Manufacturing Processes: Casting and Foundry Technologies - Comprehensive Notes

Course Code: BAMEE101
Theory components and rubrics:
- CAT-1: 15 Marks (50 marks converted to 15 marks)
- CAT-2: 15 Marks (50 marks converted to 15 marks)
- Quiz-1: 10 Marks
- Seminar: 10 Marks
- Case study: 10 Marks
- Note: Students can involve in data archives (or) archiving of datasets / data / digital resources / develop projects as part of the courses in place of assignment & quiz (Prior permission required)
- Total: 60 Marks
FAT (Final Assessment Type): 40 Marks
Laboratory: 30 hours
1) Sand mould cavity preparation for production of a casting
2) Determination of permeability number of green sand using a standard permeability tester
3) Erichsen cupping test to determine the formability of ferrous and non-ferrous metals
4) Cold work-annealing cycle for deformation of low carbon steel
5) TIG/MIG Welding
6) Gas Tungsten Arc Welding (GTAW)
7) Surface Grinding and Measurement of Surface Roughness
8) Machining Time Estimation for Drilling/Turning/Milling - Tool Wear Observation
9) Perform Drilling/Turning/Milling and measure the resulting dimensional accuracy and surface roughness
10) Machining a cavity using EDM or Cutting a complex contour using wire-EDM
Course focus: fundamental manufacturing processes, including casting, forming, joining; conventional and advanced machining; tooling and finishing; and modern manufacturing technologies such as additive manufacturing.

To introduce fundamental manufacturing processes, including casting, forming, and joining.
To develop skills in conventional and advanced machining, tooling, and finishing techniques.
To familiarize students with advanced modern manufacturing technologies such as advanced machining and additive manufacturing.

At the end of the course, students will be able to:

Explain the principles and steps involved in casting and particulate processing, including powder metallurgy and ceramic techniques.
Describe forming and welding processes, identify common defects, and discuss basic inspection methods.
Apply machining principles, including tool geometry and cutting mechanics, to conventional and abrasive finishing operations.
Select suitable advanced machining and additive manufacturing processes based on product requirements and applications.
Demonstrate basic workshop skills in casting, forming, welding, machining, and finishing through hands-on practice.

Overview: Introduction to manufacturing; primary and secondary manufacturing processes; fundamentals of casting and solidification of metals.
Casting processes covered: sand casting, die casting, investment casting, centrifugal casting, shell molding.
Casting defects and inspection methods; recent advances in casting technology.

Casting: primary manufacturing process where molten metal is poured into a mold cavity and solidifies into a desired shape; one of the oldest and most versatile metal shaping methods.
Steps in casting (general): Pattern making → Mold making → Melting → Pouring → Solidification → Shakeout → Finishing.
Solidification concepts: nucleation, crystal growth, grain structure, cooling rate effects on properties.
Typical assumption: the solidification time is often modeled with an exponent n = 2 for practical problems.

Pattern: replica of the part used to create the mold cavity.
Mold components and terms: pattern, cope, drag, sprue, runner, sprue rod, pouring cup, riser, vent, core, mold cavity, draft, pattern print, core print, core box.
Mold sections: two-part sand mold (cope and drag) with a parting line separating them.
Other terms: rammer, flask, mold making board, casting assembly, withdrawing pattern, casting.
Important relationships: pattern and mold components define the gating system and the casting geometry.

Sand casting: mold formed by compacting sand around a pattern; molten metal poured into mold cavity to form the component after solidification.
Dominant facts:
- Sand casting accounts for more than 90% of all metal castings.
- Granular refractory material (silica, zircon, olivine, chromite sand) mixed with clay and water is packed around a pattern.
Pattern and core components for sand casting visuals: gate, runner, sprue, riser, well, top cup, pouring basin, etc.

Constituents of moulding sand:
- Silica sand
- Binders (clay-based or organic binders)
- Additives (sea coal, water, etc.) during activation
- Sea coal (carbonaceous additive)
Clay binders and silica-based binders
Core materials may be used to create internal features

Refractoriness: resistance to high metal-pouring temperatures; e.g. steel ~1500 °C vs aluminium ~650 °C.
Permeability: ability to vent gases; critical to avoid defects like blowholes.
Green / Dry / Hot Strength: strength at various states (wet, dried, high temperature).
Cohesiveness / Plasticity: enables compacting around patterns and holding shape during mold-making.
Flowability: ability to conform to pattern features during rammed packing.
Collapsibility: sand must break away from casting after cooling to prevent tearing or hot cracks.
Surface Finish: texture and additives improve surface smoothness and prevent metal penetration.
Chemical Inertness: avoids reaction between sand and molten metal (important for reactive alloys).
Availability / Cost / Reusability: practical considerations for green sand and reusable backing sand.

Pattern allowances include shrinkage, machining, draft, distortion, and shake allowances, which account for metal contraction, finishing needs, parting line clearance, and pattern-shape changes during molding.

Solidification is the cooling and transformation of molten metal into a solid.
Key concepts:
- Nucleation: formation of tiny solid particles (nuclei) as solidification begins.
- Crystal Growth: nuclei grow into grains; grain structure influences strength and surface finish.
- Grain Structure: fine-grained metals are stronger with better surface finish; coarse-grained weaker.
- Cooling Rate: faster cooling yields finer grains and better mechanical properties; slower cooling yields coarser grains.

n value assumption for common problems: $n = 2$
Chvorinov’s Rule for solidification time: ts = Cm iggl(rac{V}{A}\biggr)^n
- Here, (ts) is solidification time, (V) is melt volume, (A) is mold surface area, and (Cm) is a mold constant.
- Common assumption: (n = 2).
Geometric definitions for a cylinder (example problem):
- Volume: $$V = \