ASSEMBLY LINE WORK-FLOW ANALASYS AND OPTIMIZATION
A Graduate Research
Submitted to the College of Graduate Studies
Texas A&M University-Kingsville
In Partial fulfilment of the requirement for the degree of
MASTER OF SCIENCES
Major Subject: Industrial Management and Technology
Assembly line work-flow analysis and optimization
Deepak Salagala, B. Tech., Amrita School of Engineering
Chairman of Advisory committee: Dr. Farzin Heidari
The Secondary sector of Industries basically processes raw material from the primary sector of Industries and converts them to manufactured goods and products. This sector is diverse with numerous varieties including the automotive industry, shipbuilding, machinery manufacturing, etc. which are high capital-intensive among heavy manufacturing. Then comes textiles, household electric appliances, plastic industry etc. which are less capital-intensive but high labor-intensive under light manufacturing. The secondary sector also includes oil refining, construction, food processing etc. Such industries usually include various professionals, and technicians with different background of study based on the type of industry. This project focuses on observing high labor-intense issues of light manufacturing, which is one of the corner stones of any industry generally. They have a continuous, repetitive, and sometimes tedious work all day every day! They may be technicians, assemblers, packers, warehouse workers, drivers etc. This is an attempt to make their work-life easier by analyzing the work of production assemblers, by working as one of them, analyzing the work pattern, looking for any factors with potential to decrease individual efficiency, breaking down issues related to ergonomics, and looking for any methods that could help to increase individual efficiencies and moral.
TABLE OF CONTENT
TABLE OF CONTENTS………………………………………………………………………… iii
o Assembly line Balancing, development and trends………………………………………….3
Industries are one of the three main sectors which decide Gross domestic product (GDP) of many countries, alongside Agriculture and Services. The sector with highest contribution for GDP is Service sector followed by the Industrial sector and Agricultural sector According to CIA’s world factbook’s survey report up to 2017, in 2015 about 30.5% or 22,979.832 billion USD of world’s nominal GDP was contributed by Industries and the rest of it by Agriculture (5.9% or 4,437.549 billion USD) and Services (63.6% or 47,835.275 billion USD). The top three countries with the highest percentage of contribution to GDP by Industrial sector in 2017 were the United Arab Emirates (49.80% of country’s GDP or 186.32 Billion USD), Saudi Arabia (44.20% of country’s GDP or 299.90 Billion USD), and Indonesia (40.30% of country’s GDP or 407.39 Billion USD). The top three countries with highest revenue by Industrial sector to contribute for GDP in 2017 were China (4715.35 Billion UDS or 36.50% of country’s GDP), The Unites states of America (3659.44 or 18.90% of country’s GDP), and Japan (1450.70 Billion USD or 26.90% of country’s GDP).
There are four essential sectors, three of which are major factors in contribution of GDP of almost all countries.
1) Agriculture Sector or Primary Sector: with agriculture it also is around extraction, supplying the raw material of natural products. Example: mining, quarrying, oil extraction, iron ore etc.
2) Industrial Sector or Secondary Sector: the starting point of these industries is raw material, infrastructure, methods, human, money where the raw material is converted to goods through various processing. Example: Automobile industry.
3) Service industry or Tertiary Sector: These are responsible for a smooth run for all other industries. Example: hospitals, restaurants, banks, etc.
4) Quaternary Sector: This sector involves people of high qualification who work around research, development, engineering, technology etc.
The manufacturing is a major part of the goods-producing industries under the Industrial sector. It mainly has two different classifications, which are heavy manufacturing and light manufacturing which can be defined by the type of investment, equipment used, and work load on every individual employee, according to The Bureau of Labor Statistics (BLS) The Manufacturing sector comprises establishments engaged in the mechanical, physical, or chemical transformation of materials, substances, or components into new products. Establishments in the Manufacturing sector are often described as plants, factories, or mills and characteristically use power-driven machines and materials-handling equipment. However, establishments that transform materials or substances into new products by hand or in the worker’s home and those engaged in selling to the general public products made on the same premises from which they are sold, such as bakeries, candy stores, and custom tailors, may also be included in this sector. Manufacturing establishments may process materials or may contract with other establishments to process their materials for them. Both types of establishments are included in manufacturing.
