, Volume 22, Issue 3, pp 449–472 | Cite as

Machining and surface integrity of fibre-reinforced plastic composites

  • M Ramulu
Recent Advances In Mechanical Engineering


The current focus of manufacturing research on fibre-reinforced plastics (FRP) is composed of the search for efficient processing techniques capable of providing high quality machined surfaces. Very limited work has been performed to identify the influence of manufacturing processes like edge-trimming and drilling on material performance. Recent reports suggest that process-induced damage may affect the mechanical behaviour of FRP materials. Therefore an experimental study of orthogonal cutting was conducted on the edge trimming of unidirectional and multi-directional graphite/epoxy composites with polycrystalline diamond tools. The effects of tool geometry and operating conditions were evaluated from an analysis of chip formation, cutting force, and machined surface topography. All aspects of material removal were found to be primarily dependent on fibre orientation. Discontinuous chip formation was noted throughout this study, regardless of machining parameters. Three distinct mechanisms in the edge trimming of fibre-reinforced composite material including a combination of cutting, shearing, and fracture along the fibre/matrix interface were observed. An investigation conducted on the compression, flexural and impact strength of graphite/epoxy composites machined by both traditional and non-traditional techniques, confirms that manufacturing characteristics may not only affect bulk properties but also influence the initiation and propagation of failure.


Fibre-reinforced plastics manufacturing processes process-induced damage graphite/epoxy composites 


