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Gantt chart for loading and scheduling

Short answer

A Gantt chart is a horizontal bar chart with time on the horizontal axis. It shows machine loads as bars for each machine, and progress by a thick line below the planned bar. Advantages: simple, visual. Limitations: no dependencies or critical path.

What is a Gantt chart? Explain how it is used for machine loading and progress recording, and state its advantages and limitations.

A Gantt chart (Henry Gantt, about 1910) is a horizontal bar chart in which the vertical axis lists jobs or machines and the horizontal axis is time. Each bar shows the planned start, duration and finish of an activity.

Uses

  1. Machine loading chart: each machine is a row; jobs are bars on the time scale. It shows the load on each machine and idle time, so jobs can be assigned and re-sequenced.
  2. Progress (schedule) chart: the planned bar is drawn lightly; a thick line below it shows work completed. A vertical "today" line shows if the job is ahead or behind schedule.
 Machine | Day: 1  2  3  4  5  6  7  8
 --------+-----------------------------
 Lathe   |      [Job A ][Job C   ]
 Milling |         [Job B   ][Job D ]
 Drill   |               [Job A2][..]
 Done:    ====>   (progress on A)
              ^ today line

Advantages

  • Simple to draw and understand, even by shop-floor staff.
  • Shows the whole schedule and the idle time of machines at a glance.
  • Useful for comparing planned and actual progress.
  • Low cost; easy to update.

Limitations

  • It does not show the dependencies between activities clearly, nor the critical path.
  • It becomes complex for large projects with many activities.
  • It cannot show uncertainty in activity times.
  • Rescheduling needs the chart to be redrawn.

For this reason CPM and PERT are used for large projects, while the Gantt chart is retained for shop loading and for presenting schedules.

✓ Answer checked by Claude Opus 5.5 (high effort)

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