There are four types of labor:
1) Unskilled labor: These are the group of workers who generally work with their hands and without any training or skill, these workers generally have the least amount of capital invested in them; they are usually the lowest income group. Ex: staff who mop floors.
2) Semi-skilled labor: These workers generally are little more skilled than the unskilled labor with enough mechanical abilities, skills to operate machinery, they can operate basic equipment and have a higher wage compared to unskilled workers. Ex: production assembler.
3) Skilled labor: These workers can operate complex equipment. They can complete their tasks with slight supervision. They receive an increased human capital, especially in areas like training and education which in turn fetch higher wages. Ex: welder.
4) Professional labor: These are the highest level of knowledge-based education and managerial skills. These people are usually professional and have invested the most in their careers which makes them the highest wage earners. Ex: Manufacturing engineer.
To meet high and continuous demand companies must have their manufacturing unit working with maximum efficiency, i.e. 24/7 with well-planned quarterly or annually maintenance breaks. Unskilled labor and professional labor play a crucial role in maintenance and technical support, typically during regular office hours. But, when it comes to semi-skilled labor and skilled labor they work according to their shift with three different batches working eight hours each, helping a manufacturing unit to run twenty-four hours. The difficulty level with respect to physical effort for unskilled and semiskilled labor would be higher compared to skilled and professional labor. Specially, semi-skilled workers in manufacturing industries typically have a continuous and repetitive work. The next chapter will be deeper retrospection of factors like assembly line, ergonomics related to manufacturing units and semiskilled workers majorly.
REVIEW OF LITERATURE
Assembly line Balancing, development and trends:
According to the research done by Naveen Kumar & Dalgobind Mahto in year 2013 the main aim of this review is to minimize the workload or workers and to achieve desired output through assembly lines. By following the above mentioned models it will also make work ergonomically adaptive to employees while reaching the desired goals by maximizing production and minimizing the work stations.
Line Balancing: It is distribution of work evenly, to minimize the idle time to man to machine, grouping the workers in a most efficient way to have the most effective flow of assembly production.
Assembly-line balancing: It is a process assigned from a workstation in a serial production system. It is a process of elements required to convert raw materials to finished goods. Line balancing is one of the most significant optimization techniques in industry for a lean system. It is a technique in which various identical and interchangeable parts are assembled into a final component at different work stations. Task allocation to each worker is done to achieve a higher production rate is achieved by assembly line balancing.
Single-line Assembly line: The assembly of the product is done in the same line and it won’t alternate the setup or substantial setup and the time that is used. This assembly system is known as Single Model Line.
Mixed model assembly line: It is the type of the assembly line where workers work on the same assembly line with different models. The setup time between the models would be decreased sufficiently and enough to be ignored. So, this internal mixed model determines the assembled on the same line, this kind of assembly line is called mixed model assembly line.
Multi model Assembly line: In this type of assembly line different models will be grouped together to reduce the time and money, it allows for the short-term lot-sizing issues which made in groups, this type of assembly line is called multi model assembly line.
Non-Valued added costs:
These are the factors which effect overall efficiency.
1. Cost from over production: It takes a lot of money and effort for production. There is no need of production of items which are not sold and producing an item lot before it is required. This must be minimized.
2. Excess inventory costs: A high inventory cost is not beneficial for any company. Costs associated with the inventory are space, obsolescence, damage, opportunity cost, lagged defect detection and handling. Excess inventory cost must be eliminated.
3. Processing cost: Product which has value from a customer point of view is considered non-value-added processing. This type of processing must be eliminated. Quality and inspection expenditure, service to the customer, warranty cost and loss of customer fidelity are the type of cost associated with this.
4. Transportation cost: Material movement is a significant factor associated with non-added value cost. This requires a huge amount in terms of storage and material tracking. This does not add any value to the final product. This kind of cost can be reduced.
