Since it is decided how many tables need to be manufacture in one year and assumed all the tables who are manufactured are sold, then no strategies have to be made regarding maximising sales. However, a clarification was made of goals, methods to achieve those goals and the result to have an overview of what is needed to make this manufacturing work.
To make a feasible goal, “S.M.A.R.T.” goal setting, was used as an assisting tool. To make a goal, using this method, there are five things that need to be taken in account. The goal needs to be specific, measurable, attainable, have a responsible controller and the time has to be specific.(Ballowe 2016) The result of the goal is: “The manufacturer will manufacture 20,000 desks in one year with safe working environment and meeting customer requirements as a guideline.”
Methods are the activities and tasks that need to be done in order to achieve the goal. Solutions for the methods are stated, which gives an idea of what the manufacturing has to contain in order to achieve the goal. Methods and matching solutions are stated in the table below:
Methods
Solutions
Process types
Batch flow
Transportation equipment
Conveyor belts and electric pallet lifters
Product variations
Standards, laws and customer requirements
Working environment
Ergonomics and laws
Physical environment
Mixed manual and automatic workstations
Efficient layout
Cell layout
6. Designing the overall layout of the manufacturing section
This chapter will handle the choice of flow within the manufacturing. Thereafter the design and the most optimal layout for the manufacturing process will be explained to find out the most ideal way to place each working station. Next the ergonomics will be stated for the manufacturing process. That will help with finding out how to design each workstation with the employees welfare in mind. After that, time studies that have been made are clarified. Lastly, every workstation in the manufacturing process will be thoroughly explained, where everything previously stated will be taken in account.
6.1 One piece or batch flow
The difference between one-piece flow and batch flow is when manufacturing in one-piece flow the manufacturing of the products will be faster and the utility of the facilities is better, because all the workstations are working at the same time. If manufacturing in batches, one batch with a number of products will be manufactured together, so when the first product in a batch is finished at the first workstation, it will have to wait for the rest of the products in the batch to finish. So, with a one-piece flow the manufacturing is able to manufacture faster than if done in batches. Another fact about the one-piece flow is that manufacturing problems can be detected early, because when the first desk is made inspectors can see if there are any mistakes about the desk and then adjust the manufacturing (Flowmotion 2016)
An advantage about batch flow is that you in most cases do not need as many employees as if having a one-piece flow, because not all the workstations are manufacturing at the same time. A batch flow can also be a more convenient way of working for the employees because they are not doing continuous work all the time. If the production only had full automatic workstations we would not have to consider if the work is to continuous and the speed being too fast for the employees. The manufacturing include manual working so it is necessary to have that in consideration when designing the flow and workstations.
Decision has been made to use batch flow because the production of 20.000 table a year, is not a big enough production to use the one-piece flow and that will not be economically correct. The batch flow will be more convenient because it requires fewer employees which makes the economic aspect more correct. Also the machines will be more expensive in one-piece flow because we would have to use full automatic machines in some stations and they are over twice as expensive as semi-automatic machines( Expert advice Morten Søndergaard from KJV).
The powder coating process will be outsourced, and the batch flow will work efficiently with outsourcing that process, because then the production can focus on manufacturing the other components while the table frames are being powder coated. Now moving on to the overall layout with this information in mind.
6.2 Overall layout
There are three decisions to make when designing the layout: How should the operation or process be positioned to its transforming resources, how are the various tasks allocated to these transforming resources and at last the general appearance of the transforming resources. It is important to make the right decisions regarding this, because it can cause a lot of disruptions if the layout fails (Slack 2016, p. 226)
There are four basic layout types, which are generally used: The fixed-position layout, the product/line layout, the cell layout and the functional/process layout. Often these different types of layouts are mixed with each other within the layout to make the best performing layout. Table XX below shows how different types of manufacturing processes are matched with a potential layout type. The manufacturing of the student desks will be operated in batches, therefore the range of layout types will be delimited to the functional/process layout and the cell layout (Slack 2016, p. 220). In the next section it will be discussed which type of layout suits this manufacturing and why it will be chosen.
6.2.1 Functional layout
In a functional layout, similar resources or processes are located together. It can be convenient to group them together, for example in a supermarket it is convenient to group all the frozen groceries together in one area with freezer cabinets. In this way the utilisation of transforming resources is improved.
