Lo #1 design factors in manufacturing processes (sept 2015)

Manufacturing Technology 1

Manufacturing TechnologyManufacturing Technology

LO #1 Design factors in Manufacturing Processes.(Reference pages in the e-text : 1038 ~ 1040)

Design for Manufacturing and Assembly (DFMA)Design for Manufacturing and Assembly (DFMA)

2Manufacturing Technology

Soldering

Welding

Design for Manufacturing and Assembly (DFMA)Design for Manufacturing and Assembly (DFMA)


Soldering

Definition

Consideration of all the relevant factors at the product design stage itself to achieve ease of both manufacture and assembly.

Simple Example: Design for manufacture (DFM) at a single part level, involves details such as ensuring that where a pin is to be assembled into a hole that is only slightly larger in diameter, then it is much easier if the end of the pin or the entry to the hole (or both) are chamfered or finished with a radius.

DFM/A requires the collaboration of design DFM/A requires the collaboration of design engineers and manufacturing engineersengineers and manufacturing engineers


Soldering

By forming project teams consisting of product designers, manufacturing engineers, and other specialists (e.g. quality engineers, material scientist) to design the product.

Design engineers are required to spend some career time in manufacturing to learn about the problem encountered in making things.

Manufacturing engineers assign to the product design department as full-time consultant.

General Principles and guideline in DFM/AGeneral Principles and guideline in DFM/A


1. Minimize number of components.2. Use standard commercially available components.3. Use common parts across product lines.4. Design for ease part fabrication.5. Design parts with tolerances that are within process capability.6. Design the product to be foolproof(=very simple) during

assembly.7. Minimize use flexible components.8. Design for ease of assembly.9. Use modular design.10. Shape parts and products for ease packaging.11. Eliminate or reduce adjustment required.



Assembly cost are reduced. The final product is more reliable because there are fewer

connection. Disassembly for maintenance and field service is easier. Reduced part count usually means automation is easier to

implement. Work-in-process is reduced, and there are fewer inventory

control problems. Fewer parts to be purchased, which reduces ordering costs.

1.Minimize number of components.



Welding

1.Minimize number of components : An Example



Design time and effort are reduced. Design of custom-engineered components is avoided. There are fewer part numbers. Inventory control is facilitated. Quantity discounts may be possible.

2. Use standard commercially available components.



Soldering

Welding

2. Use standard commercially available components – Examples : STD batteries, tires, bearings, screws, bolts,…



Soldering

Welding

There is an opportunity to apply Group Technology (GT). Implementation of manufacturing cells may possible. Quantity discounts may be possible.

3. Use common parts across product lines.

GT (Group Technology) ;

- Similar parts are grouped together to improve manufacturing effectiveness.

- Ex) machines, tools, and fixture.



Welding

Manufacturing cells

3. Use common parts across product lines.

- A group of equipment/resources.

- Usually arranged in the shape of “U”, which is dedicated to produce similar products or a family of parts.



Net shape or near net shape processes may be feasible. Part geometry is simplified, and unnecessary features are

avoided. Unnecessary surface finish requirements should be avoided;

otherwise, additional processing may be needed.

4. Design for ease part fabrication.



Soldering

Welding

4. Design for ease part fabrication.



Tolerances tighter than the process capability should be avoided; otherwise, additional processing or sortation will be required.

Bilateral tolerances should be specified.

5. Design parts with tolerances that are within process capability



Soldering

Design should be unambiguous. Components should be designed so they can be assembled only one

way. Special geometric features must be added to components to achieve

foolproof assembly. Orientation problems are generally reduced designing a part to be

symmetrical and minimizing the number of asymmetric features.

6. Design the product to be foolproof during assembly.



Flexible components include parts made of rubber, belts, gaskets, cables, etc.

Flexible components are generally more difficult to handle and assemble.

7. Minimize use flexible components



Part features such as chamfers and tapers should be designed on mating parts.

The assembly should be designed so that components are added from one direction, usually vertically.

Threaded fasteners (screw, bolts, nuts) should be avoided where possible, especially when automated assembly used; instead, fast assembly techniques such as snap fits and adhesive bonding should be employed.

The number of distinct fasteners should be minimized.

8. Design for ease of assembly.

Snap Fit Buckle



Modular design, or "modularity in design", is an approach that subdivides a system into smaller parts (modules or skids) that can be independently created and then used in different systems to drive multiple functionalities.

(Ex.: Car parts, furniture, fridge…..) Maintenance and repair are facilitated. Inventory requirements are reduced. Final assembly time is minimized.

9. Use Modular Design



The product should be designed so that standard packaging cartons can be used, which are compatible with automated packaging equipment.

Shipment to customer is facilitated.

10. Shape parts and products for ease packaging.



Adjustments are time consuming in assembly. Designing adjustments into the product means more

opportunities for out-of-adjustment conditions to arise.

11. Eliminate or reduce adjustment required

DFM/A – Benefits and AdvantagesDFM/A – Benefits and Advantages


1. Shorter time to bring the product to market.

2. Smoother transition into production.

3. Fewer components in the final product.

4. Easy assembly.

5. Lower costs of production.

6. Higher product quality.

7. Greater customer satisfaction.

Engineering

Lo #1 design factors in manufacturing processes (sept 2015)