Study on the Basics of Maintenance of Textile Machinery
Shafat Hossain Sajib
Noakhali Textile Engineering College
What is Maintenance?
Maintenance may be defined as the chronological activities or as the process of systematic activities done for keeping the machinery or equipments at the heat level for well run or its proper services. Proper care and maintenance of textile machinery is essential in prolonging their durability and appearance.
Aims of Maintenance:
- To maintain m/c equipment at optimum operation speed and production efficiency
- To unsure best possible level of quality of product.
- To minimize the idle time resulting from the machinery break down.
- To reduce the cost.
Importance of Maintenance:
- To increase the life time cycle of machinery and equipment
- In case of appropriate functioning.
- Better or superior quality for the product.
- Higher productivity of machines
- Wastage reduces and control.
- Economization of the process.
Effects of Maintenance:
- Due to proper maintenance reduce undue worn out of different parts and equipment as well as corrosion of the items and increase the machines life (these are the result of routine cleaning, lubricating, repairing, replacement, fitting, and refitting etc.).
- For sound or congenial operation of machinery, it is required the proper lubrication, fitting, repairing, and replacement (as per necessity).
- By the continuous operation of the machinery reduces stoppages time resulting better quality and less wastage.
Operation Involved in Maintenance:
- Setting: Setting is the activities to set or install the machine parts or required ancillaries. Adjustment also complementary word to setting used for appropriate setting.
- Checking: Checking means investigation of machine condition. It is very important work in case of maintenance. It is very skilled depends work as successful maintenance that depends on correct fault detection.
- Repairing: Repairing or altering of spares and equipment (if necessary) is to be detected and necessary measures are taken (repairing, altering, setting, adjustment).
- Overhauling: It is the work of maintenance, but not frequent or schedule work. It is done as per as necessary.
System of Maintenance:
Basically there exist 2 systems on which based different types of maintenance are done. They are:
- Break down maintenance
- Planned maintenance.
Types of Maintenance:
- Preventive maintenance.
- Productive maintenance.
- Routine schedule maintenance (cleaning, checking, lubricating).
- Remedial maintenance.
- Restorative maintenance
- Emergency maintenance.
Power may be transmitted in the following ways. They are:
- By mechanical means
- By electrical means
- By electro-mechanical means
- By hydraulic means
- Others (aeronautics)
In them the mechanical means transmission is classified in following way:
Through belt and pulley (Flat belt and flat pulley)
- V-belt and V-pulley
- Timing belt and Timing pulley
Through gears (Straight gears such as Spur gearing)
- Epicyclical gearings
- Through chain-sprocket
2 types of lubricant on the basis of viscosity
For evaluating lubricant following factors are considered:
- Specific gravity
- Flash point
- Pour point
- CST (cent stroke behavior at 40ºC both for oil and grease)
Effect of Lubricants:
- Corrosion (anti corrosion effectiveness)
- Uniformity and optimum speed attainment
- Recommended legibility of the spares and parts
- High efficiency (due to low break down stoppage of the material)
- Higher quality of the product
- Low work load on the work arm
- Less material handling
System and Procedure of Maintenance:
- For effective maintenance a no. of pre-requirement site have to met
- There must be a well defined organizational structure to and implement the program.
- Proper planning, scheduling and controlling of maintenance must be designed.
- An appropriate flow of information and data on maintenance must be devised.
- Timely supply of the spare parts and also other materials needed must be ensured.
- Personnel of varying skilled and competence must be engaged.
What are the System and Procedure of Maintenance?
The answer will depend on the aspects emphasized. It may be of two natures:
- Management aspects
- Technical aspects
In managerial aspects, system may be defined as the means which the personnel of an enterprise operate to accomplish the enterprise objects. They provide the means of translating managerial policies. Procedure will be that they are written and oral instruction which give formal sanction to a system. On the other hand of stress is given to on technical works and parameters than a system may be considered a network of related production developed according to an integrated scheme for performing a major activity or function. Procedure may be regarded as a sequence of technical operation established to ensure uniform accomplishment of recurring tasks.
