International Journal of Modern Research in Engineering & Management (IJMREM) ||Volume|| 1||Issue|| 1 ||Pages|| 11-24 ||January- 2018|| ISSN: 2581-4540
Improving maintenance management: Case Study of a Local Textile Company 1
Monageng R, 1Kommula V P, 1Mapfaira H, 1Gandure J, 1Segatlhe B T and 1 Thabano K O H 1
Department of Mechanical Engineering, University of Botswana, Gaborone, P/Bag UB0061, Gaborone, Botswana.
--------------------------------------------------------ABSTRACT-------------------------------------------------The manufacturing sector in Botswana has been rapidly growing in recent times. Maintenance management system plays a vital role in keeping equipment on condition and also major contributor for overall productivity. The current study seeks to improve maintenance management of a local textile case study company with its operations based in Gaborone Botswana. The study sought to assist the organization take advantage of low labor costs and good export policies to manufacture goods for both local and the international markets through effective maintenance management. In order to effectively compete, organizations need to produce quality products and services. In that regard, manufacturers need to reduce redundancy in business processes, redesign products using prime components and increase availability of products and services through provision of effective equipment maintenance. The case study company’s current maintenance management system is simple and not effectively contributing in terms of equipment availability. Through this present work, we were able to develop, document and implement a maintenance management system for the organization.
Keywords: Maintenance management, Maintenance management strategies, Total Productive Maintenance, Maintenance Policy --------------------------------------------------------------------------------------------------------------------------------------Date of Submission: Date, 06 January 2018 Date of Accepted: 25 January 2018 ----------------------------------------------------------------------------------------------------------------------------- ----------
I.
INTRODUCTION
Maintenance has a tremendous impact on any company’s capability to optimize its production system to meet its long-term objectives. Generally, a production system in which maintenance is not given attention produces defective products because of machine defects. Maintenance is defined as activities required or undertaken to conserve as nearly as possible the original condition of an asset or resource while compensating for normal wear and tear (Raju 2011). It can also be defined as actions necessary for retaining or restoring a piece of equipment, machine, or system to the specified operable condition to achieve its maximum useful life (Raju, 2011). Maintenance management is the process of overseeing maintenance resources so that the organization does not experience downtime from broken equipment or waste money on inefficient maintenance procedures. Maintenance management contributes in reducing equipment downtime, improving quality and increasing productivity. The maintenance cost varies from 15 to 70 percent of total production cost due to the high cost of restoring equipment, secondary damage and safety/health hazards inflicted by the failure (O'Connor, 2005). This means if this cost is not managed properly it could easily spiral out of control and lose business. Maintenance management goal is to enhance equipment effectiveness and maximize output. It strives to attain and maintain optimal equipment conditions to prevent unexpected breakdowns, speed losses, and quality defects in process (Islam, et al., 2006). There are several maintenance management strategies which organizations need to be aware of so they can customize to their environment and context. 1.1 Maintenance Management Strategies: Maintenance strategies can be divided into two groups namely planned and unplanned maintenance (Raju, 2011). Figure 1 shows one way of how different maintenance strategies can be categorized and how they can be deployed. Unplanned maintenance activities are generally restricted to correcting an emergency to prevent injury, loss of property or to return an asset to service.
