DESIGN DEVELOPMENT OF AN INDIGENOUS TRICYCLE RICKSHAW
Phase 6: Planning for consumption Step 1: Design for maintenance
5.2 Experimental construction
Experimental construction is actually the sixth step in detailed design. The prototype shop in an industry undertakes to build the first full-scale prototype once the detailed drawings are ready. In detail design stage, AutoCAD drawings were prepared earlier (Fig. 3.46- 3.49, p 107). Sometimes, the first prototype can also be ‘the end-product’. It was decided to make a full scale physical prototype. It was realized that scaled down prototype made in foam etc. as a proof of concept models- to answer specific questions of feasibility about a product could not meet many requirement for this research and full scale prototype was essential. Thus Design of Experiment (DoE) experimental physical prototypes focusing on empirical data to optimise layout and shape aspects of the product was fabricated.
There were multiple stake holders in the design development process of Dipbahan.
When the process was underway, there were several questions raised during the stage
holders. Thus they assumed that the final product will also be the same. The aim was to minimize risk during the product development process and to obtain feed back from rickshaw pullers, passengers, suppliers of components, vendors and targeted manufacturer-in this case local small enterprise. Thus the physical prototype served the purpose for communication, demonstration purpose and feasibility study.
The first full-scale prototype was preceded by full scale tape drawing based on AutoCAD drawings (Fig. 3.46 - 3.49, p 107) to facilitate its fabrication. Tape drawing is two dimensional sketch of the design in different views. Dimensional aspects were also verified prior to prototyping through trial (Fig. 5.1-5.5).
To facilitate quick prototyping and trial, the existing tricycle platform was used. This also provides easy comparison for the stability aspect of the new design with the existing one.
As the space structure was one of the main concerns in this experimental prototype metal frame structure was made on covering the upper portion of the chassis. Since the prototype was built to get the overview of the various affecting parameters such as aesthetics, ergonomics for puller and the passengers- accessibility etc. and overall safety shell of the frame was constructed using 10 mm square bars to get the desired Fig. 5.1 Obtaining data using the traditional
rickshaw platform; side view of layout with reduced leg space
Fig. 5.2 Obtaining data using the traditional rickshaw platform; side view of layout with enhanced leg space
Fig. 5.3 Obtaining data using the traditional rickshaw platform;
rear view of layout
Fig. 5.4 Obtaining data using the traditional rickshaw platform;
front view of layout
Fig. 5.5 Obtaining data using the traditional rickshaw platform; three quarter view of layout
form and shape (Fig. 5.6- 5.10). This provided freedom for modifying the curvature and form of the design with ease compared to the targeted final material like circular tubular sections that are difficult to modify. Various welding details were neglected, as it was only a Design of Experiment prototype. The experimental model was later used for the analysis purposes and also as an important reference for the construction of the final model. Further it was kept in mind that it is not always necessary to build a prototype model if final model can be built directly.
Fig. 5.6 DoE prototype, side view Fig. 5.7 DoE prototype, front 3 quarter view
Pre-production prototype of the Interim (first generation) version of Dipbahan Based on the feedback received from the DoE prototype, it was decided that next prototype will be a pre-production prototype instead of an Alpha or a Beta prototype. This not only reduces the cost and time, but provides for actual and fairly accurate cost estimates of the tricycle rickshaw for the marketing stage. Thus pre-production prototype was constructed starting with the body shell (Fig. 5.11-5.15, p 150). This was made using MS sections, circular tubes, flat bars, MS sheets etc. Process of manufacture used is for normal MS work. Pipes and other MS sections are cut to size and welded using arc Fig. 5.8 Rear 3 quarter
view of DOE prototype
Fig. 5.9 Front view of DOE prototype
Fig. 5.10 Rear view of DOE prototype
welding. The welded joints were grinded to remove unevenness in the area. After fabricating the body shell, this was painted and the following process was used.
• Sanding the shell with emery papers to remove rust.
• Application of Putty to fill up and smoothen the weld joints.
• Wet sanding to smoothen the surface.
• Spray painting with Red oxide primer.
• Spray painting with automotive surfacer.
• Final spray painting with automotive paints in desired colour.
To reduce the total cost of the project for manufacturing the newly designed tricycle rickshaw and for the ease of maintenance locally, it was decided that the standard items as per the Table 5.1, p 152 would be directly procured from the market. Thus all these components were procured and assembled with the prototyped body shell.
Availability of components from the existing bicycle and tricycle industry for outsourcing has contributed in the design and implementation of the research in several ways. First, it made the design, prototyping and final manufacturing possible with very low initial investments. If these parts were to be made in house, the capital cost for setting up the facilities would have been prohibitive, since these items require full fledged Fig. 5.11 Side view of the body shell of
pre-production prototype
Fig. 5.12 Three quarter front view of the body shell of pre-production prototype
Fig. 5.13 Front view of the body shell of pre- production prototype
Fig. 5.14 Rear view of the body shell of pre- production prototype
Fig. 5.15 Top view of the body shell of pre-production prototype
manufacturing facility with machine tools etc. that is used currently by bicycle manufacturer in the country mostly located in North India around Ludhiana in Punjab.