Necessity of System and Procedure:
Maintenance operations are characteristics by wide range and different degree of uncertainty. Those have to done by the people of varying skills. Some jobs are cyclic tasks some are not. Even in the case of cyclic tasks, the interval between the 2 constructive operational ranges quite widely from once week to all most twice a year. Also there are a few works which are alternatively overlapping. In some causes execution of certain the task is automatically implies carrying out of certain other tasks also.
Schematic Diagram of Maintenance Activities Depending on Their Uncertainity Level:
There the things are shown below:
- Routine maintenance
- Preventive maintenance
- Statuary maintenance
- Major repairing
- Erective maintenance
- Re-erective maintenance
- Overhauling maintenance
- Corrective action to be taken on the basis of the preventive maintenance.
- Emergency maintenance
- Re-storative maintenance
- Change of lay out.
Steps of Maintenance:
The steps of maintenance are:
Controllable work is considered as a planning. Since a comprehensive maintenance analysis is needed for the purpose. It is usable to cover a time spam of one year.
- Basically the decision to be taken in the 1st 2 stages of planning are more oh technical in nature then administration. It sufficient to make the following brief remarkable to indicate. The range of decision to be taken at planning stages.
- The frequency cleaning needed to be established with reference to degree of dirt and fly accumulation.
- lubrication cycle are laid down taking into account bearing design and operating speed, the re-commendation of the different oil companies may be as guide in the content.
- The frequencies and kind of routines maintenance operation are fixed with regarding the machinery manufacturing and the recommending rate of the wear precession and accuracy of settings, adjustment, loss in efficiency process faults machinery break down and above the all past experience to related matters.
- Details of preventive maintenance program suited for the particular condition the mills are finalized after taking into amount such as no of machines and types of the skilled technician’s available tools and aids are in the disposal, necessary check the lists are also developed for preventive maintenance.
- Re-storative maintenance plans like likely to neutralized during the year ahead are also taken note of. Most of the data for the steps have to be gathered from the equipment history records. If such records are not available in the mills they must be 1st made from purchase envious. Manufacturing manual and leaflets are before analysis. Additional data required can be had from production, costing and quality controls departments.
Factors should be considered and stressed during planning and maintenance:
- Timing (on over time or least over timing is considered)
- Skill of man power
Planning has defined as the various maintenance tasks to be carried out on the each machines during the course of year. Scheduling is the process of getting RIGHT man and facilities with RIGHT time and the RIGHT place in scheduling comprises the process of 3R’s.
- Minimize the delays arising from the lacks of the co-ordinates between production and maintenance schedule.
- Reduce the loss of useful man hours because of unnecessary walking tines and material handling.
- Co-ordinates multi skilled jobs to optimize the skills utilization consistent with minimum m/c down time.
- Operative idle time is minimized.
- Co ordinates with SQC to ascertain the effectiveness of the maintenance operation and their adequacy.
- Work unit
- Size of the jobs
- Man- hour scheduling in relation with the total man hour available.
- Lead time for scheduling.
All planning and scheduling without effective control and the means of enforcing then would be unless and waste of time and efforts. The aims of maintenance control are given below:
- To provide mgt with the tools, that will disclose deviation from Plane and schedules so that back logs can deal with
- To provide the feedback information from preventive maintenance.
- Check the lists and diagnostic report signaling.
- The need not only for the remedial maintenance but for reviewing the various scheduling established in the annual plans.
- The information for the QC and costing department will also the supplementary sources and feedback.
Records for the Effective Maintenance Controlling:
- Maintenance ledger
- M/C cards
- Job in complete report
- Lubricant control chart
- Over time requisition form
- Weekly work order sheet
- Maintenance chart
- Mechanical down time
- Break-down time
- Over time engagement record
- Monthly spares and lubricant consumption.
Elements of Maintenance:
1) Inspection / check up
- External – sound, noise, vibration,
- Internal – spare parts, shafts, motors and other mechanical and electrical installation
Is the application of lubricant in the machinery during operation / break down. Application of lubricant is governed by 4R’s. Such as
- Right types of lubricants
- Right place
- Right tune
- Right quality
Note: High moving parts – oil; Low moving parts – grease
3) Planning and scheduling:
Every preventive maintenance or work is pre-planned. A routine is made for maintenance and by scheduling it is followed strictly.
Training is the essential the works fours of maintenance. It increases the skilled of manpower and effect the cost of production by enhancing the productivity, quality and machine legibility.
