Bridging Program - Assignment
Module: Computer Aided Design
A company has received a financial investment to upgrade all workshops machinery to state-of-theart machines. The workshop-engineering manager has asked for your input as the computer aided
designing and manufacturing (CAD/CAM) technician to oversee the acquisition of CNC machines to
replace the old manual machine tools. This will enable computer aided design to be used to its full
potential, as designs can be directly loaded into a CNC machine which can machine the components to
a high degree of accuracy.
Once the hardware has been installed you will need to produce a solid model of a component and its working
drawing. You are also required to prepare the manufacturing model to generate the part programs to
cut the component using the CNC machine. It is vital that this is a success so the investors can
appreciate the expenditure and analyze the outputs that will increase as a result of employing such
technology.
Part A
At first, you have been asked to present a formal report to the workshop manager outlining the
information the company’s board will require to know to support this investment. The report should include
the following along with examples, illustrations and images.
•
describe the hardware and software required to run a CAD/CAM system
•
describe the general inputs and outputs of a CAD/CAM process
•
explain how the CNC machine can be used for manufacture of components
▪
describe generic steps to set up workpieces in CNC machines
▪
describe work-holding methods for CNC machines
▪
describe types of tooling for CNC machines
•
analyze the importance of use of different programming methods on CNC machines
•
perform a critical evaluation of the impact of different machining specifications/
conditions on the final product manufactured and benefits of using CAM systems over
manual techniques.
Part B
Secondly, you are required to demonstrate the use of CAD/CAM technology to fabricate a component
that that is a part of a prototype developed by the research and development team of the company. A
pictorial view of the bracket is given below with key dimension
Figure 1: Isometric-view of component
Four corner drilled holes are located in equal distances away from respective corners. All five drilled
holesare passed through the thickness of the component.
Note that if certain dimensions are missing you are free to assume suitable values; however, point out
all assumptions clearly on the report.
•
design a three-dimensional (3D) solid model of the component using a suitable CAD tool
o
prepare geometry using Constructive Solid Geometry (CSG) technique
o illustrate the solid modelling steps with screen captures of the relevant views
along with descriptions on types of modelling tools and operations which you
used in sequence
o prepare a 2D drawing showing isometric views of the solid model
•
produce a working drawing of the bracket containing specific manufacturing details and
explainyour selections
o generate a working drawing by making suitable choices for the following
•
projection method (i.e., first angle or third angle) paper size (i.e., A2, A3, A4, etc.)
scales (i.e., 2:1, 1:1, 1:2, etc.)
•
types of orthographic views (i.e., elevations, sections, plan, etc.)
•
format of title-block (i.e., no. of cells, location, content, etc.)
•
text style (i.e., font type and size, etc.)
•
dimension style (i.e., linear, angular, diametral, radial, etc.)
o apply the following drawing attributes on the working drawing
•
dimensional tolerances (i.e., general, and specific)
•
surface finishes (i.e., general, and specific) material of manufacture
o explain the basis of selection of dimensional tolerances, surface finishes and
material ofmanufacture
•
describe how different geometry manipulation methods can be used for preparing
intelligent CADmodels
•
perform a critical evaluation on the effectiveness of using CAD/CAM systems for
designing andmanufacturing components
Part C
Thirdly, you need to create the machining sequences for the component on a CNC Vertical Milling
Machine with the aid of a suitable CAM system and generate manufacturing simulations.
•
convert the data generated in CAD system to a suitable format to transfer into a CAM system
o describe the method of conversion
o include screen captures of relevant views showing important steps
•
transfer the converted CAD data into the CAM system
o describe the steps followed in the data transfer process
o include screen captures of relevant views showing important steps
•
assemble and fully-constrain the geometry in the manufacturing model
o justify your choice of orientation of the component when assembling it on
themanufacturing model
o give one screen capture of the entire graphic screen at the completion
•
create a suitable workpiece referenced to the CAD model
o explain the reasons for your judgement in deciding the profile for the workpiece
o give one screen capture of the entire graphic screen at the completion
•
generate the operation set-up of manufacturing model in the CAM system
o
describe step-by-step how the machine tool setup was performed
o explain purposes of defining machine-zero and retract-plane with respect to the workpiece
o give screen captures of the entire graphic screen illustrating important intermediate steps
•
generate computer-aided part programs and cutter tool path simulations using the
developedmanufacturing model
o give specific details on how each of the milling operations was set-up in the CAM software
o present screen-captures of the graphic screen at important steps
•
analyze the effect of applying different techniques to optimize tool path
o specify how each of the milling operations was set-up in the CAM software with
optimized cutter paths
o compare illustrations of the modified cutter paths against original cutter paths
o explain the benefits of your recommended modifications/ redefinitions
Part D
Finally, you need to produce a dimensionally accurate component on a CNC machine.
•
explain, step-by-step, how the CAM software can be used to prepare a G-code program.
Present screen-captures of the graphic screen illustrating important steps of making tape file
for a selected operation. Also, describe the process of inputting a G-code program
generated from CAM software to a CNC machine
•
describe the structural elements of a CNC Machining Centre
•
explain how the accuracy of the manufactured component can be verified
•
prepare a report on different methods of component inspection used in modern manufacturing
•
prepare a list of common data transfer methods. Make short descriptions on their
technological characteristics. Then, evaluate capabilities and limitations of each data transfer
method based on information gained from the study
Note:
submit the soft copies of all the files (solid model, working drawing, manufacturing model, and final
report)