This area produces the highest bicycles in India and also exports to all over the country.
Also the scale of operation envisaged for Dipbahan initially is too small to go for such facilities. Being manufactured by decentralized local industries for bicycle and tricycle industry, these components are readily available at very competitive price, but of substantial quality, that may not even be possible in a centralized manufacturing set up.
Second, availability of these standard quality components at very competitive price made it possible to introduce Dipbahan at an acceptable price in the market.
Third, it made the serviceability of Dipbahan a non issue, Ready availability of spares at any place that has a bicycle/tricycle garage made Dipbahan serviceable easy. Thus introduction of Dipbahan did not require setting up of spares outlet all over the places.
Thus impact of outsourced components in the design of Dipbahan was very positive.
Table 5.1 Standard items outsourced from existing bicycle and tricycle industry (Price as on 01.05.2004 in Guwahati)
Sl.
no.
Description Rate per unit Rs.
Quantity Amount Rs.
1 K W 10 gauge rim of 28” x 1 ½” size 103.00 each 3 Nos. 309.00 2 10 gauge spokes 40 nos. x 3 162.00 per gross 120 Nos. 135.00
3 10 gauge front hub 28.00 each 1 No. 28.00
4 10 gauge back hub 34.00 per pair 1 pair 34.00
5 B/bull heavy duty tyre 28” x 1 ½” size 125.00 each 3 Nos. 375.00
6 Ralson ml tube 26.00 each 3 Nos. 78.00
7 K W front mud guard 44.00 each 1 No. 44.00
8 K W rear mud guard 44.00 each 2 Nos. 88.00
9 Fork guard 20.00 per pair 1 pair 20.00
10 K W fork 97.00 each 1 No. 97.00
11 Screw racer 10.00 per set of 2 1 set 10.00
12 Ball racer 10.00 per set of 2 1 set 10.00
13 ¼ ball Apollo 15.00 per packet 1 packet 15.00
14 KW type handle 115.00 each 1 No. 115.00
15 Rickshaw brake set 35.00 per set 1 set 35.00
16 Bell 16.00 each 1 No. 16.00
17 Handle fitted Rear view mirror 15.00 each 2 nos. 30.00
18 Main axle 140.00 each 1 No. 140.00
19 06 socket 17.50 each 2 Nos. 35.00
20 06 bearing 48.00 per pair 1 pair 48.00
21 06 bearing cover 38.00 per pair 1 pair 38.00
22 BB socket 20.00 each 1 No. 20.00
23 BB axle Black 17.00 each 1 No. 17.00
24 BB cup Black 17.00 per set 1 set 17.00
25 KW gear crank -48 T 95.00 per set 1 set 95.00
26 KW pedal 45.00 per pair 1 pair 45.00
27 Cotter pin 1.50 each 2 Nos. 3.00
28 5/4 ball center 10.00 per packet 1 packet 10.00
29 22 teeth freewheel 28.00 each 1 No. 28.00
30 Freewheel plate 29 teeth 10.00 per set 1 set 10.00
31 Freewheel socket 17.00 each 1 No. 17.00
32 Heavy duty chain 62.00 each 1 No. 62.00
33 10” seat pillar 8.00 each 1 No. 8.00
34 Seat pillar socket 5.00 each 1 No. 5.00
35 Seat complete 100.00 each 1 No. 100.00
36 Heavy duty frame cup 5.00 per set 1 set 5.00
37 Frame socket 5.00 each 4 Nos. 20.00
38 Head pipe 8.00 each 1 No. 8.00
39 Lock 20.00 each 1 No. 20.00
40 Rear end reflector 5.00 each 2 Nos. 10.00
Total: A 2,200.00 All other items such as passengers’ seat, seat back and floor panels etc. were made using the traditional process and skill already available with the existing rickshaw maker.
Floor panels were made using wood covered with aluminum sheet. Seat and seat back were made using wood, springs, foam, coir fibre, springs and covered with synthetic foam leather or rexin. This was done with an objective to reduce need for training/retraining of existing skilled manpower as well as not to dislodge these people from their vocation and for the ease of maintenance. There were no side panels and left and right side near rear wheels were covered with wire net. Back panel was in Mild steel sheet and lower part of back side was in wire net. This enclosure below passengers’ seat
provided the convenient luggage space. Hood, rear and side rain guards were in synthetic foam leather / Vinyl / Reskin. In the prototype, initially trial was taken with a Fibre Glass Reinforced (FRP) hood (Fig. 5.16-5.20). Later hood and rain guards were made in synthetic tarpaulin (Fig. 5.21, p 157).