5. Motion: Any type of motion that does not add any value to the product or service is a non-valued cost. This can be reduced. Extra product handling and heavy conveyer usage fall under this category.
6. Waiting: The time spent in waiting for raw material from preceding work station, and machine down time are a few of the things that contribute to waiting time.
Terms in line balancing technique: Cycle time, lead time, bottleneck, precedence, idle time, productivity, smoothness index and balance delay.
According to research done by U.S Department of Labor, Occupational Safety and Health Administration (OSHA) in year 2000, A good ergonomics training program can help employees how to properly use equipment, machine controls and tools as well as know the correct way to perform job tasks. For example, employers should stimulate work methods that allow workers to keep their joints in a neutral position, wrists straight and elbows bent at a right angle while using tools requiring manual force to prevent unnecessary force on joints and tendons. Employers also should tell employees to avoid all side-to-side twisting and quick motions of their wrists and to keep their hands in line with their forearms while using tools or operating equipment. Employers should provide the appropriate controls or tools, as required, to reduce or eliminate difficult positions.
Ergonomics: It is a study of people’s efficiency in a work environment. More specifically ergonomics is the science of designing the work place to fit to the worker rather than physically the body to work. Designing tools, work stations and equipment to fit for the worker’s body can benefit by reducing much potentially serious, restricting work related musculoskeletal disorders (MSDs).
Importance of ergonomics: To survive in today’s competitive industrial world, industries need to have high production rates and advanced technology, for this to be achieved they need workers to work for more than eight hours a day, which includes frequent lifting, pulling, carrying and pushing of heavy objects without any help of a person or a device, working at a higher pace such as in a faster assembly line and handling tighter grips without using any kind of tools. If of all these things are combined with poor machinery, improper tools can create a lot of physical stress to the body and can lead to injury.
An increase in MSDs began in the 1970’s when these kinds of disorders started to appear on company’s illness logs. OSHA observed such companies where workers suffered with such disorders. The BLS has recognized MSDs as serious health hazards.
Musculoskeletal disorders (MSDs): MSDs are the type of disorders related to muscles, ligaments, joints, cartilage and tendons. Body parts affected by MSDs are mostly arms, fingers, hands, neck, back, wrist, legs and shoulders, although most affected body parts are arms and back. These pains can gradually develop from weeks, months and years. Prolonged exposure to ergonomic risk factor can lead to work related MSDs. Excessive movement, awkward posture, increased speed or acceleration can lead to these kinds of MSDs. Non -related work factors like obesity, arthritis, pregnancy, physiological and mental stress can also lead to MSDs. Numbness in fingers, numbness in tights, difficulty to move fingers, back pain can be the signs of work related MSDs. Treatment to these can be very expensive along with taking off from work. This problem can be rectified with simple and inexpensive ergonomic solutions, like adjusting the height of the work station to worker surface, supplying anti-fatigue masks, reducing weight and size of the items the workers lift, supplying right tools for the job and right handler for the worker. Good ergonomics is good economics.
How Ergonomics help work place: Making work place free of ergonomic hazards can have its own advantages, lower injury rate, increase productivity, improve product quality because of less errors, improve work safety, and increase worker comfort. Ergonomic hazards can be prevented by educating workers with ergonomic program, providing and encouraging the workers to participate in ergonomic programs and encourage the employees to provide a feedback if they have any ergonomic related problems. An effective ergonomic program includes management commitment and employee participation, job hazard analysis, controlling ergonomic risk, MSD management and training educating the employees.
ASSEMBLY LINE OF SMALL MEDICAL EQUIPMENT
Type of manufacturing plant:
The manufacturing plant is into manufacturing equipment used in fields like biopharmaceuticals, health sciences, pharmaceuticals etc. the jobs completed are used for experimenting, research, testing, medical purposes for human/ animals. Therefore cleanliness and quality is the top most priority. Major material used is plastic and rubber, though most of them are disposable there is also use of grade 2 plastics as some of the equipment is recycled. Following are some of the applications where the manufactured products are used.
