very good presentation

1. Product Design and
Development
CUTM1076

2. Design For Assembly and manufacturing
 Presented By:
 MD ASIF JAMAL
 Reg no – 190301160021
 Branch - Mechanical

3. Topics
1. Introduction to DFMA
2. Concepts of DFMA
3. Design of maintainability
4. Product costing

4. Introduction to DFMA
• Design for manufacturing and assembly is widely used by product designers
and engineers to design products with lesser number of parts which helps in
ease of assembly and thereby reducing the overall cost.
1. Reduces overall Cost
2. Reduces impact on Environment
3. Ease of Maintainability

5. DFMA Approach

6. Design for maintainability
• Maintainability is the degree to which a product allows safe, quick and easy
replacement of its component parts. It is embodied in the design of the product. A
lack of maintainability will be evident as high product maintenance costs, long out-
of service times, and possible injuries to maintenance engineers.
• Benefits:
• ~Cost saving
• ~Holistic sustainability
• ~Competitive advantage at home and abroad .

7. Manufacturing Costs Defined
• Product costing provides information about the monetary investments in the materials,
work in process, and physical inventory
• The cost to create a product that is to be sold in the market.
• The cost includes materials, labour, and overheads of manufacturing.

8. Elements of the Manufacturing Cost of a Product
Direct material
This needs to be considered as the raw materials which are involved
in manufacturing the product has to be included in the process.
• Labour
The labor costs are included as well such as wages, benefits,
insurance, etc. which are paid to the employees who are directly
involved in the product manufacturing process.
Overheads
These include the factory related costs which are indirectly involved
in the costs while producing the product which includes machinery
cost, etc. It includes indirect materials cost and indirect labor cost.

9. Case study : DFMA of folding chair
• Analysis of the Existing Design
A folding chair is a portable chair that can be folded flat, stored in a rack, row or on a cart.
These chairs are used for seating in areas where permanent seating is not practical.They can
be used in various indoor and outdoor function like weddings, funerals etc.The CAD model is
shown in the fig 1 below.The existing design of the folding chair consists of three round
frames and a seat, which are all fastened with the parts respect to each other.This frame
consists of a solid round frames which are much thicker when compared to the re-designed
model, making the frame heavier, hence more expensive.The costing of the existing model of
the folding chair for a batch size of 1,000 products is given in table1

10. Old Design of folding chair

11. Re-Design of folding chair
• The re-designed model of the folding chair was carried out considering the
ease of assembly and reduction in material and manufacturing process.The
model consists of a void at the top of the seat which reduces the use of
redundant parts, to the side of the frame are present two hinges which are
usually not taken into account when conducting a DFMA analysis on the
product.

12. The changes made were, them being Frame1, Frame 2 and seat.The new re-
designed CAD model is shown in fig 2 below.The re-designed design of the chair
consists of two solid frames and a seat which are all spot welded with each other
hence helping to reduce the overall number of parts of the chair from 9 to 3, also
aimed at improving the productivity.The costing detail for the new re-designed
model is shown in table 2.

13. Cost Reduced by Rs. 45 per chair

14. Conclusion
• Design for manufacture and assembly was conducted on a folding chair and a more
optimized design was created which helped improve the productivity of the
product with respect to costing. Form the case studies it was analyzed that for a
folding chair the total number parts of the chair were reduced from 9 to 3, with the
help of DFMA software.The design was modified for ease in assembly.There was a
reduction in time for assembly of the product, as well. By selection of proper
materials and manufacturing processes along with optimized assembly helped
reduce the overall cost of the folding chair from Rs. 675 per product to Rs. 607 for a
life volume of 10 units

15. References
• [1] M Dekker, G. Boothroyd, P. Dewhurst, andW. Knight, Product Design for
Manufacturing and Assembly”, NewYork, Dewhurst, P., Boothroyd,G. (2003)
‘Early Cost Estimation In Product Design’, Journal of Manufacturing Systems,
7:.183-192, 1994.
• [2] G. Lucchetta, P. F. Bariani andW. A. Knight- Integrated Design Analysis for
product simplifications. CIRP AnnalsManufacturingTechnology, 54(1):147-150,
2009.
• [3]T. Katja, J. Miikka and P. Jari-Activity-based costing and process modelling
for cost-conscious product design: A case

16. Thank YOU