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Improving maintenance management: Case Study‌
According to Ilangkumaran and Kumanan (2009) there are at least four possible alternative maintenance strategies in the textile industry and they are described in below sections 1.1.1 through 1.1.4. Preventive maintenance (PVM) : PM is the utilization of planned and coordinated inspections, adjustments, repairs and replacements in maintaining an equipment or plant. One of the main objectives is to detect any condition that may cause machine failure before such breakdown occurs. This makes it possible to plan and schedule the maintenance work without interruption in production schedule and improves the availability of equipment. Under this maintenance system an extensive inspection of each item of equipment is made at predetermined intervals (Shyjith, et al., 2008). Preventative maintenance involves performing maintenance on a machine before the time of failure. This kind of maintenance avoids loss of productivity due to machine downtime and increased costs due to stoppages in production which could have been avoided (Chan, 2005). PM is based upon the principle that ‘prevention is better than cure’. It is the maintenance carried out at predetermined intervals or according to prescribed criteria and intended to reduce the probability of failure or the degradation of the functioning and the effects limited. It has three types; Running maintenance, Scheduled maintenance and Shut down maintenance (O'Connor, 2005). Predictive Maintenance (PM) : Predictive maintenance involves the prediction of the failure before it occurs, identifying the root cause for those failures symptoms and eliminating those causes before they result in extensive damage of the equipment. The main objective is to predict an impending failure well in time, thus avoiding failures which could cause heavy penalty costs and even safety hazards. This Type of maintenance is performed continuously or at intervals according to the requirements to diagnose and monitor a condition or system (Ralph, 2006). Condition Based Maintenance (CBM) : CBM is maintenance carried out in response to a significant deterioration in a unit or system as indicated by a change in a monitored parameter of the equipment or system based on its condition or performance. CBM is most suited for high capital cost equipment and complex replaceable items and for permanent parts that deteriorate overtime or due to prolonged use. For this purpose, a good knowledge of failure data is necessary for effective implementation of condition-based maintenance and this process involves diagnosis detection and proper execution of maintenance planning (Shyjith, et al., 2008). Reliability Centered Maintenance (RCM) : RCM is used to identify the maintenance requirements of equipment. The RCM establishes functional requirement of equipment and these are then related to design and inherent reliability parameters of the machine. For each function, the associated functional failure is defined and the failure modes and effects of the functional failures are analyzed. The consequences of each failure are established which fail in one of the four categories. They are hidden, operational, and non-operational, safety or environmental (Raju, 2011). Total Productive Maintenance (TPM) : In many industries Total Productive Maintenance (TPM) is a system which is used to maintain and improve the integrity of production systems and quality through the involvement of everyone in caring for machines and equipment. TPM as a strategy avoids sudden breakdowns and helps in effective maintenance which minimizes unplanned or emergent breakdowns. In the textile industry, TPM is used in assignments like machine inspection, cleaning, lubrication, needle replacement and basic machine setting
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Improving maintenance management: Case Study‌ tasks by the machine operators. The key measurement of TPM is machine effectiveness which includes availability, performance efficiency, and Overall Equipment Effectiveness (OEE). (Senthilkumar, et al., 2012). TPM is mainly accomplished through 7 pillars which help to ensure zero defects, zero breakdown, zero waste, and zero accident with total employee participation (Raju, 2011). These seven pillars defined as follows: 1.
Focused Improvement: In this pillar, cross-functional teams are assembled with the main aim of working on problematic equipment and coming up with improvement suggestions. The use of cross-functional teams is important to have a large and varied number of employees involved to bring in different experience or views.
2.
Autonomous Maintenance: It places the responsibility of basic maintenance activities on the hands of the operators and leaves the maintenance staff with more time to attend to more complex maintenance tasks.
3.
Planned Maintenance: It schedules maintenance activities based on observed behavior of machines such as failure rates and breakdowns. By scheduling these activities, the cycle of breakdowns and failure is broken thus contributing to a longer service life of machines.
4.
Training and Education: This pillar is concerned with filling the knowledge gap that exists in an organization when it comes to TPM. Ensuring that employees are trained gives the organization a reliable pool of knowledgeable staff that can drive the initiative competently.
5.
Quality Maintenance: This ensures that equipment can detect and prevent errors during production. By detecting errors, processes become reliable enough to produce the right specification the first time.
6.
Early Equipment Management: It uses the experience gathered from previous maintenance improvement activities to ensure that new machinery reaches its optimal performance much early than usual.
7.
Safety, Health and Environment: This pillar of TPM ensures that all workers are provided with an environment that is safe and that all conditions that are harmful to their well-being are eliminated.