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  1. Abrate S, Walton D A 1992a Machining of composite materials. Part I: Traditional methods.Compos. Manuf. 3: 75–83Google Scholar
  2. Abrate S, Walton D 1992b Machining of composite materials. Part II: Non-traditional methods.Compos. Manuf. 3: 85–94Google Scholar
  3. Arola D, Ramulu M 1994 Machining induced surface texture effects on the flexural properties of a graphite/epoxy laminate.Composites 25: 822–833CrossRefGoogle Scholar
  4. Arola D, Ramulu M 1995 Manufacturing effects on the impact properties of graphite/epoxy composite.Proceedings of the 10th Annual Technology Conference of American Society of Composites (in press)Google Scholar
  5. ASTM 1986Standard test methods for the flexural properties of unreinforced and reinforced plastics and electrical insulating materials. ASTM D790MGoogle Scholar
  6. Colligan K 1993Machined edge effects on the compression strength of graphite/epoxy. MS thesis, University of Washington, SeattleGoogle Scholar
  7. Colligan K, Ramulu M 1992 The effect of edge trimming on composite surface plies.Manuf. Rev. 5: 274–283Google Scholar
  8. Ghasemi Nejjad M N, Chou T-W 1990 Compression behaviour of woven carbon fibre-reinforced epoxy composite with molded in and drilled holes.Composites 21: 33–40CrossRefGoogle Scholar
  9. Griswold N C, Massarweh W A, Hough C L 1989 Morphological structures in analysis and inspection of hole quality in fiber composites.J. Testing Eval. 17: 281–286Google Scholar
  10. Ho-Cheng H, Dharan C K H 1990 Delamination during drilling in composite laminates.J. Eng. Ind. 112: 39–47Google Scholar
  11. Howarth S G, Strong A B 1990 Edge effects with waterjet and laser beam cutting of advanced composite materials. In35th International SAMPE Symposium, pp 1685–1697Google Scholar
  12. Inoue H, Ido M 1986 Study on the cutting mechanism of GFRP. InProceedings of Int. Symp. on Composite Materials and Structures, Beijing, pp 1110–1115Google Scholar
  13. Jamil S J, Chambers A R 1991 Evaluation of surface quality of drilled holes in composite materials after high speed drilling. InAdvance machining for quality and productivity (incorporating the 2nd International Conference on the Behavior of Materials in Machining, 1991), pp 70–76Google Scholar
  14. Kaneeda T 1991 CFRP Cutting mechanism.Trans. North Am. Manuf. Res. Inst. SME 19: 216–221Google Scholar
  15. Kinkaid R 1988 Quality holes in composites with PCD cutting tools.Cutting Tool Eng. 40: 50–52Google Scholar
  16. König W, Wulf C, Graf P, Willersceid H 1985 Machining of fiber reinforced plastics.Ann. CIRP 34: 537–547CrossRefGoogle Scholar
  17. Koplev A 1980 Cutting of CFRP with single edge tools. InProc. of 3rd Int. Conf. on Composite Materials, Paris, pp 1597–1605Google Scholar
  18. Koplev A, Lystrup A, Vorm T 1983 The cutting process, chips and cutting forces in machining CFRP.Composites 14: 371–376CrossRefGoogle Scholar
  19. Krisnamurthy R, Santhanakrishnan G, Malhotra S K 1992 Machining of polymeric composites. InMachining of Composites (Columbus, OH: ASM) pp 139–148Google Scholar
  20. Lin H J, Lee Y J 1992 Strength of composite laminates with continuous fiber around a circular hole.Compos. Struct. 21: 155–162CrossRefGoogle Scholar
  21. McCarty J E 1993 Design and cost viability of composites in commercial aircraft.Composites 24: 361–365CrossRefGoogle Scholar
  22. Mehta M, Reinhart T J, Soni A H 1992 Effect of fastener hole drilling anomalies on structural integrity of PMR-15/Gr composite laminates. InMachining of composites (Columbus, OH: ASM) pp 113–126Google Scholar
  23. Miller R K 1991 Waterjet cutting: Technology and industrial applications (Liburn, GA: Fairmont)Google Scholar
  24. Mortimer J 1987 New technology brings quality to manufacture.Ind. Robot 14: 103–104Google Scholar
  25. Park J 1991Study on the effect of PCD tool geometry on the machining of graphite/epoxy composite materials. MS thesis, University of Washington, SeattleGoogle Scholar
  26. Pengra J J, Wood R E 1980 The influence of hole quality on graphite/epoxy composite laminates. InProceedings of the AIAA/ASME/ASCE/AHS 21st Structures, Structural Dynamics and Materials Conference AIAA Paper 80-0777, pp 687–693Google Scholar
  27. Philips J L, Parker R T 1987 Fastener hole considerations. InEngineered materials handbook, Composites (Columbus, OH: ASM) pp 712–715Google Scholar
  28. Pipes R B, Pagano N J 1970 Interlaminar stresses in composite laminates under uniform axial extension.J. Compos. Mater. October: 538–548Google Scholar
  29. Ramulu M, Arola D 1993 Water jet and abrasive water jet cutting of unidirectional graphite/epoxy composite.Composites 24: 299–308CrossRefGoogle Scholar
  30. Ramulu M, Arola D 1994 The influence of abrasive waterjet cutting conditions on the surface quality of graphite/epoxy laminates.Int. J. Mach. Tools Manuf. 34: 295–314CrossRefGoogle Scholar
  31. Ramulu M, Wern C W, Garbini J L 1993 Effect of fiber direction on surface roughness measurements of machined graphite/epoxy composite.Compos. Manuf. 4: 39–51CrossRefGoogle Scholar
  32. Riggs J P 1984 Emerging non-metallic structural materials used for airframes and other demanding applications.Mater. Soc. 8: 351–376Google Scholar
  33. Sadat A B 1988 Machining of graphite/epoxy composite material.SAMPE Q. 19: 1–4Google Scholar
  34. Sakuma K, Seto M 1983 Tool wear in cutting glass-fiber-reinforced plastics.Bull. JSME 26: 1420–1427Google Scholar
  35. Tagliaferri V, Di Illio A, Crivelli Visconti I 1985 Laser cutting of fibre reinforced polyesters.Composites 16: 317–325CrossRefGoogle Scholar
  36. Tagliaferri V, Caprino G, Diterlizzi A 1990 Effect of drilling parameters on the finish and mechanical properties of GFRP composites.Int. J. Mach. Tools Manuf. 30: 77–84CrossRefGoogle Scholar
  37. Wang D H 1993Machining characteristics of graphite/epoxy composites. Ph D thesis, University of Washington, SeattleGoogle Scholar
  38. Wang D H, Ramulu M, Wern C W 1992 Orthogonal cutting characteristics of graphite/epoxy composite material.Trans. NAMRI/SME 20: 159–165Google Scholar
  39. Wang D H, Ramulu M, Arola D 1995a Orthogonal cutting mechanisms of graphite/epoxy composite, Part I: Unidirectional laminate.Int. J. Mach. Tools Manuf. 35: 1623–1638CrossRefGoogle Scholar
  40. Wang D H, Ramulu M, Arola D 1995b Orthogonal cutting mechanisms of graphite/epoxy composite, Part II: Multi-directional laminate.Int. J. Mach. Tools Manuf. 35: 1639–1648CrossRefGoogle Scholar
  41. Wern C W 1991Surface characteristics of machined graphite/epoxy composites. M S thesis, University of Washington, SeattleGoogle Scholar
  42. Wood R E 1978 Graphite/epoxy composite hole quality investigation. In10th National SAMPE Technical Conference, Materials Synergisms 10: 636–650Google Scholar
  43. You S-S, Chou T-W 1988 Strength of woven-fabric composites with drilled and molded holes. In8th Conference on Composite Materials: Testing and Design, ASTM STP 972, pp 423–437Google Scholar

Copyright information

© Indian Academy of Sciences 1997

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringUniversity of WashingtonSeattleUSA

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