UNIVERSITY OF CAPE TOWN

DEPARTMENT OF MECHANICAL ENGINEERING

MEC4103F Product Design ASSIGNMENT 2 2015

Title: PLANNING AND MANAGEMENT, TECHNICAL AND COST MODELLING,

DETAIL DESIGN, LIFE CYCLE COSTS (LCC)

Type: Individual submission

Emphasis: Project planning and management

Technical and cost modelling and performance analysis

Final product requirement specification (FPRS)

Detail design

Product economics

Design File: Project planning in Planning section

Modelling and performance and cost analysis in Design, Modelling & LCC section

FPRS in Requirements and Concepts section

Submission: Latest by 10h00, 2015/04/10

Where: E-copy: Resources\Group folders\Group #\Assignment 2

Design File: To be announced

1. Each team member is to make a copy of the groups marked Assignment 1 submission and place

this copy in his/her Design Folder.

2. In consultation with your team, generate a Work Breakdown Structure (WBS) and Gantt chart for

your project, doing your planning as if you were in industry and not limited by the constraints of

the course. The chief designer is to produce a high level overview WBS and Gantt chart on which

the main activities are summarized. Clearly show the contributions by the sub-assembly designers

on your WBS and Gantt chart. Failure of doing so will result in you failing ECSA ELO8,

group work, and you will be awarded a DPR for the course. (In the event of a team member

failing to supply their contribution to you, document this fact and have it co-signed by other team

members. The offending team member will be awarded a DPR due to failing ECSA ELO8.)

3. Make a copy of your preferred concept sketch of Assignment 1 and present it as the first page of

your modelling work, discussed in the steps below

4. The chief designer:

a. With the aim of setting up your Final Product Requirement Specification (FPRS),

conceive the necessary mathematical models and conduct high level performance and

cost calculations for your device. The performance calculations include estimating power

required, loads acting on assemblies, stability, etc. As details of the sub-assembly costs

are unknown at this stage, the team has to make rough estimates of assembly and

manufacturing costs (only work in USD). A good approach is to follow the target-cost

approach as explained on pp. 114-116 of U&E. You may use any package such as Excel,

Matlab or MathCAD. Briefly summarize your assumptions, methodology and equations

used. Make sure all your symbols are defined and that your work can easily be

deciphered.

b. Following the five step process of U&E on page 105, perform the necessary calculations

to refine the TPRS towards the FPRS. Output from this step should inform the design

requirements for the various sub-assemblies. Present the FPRS in the format given in

Exhibit 6-12.

5. For each cluster, embody your design concepts by performing detail design and essential

modelling. Detail design implies deciding on assembly lay-out details, e.g., selecting bearings and

their mounting schemes, keys, gears, sprockets, pulleys, belts, etc. Factors to consider are form fit

and function, material selection, cost reduction using Design for Manufacturing and Assembly

(DFMA) techniques, environmentally responsible design employing Design for the Environment

(DFE) practices, etc. Select Original Equipment Manufacturer (OEM) devices from catalogues

(the Thomas Register of American Manufacturers is a good source for this,

www.thomasnet.com). Your output for this step must be mainly in the form of sketches with

clarifying annotations.

6. Produce a neat sketch of your assembly showing the details discussed above. No dimensioning is

yet required.

7. Essential modelling implies those algorithms and calculations deemed necessary to ensure

functional performance. These could include motion analysis, stress and deflection analysis,

bearing life calculations, etc. You may use any package such as Excel, Matlab or MathCAD.

Briefly summarize your assumptions, methodologies and equations used and present your final

results. Make sure all your symbols are defined and that your work can easily be deciphered. To

save time, you dont have to analyze each and every component in your assembly. Analyzing

two or at most three components is acceptable. It is acceptable to guess the sizes of the remaining

components based on your gut-feel. This is often done in industry during the initial stages of

product design.

8. Estimate the manufacturing costs for your cluster and summarize these in a Bill of Materials

(BOM) (see Exhibit 13-6 in the text). All costing is to be done in USD. A target costing-approach

for your cluster may be wise (see pp. 114-116 of the text). Appendices A, B, C and D of chapter

13 of the text contain useful guidelines for custom component estimations. If you cant easily find

the costs of OEM items, make intelligent guesses for these. Do not solicit prices from vendors as

it is too time consuming and you will be wasting their time for not actually making a purchase.

Provide your cost estimates to your chief designer, who is to consolidate the trailer manufacturing

costs in a high level BOM.

9. For the purposes of detail design, hand sketches are strongly recommended at this stage. You may

move on to CAD once your ideas are maturing. No working drawings are required yet.

10. Conduct an economic analysis by following the four steps on page 356 of U&E. Specific tasks to

be performed are explained below.

11. Referring to your planning as done in step 3 and your BOM of step 8, set up a base-case financial

model for your product or cluster by estimating the timing and magnitude of future cash flows

followed by calculating the net present value (NPV) of the project and each cluster. Estimate the

project and cluster costs for development, ramp-up, marketing and support. Also estimate your

volumes of sale, the unit price of your product or cluster and a period over which your product

will be on the market. On a spreadsheet, merge your project financials and schedule and calculate

your NPV in a format similar to Exhibit 17-6.

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Deliverables (page numbers indicated are maximum values):

1. Title page and anti-plagiarism declaration (first page of your submission)

2. Group work declaration (chief designer only)

3. WBS and Gantt diagram (4 pages each) 20 marks

4. FPRS (2 pages) 10 marks*

5. Copy of selected concept sketch (1 page) 5 marks

6. Detailed assembly sketch (1 page) 15 marks

7. Model description and detail design (6 pages) 60 marks

8. BOM (3 pages) 20 marks

9. Base case financial model (4 pages) 35 marks

TOTAL: Chief designer: 165 marks

Cluster designers: 155 marks

General:

1. Untidy work will be rejected and a zero score given.

2. Work not adhering to submission requirements: Mark multiplied by 0.9.

3. * Indicates marks for chief designers only.