Aluminum-based MMC machining with diamond-coated cutting tools

1. Aluminum-based MMC machining with diamond-coated cutting tools S. Durante, G. Rutelli, F. Rabezzana October 1997 Presented by: Nathan Rasmussen

2. Presentation Outline • Heading    Title of Paper, Author (s), Date • Introduce paper    Function of paper      Why important           References            • Models, Design Application    Relate to technical area in course         Parameters defined, design defined      Design principle                              • Results    Experimental equipment discussed     Design principles applied                    Data/tables/design discussed             Correlation of results with models    • Conclusions    Practical industrial use         Technical advancement         Industries most impacted 

3. Function of Paper • Investigation of an alternative solution for machining aluminum metal matrix composites (MMCs) • Machining process produces SiC powder and hard particles from tool wear which create a highly abrasive environment. • Tool life comparison of: • Standard Carbide Tooling • Polycrystalline Diamond (PCD) Tooling • Chemical-Vapor Deposition (CVD) diamond-coated Tooling

4. Importance • Aero, auto, and train industries are searching for lighter high-strength alloys • MMCs fill those needs but have traditionally required more expensive tooling like PCD inserts • Chemical-Vapor Deposition (CVD) diamond-coated inserts appear to be a promising alternative

5. References • DURALCAN Composites Maching Guidelines, 8/2/1991 • M.K. Aghajanian, C.A. Anderson, R.J. Wiener and B.R. Rossing. SAE Technical Paper, 950263, February 27-March2, 1995 • S. Durante, F. Rabezzana and G. Rutelli, in Eurodiamond ’96, Torino, 1996, p. 135. • I.E. Clark, IDR Ind. Diam. Rev., 54(3) (1994) 562. • S. Durante, in 26th AIM Congress Proceedings, Milano, 1996. • M. Eastman and C. Lane, Cutting Tool Engineering, October (1993).

6. Relationship to Course • Tool life criteria – flank wear • Some of their data could have been fit to the Taylor’s tool life equation -- vTn = C • Coating technology & insert parameters

7. Design Parameters • Benchmarks + 3 different CVD diamond-coated inserts • Two speeds & three depths of cut • Three test materials • Tool life criterion - .4mm average flank wear

8. Design Principles • Tool Material • Tool Geometry • Coatings

9. Experimental Equipment • Turning - all inserts tested with turning • All operations done on a SAG 101 Graziano Lathe equipped with a dynamometric device • Machine Capacity: P = 60 kW and n = 5000 rev/min • Inserts installed on a CSBPR 20 20 K 12 Tool Holder • Milling – Machine tool not specified • Did not test CVD diamond-coated inserts with this setup • Drilling – Machine tool not specified • Did not test CVD diamond-coated inserts with this setup

10. Applied Design Principles • Coating technology for depositing thin layers of diamond (hot filament and DC plasma jet CVD processes) • Applied a chamfer to CVD diamond coated tools to redistribute the force load on the edge • Did not take the opportunity to fit data to the Taylor’s tool life model

11. Benchmark Turning Test Results • Standard carbide cutting tools with TiN coatings have relatively short lives • PCD tools last 2.5 to 7 times longer depending on MMC composition

12. Turning with a 10 mm CVD Diamond-Coated Insert

13. Turning with a 15 mm CVD Diamond-Coated Insert • Y axis in seconds? – chipping was still a significant problem

14. Turning with a 30 mm CVD Diamond-Coated Insert • Changed the surface pretreatment • Added a 15 degree x 0.1 mm chamfer

15. Turning with a 30 mm CVD Diamond-Coated Insert • Changed the surface pretreatment • Added a 15 degree x 0.1 mm chamfer

16. PCD vs PCD Coated Inserts • 30 mm coated tool lasted roughly half that of a PCD tool • CVD inserts are indexible so may be worth the cost • If better organized then could have come up with some Taylor tool life constants for CVD inserts.

17. Conclusions • Thick CVD diamond coatings worked while thinner ones were prone to chipping • The substrate surface preparation has a significant impact on adhesion of coating • Course substrates are better than fine ones • Diamond-coated tool life still cannot be compared to PCD tool life • No real solid data or models for predicting the life of a CVD diamond-coated tool

18. Practical Industrial Use • Machining any nonferrous materials such as plain aluminum alloys or titanium • Machining Aluminum based MMCs with Al2O3 and SiC

19. Technology Advancement1 • CVD Diamond-Coated Inserts • Price is around $50 - $70 for indexible quad • Capable of high speed machining up to 6000 sfpm • Recommend using high pressure coolant for interface integrity • "Their commercial viability is proven. They can do the work and, in some applications, they are the only way to do the work." • PCD Inserts • Price is around $80 - $100 per insert for single point • They can now be formed with complex geometry • Still last longer than CVD diamond-coated inserts • Diamond-Coated Carbide Inserts-Ready, Set, Go! by Chris Koepfer, Senior Editor

20. Industries Most Impacted • PCD insert industry • Aerospace • Automotive • Trains • Racing • Any other industry looking for a lighter high-strength material that can be machined

21. Questions?