Maintenance Policy : Maintenance policies are a set of protocols that are followed to reduce the number of unexpected stoppages. Performing PVM actions at certain point of time regardless of component’s condition is defined as a Block policy. Block policy aims to maintain the component so that the failure could be avoided as much as possible that may lead to a catastrophic failure. The policy is to work as a guiding principle of how the company is to achieve its vision and goals, taking into consideration the values and methodologies of the company. A policy may be a bigger picture for the employees, feeling the attendance of doing something with the right cause. The policy is a way in which the higher objectives are translated to more concrete objectives. It is a means to explain the objectives for all employees. To get an understanding and support in these goals and objectives it is important that everyone understands the meaning of the organization policy (Mobley, 2004). Computer Maintenance Management System (CMMS) : CMMS is software that is used to schedule and record operation and preventive/planned maintenance activities associated with facility equipment. It allows managers to stay up-to-date on facilities operations, even while out of the office, on the progress of maintenance requests. The utilization of CMMS facilitates the collection, processing, and analysis of maintenance data which helps to control effectively the maintenance of an organization by properly keeping information about occurring events. CMMS are designed to gather all data related to maintenance and to file it in the history of corresponding asset. CMMS have been proven to have several impacts on the maintenance management of organizations. Some of them have been listed as reducing equipment downtime through the benefits of regular scheduled preventive maintenance, increasing equipment life, increasing productivity, reducing inventory, providing historical records to assist in maintenance planning and budgeting, and providing maintenance reports.
II.
METHODOLOGY
The research methodology employed in this work is presented in sections 2.1 through 2.2. Assessment of current maintenance system : The initial/current status of the maintenance system was assessed in order to identify the problems that were experienced regarding maintenance management. This included interviews with the maintenance manager as well as document analysis to triangulate information obtained from interview with maintenance manager. www.ijmrem.com
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Improving maintenance management: Case Study‌ Fishbone (Root cause) analysis : A root cause analysis was carried out to understand the contributing factors to system failures so that actions can be developed. Figure 2 was used to analyze the causes of defects that led to downtime in categories of material, methods, manpower and machines.
Figure 2: Fishbone Diagram
III.
RESULTS AND DISCUSSIONS
Assessment of current maintenance system: At the assessment of current maintenance system, it was found that maintenance manager is randomly called by the machine operator to repair the damaged machines. In addition there were no records of maintenance carried out on machines such as maintenance log and preventative maintenance log. Upon assessment of the current maintenance system it was found out that the problems at the company included the following: Frequent machine breakdowns: These were caused by lack of history of machine failure since there was no maintenance log. Furthermore, there is no root cause analysis to determine the cause of machine failures. Limited tools and equipment spares: Machine spares and tools were limited and this caused the machines to idle in cases where the machines had breakdowns and waiting for parts to be replaced. This problem was due to lack of strategy to order the machine parts that are used frequently. Unreliable machines in production: The company did not have preventative logs hence the reliability of machines was unknown and there was more downtime because machines randomly failed. Preventative maintenance is the diagnosis of the machine before it fails in order to avoid the unexpected failure on a particular machine. Lack of knowledge about Autonomous Maintenance: Most operators in the workshop demonstrated limited knowledge on autonomous machine maintenance which keeps machine operational. This explained observed machine high down times. Table 1 shows common types of machine failures and causes of failures diagnosed through the root cause analysis. Table 1: Types of failures and their Causes Common types of Failure Needles damage a) b)
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Needle breakage: Bent Needle:
Cause(s) of failure i. Misuse of the machine usually causes needle breakage. Using wrong sized needle. ii. A bent needle which results in low quality of products and ultimately needle breakage is commonly due to wrong insertion of a needle in the machine by the operator. iii. Top tension is too tight or thread is wrapped around something. Needle may be in loosely.
