1Module 4b Casting process (continued)

Module 4a2 Casting Principle of the process Structure Process modeling Defects/quality control Design and DFM Process variation Process design: how to determine the process parameters so that the desired product can be manufactured and defects are eliminated as much as possible

Module 4a3 Design of a casting process is to determine:  pattern, mold, sprue, gating system, mold cavity, riser parting line  pour temperature  Process goal: Mold cavity is completely filled without defect  Process constraints: casting material, casting geometry, cost, time, quality

Module 4b4 To control the shrinkage cavity to the riser Process design

Module 4b5 Directional Solidification – Forced Solidification Riser (V/A)2 > (V/A)1 Location of riser External and Internal Chills Process design

Module 4b6 Process design Design for locating parting line – determine parting line or surface Parting line or parting surface is the interface that separates the cope and drag halves of a mold, flask, or pattern and also the halves of a core in some core-making processes.

Module 4b7 The main functional requirement for determining the parting line is: the pattern can be drawn out from the mold to leave a cavity. Besides, this basic function, the selection of parting line can affect 1.Cores (as little as possible) 2.Draft (as little as possible) The core and draft cause material waste and extra steps in the casting process, which means cost increase. Process design (a) (b) (b) Is better as there is no need to have core and no need of draft; but (a) needs them.

Module 4b8 Parting line or surface determination Design features, such as round, may also put restriction to the location of parting line in the above cases Three Options Process design Parting line

Module 4b9 Casting Principle of the process Structure Process modeling Defects Design and DFM Process variation

Module 4b10 Design and DFM Original design Modified design

Module 4b11 Design for Controlling the process Design and DFM

Module 4b12 Two sections intersection causes: hot spots (gap) and stress concentration Stress concentration Fillets Hot spots shrinkage Design and DFM

Module 4b13 Fillet Holes Design and DFM

Module 4b14 Design and DFM

Module 4b15 Solution to Cavity caused due to Shrinkage Pattern shrinkage allowance Large casting, special rule: 1% - 5% Design and DFM

Module 4b16 Summary Constituents of Casting Process Mold How Mold is made Mold Materials How Pattern is made

Module 4b17 Casting Permanent casting Expandable casting One casting one mold One mold multiple casting Summary

Module 4b18 What We are Going to Look at Given a Casting Process Type of casting: expandable or permanent Surface quality Way to make mold Way to make pattern Quality Requirement Function Requirement Volume of Production Summary