Copyright 2002 Society of Manufacturing Engineers. FUNDAMENTAL MANUFACTURING PROCESSES Gears & Gear Manufacturing NARRATION (VO):

Transcription

1 FUNDAMENTAL MANUFACTURING PROCESSES Gears & Gear Manufacturing SCENE 1. CG: Gear Finishing Processes white text centered on black SCENE 2. tape 783, 01:12:24-01:17:06 peter carey narration tape 769, 05:14:02-05:14:30 zoom in, gear finishing using shaving operation CG, SUPER: Dimensional Accuracy Tooth Spacing Gear Form Surface Finish CG, SUPER: Shaving tape 779, 17:14:45-17:14:50 gear grinding operation CG, SUPER: Grinding tape 776, 14:17:07-14:17:14 gear honing operation CG, SUPER: Honing GEAR FINISHING PROCESSES ARE USED TO IMPROVE THE DIMENSIONAL ACCURACY, TOOTH SPACING, GEAR FORM, AND SURFACE FINISH OF GEARS. THE PRIMARY GEAR FINISHING PROCESSES INCLUDE: SHAVING..., GRINDING..., AND HONING. SCENE 3. CG, SUPER: Shaving tape 776, 14:04:04-14:04:07 gear placed in position for shaving operation, dissolve to next shot tape 776, 14:04:10-14:04:30 shaving operation IN SHAVING, A CUTTER WITH THE EXACT SHAPE OF THE FINISHED TOOTH PROFILE REMOVES SMALL AMOUNTS OF MATERIAL FROM THE GEAR TEETH BY A ROLLING AND RECIPROCATING ACTION. SCENE 4. tape 769, 05:26:12-05:26:23 zoom out, shaving operation THE PROCESS COMBINES CUTTING STROKES TO SIZE THE GEAR, AND FINISHING, OR POLISHING STROKES TO ENHANCE SURFACE SMOOTHNESS. SCENE 5. tape 770, 06:25:34-06:25:47 pan, cutting teeth on shaving cutting tool THE CUTTER TEETH ARE SERRATED, PROVIDING A SERIES OF SMALL CUTTING EDGES TO REMOVE THE EXCESS

2 MATERIAL. SCENE 6. tape 769, 05:23:14-05:23:46 shaving system, zoom in to process SHAVING REQUIRES EXPENSIVE TOOLS AND SPECIAL MACHINERY, BUT IS A RAPID PROCESS THAT IS WIDELY USED ON GEARS OF ALL SIZES. SHAVING IS TYPICALLY USED IMMEDIATELY AFTER A GEAR MACHINING OPERATION, BUT PRIOR TO HEAT TREATMENT. FOR THIS REASON SHAVING IS OFTEN REFERRED TO AS SOFT FINISHING. SCENE 7. CG, SUPER: Grinding tape 777, 15:12:26-15:12:38 grinding used as a gear production process tape 779, 17:13:09-17:13:27 zoom out, grinding used as finishing process FOR SOME APPLICATIONS, GRINDING SERVES AS THE INITIAL PRODUCTION CUTTING PROCESS. TYPICALLY THOUGH, GRINDING IS USED FOR GEAR FINISHING. GRINDING PROVIDES THE GREATEST PRECISION, AND IS ESPECIALLY SUITED FOR PROCESSING HARDENED GEARS. SCENE 8. tape 777, 15:15:39-15:15:53 gear grinding using cutting fluids tape 779, 17:20:07-17:20:28 zoom in, gear grinding with wheel being fed in small increments while running at high work-transverse rates GRINDING GENERATES A LOT OF SURFACE HEAT IN PARTS. TO REDUCE THIS HEAT BUILD-UP, CUTTING FLUIDS ARE OFTEN USED. HEAT BUILD-UP MAY ALSO BE REDUCED BY FEEDING THE GRINDING WHEEL INTO THE WORKPIECE IN SMALL INCREMENTS WHILE RUNNING AT HIGH WORK- TRANSVERSE RATES. SCENE 9. tape 766, 02:17:01-02:17:21 form grinding of gear CG, SUPER: Form Grinding tape 767, 03:02:09-03:02:18 intermittent grinding operation CG, SUPER: Involute-Generation Grinding GEAR GRINDING IS PERFORMED ON SPECIALIZED GRINDING MACHINES, AND CAN BE CLASSIFIED AS EITHER: FORM GRINDING..., OR INVOLUTE-GENERATION GRINDING.