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Improving maintenance management: Case Study‌ iv. Operator pulls fabric ahead of the feed dogs and causes needle to hit the needle plate. v. Fabric is too thick and too heavy for your machine. Looper damages i. When a needle is bent and repeatedly hits the looper, it may break or bend it. ii. Incorrect winding of threads on to the bobbin. iii. Excessive tension to the bobbin threads. iv. Incorrect fitting of bobbin case. Upper Thread i. Wrong threading of the machine breakage ii. Poor quality of tread iii. Irregular tension iv. Wrong timing Inferior thread may have been used, or thread may be knotted somewhere. Needle may be too fine for thread or fabric. v. Upper tension is too tight. vi. Thread may be wrapped around spool holder or thread guides, or caught on spool's thread slot. Lower thread i. Wrong threading of the machine breaks ii. Poor quality of thread iii. Irregular tension iv. Inferior thread or mis- matched thread. v. Tension on bobbin case is too tight vi. Needle plate hole has sharp edges or shuttle has rough spot
After analyzing the types of failures and their causes, a detailed investigation on root causes was performed. Table 2 presents suggested solutions to address observed common causes of the system failures. Table 2: Suggested Solutions for Major Defects with Corresponding Causes Areas Man
Machine
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Causes Carelessness
Suggested Solutions Improve supervision.
Inadequate training and operator inefficiency Machine is threaded incorrectly or excessive thread tension Dull or bent sewing machine needle and knife.
Train operators sufficiently about autonomous maintenance
Old and Defective machines Excessive pressure on the presser foot
Replace with new machines and ensure preventive maintenance Lessen the pressure on the presser foot. Slacken both tensions.
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Rethread machine and maintain proper thread tensions. Make sure the thread passes through the tension discs Replace the needle and knife with a new one.
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Improving maintenance management: Case Study‌ Method
Material
Incorrect size of the needle and thread for operation
The size of the needle and thread should be synchronized. Ensure both the needle and bottom (looper) positions are rightly fed by the correct thread type and size.
Incorrectly inserted needle
Insert the needle on correct position. Check that the bobbin is wound correctly and no loose threads or loops sticking out. Shorten the stitch length by means of the stitch regulator, especially when sewing fine fabrics. Use good quality thread.
Comparatively long stitch for the type of fabric in work. Poor quality thread Poor quality needle
Limited spare parts Improper Finishing
Use high quality needles from another brand. Needle should have high heat and wear resistance capacity. Develop an inventory control system for ordering spare parts. To cut thread properly, start regularly checking system to check the machine is properly functioning or not. Also, to Improve quality inspection system.
Documentation of maintenance practices : In order to improve the maintenance management of the casestudy organization, documentation of current maintenance management process was carried out to expose areas that needed improvement. Figure 4 below shows how the maintenance system was currently operating (AS IS model).
Figure 4: Current Maintenance process flow The proposed maintenance process flow is shown in Figure 5. www.ijmrem.com
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Figure 5: Developed Maintenance Process Flow For effective functionality, the developed maintenance process flow needed institution of assert labelling, maintenance log, inventory management system, maintenance checklist and objectives, control procedures and maintenance policy. Asset Labelling : Production machines were labelled for ease of identification and access to machine specifications. This information is also useful for documents such as maintenance log, preventive maintenance log and developing database for the machines. All machines in production, cutting, design, embroidery and ironing departments were labelled using stickers.The sticker design includes the company name and section where the asset belongs (for example P8 means the machine is from production and it is number 8 on the workshop). The stickers were pasted on the machine using a sticker labelling machine. Figure 6 shows a labelled stitching machine, the label makes it easier to identify the machine even if it is moved to a different location.
Figure 6: Sample of labelled machine Maintenance log: A maintenance log was developed and implemented upon completion of machine labelling for maintaining information about the machines in production line. Maintenance log provides a record of all work performed on the system regarding maintenance, thus it provides a history of system failures which is www.ijmrem.com
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Improving maintenance management: Case Study‌ helpful for preventative maintenance. Information on the maintenance log includes machine name, model number, asset number, department of the machine, machine location of the machine, time of failure, cause of failure and remarks. Figure 7 shows an implemented maintenance log for recording information about equipment maintenance.
