The team of ten members was tasked with designing a plant to manufacture and assemble hair dryers for use in regional peripheral warehouses, shopping malls, and shops. A well-equipped assembly area, a raw materials warehouse (RMW), a finished product warehouse (FPW), a semi-finished storage area, and service areas have all been available at the plant. Geometric and volumetric sizing, lines and/or cells and/or work departments, shelving, reception areas, shipping areas, picking areas, packaging areas, and finished product containment buildings were all the responsibility of each project team.

1. 1
Preliminary Study of an Assembling Plant
01NLHJM - Industrial Plants and Safety
Bachelor's Degree in Mechanical Engineering
2021-2022
Team N°3:

2. 2
1. Understanding the Specifications
The project focuses on designing a plant of a company that manufactures hair dryers, through
receiving the raw materials and assembling them.
The report includes a thorough study of calculation of incoming and outcoming material flows,
detailed definition of the Multi-Level Bill of Material (BOM) for each type of hairdryers (basic-
standard-luxury), and their assembling processes through diagrams. The cycle times for each
process of assembling are measured by disassembling and assembling back a hairdryer. The
production processes and overall flows are described visually by diagrams. Different variations
of layout types are studied and the one that best suits the needs of the company is chosen.
Line balancing operation is performed to find the optimal solution for number of lines and
workstations. Each type of line (basic-standard-luxury-mixed) and the workstations inside them
are studied in the Block Layout section. Moreover, the study of a workstation is carried out
including its drawing.
In the following steps the study of the warehouses (raw material warehouse and finished product
warehouse) is conducted: Load units are defined to feed the workstations, warehouse material
flow is studied, warehouse sizing is made, and ideal storage area is calculated. Performance
indices are calculated; number of handling vehicles, number of internal logistic workers and
operators for production and warehouses are determined.
Finally, material manual handling is studied by applying the NIOSH method to the workstations
which aims to take into consideration the safety. To finish off, the drawing of the whole plant is
made.

3. 3
2. Calculation of Incoming and Outcoming Material Flows
Calculation of Outcoming Material Flow (Demand):
The product demand is calculated using the formula provided by the project text:
P =
!"
(∑ #$)
&
$'(
&
$
(∑ )$)
&
$'(
&
%∗'()*
+
Where P is the production required for each product per day. C, is the number corresponding to
the English alphabetical letter of the initial letter of surname of the i-member team, N, is the
number corresponding to the English alphabetical letter of the initial letter of name of the team
member and the values for each one can be seen in table below. S is the number of students in
the team (10), DSP is the Daily Standard Production, and it is calculated by dividing the
Standard Production Rate per year, given in the project text as 280.000 units/year, to number of
days the plant operates which is 220 days can be observed.
Inserting the numbers in the formula, the ideal demand is equal to 1.493.333 units/year.
However, taking 3% scrap rate into account the actual yearly demand for raw materials is equal
to 1.538.133 units.
Calculation of Incoming Flow:
As mentioned in the calculation of outcoming flow, the 3% scrap rate helps to go from the ideal
to real value of raw material to be requested from the supplier as the raw materials are
assembled. In table below the details can be found.

4. 4
s
It is important to consider that the required production is subdivided to different models as
shown in table below. Note that these values are for components that only have 1 quantity per
product (For example, screws are twice these numbers as there are 2 switches per product).
These calculations have huge importance as they are used in the next steps like the number of
components needed per each line (basic-standard-luxury-mixed). An example of a list of parts
for basic line can be found in table below.

5. 5

6. 6
3. Planning the Assembly
Assembly has been planned for 3 different
models which share same number of
components and same assembly instructions.
For example, the components nozzle, air exit
net, front body, motor, fan, and finally back
body are present in every model however
they are different for each model and their
installation time differs as well. The
Multilevel BOM can be seen in the table on
the right.
3.1. Assembling Process
Assembly process and cycle times were obtained by disassembling and trying to reassemble a
real hairdryer by the team. There were some additional considerations made based on assembling
process being done in an industrial production area and human factors like fatigue and work
being repeated multiple times during a whole shift.
3.2. Assembly operations
Task A: Taking front body and mounting of air-exit net, absorbing pad, inner body inside the
front casing.
Task B: Grill and pre-assembled heating unit joined together.
Task C: Assembly of front casing and Task B.
Task D: Motor, septa and fan installed together
Task H: Electrical components sheath, and power plug joined.
Task E: Assembly of previous tasks involving front casing together.
Task F: Switches and buttons for control of hairdryer were installed on front body.
Task G: Front casing and inner component assemblies joined together.
Task I: Back casing components installed.
Task J: Assembly of hairdryer by joining front and back casing.

