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<ManualTopic ID="/baanerp/ti/onlinemanual/000319" xml:lang="en">
	<Header>
		<Title xmlns:ssa="http://www.ssaglobal.com" xmlns:HTML="http://www.w3.org/TR/REC-html40">Slack time and production planning</Title>
		<Keyword><Level1>Production planning and slack time</Level1>
		</Keyword>
	</Header>
	<GeneralSection><Paragraph><Link href="/baanerp/ti/glossary/glossary#SlackTime.ti" role="glossary">Slack time</Link> is the time in hours or days between the earliest possible finish date and the latest possible finish date of an operation. Slack time is deliberately introduced by the planner to reduce the risk that a delay in a single operation is passed on to subsequent operations and, as a result, upsets the overall planning. Slack time influences the calculation of production-planning dates. It influences an operation's latest possible finish date, and therefore the next operation's start date.</Paragraph>
		<List><ListIntro>Slack time can be expressed in the following time units:</ListIntro>
			<ListItem>Hours.</ListItem>
			<ListItem>Days.</ListItem>
		</List>
		<GeneralSection><SectionTitle>Slack time expressed in hours</SectionTitle>
			<Paragraph>If slack time is expressed in hours, SSA ERP uses the standard calendar calculation to determine the latest finish date.</Paragraph>
			<Paragraph>Example 1: <Link href="/baanerp/ti/onlinemanual/000330" role="manual">Slack time and planning: time in hours, planning method Forward</Link>.</Paragraph>
		</GeneralSection>
		<GeneralSection><SectionTitle>Slack time expressed in days</SectionTitle>
			<Paragraph>If slack time is expressed in days, SSA ERP does not convert these days to hours, but handles the slack time differently. To determine the latest finish date, SSA ERP first checks whether any working time is available in the calendar between the operation's earliest finish date and 12 PM (that is, the end of this day). If this is the case, that time is considered one day of slack. Note that the working time that is left of the day can, theoretically, be only one second. However, this time is still considered one day of slack. Then SSA ERP checks whether any working time is available the next day. If no time is found, this day is not counted as a day of slack, and the next day is checked for working time. For successive days, SSA ERP checks whether working time is available that can be counted as slack time. The latest finish date is the date when all slack time is used.</Paragraph>
			<Paragraph>So, a day of slack time does not consist of a fixed number of hours. The number of hours for a day of slack time depends on the working time that is defined in the <Link href="/baanerp/tc/glossary/glossary#Calendar.tc" role="glossary">calendar</Link>. For example, if you defined a working day of 4 hours, a day of slack time is 4 hours. If you define a working day of one minute, a day of slack time is only one minute.</Paragraph>
			<Paragraph>Example 2: <Link href="/baanerp/ti/onlinemanual/000331" role="manual">Slack time and planning: time in days, planning method Forward</Link>
			</Paragraph>
			<Paragraph>Example 3: <Link href="/baanerp/ti/onlinemanual/000332" role="manual">Slack time and planning: time in days, planning method Backward</Link>
			</Paragraph>
		</GeneralSection>
	</GeneralSection>
	<RelatedTopics><SectionTitle>Related topics</SectionTitle>
		<RelTopic><Link href="/baanerp/ti/onlinemanual/000325" role="manual">Calendars in Manufacturing</Link>
		</RelTopic>
		<RelTopic><Link href="/baanerp/ti/onlinemanual/000310" role="manual">Queue time compression</Link>
		</RelTopic>
	</RelatedTopics>
</ManualTopic>
