general surface finish is 12.5m.

MECH152-L27(1.0) - 35 Process Selection Suitable for grey cast iron (sand casting / investment casting) Meet general dimensional tolerance of ±0.5 mm Meet general surface finish of 12.5 µm Produce economically 350 per batch Meet the tolerance specifications stated in the drawing

MECH152-L27(1.0) - 36 Process Selection Investment casting Holes assumed to be drilled with the help of drill jigs. Processes: –Turning – for the flange face –Drilling – for the holes and spotfacing –Grinding – for the  100 mm and  50 mm bores

MECH152-L27(1.0) - 37 Process Sequencing Stock produced by investment casting with 2 mm machining allowance –Wax pattern, flasking, bake, mold, stock removal Machine the flange face by turning –Rough facing with 0.2 mm left for fine finishing Machine spotfaces by drilling Machine holes by drilling Machine bores by grinding –Internal grinding each  100 mm and  50 mm holes in four passes

MECH152-L27(1.0) - 38 Tooling and Fixtures Turning/facing tool – facing Spotfacing -  20 mm and  25 mm spot drills Drilling -  10 mm and  12 mm twist drills Grinding -  20 mm internal grinding wheel

MECH152-L27(1.0) - 39 Tooling and Fixtures