7. 7
For the basic model whole cycle
time calculations has been shown.
Assembly starts by taking front
body components and all other
components are preassembled or
directly mounted inside the front
body. Electrical and heating
components are installed and finally
assembly ends with mounting of
back body and joining them
together. Same operations were
repeated for all the models but
considering basic, standard, and
luxury models share same
component. With different models,
they also had different cycle times
(difference was obtained from the
text of project provided) which can
be seen in table.
The total task times are written in terms of seconds. The minimum
cycle time belongs to basic production, the one in the middle is the
cycle time of standard production and the one with the longest
duration is for the luxury production.
For the assembly process some workstations need screwdriver for installation of screws. Rest of
the operations are done manually by the worker for mounting of components. Components are
placed in their Odette boxes at workstations. Worker manually takes components; mounts,
installs, and joins them together.

8. 8
4. Production Process and Overall Flow
Following the diagram below, the
procedure of assembling the hairdryers of
any type (i.e., basic, standard, and luxury)
can be realized. Workstations are shown in
alphabetical format. The starting point is
from workstations A and B and the
assembling ends when tested by the
relevant expert in the testing station QC.
The figure indicated below may help in grasping the concept and the steps which our
company has followed for the assembling process. A basic hairdryer has been
disassembled to better understand the details of the process.
WS J
WS G
WS F
2 23 24 25 26 27
WS E
WS D
9 10 12
WS H
28 29
WS C
WS A
3 4 5
WS B
Pre-
assembl
ed
6
WS I
13 14

9. 9
Process Flow
The components are delivered to each relevant workstations from the Raw Material Warehouse
by means of Forklift trucks. The process is done along a straight line which will be discussed
later. *Cycle times include the putting action on the belt conveyor.
Brief discussion on the process flow: The designer has assigned some locations to the
components that are received from the Raw Material Warehouse considering also the required
space needed by the worker to freely move without any interruption. Each workstation, mainly,
has the responsibility to assemble 2 or more parts and pass it to the next workstation, however,
some of the workstations assemble the sub-assemble parts (e.g., workstation C).
5. Plant Layout
To meet demands and increase the efficiency, workstation layout is important to avoid time
consuming and organize a seamless flow of material. The organization and task done of the
workstations organized as each station's task will take approximately 39 sec. To ensure product
demand each operator works 45 minutes an hour, there are not so many operations for each
operator to reduce stress and increase line performance for OEE. Remaining approximately 15
minutes which can be used for the wasted time caused by the production could be considered in
this "extra time" (Line malfunctions, product errors etc.). This also increases the operations
trustfulness.
Since yearly production demand is around 1.500.000, out of possible types (process-oriented,
product-oriented, group, fixed position, and combination) we choose product-oriented layout
which will be the most efficient at our production. Because a change in the product design is not
expected, the production consists only of assembly operations, there is not a large amount of
variety. What it will provide to us is that the flow of product will be smooth and logical in flow
lines, minimum material handling cost will be acquired, unskilled workers can learn and manage
the production, and it will require much less travel distance. Also, we added a mixed line to
balance demand/production according to best and worst situations.
Firstly, we choose “straight line flow” to see if products flow goes smooth between the units but
this will change at continuous processes because of efficiency, length/area relations, distance
traveled, hard to find long rectangular areas to build a plant.

10. 10
At testing and packing stations, a total of 59 workstations added (47 testing, 12 packing).
Between assembly, testing, and packing stations product always will be carried by forklift (pallet
with big plastic box on it).
6. Line Balancing
Before starting with the line balancing and computations related to it, it would be a good practice
to introduce the related formulas:
§ OEE = Performance Index x Availability x Quality Rate
§ Actual Time Available = Available Time[sec] x Availability x Performance Index
§ Takt Time = Actual Time Available / Daily Production
§ Time Before Performance Index = Availability x Quality Rate x Available Time[sec]
§ Theoretical Minimum Number of Workstations = Total Task Time / Takt Time
§ As the number of lines increase, available time, in return, increases and so for new lines
added the new time is = Actual Time Available x Number of Lines
§ Actual Number of Workstations = Number of Stations x Number of Lines

