Machine Shop Practice II Study Notes

Course Overview & Evaluation

  • Course: IPE 1210: Machine Shop Practice II (1.51.5 Credit Hours), Department of Mechanical and Production Engineering, Ahsanullah University of Science and Technology (AUST).

  • Prerequisites: Mandatory use of apron and shoes in the laboratory.

  • Evaluation Marks Distribution:

    • Report: 3030

    • Attendance and Viva: 3030

    • Quiz: 4040

Lathe Machine & Operations


Schematic view of the lathe machine

  • Function: Rigid machine tools designed for machining materials by removing metal from a rotating workpiece using linear movements of cutting tools.

  • Main Components:

    • Bed: Foundation containing ways to align carriage and tailstock with headstock.

    • Headstock: Contains spindle and driving mechanism.

    • Tailstock: Holds the dead center to support workpiece, tapered shank drills, reamers, or drill chucks.

    • Carriage: Movable support holding crossfeed slide, compound rest, and tool post.

    • Feed Rod & Lead Screw: Transmit power for feed and thread cutting (uses ACME threads with half-nuts).

  • Workholding Chucks:

    • 4-Jaw Independent Chuck: Four jaws move independently for holding various shapes and centering.

    • 3-Jaw Universal Chuck: Jaws move simultaneously for automatic centering of round or hexagonal work.

  • Cutting Speed Formula:   V=π×D×N1000 m/minV = \frac{\pi \times D \times N}{1000}\,\text{m/min}

    • VV = Cutting speed (m/min\text{m/min})

    • DD = Workpiece diameter (mm\text{mm})

    • NN = Spindle speed (RPM)

  • Feed Rate: Typical roughing feed rate for soft material is up to 0.25 mm/rev0.25\,\text{mm/rev}.

  • Lathe Operations: Facing, straight turning, contour turning, taper turning, chamfering, knurling, threading, grooving, parting, boring, and drilling.

Milling Machine & Operations


Horizontal milling machine diagram

  • Overview: Versatile machine tools classified primarily into Horizontal and Vertical types.

  • Main Components:

    • Column: Houses spindle, bearings, gearbox, and driving mechanisms.

    • Knee: Supports table and slides vertically along the ZZ-axis.

    • Saddle: Provides transverse motion along XX or YY axes via perpendicular slideways.

    • Table: Features T-slots for clamping workpieces or fixtures; moves along the XX-axis.

    • Arbor: Horizontal machine extension of spindle for mounting cutters (left-hand helix threads).

    • Milling Head & Ram: Vertical machine components providing angular swivel and forward/backward positioning.

  • Milling Operations: Slab milling, face milling, end milling, slotting, slitting, form milling, side milling, straddle milling, and pocket milling.

Shaping Machine & Operations


Shaping machine diagram

  • Overview: Reciprocating machine tool used primarily for machining flat metal surfaces and removing large amounts of material.

  • Key Components:

    • Ram: Slides back and forth to drive the cutter.

    • Toolhead: Swivels on a circular plate for angular cutting and vertical depth adjustment.

    • Clapper Box: Hinged housing that prevents cutting tool drag during return stroke.

  • Quick Return Mechanism: Converts rotary motion into reciprocating motion where return stroke moves faster than cutting stroke.

  • Shaper Operations: Plain shaping, side cutting, V-grooving, slotting, T-slot cutting, and dovetail cutting.

Drilling Machine & Operations


Radial drill machine diagram

  • Overview: Precision hole-making equipment consisting of base, column, table, motor head, and spindle with drill chuck.

  • Machine Types:

    • Standard Drill Press: Fixed column layout for general drilling.

    • Radial Drilling Machine: Spindle mounts on a swiveling radial arm for machining large components.

    • Gang Drilling Machine: Multiple independent columns lined up for sequential operations.

  • Drilling Operations: Drilling, step drilling, counterboring, countersinking, reaming, deburring, and chamfering.

Grinding Machine & Operations


Reciprocating surface grinding machine

  • Overview: High-precision material removal process utilizing rotating abrasive wheels for fine surface finish and close tolerances.

  • Grinding Categories:

    • Surface Grinding: Uses rotating wheels on flat surfaces (horizontal spindle traverse/plunge or vertical-spindle rotary table).

    • Internal Grinding: Machining inside diameters and internal tapers.

    • Cylindrical Grinding: Machining external cylindrical surfaces, shoulders, profiles, and threads.

  • Grinding Wheel Types: Straight (Type 1), Cylinder (Type 2), Straight Cup (Type 6), Flaring Cup (Type 11), Depressed Center (Types 27 & 28), and Mounted wheels.

Sheet Metal Forming Operations

  • Specimen Dimensions: Rectangular box (12×8×2 inch12 \times 8 \times 2\,\text{inch}) or Square box (12×12×2 inch12 \times 12 \times 2\,\text{inch}).

  • Standard Process Steps:

    • Calculate flat layout dimensions using unfolding technique.

    • Mark stock sheet with scriber.

    • Cut layout on shearing machine.

    • Mark bend locations and corner diagonals.

    • Snip corners along diagonals with proper allowances.

    • Bend edges to 90∘90^\circ on bending machine using "opposite edge to be the next" sequence.

    • Perform cornering operation, measure final output, and evaluate discrepancies.