Development of an Integrated Drilling, Chamfering and Deburring Tool

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Gwendoline Greene
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Electrical, Electronic and Mechanical Engineering

1 Development of an Integrated Drilling, Chamfering and Deburring Tool Peter Stringer UCD School of Electrical, Electronic and Mechanical Engineering Scoil na hinnealtóireachta Leictrigh, Leictreonaigh agus Mheicniúil UCD

2 Agenda General project overview Outline of project goals What has taken place Summary of literature review Patent search Upcoming work

3 General Project Overview - Project Summary Investigation of a new drill head design Incorporating a Deburring/Chamfering tool for removal of exit side burrs For use drilling holes in the range of 2-10mm Drill head must expand on the exit side of the workpeice once the hole has been drilled, and retract to fit back through the hole Optimization and control of drilling burr formation. Kim, J. Min, S. and Dornfeld, D.A. International Journal of Machine Tools & Manufacture (2001)

4 General Project Overview Funded by Enterprise Ireland for 12 months. Proof of concept. is sufficiently robust is seen to address a viable market and is not encumbered by intellectual property considerations.

5 General Project Overview - Extra Challenges due to Many solutions exist for larger diameter holes Possible to access exit side through the hole Smaller size increases complexity greatly No access through hole Less possible space to incorporate device Possible lack of rigidity if mechanical system incorporated

6 General Project Overview - Why remove burrs? Burrs can cause Mechanisms to jam Lead to increased wear Damage electrical connections Cause personal injuries Lead to problems while connecting components

7 General Project Overview - What does burr removal cost? Estimates of between 10% and 30% of the total cost of a part In 1977 estimated cost of deburring $100 million in Canada alone

8 General Project Overview - Expected Conclusion Working Prototype Integrated into CNC machine Market potential surveyed Protection of intellectual properties

9 What has been done Literature review Patent Search Start getting information from industry Methods in common use Cost of deburring specifically for deburring

10 Literature Review 2 books on Deburring in general Burrs from drilling 44 relevant papers on Deburring Drilling Burrs produced by drilling Methods for deburring Classification of burrs One paper on integrated deburring and drilling

11 Literature Review Main researchers and locations Gillespie, L.K. Bendix corporation Dornfeld, D.A. CODEF, Berkeley, California Korea University Japanese Society for Precision Engineering

12 Literature Review How is a burr formed? Uniform Burr Initial fracture at the chisel edge (drill tip), Plastic deformation zone at chisel edge, no cutting takes place here, material near chisel edge is thinned by plastic deformation and removed by cutting Second fracture occurs at end of cutting edge Plastic zone expands to edge of drill Drill cap and burr are formed Development of a drilling burr control chart for low alloy steel. Min, S. Kim, J. and Dornfeld, D.A. journal of material Processing Technology (2001)

13 Literature Review How is a burr formed? Uniform Burr Development of a drilling burr control chart for stainless steel. Dornfeld, D.A. Min, S. Kim, J. et al. LMA research reports (2000)

14 Literature Review How is a burr formed? Transient Burr Initial and Second fracture occur at the same time, later than with the Uniform burr. As the drill advances further the strain at the chisel edge exceeds the fracture strain of the remaining material forming the crown burr shape Development of a drilling burr control chart for low alloy steel. Min, S. Kim, J. and Dornfeld, D.A. journal of material Processing Technology (2001)

15 Literature Review How is a burr formed? Transient Burr Optimization and control of drilling burr formation. Kim, J. Min, S. and Dornfeld, D.A. International Journal of Machine Tools & Manufacture (2001)

16 Literature Review How is a burr formed? Crown Burr Occurs when there are high feed rates, which lead to large thrust forces Plastic deformation occurs earlier in the drilling process Larger layer plastically deformed Strain hardening occurs at the centre region of exit surface Region becomes brittle Fracture occurs Development of a drilling burr control chart for low alloy steel. Min, S. Kim, J. and Dornfeld, D.A. journal of material Processing Technology (2001)

17 Literature Review How is a burr formed? Crown Burr Development of a drilling burr control chart for stainless steel. Dornfeld, D.A. Min, S. Kim, J. et al. LMA research reports (2000)

18 Literature Review Paper on Drilling and Deburring Deburring and Drilling in a single process. Kim, Cho, Lee, Dornfeld. IMechE (2003).

19 Literature Review Paper on Drilling and Deburring Capable of removing uniform burrs Drill must go fully through the work piece Possible problem with clearance on exit side

20 Methods of Burr minimisation Changing drill tip design Tool coatings Most significant factor is tool sharpness

21 Patent Search Pattent search carried out using the European Pattent Office website: A number of related patents were found

Patent Search Patent No: US 3940214 A1, (Waschek D.E.

22 Patent Search Patent No: US A1, (Waschek D.E.) For a twist drill with a cutter recessed into the spiral portion of the drill auger For removing burrs on both sides of the hole as the drill passes through the hole. Blade forced out by the spring.

23 Patent Search Patent No: EP A1 (EZ-Burr Tool Co.) For a deburring tool Removes burrs on both sides of the hole Blade forced out by the spring.

24 EZ Burr Tool Company EZburr.mov

25 EZ-Burr tool Available in sizes from 9.5 to 31 mm Spade drill problem removing chips when drilling deep holes Potential problem with damage to surface of drilled hole due to principle of operation

26 Summary of existing solutions Do not cater for smaller diameters Possible risk to integrity of surface of drilled hole Some can t remove all burr types

27 Upcoming Work Attempting to make contact with industry Establish current cost of deburring in industry Establish budget for tool Investigating possible methods of actuation Conceptual design Ongoing Patent Search

28 Thanks for Listening Peter Stringer UCD School of Electrical, Electronic and Mechanical Engineering Scoil na hinnealtóireachta Leictrigh, Leictreonaigh agus Mheicniúil UCD

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