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<ManualTopic ID="/baanerp/cp/onlinemanual/000335" xml:lang="en">
	<Header>
		<Title xmlns:ssa="http://www.ssaglobal.com" xmlns:HTML="http://www.w3.org/TR/REC-html40">Purchase lead time calculation</Title>
		<Keyword><Level1>Purchase lead time</Level1>
		</Keyword>
		<Keyword><Level1>Lead times</Level1>
		</Keyword>
		<Keyword><Level1>Calculating lead times</Level1>
		</Keyword>
	</Header>
	<GeneralSection><Paragraph>An important task of Enterprise Planning is to calculate and plan order start dates and order finish dates. One of the dates Enterprise Planning calculates is the lead time for purchased items.</Paragraph>
		<Paragraph>Dependent on the situation, Enterprise Planning uses one of the following three methods to calculate lead times for <Link href="/baanerp/cp/glossary/glossary#000048" role="glossary">planned purchase orders</Link>:</Paragraph>
		<List><ListItem>Based on order-specific purchase data.</ListItem>
			<ListItem>Based on the calculated lead time.</ListItem>
			<ListItem>Based on the <Link href="/baanerp/td/glossary/glossary#000011" role="glossary">supply time</Link>.</ListItem>
		</List>
		<Paragraph>The method that SSA ERP uses is determined by the supplier that SSA ERP selects to deliver the ordered goods. SSA ERP selects the supplier according to the <Link href="/baanerp/cp/glossary/glossary#000107" role="glossary">priority rule</Link> that you defined in the <GUIRef href="/baanerp/cp/rpd/cprpd7120m000" role="session">Supply Strategy (cprpd7120m000)</GUIRef> session, and is also based on the <Link href="/baanerp/td/glossary/glossary#000097" role="glossary">priorities</Link> that you specified for the eligible supplier in the <GUIRef href="/baanerp/td/ipu/tdipu0110m000" role="session">Item - Purchase Business Partner (tdipu0110m000)</GUIRef> session.</Paragraph>
		<Paragraph>The <GUIRef href="/baanerp/td/ipu/tdipu0110m000#tdipu010.oltf" role="formfield">Lead Time Horizon (Days)</GUIRef> field in the <GUIRef href="/baanerp/td/ipu/tdipu0110m000" role="session">Item - Purchase Business Partner (tdipu0110m000)</GUIRef> session determines the method that SSA ERP chooses to compute lead time for planned purchase orders. The function of the lead time horizon is comparable to that of the <Link href="/baanerp/cp/glossary/glossary#000058" role="glossary">fixed lead-time horizon</Link> that you can set for <Link href="/baanerp/cp/glossary/glossary#000047" role="glossary">planned production orders</Link>.</Paragraph>
		<GeneralSection><SectionTitle>Purchase lead-time calculation based on order-specific purchase data</SectionTitle>
			<List><ListIntro>If the finish date is within the lead-time horizon, and SSA ERP finds a valid supplier, SSA ERP first calculates the interim finish date, which is included in the purchase order sent to the selected supplier. The lead-time components that SSA ERP uses to calculate this date, and the sessions from which it retrieves these data are:</ListIntro>
				<ListItem><GUIRef href="/baanerp/cp/rpd/cprpd1100m000" role="session">Items - Planning (cprpd1100m000)</GUIRef>.</ListItem>
				<ListItem><GUIRef href="/baanerp/tc/ibd/tcibd2500m000" role="session">Items - Ordering (tcibd2500m000)</GUIRef>.</ListItem>
				<ListItem><GUIRef href="/baanerp/wh/wmd/whwmd2510m000" role="session">Warehouse - Item (whwmd2510m000)</GUIRef>.</ListItem>
			</List>
			<List><ListIntro>Next, SSA ERP calculates the final finish date, for which it uses the following data:</ListIntro>
				<ListItem><GUIRef href="/baanerp/wh/wmd/whwmd2510m000" role="session">Warehouse - Item (whwmd2510m000)</GUIRef>.</ListItem>
				<ListItem><GUIRef href="/baanerp/td/ipu/tdipu0110m000" role="session">Item - Purchase Business Partner (tdipu0110m000)</GUIRef>.</ListItem>
			</List>
			<List><ListIntro>Finally, SSA ERP computes the exact order start date based on supplier-specific data. The specific lead-time components that SSA ERP uses and the sessions in which they are defined are:</ListIntro>