Operation products, information or customers flow from one activity to another activity through the process, according to their different needs. Different customers/products will have different needs and therefore make a different route through the operation. This makes the functional layout flow pattern very complex to make.
A functional layout is characterized by having a lot of options and being combinatorially complex, meaning there are many alternative layouts. Before making a functional layout the designer needs to know a few things:
How much space each workstations needs,
If there are any constraints on the shape of the area for each workstation,
The direction of the flow and the degree of flow between every workstation,
How important it is for some workstations to be located close to each other or to some fixed points
A flow record chart is usually used to show the degree and direction of the flow in the layout (Slack 2016, p. 222, 235-338).
The advantages about this layout is the high mix and product flexibility. The layout is relatively robust in the case of disruptions and it is easy for the employees to supervise the resources being transformed (Slack 2016, p. 229).
The disadvantages about this layout is that the utilization of the facilities is low and it can give the manufacturing a high work-in-progress. Finally, the complexity of the flow can be quite hard to control (Slack 2016, p. 229)
6.2.2 Cell layout
In a cell layout you pre-select the transformed resources entering the operation or they pre-select themselves. Then they move on to one part of the operation (to meet their immediate processing needs) in which all the transforming resources are located. A cell layout is arranged either as a functional or a line layout. After the product has been processed in one cell the transformed resources may go on to another cell. A cell layout tries to order the flow and make it less complex. This is also where it distances itself from the functional layout. A cell layout is often associated with a manufacturing(Slack 2016, p. 223).
Techniques such as production flow analysis can be used to allocate products to cells. Components are grouped into families of components and the machines are given numbers. Then in the matrix components and machines are grouped together so it matches their different needs. This way, cells can be made with the components and machines which matches each others’ needs. But this is not a clear method, because not all of the machines will always fit into the grouped cells. When this happens you make something like a mini-functional layout also called a remainder cell. This cell will remove the inconvenient components from the rest of the operation leaving it with a better and more ordered flow (Slack 2016, p. 238-239)
The advantages about the cell layout is the fast throughput rate and how it can ensure the good working environment. It is also easier to train the employees, because there are not a lot of different tasks(Slack 2016, p. 229).
The disadvantages about this type of layout is the high costs of rearranging the layout. It also requires more machines or equipment, because each cell is dedicated to one component and in the same way that can give a low utilisation of the machines and equipment (Slack 2016, p. 229)
6.2.3 What type of layout will be chosen?
Choosing the type of layout will mainly depend on the level of volume and variety in the manufacturing. This manufacturing is characterized by low volume and low variety and the desks are manufactured in batches of 30, which is relatively small batches. Because the desks are manufactured in small batches of 30 an option would be to make a functional layout, because of the small number of similar products being produced, but there will not be manufactured any other products, so the machines do not need the high level of flexibility, which a functional layout gives. If our batches were larger a line layout would be more efficient, but when they are not, a cell layout will be sufficient. It should also be mentioned that a functional layout is the best fit for a low volume high variety manufacturing and a cell layout is the best fit for a high volume low variety manufacturing. As said this manufacturing is characterized by low volume and low variety, so none of the basic layout types suits this manufacturing perfect (Slack, 2016, p. 226)
A reason for choosing the cell layout is that the product has two main components, where some of their processes are very different, which makes it impossible to use the same machines. This means that these two components requires their own machines. Therefore, it would be convenient to position them in two cells with their own machines. It would be possible to find a machine, which can both cut particle boards and steel, but it will be more advanced than having two machines for each.
Using the cell layout will also decrease the throughput time compared to the functional layout and in that way it is possible to achieve a faster delivery time. Furthermore, the working environment will be good and positive in a cell layout and it is also easier to train the employees, because the range of different tasks is low(Haganäs 1977, p. 24).
The final aspect of this decision, is the future needs and requirements of the layout. If the functional layout will be chosen, the manufacturing will be able to expand with new products and easily implement them in the future, because the functional layout is easier to redesign compared to the cell layout(Slack 2016, p. 229).
To conclude, there are not a specific layout type which suits this manufacturing perfect and therefore one layout type will be chosen because of the advantages it can give this manufacturing. Considering the customer segment it has been assumed that they require a fast delivery time on 5 working days, by choosing the cell layout this will be possible for the manufacturing to achieve. Also it will be easier to manufacture the desk, because the machines can be chosen to the specific product, because they will not have to be flexible and it will make the overall layout less complex and easier to supervise. The last benefit of choosing the cell layout is also the good positive working environment. This will be the arguments for designing the overall layout as a cell layout.