Figure 7: Developed maintenance log Maintenance checklist: A checklist is a document which should be filled prior to using the machine and this document acts as a preventive maintenance log because it provides a history of which parts of the machine should be addressed. The checklist is to be filled by the machine operators daily and then be sent to the maintenance manager to view which parts of the machine have problems. Figure 8 shows a sample maintenance checklist that was developed for the case-study company. The form is mainly in two parts, the cleaning of the machine before it is used and just a general condition check of the machine. It also includes the date the machine was last used and the employee name and number of the employees who used it last.
Figure 8: Developed Maintenance checklist www.ijmrem.com
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Improving maintenance management: Case Study‌ Inventory Management System: ABC analysis is a system for inventory classification. It was used to divide inventory into three classes based on Rand volume. These classes were as follows: a) Class A - High Rand volume b) Class B - Medium Rand volume c) Class C - Low Rand volume The classification was then used to establish policies that could focus on the few critical parts and not the many trivial ones. Figures 9 and 10 show ABC calculations that were done and the graphical presentation based on the inventory order information from the case-study company. The vertical axis on Figure 10 shows the combined percentage use of the materials in the different ABC categories. INVENTORY FOR THE MONTH OF FEBRUARY 2017 Part name
Part number
Needle(blind stitch) Straight cutting blade Button clamp slide Looper Feed dog Idle gear Spiral gear SHARPENING GSTONE Yoke slide Knife Knife Pressure foot Needle bar Cloth retainer Needle bar clamp Screw Needle bar balance Needle bar thread guide Chaining finger Srew for pressure foot Screw
LW-6T-12G 10E-S/E B2552-372-000 B1239-372-000 23-216 DE 161 DE 174 MT260-E-24 B1237-372-000 B-2702-047-N00 B-2702-047-L00 DE 147 400-09083 137-77 B31123-372-00 SS-1060210-TP B3112-372-00 400-09093 122-35 DE 146 SS-4080415-SP
Inventory Unit Cost Volume (units) (ZAR) 10 24 3 3 1 2 2 1 3 20 20 2 1 1 1 10 1 1 1 4 1
78 14 107.8 82.5 214.5 99 93.5 159 47.3 6 6 52.8 89 60.5 57.2 4.4 38.5 28 19.8 4.4 5.5
TOTAL
Rand Volume (ZAR)
% of Rand Volume
780.00 336.00 323.40 247.50 214.50 198.00 187.00 159.00 141.90 120.00 120.00 105.60 89.00 60.50 57.20 44.00 38.50 28.00 19.80 17.60 5.50
23.7% 10.2% 9.8% 7.5% 6.5% 6.0% 5.7% 4.8% 4.3% 3.6% 3.6% 3.2% 2.7% 1.8% 1.7% 1.3% 1.2% 0.9% 0.6% 0.5% 0.2%
3293.00
100%
Class
78.5%
A
B 13.1%
8.2%
C
Figure 9: ABC analysis
Figure 10: Graphical presentation ABC inventory control allows inventory managers to concentrate on controlling the more significant items of stock. The aim of introducing this system is to ensure that critical parts will always be in stock to avoid downtime of machines due to limited spare parts. Class A items as shown in Figure 10 comprise of items such as needles, straight cutting blades, button clamp slides, loopers, feed dogs, idle gears, spiral gears, sharpening gstone and yoke slide which make approximately 20% of high-usage-value items which account for 78.5% of the total maintenance parts usage value. Class B items are those of medium usage, usually the next 30 per cent of items which often account for around 13.1% of the total usage value. Examples of these are pressure foots & needle bars. Class C items are those lowusage which, although comprising around 50 per cent of the total types of items stocked, probably only account for around 8.2% of the total usage value of all maintenance operations. Some examples of these items are needle bar balance and clamps, needle bar thread guide, chaining finger and screw for pressure foot. Maintenance Policy: Since the case-study company did not have any policy or set of documented maintenance procedures, a maintenance policy was developed for effective maintenance management. Maintenance policy is www.ijmrem.com
