Manufacturing, Workshop and Production Technology
What this domain tests
Manufacturing, Workshop and Production Technology tests how parts are made and how processes are selected: casting, forming, joining, machining, CNC and production organisation, with workshop safety implicit throughout.
Core rules
- Casting: a pattern is larger than the part by a shrinkage allowance and tapered by a draft allowance; a riser feeds solidification shrinkage; sand cores form internal cavities.
- Welding: arc welding uses an electrode and arc; MIG uses a continuously fed wire with a shielding gas; TIG uses a non-consumable tungsten electrode and separate filler. Clean surfaces and correct polarity matter.
- Machining: cutting speed V is surface speed in m/min; spindle speed N = 1000V/(πD) with D in mm. Feed is mm/rev; feed rate = feed × N.
- Forming: rolling reduces thickness, forging works metal by compressive blows, extrusion pushes metal through a die, and press work blanks and bends sheet.
- Production: jigs guide the tool, fixtures hold the work; CNC programs use G-codes for motion and M-codes for machine functions; lean thinking attacks waiting, overproduction and defects.
Worked example
Drill a 10 mm hole in mild steel at a cutting speed of 25 m/min with a feed of 0.2 mm/rev. N = 1000 × 25/(π × 10) = 795.8 rpm, so set about 800 rpm. Feed rate = 0.2 × 795.8 = 159 mm/min. The machining time for a 30 mm thick plate, allowing 5 mm approach, is about (30 + 5)/159 = 0.22 min, or 13 s.
Traps
Using diameter in metres without converting; forgetting the 1000 in the speed formula; applying shrinkage allowance to the pattern in the wrong direction; mixing up jigs and fixtures; ignoring approach and overtravel in time estimates; welding dirty or damp surfaces.