11. 11
§ Line Performance Index = (Total Task Time x Daily Production) / (Actual Number of
Workstations x Time Before Performance Index)
§ Line Efficiency = Total Task Time / (New Takt Time x Actual Number of Workstations)
Calculation procedure:
To begin with, according to the type of line layout, the successors for straight line and the
predecessors for the U-line must be determined and according to RPW the data must be ordered
in descending order. The second step is to choose the maximum cycle time for each type of
production in order the condition of having the new takt time to be greater than that of the
maximum cycle time be respected. Then it is necessary to choose the number of lines, regardless
of the configuration. As it is already mentioned, the number of lines increase the available time
of production, hence, the higher the number the higher the available time. However, the goal of
line balancing must not be forgotten. The third step is to re-calculate the takt time in order to
check whether the first condition has been already met or further computations in terms of
increasing the number of lines is needed. If yes, it is possible to move to the fourth stage of
computation. Before the onset of calculation of fourth step the actual number of workstations
must be computed because one of the parameters affecting the performance index is the number
of workstations. Then, with the formula given in the previous page, the line performance index is
obtained. We must re-do the procedure over and over to choose a reasonable value of
Performance index. The OEE must also be re-computed with the new value of performance
index but note that as the number of daily products already include the rejection rate, the formula
of the new OEE is the New Performance Index multiplied by the Availability.
A further computation can be done to check the line efficiency.
Line balancing calculations for basic production:
§ Considering the parameters that affect the productivity, we can decide the type of line
balancing which in return must match the takt time with production rate.
§ Availability [A] 95%
§ Performance index [P] 90%
§ Quality rate [QR] 97%
§ OEE 82.94% (multiplication of the three factors above)

12. 12
• Straight line for Basic Production
Straight line or U-Line Balancing?
We consider both approaches for all the three types of production.
The best compromise to reach and to respect the limitation (Newtakt_t > t_max) and to strive to
maintain the OEE at its maximum possible at the same time is shown in the second figure by
adopting four parallel lines of 5 total stations. The reason of having not more than four is not
only because the line efficiency decreases as the number of lines increase but the line
performance index would not change significantly.
*It is not worthy to pay a fortune cost for basic production.

13. 13
Let’s compare the results for straight line and U line by answering the following question.
Is it useful to decrease the number of workers by adopting U-line method? One may say yes at
the first glance because the costs would decrease as much, but the performance index is
approximately the same as the one derived for straight line, therefore, for the sake of simplicity
and respecting the workers convenience the straight line is chosen over the U-line.

14. 14
• U-line

15. 15
Line balancing calculations for standard production:
§ Same reasonings of the basic case, however in this case the OEE has reduced to a great
extent and comparing it with the U-line it is suitable to go for the second layout.
However, a clever choice is to choose the straight line because of simplicity and to
prevent any possible risks. For instance, the operator must easily access the parts coming
from the conveyor otherwise, damages, breakages and consequently, increase in rejection
rate would arise.
§ Straight line

16. 16
• U-line

17. 17
Line balancing calculations for luxury and mixed production:
§ Luxury and mixed production are in the same category as they have the same parameters.
§ Straight line is chosen against U-line
§ Straight line

18. 18
• U-line

19. 19
7. Defining the Block Layout
We designed the production line and operation time in workstations almost equal. Since the
number of operations and raw materials are less at workstations, we can assign only one worker
for each station and that will be enough. Automatic screwdrivers will be given to workers to
improve efficiency and save time. After the last workstation products will be placed to big
splitted plastic box to carry them to testing stations.
Total task time is 181 sec for basic product, 184.5 for standard product, 187 sec for luxury lines.
Which is total time to finish a hairdryer completely.
Basic Production ( 4 lines, 5 workstations) Standard Production (5 lines, 4
workstations)
WS1: A+B =39 sec WS1:A+I+B = 49,6 sec
WS2: C+D = 33 sec WS2: D+C+H = 46,5 sec
WS3: E+H = 39 sec WS3: G+E = 46,4 sec
WS4: I+F = 39 sec WS4: J+F = 42 sec
WS5: G+J = 31 sec

20. 20
Luxury Production (3 lines, 3 workstations) Mixed Production (3 lines, 3
workstations)
WS1: A+B+D = 68,6 sec WS1: A+B+D = 68,6 sec
WS2: C+H+E+I = 58,4 sec WS2: C+H+E+I = 58,4 sec
WS3: F+G+J= 60 sec WS3: F+G+J = 60 sec

21. 21
At testing and packing stations, a total of 59 workstations were added (47 testing, 12 packing).

22. 22
Number of Workers:
For the assembly part there are totally 58 workstations, 1 worker for each makes 58 operators,
and for each type of product there is 1 supervisor. Totally 4 supervisors.
For Testing and packing, there are 59 workstations, 1 worker for each makes 58 operators, and
for each 6 workstations there is 1 supervisor. Totally 10 supervisors.
There are 3 forklifts at the plant (1 between assembly-testing, between testing-packing we use
pallet trucks, 1 packing to FPW, 1 FPW to trucks) and there is 1 supervisor for forklifts.
(Pallet truck)
As a sum there are totally:
117 workstation operators,
15 supervisors,
3 forklift operators work at the plant.
Tools at Workstations:
Operators at workstations containing screw work perform screw fastening operations, the
workstations are equipped with industrial grade pneumatic screwdrivers providing precision and
quick operation. Remaining workstations do not perform any tasks requiring tools, but all
stations are equipped with pry tools to allow easier disassembly if need be, in rare cases.
Raw materials, trash materials etc. at workstations are stored in Odette boxes.
Assembles are carried between workstations with a manual handling system.