3 SCENE 10. CG, SUPER: Form Grinding tape 766, 02:17:40-02:18:21 zoom in, form grinding operation ending on one tooth, wheel retracts, gear indexed to next position, form grinding starting up again FORM GRINDING USES GRINDING WHEELS HAVING THE EXACT SHAPE OF THE TOOTH SPACING AND ARE ALWAYS INTERMITTENTLY INDEXING. ONCE A FORM GRINDING PASS IS FINISHED, THE WHEEL RETRACTS. THE GEAR IS THEN INDEXED TO THE NEXT POSITION, AND FORM GRINDING RESUMES. SCENE 11. continue previous shot tape 766, 02:14:33-02:14:40 pan, c.u. vitrified bonded form grinding wheels tape 766, 02:15:13-02:15:23 dressing of tooth-form on vitrified bond grinding wheel FORM GRINDING HAS TRADITIONALLY USED VITRIFIED- BOND WHEELS WITH THE GEAR TOOTH-FORMS DRESSED INTO THE WHEEL. DRESSING IS PERFORMED IN MANY DIFFERENT MANNERS AND IS NEEDED TO CONSISTENTLY RETAIN THE TOOTH-FORM CONTOUR IN THE GRINDING WHEEL. SCENE 12. tape 771, 07:17:44-07:18:05 zoom out, 'cbn' wheel OVER TIME, FORM GRINDING WHEELS WITH SINGLE-LAYER BONDED CUBIC BORON NITRIDE, OR 'CBN', HAVE GAINED ACCEPTANCE OVER THE VITRIFIED-BOND WHEELS. SCENE 13. tape 771, 07:19:23-07:19:36 'cbn' wheel grinding operation ending 'CBN' FORM GRINDING WHEELS DO NOT REQUIRE DRESSING AND CAN LAST HUNDREDS OF TIMES LONGER THAN THE VITRIFIED-BOND WHEELS. SCENE 14. CG, SUPER: Involute-Generation Grinding tape 771, 07:13:03-07:13:28 zoom out, continuous grinding of gears IN INVOLUTE-GENERATION GRINDING, A STANDARD RACK PROFILE IN A GRINDING WHEEL OR WHEELS IS USED TO GENERATE THE INVOLUTE FORM. THE GEAR TEETH ARE

4 FINISHED BY AXIALLY ROTATING THE WORKPIECE WHILE IT IS RECIPROCATED IN AN ANGULAR DIRECTION DEPENDENT UPON THE GEAR TYPE BEING GROUND. SCENE 15. tape 779, 17:18:03-17:18:11 intermittent grinding CG, SUPER: Intermittent Grinding tape 766, 02:23:39-02:23:46 continuous grinding of gears CG, SUPER: Continuous Grinding INVOLUTE-GENERATION GRINDING IS PERFORMED USING EITHER INTERMITTENT GRINDING..., OR CONTINUOUS GRINDING. SCENE 16. CG, SUPER: Intermittent Grinding tape 767, 03:01:39-03:01:59 intermittent grinding using cup wheel with gear profiles tape 779, 17:17:19-17:17:32 zoom in, intermittent grinding using two single-rib wheels tape 779, 17:21:37-17:21:48 wheel retracting, cut to next shot tape 779, 17:23:03-17:23:12 workpiece indexed to new position INTERMITTENT GRINDING MACHINES PRIMARILY USE PROFILES DRESSED ON CUP WHEELS..., OR ON ONE OR TWO SINGLE-RIB WHEELS..., ONCE A GRINDING PASS IS CONCLUDED, THE WHEEL, OR WHEELS, RETRACT..., AND THE WORKPIECE IS INDEXED TO THE NEXT POSITION FOR GRINDING. SCENE 17. CG, SUPER: Continuous Grinding tape 767, 03:02:58-03:03:07 c.u. continuous grinding of gear tape 766, 02:11:08-02:11:15 zoom out, wheels with rack profile dressed in outer diameter tape 767, 03:03:21-03:03:38 wide, continuous grinding of gear CONTINUOUS GRINDING USES GRINDING WHEELS WITH THE RACK PROFILE DRESSED HELICALLY ON ITS OUTSIDE DIAMETER. THE GRINDING WHEEL TURNS IN TIMED RELATIONSHIP WITH THE GEAR AS IT PASSES AXIALLY ACROSS THE GRINDING WHEEL. SCENE 18. CG, SUPER: Honing tape 776, 14:18:27-14:19:05 zoom out, honing of gear HONING INVOLVES MESHING THE WORKPIECE IN CROSS- AXIS RELATIONSHIP WITH AN PLASTIC ABRASIVE- IMPREGNATED GEAR-SHAPED TOOL. THE TOOL IS THEN TRAVERSED BACK AND FORTH PARALLEL TO THE WORKPIECE

5 AXIS. HONING IMPROVES GEAR SURFACE FINISH AND CAN CORRECT ERRORS IN PROFILE GEOMETRY. --- FADE TO BLACK ---