Details of other materials used with their contribution to total cost of fabrication is provided in Table 5.2, p 154. The labour cost for fabrication of one new design tricycle rickshaw on job work basis is shown in Table 5.3, p 154.
Wooden backed, coir padded, reskin covered seat and backrest
Branding and space for advertisement
Fig. 5.16 Side view of pre-production prototype
Fig. 5.17 Three quarter front view of pre-production prototype
Fig. 5.18 Three quarter rear view of pre-production prototype
Fig. 5.19 Front view of pre-production prototype
Fig. 5.20 Rear view of pre-production prototype
Table 5.2 Items procured from various sources: (Price as on 01.05.2004 in Guwahati) Sl
no.
Description of materials Rate Rs. Quantity Amount Rs.
1 MS tubes 25.4 mm dia, 350 Gms/RFt 40.00/Kg 100 RFt-35 Kg 1,400.00 2 MS flat 40.0 x 6 mm, 400 Gms/RFt 40.00/Kg 15 RFt- 6 Kg 240.00 3 MS flat 50.0 x 4 mm, 700 Gms/RFt 40.00/Kg 1.4 RFt- 1 Kg 40.00 4 MS angle 40 x 40 X 5 mm, 660 Gms/Rft 40.00/Kg 1.1 RFt/ 0.725 Kg 29.00 5 MS flat 25.4 x 4 mm, 180 Gms/RFt 40.00/Kg 1.1 RFt/0.2 kg 8.00
6 Welding rods 100.00/Pkt 1 packet 100.00
7 Vinyl fabric for hood, seat, rain guard flap 100.00/m 4 meters 400.00 8 Wood for seat and floor 12”X 1” X 18” 200.00/ Cft 1.5 Cft 300.00
9 Sponge for seat & backrest 35.00 6 Sqft 210.00
10 Aluminium sheet for floor 40.00/Sqft 6 Sqft 210.00
11 Wire mesh for luggage space 20.00/Sqft 6 Sqft 120.00
12 MS sheet for back panel 20 Gauge 40.00/Sqft 5 Sqft 200.00
13 Nuts and bolts etc. 1 Kg 48.00
14 Duco automotive putty 160.00/Kg 0.250 Kg 40.00
15 Duco primer & surfacer 150.00/Ltr 1.0 litre 150.00
16 Duco paints 160.00/Ltr 1.0 litre 160.00
17 Duco thinner 110.00/Ltr 1.5 litre 165.00
Total: B 3,820.00 Table 5.3 Labour charges for fabrication of designed tricycle rickshaw on job work basis
Sl.
No
Description Rate Rs.
per rickshaw
Amount Rs.
1 Bending 20.00 20.00
2 Cutting & grinding 200.00 200.00
3 Welding & grinding 400.00 400.00
4 Painting 200.00 200.00
5 Fitting of wheels with spokes, balancing 30.00 30.00
6 Fitting of gears, axles, chains, handles, fork 70.00 70.00 7 Stitching & fitting of hood, rain flap, back cover etc. 250.00 250.00 8 Carpentry work for making the seats, floor 100.00 100.00
9 Fitting Seats etc. 30.00 30.00
Total: C 1,300.00 Total (A+B+C) 7,320.00 An overhead of 10% is required over the above amount to cover indirect
cost of supervision etc. Profit is not considered at this stage, since it is to be manufactured by an NGO under a scheme.
D 732.00
Grand Total(A+B+C+D) 8,052.00 Cost of Standard items from existing rickshaw industry as percentage of total cost : 30%
Cost of other items bought out from various sources as percentage of total cost : 52 %
Labour cost as percentage of total cost : 18 %
The various category of cost as percentage of total cost indicated in the above cost calculation provides vital clues about a process, working capital requirement and capital investment required in addition to dependence on outside vendors for the success of the product. It also provides an indication of flexibility of the process and area where cost cutting measures are to be initiated. In case of Dipbahan it is seen that, standard items outsourced from existing rickshaw industry is 30% of the total cost; cost of other items bought out from various sources is 52 % of total cost and these items are actual input to
the process as raw materials such as steel section, fittings, reskin etc that are processed in the factory; and labour cost is 18% of the total cost.
To reduce the total cost, the highest effort must be in the second category comprising 52% of this cost. A reduction of approximately 2% in this category will lead to reduction of 1% in total cost. Similarly labour cost is anyway way below the other cost component and thus effort in reduction in labour cost may not provide much reduction in total price.
Sometime, expenses incurred in effort to reduce this cost may out weigh the benefit.
Costs breakup provided in percentage for different category conveys very substantial information for evaluating or formulating a project proposal from the point of view of cost accountancy and manufacturing.