According to Vijay Singh, Ph.D. of wave biotech, the usage of large manufacturing facilities dedicated to a single product production is not very popular these days, the urge and demand for biosimilar products for monoclonal antibodies have put a pressure on manufactures to produce products at lower costs. Single-use technologies and continuous upstream processes have proven to be cost-efficient options to increase biomass production.
Single Use: Disposable sterile means no cleaning, cross contamination or validation. Cells contact only disposable sterile biocompatible plastics. All materials conform to USP Class VI and ISO 10993.
Closed System: These are mainly used for current good manufacturing practice (CGMP) primarily around commercial production. Cell bag bioreactors, including all fittings and filters, are delivered sterile and ready for use. No biosafety cabinet is required for inoculation or sampling.
Versatile: Numerous instrument configurations specifically designed for suspension, micro-carrier, batch, and fed-batch or perfusion culture.
Scalable: Due to inherently limited mass transfer surface area Spinners, roller bottles, and similar systems are not scalable. Scalable products are being produced.
Advantages of single use biomedical bioreactors:
• Cost reduction
• Increase in productivity
• Easy disposable
• Less energy demand and water use
• Time savings
• Reduction risk of cross contamination
According to Global newswire till May 2017, Bioreactors are one of the most commonly used in the biologics industry; there are two main types of bioreactors, multiple-use which is made by stainless steel and single-use bioreactors which are usually disposable. This means there could be a lot of demand; it obviously attracts lot of man power and continuous production.
Bioreactor market size is expected to exceed 1.9 Billion USD by 2024; according to a new research report by Global Market Insights, Inc. Growing chronic disease frequency and increasing research in the field of biopharmaceuticals will affect the global bioreactor market size.
The evaluation of personalized medicines has changed the way many diseases are identified, classified, and treated. The increase of personalized medicine popularity in market, involves a certain group of population that will further drive the bioreactor market size.
According to, Global Demand of Global Blood Tubing Set Market Research Report 2018 Analysis, Competitive Strategies, Regional Outlook and Forecast, Tubing sets can be of many types, depending on the type of usage of tubing set they might be long or thin or thick tube, with nozzle on both the ends. There are different types in them like blood tubing set; IV tubing set are some of the examples.
The blood tubing sets are mostly used to transport blood or fluids to a patient’s vascular access device from a hemodialysis.
The global average price of Blood Tubing Set has been decreasing, from 3.42 USD/Unit in 2013 to 3.02 USD/Unit in 2018. With this happening the global economy, prices will be in decreasing in the following five years.
The proportion of blood tubing set used for adults in 2017 is about 87%, it includes adults and kid’s usage of tubing sets.
Blood Tubing Set is commonly used in Dialysis Center and Hospital & Clinic. The most part of Blood Tubing Set is used in dialysis center, and the proportion in 2017 is 69%.
The global Blood Tubing Set market is valued at 1620 million US$ in 2017 and will reach 2640 million US$ by the end of 2025, growing at a CAGR of 6.3% during 2018-2025.
Single used bioreactors
Single-use bioreactors are commonly used in the field of mammalian cell culture and are now quickly replacing conventional bioreactors. As a replacement for the culture vessel made from stainless steel or glass, a single-use bioreactor is equipped with a disposable bag. These disposable bags are usually made of a three-layer plastic foil. One layer is made from Polyethylene terephthalate or LDPE to provide mechanical stability. A second layer made using PVA or PVC acts as a gas barrier. Finally, a contact layer is made from PVA or PP.
As most of the bioreactors single use bioreactors all bioreactors are single use, the demand for these kinds of reactors is also very huge. Complex in nature as there can be sub assembly’s which can lead to longer lead time which means there will be a requirement of man power, as automation can be difficult for such integrates assembly and man power is essential it includes production assembler who are semi-skilled labor, quality inspectors and supervisor who are skilled workers are required at the assembly line, to manufacture individual parts before assembly there may be skilled labor involved.