6.3 The layout
A part of Knut Haganäs’ theory about the four phases of factory planning will be used to design the layout: Parts of the “main plan” and the “detailed plan”. The main plan includes the size, form and position of every department in the factory. The detailed plan includes the position of each workstation and the design of each workstation in details including machines and equipment, which will be looked into in chapter 6.7.
The first step in Haganäs’ method is to make a preparatory analysis: Which components does a finished product contain, which processes are needed to make these components and in which order will these processes be carried out. All these questions have already been answered in previous chapters and they can therefore be put into a table with additional information, which is seen below in table XX.
Function
Department
Comment
Area (m2)
Code
Close to..
Finished products storage
– Products ready for shipment
– Screws
– Leg plugs
?
A
X, F, G
Raw material storage – table top
– Particle boards
– Laminate
?
A1
B, C, X, F
Raw material storage – table frame
– Steel tubes
?
A2
D, E, X, F
Table top cutting
– Panel cut machine
(noise)
12m2
B
A1, C
Table side laminating
– Laminating machine
34m2
C
B, A1, F
Leg/frame cutting/grinding/drilling
– Steel cutting machine
40m2
D
A2, E
Table frame welding
– Welding machine
(Smell)
16m2
E
X, A2
Assemble table components
– Drilling machine
– Rubber head hammer
18m2
F
G, X, A, A1, A2
Packing
– Wrapping machine
16m2
G
F, A
Exit/coating
– Shipping and receiving gates
–
X
A, F, E, A2, A1
With this information a figure has been made placing the departments according to their needs. This is shown in figure XX below here.
So, the first drawing of the layout has been made placing the workstations after their internal relations, which were illustrated in table XX. This has resulted in making three shipping and receiving gates, so each storage are close to a gate. As seen in figure XX, three cells have been created. Cell one is for making the table tops, cell two is for cutting and welding the table frames and cell three is for assembling and packing the finished desk. The outputs from cell one and two will meet in cell three, ergo these cells both need to be placed close to the third cell. It should be noted that in this figure the size of the departments have not been taken into account. Therefore a new figure will be made with the right sizes of the departments and a realistic size of the factory including the fact that both cell one and two need to be positioned, so they are close to the start of cell three. It should be noted that the size of the storage departments are unknown, because inventory management has been delimited from this assignment, so it is unknown how much there is stored and how much room the storages take up.
Below here is shown the new figure of the layout. In figure XX departments have been placed in the right direction of the flow, illustrated with arrows, and the figure is made to show a realistic size of the factory. Figure XX has the area of the departments included and the special needs of the departments have also been taken into account. Department B is positioned in the left corner by itself, so the noise from the table saw will not disrupt the workstations around it. Department E will be a ventilated area, because of the welding. It is also illustrated in figure XX where each component is stored before assembly, where the raw materials are stored and where finished products are stored in the factory. Cell one and cell two are also positioned, so they are close to the third cell, as mentioned previously. Inside cell three workstation F and G will be designed as a line layout, because of the way the product will be assembled and packed. This will be elaborated in section 6.7.5 and 6.7.6.
Thus, this layout has been designed taken the pieces of information from table XX into account. Below here the final layout is shown without arrows and explanations in figure XX.
In the next sections of chapter 6, there will be looked more into the detailed design of the layout. How each workstations is designed and how the working environment is secured for the employees. Later on in chapter 7 transport, work cycle, quality management and flow of material and information will be added to the final layout.
6.4 Ergonomics and laws
This factory is located in Denmark, so the danish laws need to be followed when designing work stations and calculating breaks for the employees on our factory.
According to danish law system employees require half an hour break if they are working over five hours a day (HK 2016c). The employees in the factory work full time, so 30 minute breaks need to be calculated for each employee when estimating production time. In Denmark, full time employees work for 37 hours a week, therefore the employees in the manufacturing are required to work a minimum of 37 hours every week.
There are also laws that tell how much weight employees can maximum lift a day, and we need to ensure that our employees doesn’t get any injuries while working. Everything the employees need to lift and carry under 3kg, are not according to the danish law hard lifting, but there are special rules for lifts over 3kg.
