Bruce Mayer, PE Licensed Electrical & Mechanical Engineer BMayer@ChabotCollege.edu

1. Engineering 11 ManufacturingProcesses Bruce Mayer, PE Licensed Electrical & Mechanical EngineerBMayer@ChabotCollege.edu

2. Select Manufacturing Processes • Manufacturing process decisions • Deformation processes • Casting processes • Sheet metalworking • Polymer processing • Machining • Finishing/Joining • Assembly • Material-Compatibilities & Process-Capabilities • Material costs, Tooling costs, Processing costs

3. Make a Mountain Bike • Select Processes to Manufacture a Bike Handle Bar Top Tube Seat Post Saddle Fork Front Brake Rear Brake Down Tube Rear Derailleur Pedal (Courtesy of Trek Bicycle, 2002)

4. Manufacturing Process Decisions • How to choose the specific manufacturing processes? • How do the selected materials influence the choice of manufacturing processes? • Would product function or performance issues influence the choice of processes? • What criteria should be used to select processes? • What are the Priority of the Criteria? • Who makes the final decisions?

5. Design for Manuf (DFM) Guidelines • Keep Functional & Physical Characteristics as SIMPLE as Possible • Simple & Sturdy parts are Easier to Make, and have Higher Reliability • Design for the LOWEST COST Production Method • Critical for HI-VOLUME Parts

6. Design for Manuf (DFM) Guidelines • Design for the Minimum Number for Processing Steps (what’s a “step”?) • Try to ELIMINATE Steps thru Thoughtful Product Design • Specify Tolerances NO TIGHTER than Actually Needed • OverToleranced Design leads to Increased Cost thru • UnNeeded Processing Efforts • “False Positive” Scrap

7. Part-Processing Sequence • Primary Process  alter the (“raw”) material’s basic shape or form. e.g., • Casting • Rolling • Forging • Drawing • Molding • Extruding • That is, take a “bolb” of material and give it a basic shape; e.g. • Angle Iron • Tube/Pipe • Sheet/Plate

8. Part-Processing Sequence • Secondary Process  add or remove geometric features from the basic forms alter the (“raw”) material’s basic shape or form. e.g., • Machining of a brake drum casting (flat surfaces) • Drilling/punching of refrigerator housings (sheet metal) • Trimming of injection molded part “flash”

9. Part-Processing Sequence • TertiaryProcess  surface treatments. e.g., • Polishing • Painting • Heat-Treating • Joining • Plating • Anodizing • Thin Film Coating

10. Compatibility with Selected Materials Dimensional Accuracy and Tolerance Size & Weight Capacity Lead Time Min/Max Production Quantities Surface Finish Need for Post-Process Operations e.g., Heat Treating Process Selection Criteria

11. Influence of Special Desired Features e.g., Threaded Inserts, DoveTail Grooves Materials Availability Need for Special Tooling PostProcess Finish Operations Special Handling Equipment Special Inspection Equipment Yield i.e., Scrap Rate Cost Factors

12. Manuf Process Classifications

13. Rolling Extrusion Drawing Forging Deformation Processes • Rolling Rollers in compression thick slab thin sheet Plastic deformation

14. Roll To Different Final Shape bloom structural ingot sheet or coil slab billet bar or rod

15. Extrusion & Drawing • Extrusion • Drawing Extrusion Die Drawing Die OutPutCross Sections OutPutCross Sections Ram Pulling force Billet Billet

16. Ram pressure Flash Blocked preform Gutter Forging (Closed Die Version)

17. Casting Processes • Sand Casting • Die Casting • Investment(a.k.a. “LostWax”) Casting 

18. Cope Riser Core Flask Sprue Runner Parting line Gate Drag Sand Casting

19. Moving die Stationary die Molten metal Plunger Ejector pins Sprue Parting line Die Casting

20. Investment Casting Ceramic mold (hardened slurry) 4-part pattern tree Wax pattern is cast Wax removed by melting Molten metal solidifies in cast Ceramic mold is removed

21. SheetMetal Fabrication • Drawing • Punching • Shearing • Spinning • Bending • Blanking 

22. Deep Metal Drawing

23. Metal Spinning

24. PolyMer Processes • Compression Molding • Blow Molding • Injection molding • Transfer Molding • Reaction InjectionMolding (RIM) 

25. Blow Molding

26. Injection Molding

27. Compression Molding

28. Ram pressure Ram Heated mold Sprue Charge Part Transfer Molding

29. Machining Processes

30. Machining  Material Removal • Sawing ≡ using a toothed blade. • Milling ≡ form a flat surface by a rotating cutter tool. • Planing ≡ using a translating cutter as workpiece feeds. • Shaping ≡ form a translating workpiece using a stationary cutter. • Boring ≡ increasing diameter of existing hole by rotating the workpiece. • Drilling ≡ using a rotating bit forming a cylindrical hole. • Reaming ≡ to refine the diameter of an existing hole. • Turning ≡ form a rotating workpiece. • Facing ≡ form turning workpiece using a radially fed tool. • Grinding ≡ form a surface using an abrasive spinning wheel. • Electric Discharge Machining ≡ by means of a spark.