23. 23
Flow At Layout
1) Components arrive from RMS in palletized boxes following the 3 main corridors to
spread related pieces to lines.
2) Finished products at the lines placed in a large splitted plastic box on a pallet.
3) Forklifts collect related products and carry them to the testing and the packing area.
4) Tested products are packed in primary boxes.
5) Products in primary boxes placed in secondary boxes (each carries 8 primary boxes) and
palletized.
6) Packed products carried to finished product storage area (FPS).
7) Trucks loaded from FPS and products shipped.
After those calculations flow is changed to a U-flow, even though in the previous chapter it was
stated that the straight line is more beneficial over U-line. It is changed to use the area more
efficiently, considering road-lengths of forklifts.
Benefits of implementing proposed layout are:
➢ As the number of parallel production lines is 9 at one side and 6 at one side it
gives way to possible cluttering at workspaces if all lines were placed in a single
section, thus dividing them in two equal sections provides sufficient space for not
cramped flow.
➢ A dedicated Assortment area for each section reduces chances of clustering of
corresponding component pallets at required workstation saving space. It also
enables faster delivery of components to workstations.
➢ Furthermore, this eliminates traffic near production lines, a safety factor to be
considered to reduce the probability of accidents at the production line.
➢ Close assembly, testing, packaging areas and U-shaped-flow ensures short
distances between places and that ensures faster delivery and small areas to build
plant (Economic and time saving).

24. 24
PRIMARY SKETCHES U-FLOW
EXPLAINED UNITS OF PRIMARY SKETCHES
Workstations and Odette boxes and things related to them are explained in more detail in the
following part…

25. 25
8. Workstation
To build a proper workstation that is appropriate for an employee, we must consider numerous
aspects supplied by ergonomics guidelines – the science of reducing musculoskeletal injuries in
the workplace. It is important to remember that safety and health issues are an intrinsic aspect of
workstation design.
To begin, we should analyze general anthropometric statistics to ensure that our workplace is
suitable for a typical man or woman. The height of the reference worker is 175 cm (average in
Europe and the world). The table will be constructed for standing work, but each employee will
be given an adjustable chair for maximum comfort. Working while standing or sitting allows the
operator to move around and reduces the effects of weariness.
Secondly, the length of the table should allow the operator to work comfortably while not
restricting any hand motions and allowing any necessary tools to be located as close to the point
of usage as possible. The suggested length of 1.9 m is an adequate length.
The location of parts and tools is also significant. All objects to be utilized should be arranged in
such a way that the hands are relieved of as much effort as possible. The further we seek for
anything, the more expensive and exhausting that reach becomes. The arm reach distance is
defined as the distance at which the hand is in its most relaxed position when reaching for an
object.
The shelves will be divided into two tiers, each with four containers. Furthermore, the shelves
will be 15° tilted to facilitate reaching for distant portions while maximizing the use of gravity
(one of the principles of ergonomics).

26. 26
9.1 Definition of Load Units – Raw Material Storage
A load unit is defined as a pallet plus the Odette boxes on top of it, so the number of pallets
represent the number of load units. It is important to note that the number of Odette boxes vary
as there are 3 types of Odette boxes with different dimensions. Including the dimensions of the
pallet, the dimensions of the boxes are given in the table below:
*It is important that an EU Pallet can be stacked with boxes up to a height of 1.2m. However, the
height that it is possible to start placing the boxes on the pallet is 0.15 m and this distance is
needed for the forklift to enter and lift the pallet. Therefore, after it is deducted the useful height
becomes 1.05 m.
It can be thought that dividing the volume that a pallet can carry to the volume of the Odette
boxes, the number of Odette boxes a pallet can carry could be calculated. However, the divisions
must be integers and if the number is a decimal, it must be rounded down. In table below how
many boxes a pallet could carry is calculated:
*For Odette box type 1 and type 3, the length of the box corresponds to the length of the pallet,
width of the box corresponds to the width of the pallet, and the height of the box corresponds to
the height of the pallet. However, the width of Odette box type 2 corresponds to the height of the
pallet, and this is done in order to maximize the number of boxes a pallet can carry.
The Odette boxes’ dimensions are defined however their weights haven’t been presented so far.
In order to do that, as it was stated in part 1, a hairdryer was disassembled by our group members
and each part’s weight was measured including their dimensions. In the table below a table about
the weight and quantity per box is given:

27. 27
Table 9.1.3
For each box mass the calculation is as follows:
(#components inside the box per day * unit weight) + Odette box mass
9.2 Definition of LU – Finished Product Storage
Table 9.2.1
In ideal conditions, the hairdryer production department produces on average 6782 boxed
hairdryers in total per day for storage and subsequent shipment to regional buyers. To define the
Load unit for finished product storage operations, EPAL EURO PALLET 1 (EPAL 1) has been
used to have a similar location size for the finished product storage with raw material storage, to
avoid extra costs from the purchase of further pallets and to be more efficient. Therefore, the
ideal capacity of the load unit is determined as 1200x800x1110 mm in order to stack the
products safely to the warehouse and load to the trucks in an efficient way, which could carry
128 hairdryer boxes each. However, this layout would make it too hard to secure them on the
load unit with fastening belts. To facilitate this task, we define a secondary box with dimensions
300x400x480 mm, which can hold 8 hairdryer boxes 300x200x120 mm. Also, this perfectly fits
to the load unit and load unit capacity remains the same.
Considering the demand, 255 LU would be shipped every week. Looking at the weight aspect,
taking the single secondary box’s weight as 640g and the single product box to be 160g, the
weight EPAL 1 will have to support is 122.7kg, which is much lower than the recommended
1500kg, hence there are no weight constraints when it comes to load units of the finished
product, considering the weight of the hairdryer itself which is 520g. Therefore, the load unit
chosen for the finished product storage is the EPAL 1 due to convenience and the dimensions,
but most importantly due to its suitability to the task.

28. 28
10.1 Load Unit Calculations and Material Flow- Raw Material Storage
Components are received inside their Odette boxes which has been placed in palettes. Pallets are
received in dock area and unloaded to storage areas. Then they are sent in their Odette boxes for
usage in assembly workstations.
In order to create a weekly delivery plan of pallets, we take into consideration our weekly
consumption of raw materials. By optimizing and grouping correct number of materials, we can
get certain values for optimization of how many trucks will be needed for deliveries. Following
calculations separates in common and different components for each model of hairdryer we will
be producing
Same calculations have been done for luxury and standard models also considering the
components that will be used in common for all the models together.

29. 29
Team has made measurements of each component and determined their size and volume in order
to find appropriate size of Odette box type, which then will be placed on pallets and received in
trucks.
Optimizing deliveries team decided grouping deliveries of some components in order to get close
values of load units for each delivery. This gives us a better chance of making balanced weekly
plan with no shortages of material flow or excess flow which would require more workers.
Weekly plan has been chosen in such a way to receive certain groups 3 at a time while receiving
some groups 2 a day to optimize and get same amount load units throughout the whole week. In
the tables below it can be seen how groups were spread around the week and in one below it has
been stated in detail which components we will be receiving in that working day.

30. 30
In this case total peak inventory reaches 221 pallets.
10.2 Load Unit Calculations and Material Flow - Finished Product Storage
The finished product storage is a product dedicated one with fixed allocation criterion. Our
finished product warehouse can guarantee 10 working days of inventory to mitigate the risks of
stockouts caused by uncertainties in supply and demand. An adequate safety stock will ensure
our business to operate smoothly.
The finished and packaged hairdryers are then grouped with other products of same type (basic,
standard, luxury) in a secondary box that is defined in the previous step 9. The secondary boxes
are then placed on an EU pallet and transferred to the finished storage warehouse via
counterbalanced forklift trucks which will be studied in the later step 12. As the load unit and
pallet dimensions defined in the previous step 9, a pallet will carry 16 secondary boxes which
contains 8 finished products. As a result, a pallet is going to carry 128 hairdryers.
Average daily demand can be calculated as:
-./0 12/.$345/0 12/.
6

31. 31
After calculating the average demand per day, we can determine the load units per day,
then load units per week (5 working days).
The weekly demand will be equal to 255 LU, our safety stock condition is 10 working days of
inventory:
Safety Stock = LU per 10 days = 510 LU
For the peak inventory calculation, we will need the outgoing flow. Our business has a
shipment plan of 2 times per week (Mondays and Thursdays).
Outgoing demand =
255
2
= 127,5 LU

32. 32
Peak Inventory = Storage Capacity = 596 LU
11.1 Definition of Warehouses and Other Storage Areas – Raw Material Storage
A product-oriented storage system with fixed allocation criteria is followed, Raw Material pallets
are stored employing a Push-back racking system to reduce the Aisle Allowance (saving space),
and to take advantage of the gravity.
Static sizing:
The table below summarizes the location of each LU. It has been decided to add 100 mm
clearance for both length and width; on the other hand, 150 mm clearance for the height.
A Forklift has to be chosen, to know the maximum level which can be reached. After having
consulted the STILL catalogue, A high lift, counterbalanced forklift is selected since it provides
all the specifications required to meet our needs:
Number of Levels: By knowing the lift height (Hforklift) Number of levels can be calculated as
follows:
Int E
7*+,-.$*/
8.+01/$+2
F + 1 , Which Is equal to 6

