Resources and shift calendars: understanding available production capacity

Capacity depends on who and what is available, their capability and their working time. A machine may exist but lack an operator; an operator may be present but lack a required skill. A shift calendar describes available time, including breaks and holidays.

DNA Resources records labor, machines and tools with work center, calendar, hourly cost, daily hours and capabilities. Work centers and resources use shift calendars to establish working days and shifts. This supports a more credible schedule than assuming every resource works continuously.

Capacity is more than machine count

A production resource needs the right capability and available time. A machine without the required tool cannot perform every operation. An operator may be available but lack a necessary skill. A calendar day may contain many hours during which the plant does not work.

These constraints explain why a simple count of machines or people is not enough to promise output. Capacity planning needs a credible representation of the actual operating conditions.

A working-time example

An eight-hour shift with a one-hour break provides seven scheduled working hours before other losses. A job needing ten hours cannot be promised within that shift merely because the calendar day has 24 hours. A holiday must also be reflected in the applicable calendar.

The seven hours are scheduled working time in the example, before other losses. Unplanned downtime, reduced speed, or quality problems can reduce effective output further. Scheduled capacity and achieved capacity are related but distinct measures.

How DNA represents the resources

DNA resources can describe labour, machines, and tools with work-centre relationships, calendars, costs, daily hours, and capabilities. Shift calendars establish working days and shifts, including the relevant breaks and holidays.

The relationship between a work centre and its resources should reflect the real process. A job requiring both an operator and a specialised machine depends on both being available in a compatible period.

A practical scheduling decision

A planned operation needs ten machine hours and a qualified operator. The machine is free tomorrow, but the operator is assigned elsewhere for half the shift. Scheduling the full job tomorrow solely from the machine's calendar would create an unrealistic commitment.

The business may need a later date, a qualified alternative resource, or a different approved method. The correct response depends on the actual capability and capacity constraints rather than an arbitrary date change.

Keeping assumptions current

A calendar or resource definition can become stale when shifts, holidays, staffing, or equipment change. Planning can continue producing precise dates from those outdated assumptions, but the precision does not make the plan feasible.

Resource and calendar maintenance therefore supports customer promises as well as factory scheduling. The useful capacity model explains who and what can perform the work, during which time, and under which cost and capability assumptions.