5) Recording and analysis:
Work done and matter of maintenance should be properly recorded. Recording is the very important for their maintenance guideline and trouble shooting. Remedial measures taken for a particular trouble and its result during machine operation are also great importance for future schedule and activities. Frequency of fault detection corrective measure etc analysis is the criterion for maintenance job.
Storage of Spare Parts:
- Slow moving items (Available as per scheduling)
- Fast moving items (Always available)
- Lubricants should be available as per desired grade and amount.
- Tools and equipments should also available in the maintenance department.
Lubricants and Lubrication’s:
Lubricant is the organic compound higher molecular wt used in the m/c to protect corrosion and possibility of failure. Lubrication is the process of application of lubricants in machinery during operation or maintenance. Follow of 4R’s play vital role in congenial role of machine.
Importance of Lubricant:
- Reduction of wear and tear Reduces m/c maintenance time and cost.
- Synchronized m/c operation appropriate rpm of m/c in optimal speed and uniformity of speed.
- Legibility assurance of m/c and m/c parts.
- Higher operating efficiency less idle time and stopping.
- Better quality of products: due to well-running and disturbance are the causes of better quality products. Reduces m/c stoppage frequency, so attainment of the higher quality.
- Reduces fatigue and boredom of work forces due to well running less stoppage and troubles.
- Develop ergonomics and improve working environment.
- Above all maintenance, reduce work load and cost of overall manufacturing.
Types of Lubricant:
Lubricant can be classified broadly on their viscosity and specific viscosity
- Grease – higher viscosity and lower fluidity
- Oil – lower viscosity and higher fluidity
Characteristic of Lubricant:
- Specific gravity
- Flash point
- Pour point
- CST (Centistroke)
- Acid no of parts per million (ppm)
Selection of Lubricant:
Selection of lubricant is governed by following factors:
- Types of gear/bearing or point of lubricants
- Speed of gears/shaft (in case of seal box of gear)
- Reduction ratio
- Operating temperature
- Input horse power
- Nature of load provided
The lubricant must reduce friction, prevent wear and tear on the corrosion and carry the load needed to keep the m/c operation at higher efficiency level.
Furthermore the lubricant is required to maintain its physical characteristics and performance characteristics for a long period of time without any degradation.
Recommendation of m/c manufacturer in the selection of lubricant and the frequency of lubricant are important and to be taken as broad guide line.
Special consideration for the lubrication of the textile machinery:
- Maintain low power consumption
- Protection against corrosion
- Avoidance/safety from staining of product (yarn, fabric…etc)
Functional Properties of Lubricant:
Outcome from the physical properties
- Lubricant must be resist oxidation
- Lubricant must be resist carbon formation
- Lubricant must be resist rust formation
- Lubricant must anti-foaming
- Lubricant must be resist extreme load
- Lubricant must possess required viscosity
- Lubricant must act goods cleaning agent (CCl4, petrol, diesel)
Gears are toothed disc/pulley used for power transmission.
- Straight gears/plain gears (used for power transfer at 180º angle)
- Helical gears (for avoiding slippage)
- Bevel gears (for transfer at 900 angle)
- Worm gear/wheel (for reduced power)
- Sprocket wheel (straight transfer)
Plain disc which transmitted power by belt.
Bearing (Anti-friction element):
It is an anti-friction element used to safe the rotary equipment from the frictional element.
On the basis of shape-
- Ball bearing (Used in high speed terms)
- Roller bearing (used large dimension terms)
- Needle bearing (used in low speed terms)
According to lubrication facilities-
- Open bearing (gradual lubricant)
- Sealed bearing (no requirements of lubrication)
Anti-friction arrangement used to safe the rotating shaft at very lower level rpm from corrosion.
Pulley and Belt:
- Flat pulley + Flat belt
- Grooved pulley + V-belt
- Toothed on timing pulley + Toothed belt (short distance and low speed)
- Flange pulley + Flat belt
Factor must be considered for maintenance schedule:
- M/C type (mechanical, electrical, mechatronics basis)
- Danger level/Risk level
- Operational tenure (operational period round the clock / shift basis / weekly / occasional)
- Nature of the equipment
- Availability of man power and skilled
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Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.