1. ME8793- PROCESS PLANNING & COST ESTIMATION
Dr.C.DHARMARAJA
Assistant Professor
Department of Mechanical Engg,
University College of Engineering -Dindigul
2. INTRODUCTION TO PROCESS PLANNING 9
Introduction – Methods of process planning – Drawing
Interpretation – Material evaluation – Steps in process
selection – Production equipment and Tooling selection.
Unit – I
3. Introduction
• Manufacturing:
making of products from raw materials using
various processes, equipment, operations and
manpower according to a detailed plan.
6. PROCESS PLANNING
comprises the selection and sequencing of processes and
operations to transform a chosen raw material into a
finished component.
•
• It is the act of preparing detailed work instructions to
produce a component. This includes the selection of
manufacturing processes and operations, production
equipment, tooling and jigs and fixtures.
• It will also normally include determining manufacturing
parameters and specifying criteria for the selection of
quality assurance (QA) methods to ensure product quality
13. Types of process planning
• Manual process planning
– Traditional approach
– Workbook approach
• Computer aided process planning
– Retrieval process planning (variant)
– Generative process planning
14. Traditional approach
• Manual
• Based on process planner experience
and intuition it will vary.
• Stages
Stage 1 process planner interpret
product drawing
Stage 2 refer manual
Stage 3 documenting routing sheet
15. Workbook approach
• Modified version of the traditional
approach
• Referring workbook
• Workbook which contains
predetermined sequence of operation
(standard procedures).
16. Advantages of manual process planning
• Suitable for small scale industries.
• Highly flexible.
• Low investment costs.
17. Disadvantages of Manual process planning
• Time consuming process.
• Need a skilled process planner.
• Possibilities for human error.
• Inconsistent process plan.
18. Computer aided process planning (CAPP)
why we need to go for CAPP?
• Overcome the drawbacks of Manual process
planning.
• Reduce the routine work of manufacturing
engineer.
• Act as an interface between CAD and CAM.
19. Benefits of CAPP (2 mark)
• Productivity improvement.
• Production cost reduction
• Elimination of human error.
• Product standardization.
20. Approaches of CAPP
• Retrieval CAPP system (variant
approach)
• Generative CAPP system
21. Retrieval CAPP system
• Concept similar parts will have
similar process plan.
• Process plan for a new product is created
by recalling, identifying or retrieving the
existing plan for similar product.
23. Advantages of retrieval CAPP
• Once a standard plan is produced,
similar plans can be produced using
existing plan.
• Simple programming (when compared
to Generative type).
• Easy to learn and use.
• Commercially available retrieval CAPP
systems are MultiCapp and MIPLAN
24. Generative Process plan
• In generative approach, the process plan
were generate process plan automatically
without any reference to prior plan.
• Concept the concept is based on
decision logics and pre-coded
algorithms.
25. Components of Generative process
plan
Part
description
Sub system (define
machining
parameters)
Subsystem (define
sequence of
operation )
databas
e
Report
generator
26. Advantages of generative CAPP
• Generate consistent process plan.
• New components can planned easily
• Integrating with an automated
manufacturing facility.
• Example APPAS,CMPP,EXCAP,XPLAN
27. Drawing interpretation
• First step
• Getting information from the drawing.
• Prepared by design department.
• Details required
– Material of the component, its designation
– Number of parts to be produced
– Weight of the component
– Dimensions of the part
– Dimensional and geometric tolerances
– Size and accuracy of the parts
36. Information on the drawing sheet
required
• Geometric and dimensions (complete dimensions)
• Material specifications (material code , example SS310)
• Notes of special material treatments (like heat treatment)
• Dimensional tolerances (upper limit and lower limit eg: 10±0.2)
• Geometric tolerances (straightness, flatness, roundness)
• Surface finish specifications (roughness and waviness)
• Tool references
• Gauge references
• Quantity to be produced
• Part lists
37. Material Evaluation
• Second activity of process planning.
• Material selection (done by design engineer)
– Choose the material
• Material evaluation (done by process
planning engineer)
– Check the chosen material for further process
41. Metals
• Based on iron content
– Ferrous(iron more)
– Non ferrous (iron content
less)
42. Ferrous
• Ferrous
– Steels (carbon percentage less than
2%)
– Cast iron (carbon percentage more than
2%)
43. Steels
• Steels
– low alloy steel (percentage of alloying element is
less than 5 %)
• Low carbon steel (mild steel) (carbon percentage less
than 0.25%)
• Medium carbon steel (0.25 % to 0.6 % )
• High carbon steel (more than 0.6 %)
– High alloy steel (percentage of alloying
element is more than 5 %)
• Tool steel
• Stainless steel (chromium content is more than 12 %)
44. Cast Iron
• Cast iron (carbon percentage more than 2 %)
– Grey most widely used
– White hard and brittle
– Malleable highly malleability
– Spheroidal Graphite cast iron (SG cast iron)
high ductility.
45. Non ferrous materials
• Non Ferrous materials (iron content low)
Example Aluminium, Copper, Lead, Tin, Zinc,
Nickel, Titanium, Magnesium
• Properties
– Light in Weight.
– High electrical and thermal conductivity.
– Better resistance to corrosion.
– Ease of fabrication.
– Colour.
46. Polymer
• Polymers a substance which has a
molecular structure built up chiefly or
completely from a large number of
similar units bonded together.
48. Ceramics
• Ceramics A ceramic is any of the
various hard, brittle, heat-resistant and
corrosion- resistant materials made by
shaping and then firing a nonmetallic
mineral, such as clay, at a high
temperature.
49. Ceramics Properties
• Ceramics are strong, hard and
brittle.
• Can be used at high temperature.
• They are good thermal and
electrical insulators.
58. Factors in process
selection
• Material form
• Component shape and size
• Economic consideration
• Dimensional and geometric
accuracy
• Surface finish
• Batch size
• Production rate
59. Steps in Process
Selection
• Drawing interpretation (process-shape matrix)
• Identification of critical processing factors
(process material matrix)
• Comparison of potential manufacturing process
(compare)
• Identification of suitable process (select)
66. Stages in tooling selection
• Evaluation of Process and tooling selection
• Analysis of machining operations
• Analysis of workpiece characteristics
• Tooling analysis
• Selection of tooling