33. 33
Basic Module: A Basic Modulus is the unit of elementary geometry, repeated neatly reproduces
the plan of the store and the basic module depends on storage system:
Abm = (6*b + c)*a , equal to 10,521 [mm]
where,
a= width of location
b= length of location
c= working aisle width
• Number of LU per module: N (LU/bm) = 6* N (levels), Which is equal to 36 [LU]
• Theoretical Footprint: alu = N(LU/bm) / Abm , equal to 0,29 [m2
]
• Ideal Storage Area: Ath = alu * SC , equal to 64,6 [m2
]
Layout of Warehouse: To choose the best layout for the warehouse, we compare the hair comb
and fishbone strategy. It is assumed the input and output points are in the middle of the longest
side. By comparing both layouts we observe that the area wasted in Fishbone strategy is less,
therefore in order to reduce the waste and capacity the Fishbone strategy is chosen.
Dynamic Sizing:
In this section, the handling capacity will be obtained, which is the flow of pallets per hour into
the Warehouse and from the Warehouse to the Intermediate buffer, equal to HC = 8,05.
We now calculate the average distance (L) and vertical distance (H) in raising and lowering from
level travelled by a forklift in the warehouse as follows:

34. 34
L =
910/
:
+
;10/
6
, equal to 8,39 [m]
H =
<.343. = >
6∗8
, equal to 2,96 [m]
The throughput time can be worked out using the formula:
𝑇throughput =
:∗?
;/,143.
+
6∗7
;.$*/
+
6∗7
;.+63,
+ 4 ∗ T@,A.B
Tthrough. = 268,32 [s]
11.2 Definition of Warehouses and other Storage Areas – Finished Product Storage
As already mentioned, our finished product warehouse has a fixed allocation criterion. Every
single rack has the same type of hairdryer. For the storage rack decision, drive-through is going
to be the way to proceed as it has several advantages that suits our case. The most important
advantage that we can exploit is that it has an increased density of pallets to decrease the
warehouse footprint.
Also, FIFO (first in first out) stock rotation is a feature of drive-through rack system. This will
allow us to ship the products that we store in the first place, every hairdryer waits less in the
warehouse.
For the location dimensions, 100 mm clearance from each side is defined length-wise, 150 mm
clearance from each side width-wise and finally 150 mm clearance height-wise.

35. 35
Final dimensions of the load units and rack dimensions are demonstrated in the table below:
Basic Module:
In 1 row of the drive-through rack, we store 10 load units which implies b=10x12 m; a=1m;
c=4,88m.
Selectivity Calculation:
We can reach the first and the last load unit in a drive-through rack and we have defined 6 levels
for our rack so:
Selectivity =
12LU
60LU
∗ 100 = 20%
In our case, the selectivity doesn’t need to be high because every rack and its levels will contain
a single type of product. An operator can easily make their choice of LU.

36. 36
As for the handling capacity calculation, 905.2 products are moved which means 7 load units per
hour will be the required handling capacity.
The Rotation Index:
To calculate the rotation index (inventory turnover), we employ the following equation:
Inventory Turnover =
Sales
Average Inventory
We consider 10 working weeks for the outgoing product flow,
Sales = Peak Inventory ∗ 10 = 5960
Rotation Index =
5960
298
= 20
Final Sizing of the Finished Product Warehouse:
The sizing of the warehouse is determined as demonstrated below in the tables. Final layout is
constituted of 1 loading aisle, 1 unloading aisle and 2 secondary aisles.

37. 37
12. Internal Logistics – Raw Material Storage
Number of Forklifts Required:
The number of Forklifts has to be enough to meet the Required Handling Capacity:
N =
C∗71∗ D/7,+897.
+EFF
Where, k – safety factor is assumed as 1.2, therefore, the number of forklifts required = 1
Actual Handling Capacity:
Once the number of FLT dedicated to the storage area has been decided, the Actual Handling
Capacity can be computed, and it must be higher than the required one, which is verified in our
case.
HCact =
<∗+EFF
D/7,+897.
HCactual = 13 [LU/h]
Receiving Area:
The aim is to compute the number of docks required. Knowing the number of docks, the
necessary number of FLT can be obtained (one FLT per dock).
The sizing procedure follows the steps described below:
• LU Dimensions: For each LU, the dimensions have to be defined (length, width, height).
• Number of LU per shipment: once the dimensions are known, it is vital to figure out the
number of LU so that the overall volume can be estimated.
• Deciding the n. of Trucks required: To house the volume of LU a truck model has to be
chosen.

