Broching tool

We have made PPT on different method to manufacturing gear

1. BROACHING 14BME20 14BME131D 14BME132D 14BME133D 14BME135D 14BME136D

2. Introduction : Broaching is a method of removing metal by tool that has a successively higher cutting edges in a fixed path. Each tooth removes a predetermined amount of material which is limited to about 6mm of stock or less.

3. A broach is effectively a collection of single point cutting tools arrayed in sequence, cutting one after the other; its cut is analogous to multiple passes of a shaper. The broach contains three distinct sections: One for roughing, Another for semi-finishing, and The last one for finishing . Roughing broach Semi finishing Broach Finishing Broach

4. Broach tool : Ref://en.m.wikipedia.org/wiki/file:Broach_geometry.png

5. Broach tool Front Pilot : center the broach in the hole before the teeth begin to cut . Roughing and semifinish teeth : They remove most of the stock in the hole. Rear pilot : They support the broach after the last tooth leaves the hole. Land : The top portion of the tooth is called the land and in most cases ground to give a slight clearance. Radius : provides tooth strength & assists cutting of the chips of cutting material. Back clearance high – rough teeth Back clearance small – fine teeth small the angle less broach will be loss for this reason finishing teeth provided small amount of land.

6. BROACH MATERIAL:- Properties – high strength , hardness ,toughness and good heat and wear resistance Now-a-day cemented carbide replace by insert of tungsten. Most broaches are made from 18-4-1 tungsten chromium vanadium steel . carbide broaches are used extensively in broaching of cast iron in automotive field. Tin coated carbides provides much longer tool life in broaching. Since speed is usually quite low.

7. Classification of broaching Machines : According to nature and direction of cutting Horizontal Broaching Machine Vertical Broaching Machine Continuous Broaching Machine According to the purpose Internal Broaching Machine External Broaching Machine

8. Horizontal Broaching Machine Generally of pull type. Mostly used for internal broaching. Consists of bed little more than twice the length of the stroke. Take more floor space than VBM. Can handle long broaches & heavy W/P. Used primarily for broaching keyways, splines,slots,round holes. 1- Pulling Head 2- Broach 3- Work fixture (REF. P-537,Work shop technology By Hajra Choudhury)

9. Vertical Broaching machine Can be either of push or pull type push is more common . Mostly used for surface operation. Economical of floor space than HBM. Generally can be operated with Hydraulic or electro-mechanical drives but hy d raulic drives are mostly preferred due to less cost. (REF. P-538,Work shop technology By Hajra Choudhury )

10. Ref:http :// images.slideplayer.com /16/4895047/slides/slide_25.jpg

11. Continuous broaching machine : Used for mass production of small parts. ROTARY CONTINUOUS BROACHING MACHINES- Workpiece is loaded on rotating table & broach is stationary. HORIZONTAL CONTINUOUS BROACHING MACHINES- Workpieces are loaded into work holding fixtures mounted on continuously moving chain & broach is stationary.

12. (REF. P-539,Work shop technology By Hajra Choudhury)

13. Chip Space and Chip Breakers Chip space is essential between adjacent teeth to accommodate the formed chips without crowding. Tool depth is made one-forth to half of the pitch and never exceed one sixth of broach diameter. Chip breaker in the form of narrow groove are ground in staggered pattern along the roughing and semi finishing teeth . Chip breakers avoid the formation of complete annular ring-shaped chip which can’t be easily removed from the broach . Chip breaker are also provided on surface broaches to brake up the wide chips. The number of chip breakers per tooth for round broaches varies from 6 to 12 depending on broach diameter

14. Video……

15. Types of broaching : There are many types of broaching methods being used, but mainly there are two main types of broaching. They are Surface Broaching Internal Broaching

16. Ref:https ://static- content.springer.com /image/ chp.gif

17. SURFACE BROACHING : Surface broaching is very simple as either the workpiece is moved against a stationary surface broach, or the workpiece is held stationary while the broach is moved against it. INTERNAL BROACHING It i s the process by clamping the work piece into a special holding fixture, called a w ork holder , which mounts in the broaching machine. The broaching machine elevator, which is the part of the machine that lowers the broach through the workpiece . Once through, the broaching machine's puller (a hook), grabs the pilot of the broach. The elevator then releases the top of the pilot and the puller pulls the broach through the workpiece completely.

18. Ref:http :// www.nptel.ac.in /courses/112105127/ pdf /LM-26.pdf

19. Ref: //en.m.wikipedia.org/wiki/file:Broach_types_and_examples.jpg Internal Broaches

20. APPLICATIONS:- Broaching a key in a hole with a keyway broach. Broaching hole with a round back. Surface broaching with a contour broach. Broaching a spline hole with a spline broach.

21. ADVANTAGES High production rate than milling planning boring etc . High dimensional form accuracy & surface finish. Roughing & finishing in single stroke of same cutter. Needs only one cutting motion. Extremely suitable & economic for mass production . Accuracy of surface finish is up to 0.1 Micron

22. DISADVANTAGES :- Only through holes & surfaces can be machined . Design manufacture & restoration of broaches are difficult. Tooling cost is very high and process is adopted only in mass production. Surface to be broached should not have any obstruction. Tool is made for particular job only and cannot be used in range of applications.

23. REFERENCES :- R.K Jain Production Technology Page No: 578 to 584 ELEMENTS OF WORKSHOP TECHNOLOGY VOL:2 MACHINE TOOLS BY S.K. HAJRA CHOUDHURY. http://m.author stream.com/presentation/mihir05-1573819-broaching/ browsed on 20/04/2016. https://en.m.wikipedia.org/wiki/Broaching_(metalworking) browsed on 14/04/2016.

24. Q ueries ??