Overview of Manufacturing Analysis and Cost Estimating

In order to attain the required cost and quality goals or targets for products it is necessary for design teams to conduct a number of interrelated product assessment activities.

Technical product performance is the main factor but this has to be met whilst ensuring that the product meets the customers quality and price expectations. The designer is faced with a multitude of possible manufacturing alternatives and very often he does not know the full range of manufacturing processes that are available to him.

Failure to get the trade-off between the commercial and technical factors leads to late and costly engineering changes, coping with inapropriate manufacturing processes or commercial failure.

Consequently there is a need to have access to specialist knowledege across a range of manufacturing processes to enable good commercial and technical design descisons to be made from a range of possibilities. Many companies quite simply lack the necessary process knowledge and or the business and engineering processes to select from an ever widening range of manufacturing alternatives.

A number of researchers have set out to discover what can be done in this area. To that end Swift and Booker of Hull and Bristol Universities presented their research in the book called "Process Selection - from design to manufacture." The information on this website is a simple embodiment of the methods they recommend. For a full description of the methods and processes please refer to their book (ISBN: 0-7506-5437-6)

The information used here is derived from the 1st edition of the above book but serves to illustrate the points made concerning the appropriate selection of a manufacturing processes for a given part.

The material prices used in this demonstrator are from 2002. Therefore the costs generated from the engine are only suitable as a comparison or relative manufacturing cost index for selecting the most cost effective process. Some tuning and incorporation of the later research findings would be necessary to create a process selection tool for a particular company. A simple update using the latest material prices would probably serve to enable the tool to be used to set a Target Cost for piece parts in a product assembly. The tool is written in Visual Basic and uses MS SQL as its database and could be incorporated into a PLM tool as part of a manufacturing process selection workflow for the concept design phase.

Value Driven Design would be most pleased to discuss what we could do for your company in this area.

Cost Model Development

The cost model was developed with knowledge-engineering input from a number of companies across a range of industries. For details on how the cost model was developed see the reference book. The cost model is defined as shown below:-

Manufacturing Cost M_i = VC_mt + R_cP_c where

V	is the volume of material required in order to produce the component.
Cmt	is the cost of the material per unit volume in the required form.
Pc	is the basic processing cost for an ideal design of a component for a specific process.
Rc	is the relative cost coefficient assigned to a component design taking into account :- Shape Complexity Suitablity of material for processing via the process selected Section dimensions Dimensional Tolerances Surface Finish

Title Author : Publisher ISBN	Cover	Remarks Recommended books are listed below. If you wish to purchase any, click on the cover image and you will be taken to the Amazon bookstore.
Process Selection: from design to manufacture Swift & Booker : Arnold or Wiley ISBN: 0-7506-5437-6		Contains basic theory and drivers for the TeamSET Manufacturing Analysis (MA) module in addition to some others. A total of 48 processes are documented. Some process and shape classification is provided. 2nd edition more extensive.
Materials Selection in Mechanical Design Michael F. Ashby : Butterworth-Heinemann ISBN: 1-8561-7663-0		Describes a procedure for materials selection in mechanical design, allowing the most suitable materials for a given application to be identified from the full range available.  Now in its forth edition.