Foundry
Principles of Foundry Technology
P. L. Jain
Tata McGraw-Hill Education, 2003 - Founding - 401 pages
Process Information Maps (PIMs/ PRIMAs) are required for process planning and process industrial engineering.
Industrial Engineering ONLINE Course
Process Industrial Engineering FREE ONLINE Course (Module)
Process Information Map - PIM - PRIMA - Contents
Seven Sections on Characteristics and Capabilities of the Process: (We can increase the number as we understand requirements in our practice)
Process description:
Materials that can be processed
Process variations
Economic considerations:
production rate,
minimum production quantity,
tooling costs,
labor costs,
lead times,
other points specifically relevant to the process.
Typical applications: Components or Assemblies that are have been successfully manufactured or fabricated using the process. (In a specific company various part numbers made using the process can be recorded)
Design for Manufacturing Issues: Typical surface roughness and other details achieved by the process, Limitations and facilitating features that are relevant to the design of the part as well as standard information on minimum section, size range and general configuration.
Quality issues: common process faults and prevention measures, Process capability chart.
Process description
Materials Processed
Most metals
Most popularly Ferrous and Aluminum alloys.
Difficulties encountered in casting lead, tin and zinc alloys, also refractory alloys, beryllium, titanium and zirconia alloys.
Process variations
. Green sand casting:
. Dry sand: An oven is used to cure the mold. Additional expenses and time of drying.
. Skin-dried sand: the mold is dried to a certain depth. Used in the casting of steels.
Patterns
. Patterns: one-piece solid patterns; split patterns; match plate patterns for high volume production.
. Wooden patterns: for low-volume production only.
. Metal patterns: for medium to high-volume production. Hard plastics are also being used increasingly.
. Cosworth casting: Low pressure filling of mold. Benefit: Better integrity, accuracy and porosity of
casting. Longer production times and higher tooling costs.
Economic considerations
. Tooling costs low.
. Equipment costs low.
. Direct labor costs high proportion of total cost.
. Production rates of 1–50/h, but dependent on size.
. Patterns easy to make. Reusable.
. Economical for low production runs of less than 100.
. Material utilization low to moderate. Twenty to fifty per cent of material lost in runners and risers.
. Both runners and risers and metal wastes may be recycled.
. Sand is recycled.
. Additional finishing activities to be done. Cleaning and fettling required to remove gates and risers. Parting lines may also need finishing by hand.
Typical applications
. Engine blocks
. Cylinder heads
. Manifolds
Design for Manufacturing Issues
. Sizes ranging 25 g–400 t in weight.
. High degree of shape complexity possible.
. Loose piece patterns can be used for holes and protrusions.
. Bosses, undercuts and inserts possible.
. Design of gating system for delivery of molten metal into mold cavity is to be done.
. Placing of parting line important. Avoid placement across critical dimensions.
. All intersecting surfaces must be filleted to prevent shrinkage cracks and eliminates stress concentrations.
. Cored holes greater than 16 mm.
. Machining allowances usually in the range 1.5–6 mm.
. Draft angle ranging 1–5 degrees
. Minimum section thickness typically 3 mm for light alloys, 6 mm for ferrous alloys.
Quality issues
. Material strength inherently poor.
. Castings have good bearing and damping properties.
. Castings generally have rough grainy surfaces.
. Surface roughness a function of the materials used in making the mold and ranging 3.2–50 mm Ra.
. Not suitable for close specification of tolerances without secondary processing.
. Molding sand must be carefully conditioned and controlled.
. Most casting defects can be rectified by conditioning of sand.
. Casting shrinkage and distortion during cooling governed by shape.
. Extensive flat surfaces prone to sand expansion defects.
. High porosity and inclusion levels common in castings.
. Inspection of castings important.
. Defects in castings may be filled with weld material.
Please suggested additional points to be added.
Related Research and Articles
Process selection methodology for near net shape manufacturing
Daniele Marini & Jonathan R. Corney
The International Journal of Advanced Manufacturing Technology volume 106, pages1967–1987(2020)
https://link.springer.com/article/10.1007/s00170-019-04561-w
Chapter 4. Material Selection and Process Evaluation
Book of Peter Scallan
PRIMA table is shown in the chapter and its application is shown in examples.
https://books.google.co.in/books?id=R7GkqkbZbPIC&pg=PA109#v=onepage&q&f=false
2003
https://books.google.co.in/books?id=R7GkqkbZbPIC
Methodology for Metalcasting Process Selection
S. Karthik, C. W. Chung, K. Ramani and M. M. Tomovic
SAE Transactions
Vol. 112, Section 5: JOURNAL OF MATERIALS AND MANUFACTURING (2003), pp. 101-110
https://www.jstor.org/stable/44699561?seq=1
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