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Improving maintenance management: Case Study‌ a statement of principle used to achieve maintenance objectives and guide maintenance management decision making. Maintenance management can be defined as the organization of maintenance within an agreed policy. The key requirements and procedures that were covered in the developed maintenance policy include Maintenance Objectives, Metal Control Procedure, Maintenance Plan-Preventive and Work Allocation, and Training of Staff. Maintenance Objectives: Effectiveness of the maintenance is measured by the ability of the policy to achieve the desired outcomes regarding maintenance in the organization. The following are the objectives of the maintenance policy developed for the case-study company. 1. To keep the maintenance cost per production item produced as low as possible. 2. To keep the quality of the product very high. 3. To keep the downtime for critical equipment as low as possible. 4. To keep maintenance cost as low as possible. 5. To provide effective and trained personnel. a)
Metal Control Procedures: Since the organization uses a lot of sharp objects in their production processes, there was a need to develop metal control procedures under the maintenance policy. These procedures were designed to cover all the actions that must be carried out when handling sharp objects in different task.
Sewing and Knitting Needle Control: Needle control policy covers the strict control of all needles to ensure that the only ones in use are for the manufacturing process and that the disposal of all worn or broken needles is carried out by authorized personnel. The only needles allowed at work stations are those currently needed to operate the machine process. No spare needles should be held at machine point therefore new needles are kept in a locked location only to be accessed by trained or authorized personnel. Worn and damaged needle replacement: Needles which are worn or damaged but not broken are to be collected and a new needle must be issued by the authorized personnel. Old needles are to be disposed of into a sealed jar or tin with a small opening in the top. The jar must be kept in the secure location and disposed of responsibly. When a needle breaks, the operation must be stopped and the maintenance supervisor be informed. All the needle pieces must be located and checked against a whole needle to make sure all the pieces have been found. The pieces must be immediately attached to the record sheet with clear adhesive tape and fully recorded with all information. A new needle may only be issued when it is confirmed that all the needle pieces are found. If all needle pieces cannot be found then the product being worked on and any other work near must be placed into a bag or box and taken to the isolation area for further checking. The workplace must be checked with a hand-held metal detector or magnet before work restarts. The handheld detector must be calibrated and operating correctly, using the 1.2mm test piece before being used. Check for the missing needle pieces in the isolation area. If found, all the pieces are to be recorded on the record sheet as normal. Knives, blades, scissors and snips can be used in every area of the factory from cutting rooms to warehouses. All new and used cutting blades for band knives and straight knives must be kept in a locked cupboard with access only by the cutting room maintenance supervisor. Records must be kept of new blades in stock, issued blades and returned blades so that every blade is accounted for. The instructions should be considered pertaining to the sharp objects in the workshop; 1. Under no circumstances can old blades be turned into knives for use in the production area. 2. Old blades must be disposed of responsibly on a regular basis. 3. Where knives are needed to open containers; these should have a retractable blade, be numbered and stored at the end of each day in a secure cupboard. 4. Small scissors and snips must be tied to work stations and this applies to all areas used for cutting, sewing, inspection, pressing and warehouse. 5. Large scissors in the cutting room and sample room are to be numbered and stored in a secure cupboard at the end of each working day. The supervisor responsible for scissors must check all have been returned to ensure that they are not lost or stolen. 6. Proper care must also be ensured when the operators are holding sharp tools; they must be held with the blades pointing downwards to avoid injuring one another. b) Maintenance Plan-Preventive and Work Allocation: Maintenance will be carried out by the maintenance manager on regular basis to keep the production machines working. Information about the www.ijmrem.com
