1. Advisor: Dr. Khalifa Harib
Machining of sculptured surfaces using CNC Machine Tools (Mechanical Engineering)
Ahmed Ishaq Al-Balooshi
Abdulaziz Al-Obaidli
Mohammed Al-Habshi
Advisor: Dr. Khalifa Harib

2. Preview Abstract Background Theory Methods & Techniques
Results & Discussions
Concluding Remarks
Questions

3. Abstract Goal To Achieve This Goal
To machine 3-D sculptured surfaces using CNC machine Tools.
To Achieve This Goal
Sculptured Surface representing the 3-D shape of a shoe sole was selected

4. Abstract The importance of this project What is new in this Project ?
The need of background theory

5. Abstract Project Modules Establishing the link between the CNC & PC
Acquisition of control points of a shoe sole for geometric modeling using parametric surfaces
Geometric modeling of the shoe sole
Machining of the shoe sole cavity

6. Background Theory

7. Background Theory Fundamentals of Milling
Milling is the process of cutting away material by feeding a work-piece past a rotating multiple tooth cutter

8. Background Theory Fundamentals of Milling
Milling Machine
The machine for holding the work-piece, rotating the cutter, and feeding it is known as the Milling Machine

9. Background Theory Fundamentals of Milling
CNC Machine
CNC: Computer Numerically Controlled
The most advanced CNC milling-machines is the 5-axis machine

10. Background Theory Fundamentals of Milling
History
The first NC machine was developed by MIT by a commission from US Air Force in It was demonstrated in 1952
Advantages
Easier to program, change a program
NC machines are safer to operate
Cheaply production of Complex geometry
Usually generates closer tolerances than manually operated machines

11. Background Theory Fundamentals of Milling
CNC Tools
Material Blanks
Work-pieces
Cutting Tools
End-mills, V-mills
Nose-Ball mills
Collets
Tools Holders

12. Background Theory Fundamentals of Milling
NC Programming
The programmer writes the instructions for the machine controller to specify:
Loading/unloading cutting tool
Cutting conditions (speed, feed, coolant)
Start point and end point of a motion segment
How to move the tool with respect to the machine?

13. Background Theory Fundamentals of Milling
NC Programming
The format for each “instruction" is:
ADDRESS[VALUE]
Cartesian system used to specify positions
Left Hand rule used to specify the motion direction

14. Background Theory Fundamentals of Milling
Modern Machining System
Complex shapes need to be produced
Complex Mathematical Functions & Programming
CAD/CAM
Softwares

15. Background Theory Connection Cable Interface
Ethernet Connecting
Ethernet is a local area technology, with networks traditionally operating within a single building, connecting devices in close proximity

16. Background Theory Fundamentals of NURBS
NURBS: Non-Uniform Rational B-splines
Considered as a powerful tool for geometric design.
Played a pig role in the CAD/CAM world

17. Background Theory Fundamentals of NURBS
A NURBS surface with control points Pij (0≤i ≤ m, 0 ≤ j ≤ n) can be defined as

18. Background Theory CAD/CAM Softwares
MasterCAM
Founded in 1984.
MasterCAM is an integrated CAD/CAM software package.
By MasterCAM we can create geometries and prepare engineering details, graphical tool-paths, and NC code.

19. Background Theory Fundamentals of Machining Parameters
Feed rate (mm/min)
= feed per tooth (chip thickness)
= number of cutter teeth
= rotation of the cutter, rpm

20. Background Theory Fundamentals of Machining Parameters
Cutting Speed & Spindle Speed
S = Cutting Speed in m/min
D = tool outside diameter
rpm = tool rotational speed
Cutting speed should be in the range of 80 – 100 m/min

21. Methods & Techniques

22. Methods & Techniques Procedures “General”
Geometric & Tool-path Modeling
CNC Machine Tools
Machining
PC to CNC Link
Real Object No
Yes
Accepted
Finish

23. Methods & Techniques Procedures “Our Case”
Familiarization with the machine
Machining
Establishing Connection CNC  PC No
Yes
Accepted
Finish

24. Methods & Techniques Selected Application
Application: Create a casting mold for the shoe sole as one part
In-Sole
Out-Sole
Slip-Sole

25. Methods & Techniques Selected Application
After Casting is taking Place
Male Part
Female Part

26. Methods & Techniques Creating the Male Part of the Mold
Complexity of the Male Part
The male part couldn’t be designed on any CAD/CAM software using the standard 3-D shapes i.e. box, sphere, cone …etc.
The complexity of the male part design is coming from the fact that the male part surface should reflect the curvatures of the human foot

27. Methods & Techniques Creating the Male Part of the Mold
To understand the curvatures of the human sole a clay sculpture of a human sole was created.

