Line Balancing & WIP Management PDF

Line Balancing  LINE BALANCING What is a line? A line is defined as a group of operators under the control of one production supervisor What is balancing? The method of line balancing will vary from factory to factory & depends on the type of garments manufactured. ...

Line Balancing  LINE BALANCING What is a line? A line is defined as a group of operators under the control of one production supervisor What is balancing? The method of line balancing will vary from factory to factory & depends on the type of garments manufactured.  Applications of line balancing 1. Setting up a line 2. Running a line setting up a line:- Before a new style comes onto a line, it is necessary to establish the operation sequence, the time & the type of equipments required to manufacture the style Methods for setting up a line 1. Calculating how many operators will be necessary to achieve a given production rate/hr 2. Calculating how many garments can be produced by a given number of operators Required information for balancing calculation Number of operators Operation sequence with standard time Out put from a given group of operators. Types & number of machines available Operator’s performance level  Balancing calculation Effective utilization of machine & manpower. Theoretical out put = number operators X 60 (minutes/hr) Total SMV Balance efficiency (%) = lowest out put (from balance) X 100 Theoretical out put Line forecast out put = theoretical out put X expected line performance (%)  Exercise 1: Number of operators for allocation = 13, expected line performance =75% Works M/C operatio STD SMV %= Operator Operator Balance Out put= tati n time (SMV/Total SMV)x allocation allocation Actual operator X 60 on 100 (theoretical)= (actual) (min/hr) Total operators SMV (operation) x SMV % 1 Over edge Join sho 0.54 7.98 1.03 1 111 2 Over edge Attach 0.85 12.57 1.63 1.5 105.8 collar 3 Lock stitch Finish 0.8 11.83 1.53 1.5 112.5 collar 4 Over edge Sleeve 0.84 12.42 1.61 1.5 107.14 attach 5 Over edge Sleeve IS 0.76 11.24 1.46 1.5 118.42 & SS 6 Flat stitch Bottom 0.74 10.94 1.42 1.5 121.62 hem 7 Flat stitch Sleeve 0.83 12.27 1.59 1.5 108.43 hem 8 Button hole Front 0.71 10.50 1.36 1.5 126.76 m/c placket 9 Button stitch Front 0.69 10.20 1.32 1.5 130.43 m/c placket Total 6.76 100% 13 13  Note operators allotted in decimal figure (1.5) ,which is not possible we have to consider that operator should work for at least half of the working hr for any operation when allotted for a operation , which is shown by.5 operator. For theoretical balance two small operations can be combined or one long operation can be divided with considering m/c type, operation sequence and operator’s performance. Calculation Theoretical out put = (13 /6.76)x 60 =115.38 Balance efficiency (%) = 105.8 X 100 =91.72 % 115.38 Line forecast out put =115.38 X 75 % =86.53 Due to factors such as machine break down, absenteeism, in compatible performance between operators, the supervisor will constantly have to re assess the balance between operations. How to calculate the no. of operators or machines necessary to achieve a target ? Exercise -1 Calculate the no. of operators required for a order qty of 1920 pcs, delivery time -40hrs, work content of garment =10 SM 2. Running a line A supervisor plays vital role to run a line. Key areas 1. There should be reasonable WIP (1 hr work) between operations. 2. Line floaters should be used to cover absenteeism. 3. Ensure that the mechanics keep the machines regularly serviced. 4. Eliminating bottle neck 5. Should carry out & check balancing production at 2 hrs interval of time. 6. Adequate cutting buffer to avoid no work for line & also arrangement of accessories & trims. 7. Optimum utilization of m/c & man power.  Skill inventory A record of operator’s performance on different jobs is called skill inventory This consists of list of the people in the section or factory, which shows their expected performance at various types of work. It provides for effective utilization of operator’s efficiency.  Balancing Exercise Rule of the exercise 1. Allocate specialist operators first 2. Use operators on operations they can do best 3. Enough hours must be worked on each operation to give the required out put, in this case1000 pieces/day 4. An operator should work for minimum ½ hr at any allocated operation i.e. In two hours an operator can work for maximum 4 operations 5. Check that enough m/c of right type is available. 6. Do not allocate floaters, as they are intended to cover absenteeism. 7. Maximum WIP should be 200pieces between operators. & WIP in the line 400-600Pcs 8. No. Of pieces /bundle are 20 pieces. Skill Matrix  Line Balance Option 1 Option 2 Option 3  Case 2 Absenteeism Conditions for a normal working day:- Gita absent at 8.00 AM Urvasi sick & Sunil went home at 10.00 AM Urvasi & Sunil are back at 12 PM Kalindi went & Gita returns at 2.30 PM Balance the line with the above conditions with rule of the exercise for the normal working day.  Case 3: Absenteeism Conditions for a normal working day:- Sangita absent from 8:00 -10:00am Sunil absent from 12:00-2:30PM Kalindi absent from 2:30-4:00PM Balance the line with the above conditions with rule of the exercise for the normal working day Case 4: Absenteeism Conditions for a normal working day:- Ramar absent from 8:00 -10:00am Bhanu absent from 12:00-2:30PM Sangita absent from 2:30-4:00PM Balance the line with the above conditions with rule of the exercise for the normal working day