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Improving maintenance management: Case Study‌ maintenance activities should be should be continuously updated Duties of the maintenance manager could include at least the following inspecting the facility, checking electrical units of machines, ordering parts and equipment, recording daily maintenance activity and preparing work schedules. Machine operators should record the maintenance checklist before using any machine. The proposed maintenance strategy for the organization is preventive maintenance. Each property will have a Preventive Maintenance Schedule that will be completed by the maintenance manager. Preventive maintenance will be done based on the history provided on the maintenance log. The following points are to be checked consistently cleaning, lubrication, periodical service. The below cleaning regime could be used. Table 3: Cleaning Procedures # Descriptio n
Schedul e
Mode of cleanin g Cotton
1 Spool stand
Everyda y
2 Machine head
Everyda y
Cotton
3 Hook shuttle
Twice a week
Soft Brush
4 Oil tank
Everyda y
5 Bottom oil tank
Once in a week
Brush Tweeze r/ Magnet Blower
Remarks
Ensure that there is no Pins, labels, and buttons other than the thread cone on the spool. Remove the complete dust from the entire areas including Bobbin winding area, Knee lifter connecting areas, backside of the machine arm. Unscrew the needle plate and remove the dust and threads and clean the feed dog, trimming mechanism, hook set areas, feed bar areas etc., Where the flap and thread etc., Will accumulate. Check there is no pins, bits of cloth and bits of thread, labels etc., in the oil tank and edge of the oil tank.
The table 4 below was also developed to assist with Preventive Maintenance in terms of what to check and when in order to achieve the preventive maintenance strategy. www.ijmrem.com
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Improving maintenance management: Case Study… Table 4: Stitching Machine Check Points Description
Schedule
Remarks
Needle
Daily
• • • •
Thread
Daily
Thread stand
Daily
Thread cone
Once in 15 days Thread to be replaced 800 to 1200 M/C
• Make sure the thread is suitable to the fabric and sizes of the needle. • To release the thread freely match the angle of spoolholder and thread hanger assembly. • Should be kept vertically on the thread spool. • Thread guides/Tension disk/spring to be change if grooved damaged.
Thread guide holes
Thread check spring
Needle thread tension
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Check type of the needle Check size of the needle Check position of the needle Check needle point of the needle (suitable to the fabric) • If the needle is bent/broken/ blunt
depending on the condition of the spring Daily
Bobbin thread tension
Daily
Hook/Loope r timing
Every 15 days
Pressure foot feed dog/ Needle plate Pressure
Every 15 days
Every 15 days
• The spring to be adjusted according to the thread and the fabric • Check threading: Threading should be done properly (should pass through every hole of thread guides) • Tension shoulder be kept as light as possible. Check the bobbin condition, if damaged/ bent to be replaced. • Bobbin winding: Make sure the bobbin is evenly wind with even tension. • Bobbin thread tension: To be adjusted as per the fabric and the thread. Check the timing of hook/looper and needle (refer to the service manual) • Check hook/looper point daily whether it is damaged. Make it smooth or replace it. • Check the needle plate hole daily whether it is damaged. Make it smooth or replace it. • Use the correct types of the needle plate/pressure foot/feed dog according to the fabric and operations. • Pressure should be adjusted according to type of fabric and operation.
