Page 468 - Orlicky's Material Requirements Planning

446 PART 4 Looking Backward and Forward

FIGURE 26-14 600

Planning and
order multiple for 500
Part 408.
Part: 408 Buffer
Lead Time: 10 Days Profile: M21
400 Available
Top of Green 500
Stock
Top of Yellow 400 Position
300
Top of Red 200
Available Stock 350
200
Order Min 20
Order Multiple 20
100
Order Max None
0
408

In this case, the available stock position is at 350, placing it in the rebuild zone. In
order to get to the top of green, a recommended quantity of 150 would be required. In
this case, however, there is an order multiple that does not allow ordering 150. Instead,
to reach the top of green, 160 (eight multiples) must be ordered.
Figure 26-15 shows the available stock position after the quantity of 160 has been
ordered. Note that the available stock position is now above the top of green. Rules can
be constructed to affect the recommended supply quantity in relation to order multiples
to minimize over top of green situations. An example would be to limit over top of green
situations to occurrences where the over top of green with an additional order multiple
is less than the under top of green without the additional order multiple.

Highly Visible Priority
As introduced in the preceding example (Figure 26-13), all replenished buffer parts are
managed using highly visible zone indicators, including the percentage of depletion of
the buffer (frequently called buffer penetration). This is a far simpler and faster approach
than to have to sift through the planning-message queue to determine real and relative
priority. The buffer status in DDMRP relates to the available stock position. The recom-
mended order quantity will be the quantity to bring the available stock position to the top
of the green (which is the top of the buffer).
Figure 26-16 shows what a planning screen could look like under DDMRP tactics.
This view is filtered by critical, high, and medium priority (all of which require planning
action). Note that there is both the general color reference and discrete reference to per-
centage remaining of the buffer. The highest-priority item is PPJ. The PPJ available stock
position places it in a net negative position by a quantity of over the total buffer top of
green (TOG).