1. JAIPUR NATIONAL UNIVERSITY Presented By:- Md. Raja Hussain 4ME 104 Presented To :- Mr. Tashnim Kaishar

2. Grinding Wheel Mounting and Dressing

3. Grinding Grinding is a material removal process accomplished by abrasive particles that are contained in a bonded grinding wheel rotating at very high surface speeds. The rotating grinding wheel consists of many cutting teeth ( abrasive particles ) and the work is fed relative to the rotating grinding wheel to accomplish material removal.

4. INTRODUCTION TO GRINDING PROCESS It is the only economical method of cutting hard material like hardened steel. It produces very smooth surface, suitable for bearing surface. Surface pressure is minimum in grinding. It is suitable for light work,which will spring away from the cutting tool in the other machining processes.

6. Grinding Process

7. GRINDING WHEEL DRESSING &TRUING Dressing refers to the removing of clogs and blunt abrasive grains from the surface of the grinding wheel. Dressing exposes the cutting edges which restore the correct cutting action of the wheel. Dressing is done on a glazed or loaded wheel to recondition it. Truing refers to the shaping of the wheel to make it run concentric with the axis. When a new grinding wheel is mounted, it must be trued before use to remove the run out.

8. Properties of a Trued and Dressed Wheel Produce accurate workpieces and good surface finish Use minimum of grinding power Produce work without burn, surface damage, or chatter marks Increase material-removal rates and lower grinding costs

9. GLAZING & LOADING When the surface of a grinding wheel develops a smooth and shining appearance, it is said to be glazed. This indicate the abrasive particles on the wheel face are not sharp. These are worked down to bond level. When soft materials like aluminium, copper, lead, etc. are ground the metal particles get clogged between the abrasive particles. This condition is called loading.

10. Procedure for Truing a CBN Wheel Example assumes use of an impregnated diamond wheel to true SBN resin-bond (100% concentration) wheel 1. Mount CBN wheel on grinder, snug up flange nut, and indicate wheel circumference to within.001 in. or less runout 2. Tighten flange nut securely  82-10

11. 3. Clean magnetic chuck and place diamond holder on left-hand side of chuck Cover as many magnetic inserts as possible Energize chuck 4. Adjust grinder table to locate diamond nib about 12 in. to left of wheel centerline Lock table in position 5. Lower wheelhead by hand until just touches piece of paper held between wheel and diamond  82-11

12. 6. Turn grinder crossfeed handle so diamond clears edge of wheel 7. Lightly coat wheel surface to be trued with wax marking crayon 8. Start grinder spindle and feed wheelhead down in.0004 in. increments until contact made with diamond 9. Direct coolant to wheel-diamond interface 10. Feed diamond across wheel face at 3 to 12 in./min 11. Continue truing until crayon removed  82-12

13. Dressing a CBN Wheel After truing, surface smooth, no abrasive grains sticking out Wheel cannot cut Wheel bond must be partially removed or lowered to expose abrasive crystals Simplest, least expensive and most popular method of dressing is with aluminum oxide dressing stick or block  82-13

14. Procedure For Dressing a CBN Wheel 1. Select 200 grit, C-grade aluminum oxide dressing stick 2. Hold dressing stick in vise so half of thickness above vise jaws 3. Mount vise on magnetic chuck so dressing block parallel to table travel 4. Lower stationary wheel until just touches top of dressing stick  82-14

15. 5. Use crossfeed handle to bring edge of dressing stick even with edge of wheel 6. Move table so wheel just clears right-hand end of dressing stick 7. Start grinder spindle and coolant Feed wheel down about.020 in. 8. Using slow but steady feedrate ( 5 to 10 ft./min) take one pass lengthwise along dressing stick  82-15

16. 9. At end of pass, index table slightly less than width of grinding wheel 10. Repeat procedure until width of dressing stick ground 11. Downfeed wheel after full surface of dressing stick has been ground 12. When grinding wheel appears to be cutting dressing stick freely, stop and inspect wheel face Surface feels rough – dressing complete  82-16

17. THANK YOU