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Improving maintenance management: Case Study… However the above-mentioned tips are more useful to the sewing room personnel. Sewing mechanics can prevent the sewing defects by maintaining the care of the industrial sewing machines. Defect free seam and stitches of garments are always having the value-added products that gain more profits. Seams quality must be obtained through the preventive maintenance of the industrial sewing machines respectively Training of all Operators on Autonomous maintenance: The core idea of autonomous maintenance is to provide the operators with more responsibility and allow them to carry out preventive maintenance tasks. All workers in the production unit must be properly trained in order for the preventive maintenance to be effective. Autonomous maintenance should be made part of induction training programmed. This Training is essential to avoid unnecessary breakdown of equipment. The operators should be taught autonomous maintenance to avoid downtime of machines. Autonomous maintenance is independent maintenance carried out by the operators of the machines rather than by dedicated maintenance technicians. This is the core concept of TPM. TPM holds the involvement of everyone as one of its key principles and thus makes the operators who use the machines more responsible for the upkeep of the machines as well as the running of them. Training of the Operators will involve several aspects as outlined below: Theoretical Training Theoretical training is about imparting basic knowledge of machine components and functions. To perform properly the most important task such as machine cleaning, operators should fully understand the objectives of autonomous maintenance and be even able to deliver improvements in equipment reliability. Initial Cleaning and Inspection: The initial cleaning of the machines is essential for high-quality maintenance. It includes the thorough cleaning of the equipment and its surroundings. The purpose is to ensure that the machine performance is fully restored by identifying and eliminating all signs of deterioration. The cleaning and inspection should be done by the operators so that they become familiar with the machine details and can see where dirt accumulates and how and what problems are occurring. The inspections that should be done on machines could include; • Leak detection • Checking of loosened bolts • Lubrication inspection • Correction of defective items • Removal of material rests from oil or water Removal of dust and dirt and therefore reduction of paint corrections Eliminating Contamination: After the initial cleaning has been performed and the equipment has been restored again, it is highly important to make sure that it does not deteriorate again. This happens by eliminating all possible contamination sources and improving accessibility for cleaning and maintenance. During cleaning it will be vital to identify where the dirt that is removed is coming from; is it being produced inside the machine or is it coming into the machine from outside. The sources of these contamination can then either be removed or minimized. Maintenance manager should consider the following possible solutions: • Maintain cleaning standards • Achieving lasting cleanliness by avoiding soiling • Promoting cleanliness • Encouraging operators to keep order • Operators should be shown how to facilitate the planned inspections Developing Standards for Cleaning, lubrication and inspection The establishment of standards for operations of cleaning, inspection and lubrication follows the suggested lubrication and inspection schedule. This is the step, which can be individually adjusted from the operators to every machine. Inspection and Monitoring could involve the following: • Checking lubrication level • Locating leaks • Tightening loose bolts • Identifying possible mechanical problems as cracks • Performing mechanical adjustments: tension measurement and regulate sensors Finalizing Standards: The last step for a successful implementation of autonomous maintenance is to finalize all provisional standards and establish a process for autonomous maintenance to be carried out by the operators in the workshop. www.ijmrem.com
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Improving maintenance management: Case Study… Equipment Monitoring and Control: Top management of the company should be responsible for coordination and monitoring of the maintenance activities. Continuous review of workflow will ensure that the management of the property is aligned with client’s expectations and vision. Staff at all levels will be managing and maintaining the property utilizing the standard checklists and work flows. Safety and Occupational Standards: It is essential to implement appropriate risk assessment procedures for maintenance operations, as well as employing adequate preventive measures to ensure the safety and health of workers involved in maintenance activities. After maintenance operations are complete, special checks (inspections and tests) should be carried out to ensure that maintenance has been properly carried out and that new risks have not been created. During the whole process, good maintenance management should ensure that maintenance is coordinated, scheduled and performed correctly as planned, and that the equipment or workplace is left in a safe condition for continued operation.
V. CONCLUSIONS The aim of this study was to assist the local textile company to develop and implement an effective maintenance management strategy. The maintenance management system of the organization was initially based on the unplanned emergence maintenance management which meant machines were only fixed after they breakdown. This reactive system was not suitable for the organization as the company lost lot of time in reacting to these emergency breakdowns. The system is now changed to preventive maintenance which aims to prevent the machines from breaking down hence ensuring that there is minimal downtime. ABC control system has also been used to ensure that machine spare parts are ordered optimally so that there is minimal to no downtime of the machines due to unavailability of spare parts.
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