38. 38
Knowing the number of LU and the type of truck, the number of trucks can be computed. To
calculate number of delivery trucks, we consider the maximum load units that will be delivered
at once for production. To satisfy the volume needed for that number of LU we will need 2
trucks of this type for each receiving day.
Due to the low Truck Rate, it has been decided to use one dock for RMS.
Number of Workers:
The total number of workers is obtained considering:
• Number of internal logistic worker: 1 driver each FLT and 1 supervisor to assist the
forklift drivers with their operations.
• Number of operators dedicated to production: 1 worker per WS + 1 supervisor every 4
lines.

39. 39
12. Internal Logistics – Finished Product Storage
Number of Forklifts Required:
Same forklifts have been used with the raw material
storage. To calculate number of forklifts required for the
finished product warehouse operations, the number of
hairdryers on each pallet is required and it is 128. Using
this number products per hour can be obtained as 905.2 and therefore the total required Handling
Capacity can be found as 7 LU/h. Assuming safety factor (k) as 1.2, total number of forklifts
required can be found as 1, which is equal to the number of forklifts required in RMS. Including
assembly to testing, testing to packaging, packaging to FPW, and FPW to docs, the total amount
of forklifts can be found as 4.
Actual Handling Capacity:
Actual Handling capacity of the warehouse is calculated by the following formula,
As HC(act) > HC, the number of forklifts required has been found as 0.64. Therefore, HC (act) =
13 LU/h

40. 40
Internal Logistic Operators:
To efficiently operate the warehouse and controlling the load on each operator, one forklift
operator per forklift can be used to carry the stocking and retrieving of load units from
warehouse and one supervisor for both products to oversee and assist the forklift drivers with
their operations. Also, there is 47 workstations in testing and 12 workstations in packaging area,
so there will be 1 operator for each workstation and 1 supervisor for every 6 operators to assist
the operators and make sure the material flow is correct.
13. Study of Material Manual Handling
The NIOSH Lifting Equation is implemented to assess the risk associated with the lifting and
lowering actions that are done by workers to move the boxes from the pallets that come from raw
material storage to the workstation defined in the previous step 8. The primary parameter of the
NIOSH method is the RWL (Recommended Weight Limit) which defines the maximum
acceptable load that nearly all healthy workers could lift in an 8-hour shift without increasing the
risk to injure the lower back. Several more parameters must be considered in order to employ the
NIOSH method.
First and foremost, the weight of each box that the worker will manually handle must be under
25 kg (maximum load a worker can carry) according to EU regulations. So, the load constant LC
will be equal to 25 in our calculations. Odette boxes that contain quantities such as back body
etc. are heavier because they contain more units or heavier components so they should be splitted
in pieces to be lower than 25.
The safety conditions are below:
1- LI < 1,25
2- LC = 25
With this in mind, we will be implementing the NIOSH method to the selected odette boxes.
Step 1. Measuring Task Variables and Determining Multipliers:

41. 41
Horizontal locations are obtained through an experimental calculation. The worker takes the box
from the pallet and moves 25 cm horizontally to arrive to the workstation. Using the horizontal
multiplier table below, HM is found and will be implemented in the data tables.
Vertical locations are calculated by using the defined Odette boxes dimensions and the EU pallet
dimensions. Initial vertical locations will contain the height of the pallet (15 cm). The operator
unloads the boxes onto the workstation which has a fixed height of 73 cm. Every variable row
location can be found in the tables above. Vertical multiplier VM is obtained through the
equation below:
VM = 1 − |0,003 ∗ (V − 75)| if V < 175cm
For the vertical travel distance multiplier DM, another equation must be adopted:
DM = 0,82 +
4,5
D
if D < 175 cm

42. 42
As for the asymmetric angle (A), there are no trunk twists during the operation, starting angle
and finishing angle are both equal to 0 deg so the asymmetric multiplier AM = 1.
For the frequency of the actions calculations, we need to move 256 type 1, 48 type 2 and 468
type 3 boxes.
The duration of the activity lasts an hour, so the duration is considered as short.
Our defined Odette boxes have a good coupling to reduce the maximum grasp forces required.
As the boxes have an optimal design with handles, coupling multiplier CM = 1.
Final data tables are shown as below:

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Step 2. Calculation of Frequency Independent Recommended Weight Limit for each Subtask

44. 44
Step 3. Calculation of Recommended Limit Weight of each Subtask
Step 4. Calculation of the Lift Index for each Frequency Independent Subtask (FILI)

45. 45
Step 5. Calculation of the Lifting Index for each Subtask

46. 46
Step 6. Calculate Variable Lifting Index VLI
Each of the Variable Lifting Indexes are lower than 1.25 so that signifies that the design of the
lifting and lowering actions are considered safe, risk of the worker’s health should be minimal.

