![CUTTING FORCE VARIATIONS
30-18
FMAX[kg]=a[mm2
]*re[KG/MM
2]*
n
Where
a=areaofmaterialrequired.
re=specificresistanceofcutting.
n=numberofcuttingteethsimultaneously.
n=l/p
Where](https://image.slidesharecdn.com/pptonbroachingvirendrarathore-170209145541/85/Ppt-on-broaching-18-320.jpg)
Ppt on broaching
- 1. 30-1 By : VIRENDRA RATHORE Manufacturing Engg. Roll no. 163517
- 2. BROACHING 30-2 Broaching is a maching process that uses a toothed tool,called a broach ,to remove material. Broaching is a similar technique to shaping with a long multiple-tooth cutter.
- 3. Traced back to the early 1850. During world war 1,broaching was used to rifle gun barrels. Requirements of close tolerances and reduced cost need broaching. HISTORY AND REQUIREMENT 30-3
- 4. 25-4 30-4
- 5. These machines are designed for pull broaching, surface broaching, continuous broaching, and rotary broaching 25-5 HORIZONTAL BROACHING
- 6. These machines can be designed for push broaching, pull- down broaching, pull-up broaching, or surface broaching. 30-6 VERTICAL BROACHING
- 8. ROTARY BROACHING 30-8 Where Θ=off- axis angle, Θr =rake, Θf = front releif, W=width across corners, dp = pilot diameter
- 9. BROACHING TOOL WHERE P=pitch, γ=clearance angle, α=rake angle. RPT=rise per tooth,L=land. R=radius of the gullet. D=depth of the tooth. 30-9 Broaching tool geometry
- 10. Broaching Tools Design and construction considerations – Material to be broached – Size and shape of cut – Quality of surface finish – Part tolerance – Productions rates – Type of machine –Workholding method – Strength of the workpiece 30-10
- 11. DESIGN 30-11
- 12. 30-12 BASIC PRINCIPLE OF BROACHING
- 13. WORKING Uses a single pass for finished shapes or sized. Uses a multipoint cutting tool (broach) . The rise per tooth determines the amount of material removed and the size of chips. 30-13
- 14. Chip breaker Features on Broaches 30-14 Figure 24.22 Chipbreaker features on (a) a flat broach and (b) a round broach.
- 15. MATERIAL OF BROACH Based on cutting tool material properties. Mostly made up of HSS. Ceramic are not used as low speed. Cemented carbide segments or replaceable inserts are also used specially for CI and steels. TiN coating provide high life. 30-15
- 17. Broaching products 32-17 Complex hole shapes cut by broaching
- 19. Mechanics of metal cutting in broaching 30-19
- 20. •The cutting force in broaching can be expressed generally by three differential components which are directly related to the chip load area and the contact length between the cutting edge and the workpiece such as, dft = Ktc × hi × dli + Kte × dli, dff= Kfc × hi × dli + Kfe× dli, dfr = Krc × hi × dli + Kre × dli. dft =differential component of tangential force, dff =differential component of feed force, dfr =differential component of radial force. dhi and dli are chip thickness and length of the cut for infinitesimal element along the cutting edge respectively. kc and ke are cutting and edge constants. 30-20 Force model for orthogonal broaching using B-spline interpolation of cutting edge.
- 21. 32-21
- 22. B SPLINE INTERPOLATION OF CUTTING EDGE 25-22
- 23. 25-23 Data points D and control points P can be organized in a system of equations consisting of (n + 1) × (n + 1) matrix as shown:
- 24. 25-24 Fig. 4. B-spline interpolation of cutting edge.
- 25. Calculation of Chip Load and Contact Length for Orthogonal and Oblique Broaching 25-25 Orthogonal broaching
- 27. 25-27 Contd... where s, e, i, i − 1 indicate start of the cut, end of the cut, current cutting edge,and previous cutting edge respectively
- 31. Very high production rate (much higher than milling, planing, boring etc.) High dimensional and form accuracy and surface finish of the product . Roughing and finishing in single stroke of the same cutter . Needs only one motion (cutting), so, operation and control are simpler. 25-31 WHY TO PREFER IT
- 32. • Design, manufacture and restoration of the broaches are difficult and expensive. • Defects or damages in the broach (cutting edges) severely affect product quality. • Only through holes and surfaces can be machined. • Economic only when the production volume is large. 25-32 WHY TO AVOID IT
- 33. BROACHING PROCESS ARE VERSATILE.WITH THE HIGH SCOPE IN FUTURE. THERE ARE CERTAIN THINGS TO BE RESOLVE OUT BUT IN THE FUTURE IT WILL CONTRIBUTE MUCH IN MACHINING. FORCE VIBRATION ARE TO BE RESOLVE OUT AND TOOL COST. 32-33
- 34. "Linear Broaching Made Simple With Benz LinA/LinS". www.cutwel.co.uk. Cutwel. "Rotary Broaching on a Bridgeport" (Video). Polygon Solutions Inc. 15 December 2010. Retrieved 24 May 2011. http://en.wikipedia.org/wiki/Broaching. High speed broaching of hard machining materials.V.F. Makarov, D. I. Tokarev, V.R. Tyktamishev. Prediction of cutting forces in broaching operation,Article in Journal of Advanced Manufacturing Systems · August 2013 32-34
- 35. 32-35