28. Methods & Techniques Creating the Male Part of the Mold
Control Points
Digitizing

29. Methods & Techniques Creating the Male Part of the Mold
1st Technique :
Modifying the digitized data and use it as control points to define different splines.
Creating rule surface from the defined splines
2nd Technique :
Define cross & along splines from the digitized data
Creating swept surface from the defined splines

30. Methods & Techniques Creating the Male Part of the Mold
1st technique Modification:
1. Taking less number of control points in drawing each spline.
2. Changing the depths which make the complex curves to acceptable values.
3. Drawing the splines in y-direction instead o x-direction

31. Methods & Techniques Creating the Male Part of the Mold
1st technique Modification: y y x x
Splines Drawn in X-Direction
Splines Drawn in Y-Direction

32. Methods & Techniques Creating the Male Part of the Mold
Modification Result:
Result still very
hard to machine
and still need
more modification
Unneeded details
This area should be scaled down
New modification includes:
Scaling dawn the heel area
Changing some control points at finger area
Appling slope of 0.1

33. Methods & Techniques Creating the Male Part of the Mold
2nd Modification Result:

34. Methods & Techniques Creating the Male Part of the Mold
2nd technique:
Cross Splines defined by 3 control points
Control Point 1 X Y Z
located on the internal shoe boundary from left
0 + elevation coming from the slope
Control Point 1 X Y Z
Middle point
z + elevation coming from the slope
Control Point 1 X Y Z
located on the internal shoe boundary from right
0 + elevation coming from the slope

35. Methods & Techniques Creating the Male Part of the Mold
2nd technique:
Along spline defined by 4 control points
Along Spline
C 1
C 2
C 3
C 4
55,3,25.7
60,50,21
70,130,13
75,260,0

36. Methods & Techniques Creating the Male Part of the Mold
2nd technique:

37. Methods & Techniques Creating the Male Part of the Mold
2nd technique Result:
The result of the second technique was satisfied
The heights of the shaded area were decreased more

38. Methods & Techniques Creating the Female Part of the Mold
Importance of the Female Part
The female part of the shoe sole mold is important as much as the male part, because it contains the cavity, the 2-D boundary of the shoe sole, and the pattern of the bottom shoe sole which is the slip-sole area

39. Methods & Techniques Creating the Female Part of the Mold
The inner boundary was created by offsetting the outer one and by applying trimming functions
The 2-D outer boundary was created using control points defined from digitized hand 2-D sketching

40. Methods & Techniques Generating NC Code files
Tool-path of the cutting tool should be created in order to generate the NC code files and send it to the machine for machining.
Tool-paths were created in MasterCAM software.

41. Methods & Techniques Generating male part NC Code
Stock was defined for the created male part surafce

42. Methods & Techniques Generating male part NC Code
Surface Rough flow line tool-path
2-D contour tool-path
Tool = HSS ball nose D(14mm)
Feed = 1000 mm/min
Spindle = 2000 rpm
Max Depth = 4 mm
Width = 14 mm
Tool = HSS ball nose D(14mm)
Feed = 1000 mm/min
Spindle = 2000 rpm
Depth = 5 mm (7 layers)
Width = 14 mm

43. Methods & Techniques Generating male part NC Code

44. Methods & Techniques Generating male part NC Code
Surface Rough flow line tool-path
2-D contour tool-path
Tool = HSS ball nose D(14mm)
Feed = 1000 mm/min
Spindle = 2000 rpm
Max Depth = 1.25 mm
Width = 14 mm
Tool = HSS ball nose D(14mm)
Feed = 1000 mm/min
Spindle = 2000 rpm
Depth = 5 mm (7 layers)
Width = 14 mm

45. Methods & Techniques Generating male part NC Code

46. Methods & Techniques Generating male part NC Code
Surface Rough flow line tool-path
2-D Pocket tool-path
Tool = HSS end mill D(14mm)
Feed = 1000 mm/min
Spindle = 2000 rpm
Max Depth = 4 mm
Width = 14 mm
Tool = HSS end mill D(14mm)
Feed = 1000 mm/min
Spindle = 2000 rpm
Depth = 5 mm (7 layers)
Width = 14 mm