47. 47
14. Plant Layout Description
Understanding what the best configuration for the plant would be in terms of operations direction
was the first step in designing the layout. Due to the combination of four independent assembly
sections (totally 15 assembly lines) within a single building, it was critical that there be a good
amount of flexibility and a moderate degree of simplicity, allowing the business owners to fix
potential problems more easily in the production line. While designing layout things we were
careful about:
● Minimum area possible for plant,
● Accessibility to every unit of plant easily,
● Less length of roads for forklift trucks,
● Most efficient flow shape,
● Safety, traffic less and less accident rate (wide aisle and worker areas at
workstations)
● Offices are easy-to-access areas of the plant,
● Less base areas for storage, more base areas for workers.
● Using height for storage beside the base area.
●
Considering these U-flow was the best solution for our plant according to our minimum areas for
assembly, testing, packing and storage and with that CAD sketch of 1:250 scale is drawn.
The “Unloading Area” is the first stop, where raw material pallets are unloaded from the vehicles
that are transporting them. The amount of truck parking spots is made one and common with
FPS because of the daily demand and quantity of pallets required to be received on receiving
days, as well as the time at which said trucks are there for hairdryers. Since just four trucks are
used per day (2RMS - 2FPS) and it takes 45 minutes to load or unload a truck, one doc is
sufficient for both locations. These parking spaces are conveniently located outside of the main
building, at the beginning and end of the building, where the flow of operations begins. Because
of its location, where the truck road is located (the entrance), this truck slot does not affect
buildings area notably.
Second stop is the “Raw Material Storage”. After being unloaded from the trucks, raw material
pallets are stored here. Fishbone storage is the type of storage for this facility. Push back racks
are used for this storage because of its advantages, which are:
● Higher density,
● Compatible with a standard forklift,
● Faster loading and unloading than other systems,
● Easier stock rotation,
● Reduced stock damage,
● Saves up to 90% of warehouse space compared to traditional pallet racking.

48. 48
Main aisle width is 4.88 according to turning radius, pallet dimension passing forklift fork and
clearance (12 inch). The total area of this facility is 550.7 m2
(32.47 x 16.96) [width x length].
Height of this storage area is 7.9 which is enough for a 6-level rack with load units and
clearances.
Third stop is assembly lines, totally containing 15 lines, 58 workstations each workstation with 1
operator. At the beginning of each area of production (basic, standard, luxury, mixed) there is an
area for picking area (pallets). There is 1m of workspace for workers to move safely. This
facility is positioned close to raw material storage and the shortest road possible is designed. The
proximity is necessary to allow operations to be more efficient. But also, lines are divided to two
for ease of distribution and collection of products.
Fourth and fifth stops are testing and packaging areas. Same desk and workstation designs used
as in assembly, but the difference is pallet area is taken to the back side of workers area because
testing and packing lines need to contain more pallets at each line. Pallet trucks can be used to
move pallets inside the workstations or to carry tested products to packaging stations which are
at the end of line.
Last but not least, sixth stop is the finished product storage, where finished products are stored
and after when needed loaded to trucks to ship 3 times a week, 2 trucks each(for FPS) according
to our demand. Facility is placed right next to raw material storage to use a 2 dock there should
be 18m maneuvering space since docks are away from each other. Also, length of the other
facilities is the most proper to this design to make occupied area less. Drive through racks are
used at this storage. Since drive through is selected, a hybrid model of fishbone and hair comb is
used as a layout. Drive-through racks are used for this storage because of its advantages, which
are:
● Warehouse space optimization,
● High-density storage,
● Easy to move, change the structure, and upgrade as needed,
● Great for storing a large number of homogenous materials,
● Low maintenance and low assembly costs.
1 main aisle width is 4.88, 1 main aisle width is 6.33(truck uploading side) and 1 secondary aisle
width is 3.43. The total area of the facility is 475.18 m2
(24.97 x 19.03) [width x length]. Height
of this storage area is 8.9 which is enough for a 6-level rack with load units and clearances. This
facility is enlarged just a bit from aisles to use the same wall as the RMS facility.
Offices are placed to a location to easily access storage, testing-packing and assembly areas, so
that they can manage and interfere problems at lines.
Bathroom has capacity of 9 people.

49. 49
First aid room and canteen placed at the bottom part where nothing placed for production so that
it doesn’t block the product area and they are both close to production, storages, and offices.
Also, it can be accessed easily with the main aisle.
Parking spots for workers are placed outside of the plant. Having looked at each facility
individually, the complete layout of the plant is constructed. The final plant layout is attached at
the end of the report. Related calculation tables for the layout placed below.
RMS DIMENSIONS
FPS DIMENSIONS

50. 50

51. 51
15. Plant Drawing