31. Surface Finish Capability

32. Finishing Processes

33. Anodizing

34. Assembly  Joining

35. Gas Shielded Arc Welding • MIG (Metal Inert Gas) • a.k.a., Gas Metal Arc Welding (GMAW) • METAL Wire Electrode CONSUMED • TIG (Tungsten Inert Gas) • a.k.a., Gas Tungsten Arc Welding (GTAW) • TUNGSTEN Electrode NOT Consumed

36. COMPATIBLE materials & processes Matls & Manuf Compatibility Material Properties Manufacturing Processes

37. Material-Process Compatibility

38. Manufacturing Costs Total Manufacturing Cost = Material + Tooling + Processing raw mat’ls molds labor  fixtures electricity jigs supplies tool bits O/H (deprec.) TMC = M + T + P (6.1)

39. Material Cost per Part Let M = total materials costs (raw, bulk) q = production quantity Then material costs per part, cM is cM = M/q = (cost/weight x weight) / number of parts Let’s reorganize the variables in the equation above cM = [cost/weight] [weight/number of parts] = (cost/weight) (weight/part), and therefore cM = cost/part

40. Material Cost per Part (cont.) Let cw = material cost per unit weight, and wp= weight of finished part ww= weight of wasted material (the scrap)  = Scrap-to-Useful Ratio → [wasted material weight]/[finished weight] = ww / wp Then the material cost per part, cMis cM= cw(wp + ww ) = cw(wp + wp ) (6.2) cM= cwwp (1+ ) (6.3) e.g. sand casting cM= ($1/lb)(1lb/part)(1+.05) = $1.05/part

41. Tooling Cost per Part Let T= total cost of molds, fixtures per production run q = number of parts per run Then cT= T/q (6.4) e.g. sand casting cT = ($10,000/run) / (5000 parts/run) = $2.00/part

42. Processing Cost per Part • Let • ct = cost per hour, (machine rate + labor) • t = cycle time (hours per part) • then cP = ct t (6.5) • e.g. sand casting • cP = ($30/hr) (0.3 hrs/part) = $9/part

43. TOTAL Cost per Part Cost per part, c = cM + cT + cP c = cw wp (1+ ) + T/q + ct t (6.6) e.g. sand casting c = $1.05 + $2.00 + $9.00 c = $12.05 / part

44. Example  5000 Part Run $45 of Bronze Part is due to Machining

45. Run Volume Sensitivity A ≡ Sand CastingB ≡ Inj. MoldingC ≡ Machining

46. How to Lower Part Cost • In Cost Eqn Minimize the SUM of Terms c = cw wp (1+ ) + T/q + ct t (6.6)       • purchase less expensive materials, • keep our finished part weight low • produce little manufactured waste (scrap, flash, etc.) • design simple parts that require less expensive tooling • make many parts per production run (i.e., use large quantities between ReTooling) • choose a manufacturing process that has a low-cycle-time & low-cost-per-hour

47. All Done for Today ElectroChemicalMachining ECM

48. Engineering 11 Appendix Bruce Mayer, PE Registered Electrical & Mechanical EngineerBMayer@ChabotCollege.edu

49. ElectroPolishing • Benefits of Electropolishing - Electropolishing produces a number of favorable changes in a metal part which are viewed as benefits to the buyer. All of these attributes translate into selling advantages depending upon the end use of the product. These include:                  • Brightening                  • Burr removal                  • Total passivation                  • Oxide and tarnish removal                  • Reduction in surface profile                  • Removal of surface occlusions                  • Increased corrosion resistance                  • Increased ratio of chromium to iron                  • Improved adhesion in subsequent plating                  • Reduced buffing and grinding costs                  • Removal of directional lines                  • Radiusing of sharp edges                  • Reduced surface friction                  • Stress relieved surface                  • Removal of hydrogenElectropolishing produces the most spectacular results on 300 series stainless steels. The resulting finish often appears bright, shiny, and comparable to the mirror finishes of "bright chrome" automotive parts. On 400 series stainless steels, the cosmetic appearance of the parts is less spectacular, but deburring, cleaning, and passivation are comparable.

50. ECM • What is the Electrochemical Machining Process ?    The process is based on Michael Faraday's Law ofelectrolysis, which is normally used in the electro plating of metals. Electrochemical machining is the reverse of plating, the work-piece is made the anode, which is placed in close proximity to an electrode (cathode), and a high-amperage direct current is passed between them through an electrolyte, such as salt water, flowing in the anode-cathode gap.  Metal is removed by anodic dissolution and is carried away in the form of a hydroxide in the electrolyte for recycling or recovery.   • A major advantage of electrochemical machining is that it can be used as a de burring or machining process on any metal, no matter how hard or corrosion resistant it is, without creating any residual thermal or mechanical stress in the work-piece.  • The ECD process produces smooth, burr free edges and ECF can produce smooth, three dimensional forms with a good surface finish in single plunge forming pass. The process is simple to operate and offers fast production rates for difficult to conventionally machine alloys, with low running and tooling costs. •  ECM does not create any physical or thermal stress during machining and components may be machined either before or after heat treatment. Metal removal rates are approximately 60 cubic mm per minute per 1000 amperes DC current employed. Surface finish may be less than 0.4 microns for some materials.  Otherwise difficult to conventionally machine alloys can be easily machined or de-burred by ECM. • Examples include the stainless steels, high performance and high temperature alloys such as Inconel, Rene, Hastelloy, Titanium, Waspalloy and the latest generation corrosion resistant nickel alloys such as 617 and Alloy 59.