Chapter 7
Warehouse Operations
Answers to Problems at the End of Chapter 7 7-1
SECTION 7.4-7.5
7.1 A project to evaluate existing dock area, including receiving and shipping, will allow the
determination of those aspects that can potentially prove economically advantageous. The
following is a partial list of such aspects that warrant attention.
Eliminate the receiving area. For some materials, e.g., large and bulky ones, drop
shipping (having the vendor ship to the customer directly) can save the time and
labor associated with receiving and shipping.
Reduce or eliminate staging in the receiving and shipping area. Determine the
location assignment and product identification prior to receiving the product so that
7.2 This problem should not be assigned if the students have not been exposed to either
Monte Carlo simulation or queueing theory. In Chapter 10, we provide queueing models
Answers to Problems at the End of Chapter 7 7-2
7.3
7.4 The impact on space requirement of this proposal is that 90-degree docks require greater
apron depth but less bay width, both impacting outside space requirements, as well as
7.5 Permanent, adjustable dockboards are fastened to the dock and are not moved form
position to position. Therefore, the dock board may be longer and wider than portable
7.6 A survey of the receiving areas on a typical campus shows that most dock and carrier
7.7 Increases in the length of trucks imply that more space will be needed to maneuver trucks
plant/warehouse may need to be modified to better accommodate longer trucks/trailers.
SECTIONS 7.6-7.7
7.9
Strict order picking, i.e., each batch is an order, or single-order-pick (SOP),
Answers to Problems at the End of Chapter 7 7-5
Batch picking two or more orders with downstream sorting, or pick-and-sort (PAS)
7.10
Traveling to, from, and between pick locations,
7.11
Simple ranking of SKUs based on the ratio of pick frequency (the number of times
a SKU is requested) to shipped cube (the product of unit demand and unit cube)
7.12
Popularity of items or SKUs
7.13 Travel time per line item picked … sorting
7.18
Introduction of Just-in-time operating program
7.21 Visiting a typical warehouse may bring about the following discoveries:
Both dedicated and randomized storage schemes are used.
The main mode of transporting materials within the warehouse is counterbalanced
lift trucks, also known as fork lift truck.
The warehouse is mostly clear of clutter, but the item pick area could benefit from a
7.22a Total cube demand for item A
= (100 units) x (1 ft3 / unit A)
7.22c Item A: [(100 units / 50 weeks) x (1 ft3 / unit A)] = 2 ft3 / week.
7.23
When product volume is low and/or product is to be stored for short periods of
time, i.e., work in process, storing the product directly on the floor is practiced
Answers to Problems at the End of Chapter 7 7-8
7.24 A detailed approach to storage space planning for the 1200 different SKUs this
warehouse would have to receive, store, and ship is not possible with the data given.
Dedicated storage locations (and class-based dedicated storage locations) remain active
even after stock has been removed from that location and the location is empty. This is
partly due to the fact that the number of openings assigned to an SKU must accommodate
Answers to Problems at the End of Chapter 7 7-9
the SKU. The SKU having the highest ranking is assigned to the preferred opening, with
the lowest-ranking SKU assigned to the least-preferred openings. Because fast movers
7.25 The receiving/shipping ratios (the ratio of the trips to receive and the trips to ship a
material) for each of the products A-N are calculated and given in the following table. A
than 1.0 indicates that fewer trips are required to receive the product than to ship it.
Therefore, products having ratios less than 1.0 should be located closer to shipping.
Products A, C, D, J, and M should be closer to shipping.
Product
Monthly
Throughput
Qty per
Receipt
Trips to
Receive
Avg.
Customer
Order Size
Trips to
Ship
Receiving/
Shipping
Ratio
A High 300 pallets 30 2.0 pallets 150 0.20
B Low 200 cartons 50 4.0 pallets 50 1.00
C Low 10 pallets 10 0.2 pallet 50 0.20
D High 400 pallets 400 0.5 pallet 800 0.50
E High 6,000 cartons 1,000 10.0 cartons 600 1.67
F Low 40 cartons 40 2.0 pallets 20 2.00
G High 200 cartons 200 1.0 pallet 200 1.00
H High 9,000 cartons 2,250 5.0 cartons 1,800 1.25
I Low 50 pallets 50 1.0 pallet 50 1.00
J High 500 pallets 500 0.7 pallet 715 0.69
K Low 80 pallets 80 2.0 pallets 40 2.00
L High 400 pallets 400 1.0 pallet 400 1.00
M High 7,000 cartons 1,167 3.0 cartons 2,334 0.50
Answers to Problems at the End of Chapter 7 7-10
7.26 Minimum Total Cube Requirement:
Therefore, the practical dimensions for the block stacking storage area are 390 ft wide by
300 ft deep.
H
N
F
B
I
A
J
D
M
C
L
G
K
E
Receiving
Main Aisle
Shipping
Answers to Problems at the End of Chapter 7 7-11
7.27 Cube utilization increases as products are more densely stored in a warehouse. Thus,
7.28 The slightest advantage that layout (a) has over layouts (b) and (c) of Figure 7.36 is that
Receiving Area
Shipping Area
113+ ft
390+ ft