				<ListItem>Transport time: SSA ERP calculates the transport time based on the distance between the <Link href="/baanerp/tc/glossary/glossary#ShipfrBusine.tc" role="glossary">ship-from business partner</Link> address, and the address of the receiving warehouse business partners, distance tables, and <Link href="/baanerp/tc/glossary/glossary#Carrier.tc" role="glossary">carrier</Link>.</ListItem>
				<ListItem>Business partner supply time: <GUIRef href="/baanerp/td/ipu/tdipu0110m000" role="session">Item - Purchase Business Partner (tdipu0110m000)</GUIRef>.</ListItem>
				<ListItem><Link href="/baanerp/td/glossary/glossary#000040" role="glossary">Internal processing time</Link>: <GUIRef href="/baanerp/td/ipu/tdipu0110m000" role="session">Item - Purchase Business Partner (tdipu0110m000)</GUIRef>.</ListItem>
			</List>
		</GeneralSection>
		<GeneralSection><SectionTitle>Purchase lead-time calculation based on calculated lead time</SectionTitle>
			<List><ListIntro>If the finish date of the <Link href="/baanerp/cp/glossary/glossary#000048" role="glossary">planned purchase order</Link> is outside the supplier's lead time horizon, SSA ERP computes the order start date based on the calculated lead time, which is the rough purchase item lead time. SSA ERP offsets the calculated lead time from the finish date to find the start date. The calculated lead time is the sum of the following lead-time components:</ListIntro>
				<ListItem>Internal processing time ( <GUIRef href="/baanerp/td/ipu/tdipu0110m000" role="session">Item - Purchase Business Partner (tdipu0110m000)</GUIRef>.</ListItem>
				<ListItem>Business partner supply time ( <GUIRef href="/baanerp/td/ipu/tdipu0110m000" role="session">Item - Purchase Business Partner (tdipu0110m000)</GUIRef> ).</ListItem>
				<ListItem>Transport time (based on the distance between the <Link href="/baanerp/tc/glossary/glossary#ShipfrBusine.tc" role="glossary">ship-from business partner</Link> address, and the address of the receiving warehouse business partners, distance table and <Link href="/baanerp/tc/glossary/glossary#Carrier.tc" role="glossary">carrier</Link>.</ListItem>
				<ListItem>Business partner safety time ( <GUIRef href="/baanerp/td/ipu/tdipu0110m000" role="session">Item - Purchase Business Partner (tdipu0110m000)</GUIRef> ).</ListItem>
				<ListItem><Link href="/baanerp/wh/glossary/glossary#000395" role="glossary">Inbound lead time</Link> ( <GUIRef href="/baanerp/wh/wmd/whwmd2510m000" role="session">Warehouse - Item (whwmd2510m000)</GUIRef> ).</ListItem>
			</List>
			<Paragraph>Next, SSA ERP computes the finish date by offsetting the business partner safety time and the inbound lead time from the requirement date. This is necessary because these two lead-time components must be excluded from the supplier's <Link href="/baanerp/wh/glossary/glossary#000409" role="glossary">planned receipt date</Link>.</Paragraph>
		</GeneralSection>
		<GeneralSection><SectionTitle>Purchase lead-time calculation based on supply time</SectionTitle>
			<Paragraph>If SSA ERP cannot find a valid supplier for the purchase order, or if the supplier that SSA ERP selects has no capacity left, it plans the order without a supplier. In this situation, the only purchase-related lead time component SSA ERP uses is the <Link href="/baanerp/td/glossary/glossary#000011" role="glossary">supply time</Link> that you defined in the <GUIRef href="/baanerp/td/ipu/tdipu0101m000" role="session">Item - Purchase (tdipu0101m000)</GUIRef> session. This is a substitute for the more specific lead-time components such as <Link href="/baanerp/td/glossary/glossary#000040" role="glossary">internal processing time</Link>, business partner supply time, transport time, and business partner safety time which SSA ERP uses if it cannot find a valid supplier for the purchase order.</Paragraph>
		</GeneralSection>
	</GeneralSection>
	<RelatedTopics><SectionTitle>Related topics</SectionTitle>
		<RelTopic><Link href="/baanerp/cp/onlinemanual/000317" role="manual">Cumulative order lead times and horizons</Link>
		</RelTopic>
		<RelTopic><Link href="/baanerp/cp/onlinemanual/000161" role="manual">To compute supply lead-times</Link>
		</RelTopic>
		<RelTopic><Link href="/baanerp/cp/onlinemanual/000316" role="manual">Lead times and horizons</Link>
		</RelTopic>
	</RelatedTopics>
</ManualTopic>
