PPCE 1324.pptx process planning and cost estimation

CME396 -Process Planning and Cost Estimation
1
Dr.Pon.Azhagiri/AP/Mech/UCE-BIT/Anna UniversityTrichy

UNIT – I INTRODUCTION TO PROCESS PLANNING
• Introduction
• Methods of process Planning
• Drawing Interpretation
• Material evaluation
• Steps in process selection
• Production equipment selection and tooling selection
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Process Planning and Cost Estimation
• Process Planning
• Process planning is defined as the determination of the processes and the sequence of
operations required making the product.
• It consists of devising, selecting and specifying processes, machine tools and other
equipment to transform the raw material into finished product as per the specifications
called for by the drawings.
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• Objectives of Process Planning
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• Details required for Process Planning
• Detailed engineering drawings
• Knowledge of materials for manufacture
• Knowledge of manufacturing processes
• Knowledge of jigs and fixtures
• Knowledge of the relative costs of materials, processes and tooling
• Manufacturing parameters (speed, feed etc) and costs
• Knowledge of inspection/QA procedures and specifications
• Cutting tool materials
• 1. Carbon steels, 2. High speed steels (HSS),
• 3. Cobalt alloys and 4. Carbides. 5

• Interpret any one geometric tolerance symbol
• Symbols used for Geometric tolerance
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• Unilateral Tolerances
• Unilateral Tolerances are those when variation in actual dimension of the part can be
tolerated to only one side of the given Nominal value .
• Example. φ25 (+ 0.5).
• Bilateral Tolerances
• Bilateral Tolerances are those when variation in actual dimension of the part can be
tolerated to both sides of the given Nominal value .
• Example. φ25 (+/- 0.5).
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• Methods/Approaches to Process Planning
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• Factors considered on the selection of Machinery (Equipment)
• Volume of production (Quantity to be produced) i.e., Number of
components to be produced.
• Quality of finished product, and
• Advantages and disadvantages of the various types of equipment
capable of doing the work.
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• Advantages of computer aided Process Planning
• Efficient processing
• Standardized procedures
• Shorter development time
• Lower hardware costs
• Contingency allowance
In a shop, there may be small delays due to
• 1. Waiting for the inspector.
• 2. Consulting the supervisor.
• 3. Obtaining special tools etc.
These delays are of very short duration. The allowance given to compensate these
delays is called contingency allowance. Generally 5% of basic time is given as contingency
allowance. 10

Activities/Steps in Process Planning
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Problem 1.1 In the figure, interpret the meaning of (a). Dimensional tolerance symbols,
(b). Form tolerance feature control frames, (c). Surface finish symbols
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(a) Dimensional tolerance symbols
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(a) Form tolerance feature control frame
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(a) Surface finish symbols
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Process Planning Methods/Appraches
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Process Planning Methods- Manual Process Planning
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Process Planning Methods- Manual Process Planning
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Manual Process Planning - Advantageous
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Manual Process Planning - Disadvantageous
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Computer - Aided Process Planning (CAPP)
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Computer - Aided Process Planning (CAPP)
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Computer - Aided Process Planning (CAPP) - Frame-work
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Computer - Aided Process Planning (CAPP) - Advantageous
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Steps in Computer - Aided Process Planning (CAPP)
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Flow diagram - Computer - Aided Process Planning (CAPP)
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Parameters
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Parameters
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Parameters
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- Methods
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- Methods
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- Methods - Factors
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- Methods
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- Methods
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- Methods - Factors
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- Methods
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Problem 1.2 Discuss the production equipment and tool selection for the given below component
• Solution
(a) Evaluation of process and machine selection.
As stated in the problem, the process identified is turning and the machine tool is a.
This limits the tools to select from to those we have in machine shop. small bench lathe
(b) Analysis of machining operations.
The operations identified are facing, roughing, finishing and parting off. From this, two
specific tools can be identified:
• Turning/facing tool- facing, roughing and finishing;
• Parting off tool- parting off
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Discuss the production equipment and tool selection for the given below component
(c) Analysis of work piece characteristics.
• The fact that the work piece material is brass means that HSS tool is more than
sufficient to carry out all operations. This is due to brass being highly machinable
material.
• However, in terms of work piece and tool geometry, there are two issues to be
considered. In terms of the facing and roughing out, a left-handed tool will not be able
to completely finish the arc in the middle of the part.
• There are two options that can be considered. The first is to produce half the arc with
the left-handed tool and change to a right-handed tool for the other half. However, it
would be much simpler to use a contouring tool for the complete arc. Furthermore, a
contouring tool will be required for the 'chamfered groove' to the left-hand end of the
part. Therefore, it makes sense to use the contouring tool for both features, rake
angles permitting, as this uses the least number of tools.
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Discuss the production equipment and tool selection for the given below component
(d) Tooling analysis.
From the above stages, the following tooling list and operation description can be
generated:
• Facing: left-hand turning tool
• Roughing: left-hand turning tool
• Finishing: contouring tool
• Chamfered groove : contouring tool
• Parting off: parting-off tool
Face the end and rough out the excess material with the left-hand turning tool. The
majority of the turning can be carried out with the left-hand turning tool. However, the
radius and the chamfered groove will be machined with the contour tool and finally the part
will be cut from the billet by the parting off tool.
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Thank you
Dr.Pon.Azhagiri/AP/Mech/UCE-BIT/Anna UniversityTrichy 69

PPCE 1324.pptx process planning and cost estimation

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