Essential sections in the manufacturing plant I worked:
The plant contains manufacturing unit up to 70% of the place, rest of the area is used to accommodate various departments like human resources department, customer service department, sales department, research and development department, then, drafters, manufacturing engineers, site leaders, conference rooms, etc. The manufacturing unit comprises of three main sections, they are airlock, warehouse, and clean rooms. These are well planned to be able to provide a smooth and minimal travel distance of the jobs to avoid any delay or complicated travel of jobs. Airlock room is directly accessible to three of four cleanrooms, warehouse waiting compartment. This planning helps the completed jobs to have a smooth flow from cleanrooms through airlock room to warehouse.
Airlock room: This is the inventory of major supplies used by the production assemblers. Up to 30 varieties of packing bags, cable tie tension cutters, scissors, measuring tapes, paper work related to the individual jobs, different types of cable ties, Isopropyl alcohol, it also consists of a segment where the rest of waste from all the cleanrooms is placed, it is well maintained by emptying and cleaning periodically each day.
Clean rooms: These are the places where some of the parts are made and jobs are assembled. There are three types of clean rooms. First type of clean room contains skilled workers who convert raw plastic sheets in to plastic bags of desired sizes and shapes i.e. according to the job requirement. On each working site there will be one skilled worker, they operate semi-automatic machines and/ or monitor automatic machines. These parts with all required other parts are sent to the second or third type of clean room; these clean rooms are essentially for assembling the parts of individual jobs. Major difference between second and third clean rooms is that they assemble three-dimensional and two-dimensional jobs respectively.
Warehouse: The completed jobs from the clean rooms are sent in bins through airlock room to the warehouse waiting compartment, all the bins and jobs are labeled after packing, and it gives the warehouse worker a clear picture of the place to store the completed job in the warehouse. Warehouse comprises of very tall racks up to thirty feet with different compartments, all the jobs are arranged in such a way which avoid unnecessary movements and be efficient. Warehouse is the final place for the job to be in the manufacturing plant, after which the completed jobs in the bins are moved to the shipment containers and the containers are shipped through road to designated places.
Flow from raw material to finished product:
Parts acquisition: Assembly unit is the center for all job completions in this particular plant. Here, Parts for assembly are attained in two ways.
One way is acquiring specific parts for the job through various suppliers; these usually include parts with intricate shapes and are complexity in their manufacturing methods. In order to meet the due dates of the jobs of the client these parts required to be ordered in a planned and organized way beforehand with standard supplier or suppliers who do not compromise on quality, deliver with optimum speed. They should be top in reliability. As most of the jobs are used in fields like biopharmaceuticals, tubing sets for research, or can be used for human medical purposes the quality need to be in a premium level.
The second way to attain parts is self-manufacturing them; typically these are the majorly used parts. They are connectors, tubes and bags. These are used in every single job one way or the other. So, for the fabrication of essential parts like plastic bags raw material is received in rolls of plastic; prefabricated long tubes of different diameters are received based on the requirement through tube cutting tubes of specified length and specified count are made individually for jobs as required
Assembly-line to warehouse functioning: Each job is individually assigned to corresponding supervisor depending on the job priority; the assigned job’s blue print is distributed to each member of the group, every member need to get a full understanding of the job assembly about to perform, a group consists of five to eight people depending on the availability and requirement.
After which group members will pick parts from job’s bin which contains all parts, count the parts and start assembling according to the requirement under the guidance and thorough monitoring of the supervisor.
Then Quality inspector or Quality control looks in each and every job carefully and keep a track of number of jobs passed the quality check, any job which needs rework is disqualified and sent back to rework, this can effect efficiency, so supervisor’s try to .
All the jobs qualified in quality inspection are sent for packing. Depending on the sensitive parts of the job bubble wrap is used before packing in the plastic bags; the size of plastic bag used for packing is different for different sizes of the job.
The Packed jobs are now sealed by either a vacuum sealing machine or hydraulic sealing machine by the group members and labeled.
These jobs are finally checked by the supervisor and placed in a storage come shipment bin, after all the jobs are completed and count of the quality inspector is matching the number of jobs to be assembled; the shipment bins which have wheels beneath are moved to warehouse waiting compartment from where the warehouse worker will be storing the bin in designated are, the information about the designated area is retrieved when warehouse worker scans the label on the storage come shipment bin.