The figure above shows how many kilograms and in what positions the employees can lift the equipment, so their bodies does not get damaged. The green area in the bottom shows that the lift is not damaging for the health, but repeatedly lift can be damaging in some cases. The yellow area shows lifts that can be damaging for the employees health, if the lift is not done correctly in the right body position and under the optimal circumstances.
In the red area the lifts that employees makes are unquestionably damaging for their health (HK 2016b).
The danish law system has also implemented a law for the three body positions of lifting showed in the figure above. The first position to the left in the figure, is lifting close to the body and in this position the employees can lift maximum 10 ton a day, when all the weights from different lifts are added together. The position in the middle, where the employees are lifting from around 30 centimeters from the body, the maximum weight the employees can lift a day is 6 ton. The last position to the right in the figure, is a position where the workers are lifting from around 45 centimeters from the body and in this position the employees can lift in a total weight of 3 ton a day.(Arbejdstilsynet 2005)
The lifting positions and laws about how much weight employees can lift a day, is relevant for the manufacturing because the employees are working with materials such as steel and laminated tree. These materials can weigh a lot, therefore these laws need to be known and taken into account when designing the workstations.
The employees also need to wear safety shoes, because they are handling sharp and heavy weight. When the table legs have been cut, the shapes of the pipes is very sharp before being grinded. If a pipe falls down on a worker’s foot then it can cause damage and broken bones. To prevent this damage, the employees need to wear safety shoes with the proved mark “EN 345 S1”. This mark includes safety shoes with hard protection so the workers cannot get injured if they drop a steel pipe on their feets or other sharp and heavy materials. The mark “EN 345 S1” is also proved by the government (Danskerhvervsbeklaedning 2016).
The danish law for noise in a production states that the environment the employee works in, must not be more noisy than 85 decibel if it is under that limit, the employee can work at the station for 8 hours without being affected by noise (HK 2016a).
The welding station in the manufacturing has to fulfill special rules and laws, the ten rules and laws are described below (Industriens Branchearbejdsmiljøråd 2006). When the operator is welding at the station there will be smoke, and therefore a suction is needed at the welding station so the smoke doesn’t get out in the production room. The operator also needs to have a mask with strong glass to protect the eyes from the light and rays. The rays can also damage the operator’s skin so the operator needs to wear cloths and gloves that covers the skin and can resist sparkles from the process. At last the operator at the welding station also needs to have hearing protection because the noise is loud when the operator is operating close up to the welding process.
6.5 Methods of collecting time data
In the manufacturing of the tables, the times in the different processes has to be known so the layout and throughput times can be estimated. To estimate the times in the processes, observation and illustration of the different processes has been made.
Videos from youtube have been very useful, because the videos that have been used to indicate times in the processes have showed the machines worktimes. It has also been taken into account that some youtube videos have been edited so the time in video is faster, therefore youtube videos with real times have only been used to indicate process times.
Table from the group room and loaned Ikea table from another group was used to help calculating missing process times, which could not be found in any youtube video. The Ikea table is very similar to the table in the manufacturing because it has the same dimensions and is being assembled in the same way. The tables were reassembled and a video documentation was made to estimate the exact times. To get the most reliable times, the techniques from “Niels Helner, Tidsstudier, København Teknisk Forlag 1969” was used. The videotape of each station is one long videotape of the processes in the station, this is an ideal method because then the concrete and correct times for the whole station is available and also the times for each processes in the station (Helner, Niels 1969). One of the most important techniques used, was to take times on the operator assembling the table and when the operator’s times did not improve it was known what the fastests time the operator could make the process was achieved (Helner, Niels 1969). Operators were picked from the group to make the different assembling processes. Uncertainty in the times has to be in consideration because a deviation on the times is possible depending on the operator and environment, because experiment of assembling the tables was made in the group room and not in a real factory. Sometimes the environment can affect the times in the processes.
The method used to collect the time data was found by the quantitative method (denstoredanske 2016), where a lot of data in this case times are collected. When using the quantitative method, it is only looked at the time it takes for the operator to do the process and not focused on other factors. So the quantitative method was used because it is ideal for collecting a lot of data and only focusing on specific factors and in this case it was times in the processes.