47. Methods & Techniques Generating male part NC Code
Surface finish flow line tool-path
Tool = HSS ball nose D(14mm)
Feed = 1000 mm/min
Spindle = 3000 rpm
Max Depth = 1.25 mm
Width = 1 mm

48. Methods & Techniques Generating male part NC Code
Unsatisfied
Unsatisfied
Satisfied

49. Methods & Techniques Generating Female Part NC Code
Stock was defined for the created male part surface

50. Methods & Techniques Generating Female part NC Code
2-D pocket tool-path
2-D pocket tool-path
Tool = HSS end mill D(14mm)
Feed = 1000 mm/min
Spindle = 2000 rpm
Depth = 5 mm (8 layers)
Width = 14 mm
Tool = HSS ball nose D(8mm)
Feed = 1000 mm/min
Spindle = 2000 rpm
Depth = 3 mm (1 layers)
Width = 8 mm

51. Methods & Techniques Generating Female part NC Code.
Result was verified and satisfied

52. Results & Discussion

53. Results & Discussions Machining the mold
After verifying the geometry design of the two parts of the mold, the NC codes files were sent to the CNC machine.
The machining take place on three different materials: wood, acrylic and mild steel.

54. Results & Discussions Machining Male Part
Used tool-paths:
Surface rough flowline
2-D contour
Result of machining the male part created by following the 1st technique on wood work-piece

55. Results & Discussions Machining Male Part
The work piece break
Used tool-paths:
Surface rough flowline
2-D contour
Result of machining the male part created by following the 2nd technique on acrylic work-piece

56. Results & Discussions Machining Male Part
Used tool-paths:
Surface rough flowline
2-D contour
Result of repeating the machining the male part created by following the 2nd technique on wood work-piece

57. Results & Discussions Machining Male Part
Used tool-paths:
Surface rough flowline
2-D pocket
Surface finish tool-path
Result of machining the male part created by following the 2nd technique on wood work-piece

58. Results & Discussions Machining Male Part
Used tool-paths:
Surface rough flowline
2-D pocket
Surface finish tool-path
Result of machining the male part created by following the 2nd technique on acrylic work-piece

59. Results & Discussions Machining Female Part
The tools exceed the supposed depth and break through the work piece
Used tool-paths:
2-D pocket in two operations
Result of machining the female part on acrylic work-piece

60. Results & Discussions Machining Female Part
Break reasons & soltions
The break through was happened because the 8 mm in diameter cutting tool was longer than the 14 mm in diameter cutting tool which was used to take the datum point of the work piece.
An offset of difference in length between the two cutting tools should be considered and defined on the CNC machine in order to avoid this problem

61. Results & Discussions Machining Female Part
Used tool-paths:
2-D pocket in two operations
Result repeating the machining of the female part on acrylic work-piece

62. Results & Discussions Machining Female Part
Used tool-paths:
2-D pocket in two operations
Result of machining the female part on mild steel work-piece

63. Results & Discussions Machining Female Part
Break reasons
Tool break was happen because the cutting tool was entered the work-piece suddenly and perpendicularly to a depth of 5 mm and experienced a very high reacting force which resulted in the break of the tool.

64. Results & Discussions Machining Female Part
Solutions:
Changing the method of entering the work piece from a sudden perpendicular entering to gradual helical entering.
Using carbide cutting tools with two flutes.
Using a coolant while machining taking place.
Using mild steel manufactured for machining purposes

65. Results & Discussions Casting result
After machining the two parts of the mold, wax is injected in the mold in order to create the designed shoe sole.

66. Concluding Remarks

67. Concluding Remarks Machining Female Part
The objective of the project was achieved
EDM technique can be used for machining molds on mild steel or other tough materials
It is recommended to involve industrial partner to such projects so that the project outcomes can be transferred to the industry

68. Concluding Remarks Machining Female Part
4. customized geometric modeling software can be developed to optimize the machining of sculptured surface by optimizing the NC program.
5. This project will be beneficial for UAE University students by encouraging them to do similar projects and transfer this technology to the society to build healthy and diversity UAE economy.

69. Thanks for Listening