Simulation Experimentation

7.5 Simulation Experiment
Once the base ‘push’ and ‘pull’ theoretical accounts were validated and verified, the following measure was to make up one’s mind on patterns that could be included in the simulation survey and their degree scene. So, the simulation experimentation was carried in two phases.
7.5.1 Initial Experiment

The initial experimentation was used to make up one’s mind the degree of alterations to be made and for confirmation of patterns. Along with the present position, following fluctuations were considered for initial experimentation.

Layout alteration: layout alteration with alterations in machine location and cell layout
Setup clip: 25 % less and 50 % less
Average clip to mend ( MTTR ) : 25 % less, 50 % less and 25 % more
Pull Model: 100 % production as per agenda and no FGI available, 100 % production as per agenda and existent FGI
Rejection: 25 % less and 50 % less
Load and unload clip: 25 % less and 50 % less.

Table 7.6 Consequences of mated T-test for past informations cogency of ‘push’ type simulation theoretical account

J9

4833

6256

– 0.37

0.087

2.044

775

5023

0.178

0.697

0.408

– 4058

2357

0.776

0.004

– 4.555

J8

1092

2663

1.085

0.319

1.085

749

1138

0.79

0.132

1.741

– 343

1586

0.305

0.588

-0.573

J7

-1590

2204

0.122

0.105

-1.909

145

1221

0.633

0.764

0.314

1735

2696

-0.033

0.14

1.702

J6

1355

3942

0.028

0.398

0.91

402

453

0.947

0.057

2.347

-953

4124

-0.074

0.563

-0.612

J5

1990

5675

0.486

0.389

0.928

2222

2112

0.599

0.032

2.783

232

5794

0.57

0.919

0.106

J4

1146

5971

0.089

0.63

0.508

1587

1714

0.659

0.05

2.449

441

7322

-0.5

0.879

0.159

J3

9397

13869

-0.104

0.123

1.793

-187

7261

0.613

0.948

-0.068

-9584

11326

0.223

0.066

-2.239

J2

1225

4359

0.965

0.485

0.744

2955

12010

0.685

0.539

0.651

1730

10457

0.706

0.677

0.438

J1

2087

7608

0.976

0.495

0.726

2650

22431

0.74

0.765

0.313

563

18773

0.763

0.939

0.079

Stat. Parameter

Mean

Std. Dev.

Correlation

p-value

t-value

Mean

Std. Dev.

Correlation

p-value

t-value

Mean

Std. Dev.

Correlation

p-value

t-value

Comparison between

Planned- Actual

Planned- ‘push’ theoretical account

Actual- ‘push’ theoretical account

Production sequence: high to low volume and low to high volume
Handiness: 25 % less and 25 % more
Raw Material Schedule: current natural stuff procurance program, agenda bringings after 5 yearss, with and without opening RMI, 5 % extra stuff procurance, with current bringing public presentation, 100 % bringing measure and bringing public presentation

7.5.1.1 Layout Alterations
The layout to be used for the JIT system should hold maximal visibleness, lower limit walking, minimal stuff handling, facilitates monitoring of work come ining and go forthing the cell and workers can handily collaborate to smooth flow and address jobs. Schonberger ( 1982 ) , Korgaonker ( 2005 ) and other research workers have stressed on the usage of streamlined U shaped layout and formation of fabricating cells based on group engineering ( GT ) attack. The current layout of the imperativeness machine store is a combination of U-shaped and L-shaped layout. The country of the imperativeness store is 625 m2including the country required for imperativeness machines, rework country, racks for hive awaying the dies and tooling which is non excessively large for the stuff and tool motion. The P9 machine was the lone machine outside the close U-type. The operator and the stuff have to be placed in the gangway. So, consequently the machine P9 was shifted in topographic point of P6, which is non being used. The infinite restraint besides does non let the change of current layout into the complete U type layout.
The layout was analyzed to verify the locations of the machines within the given layout. From-To chart showed that the current layout produces minimal backtracking.
In order to use group engineering ( GT ) attack, two types of cells were formed. As shown in Table 7.7, two cells were formed based on fabrication properties and by switching some of the operations performed on machines P5, P7 and P8. The measure of constituents J5 and J8 is really less as compared to occupation J1, J2 and J3. So, it would non be advisable to save the machines P5, P7 and P8 entirely for these two occupations. So, it could be considered that the imperativeness store with 11 machines formed one cell.
In another attack, the simulation theoretical account was developed in which the machines with similar capacities were grouped together to organize the cell as shown in Table 7.8. The first bin of a batch selects the first available imperativeness in the cell assigned to that operation. If none of the imperativenesss are available, the bins wait until a imperativeness is available. After a imperativeness has been selected, all bins in that batch will be routed to the selected imperativeness for that peculiar operation. The production public presentation of this layout was compared with the base ‘push’ theoretical account stand foring current scenario. It was observed that monthly production of J2, J3 and J5 is drastically reduced while the addition in the production of J1, J8 and J9 is really fringy. Similarly, lead clip additions drastically and machine use besides reduces. Therefore, both the attacks have shown negative tendencies of steps. So, it was decided to follow the current layout as the best suited option.
Table 7.7 Cell formation based on fabrication properties

Cell No.

Press machines in the cell

Jobs manufactured in the cell

1

1, 2, 3, 8, 9, 11, 12
7 machines

1, 2, 3, 4, 6, 7, 9
7 occupations

2

4, 5, 7, 10
4 machines

5, 8
2 occupations.

Table 7.8 Cell formation based on machine capacity

Cell No.

Press machines in the cell

Capacity

1

4, 5

40 Short ton

2

7

80 Short ton

3

3

100 Short ton

4

2, 8, 9

110 Short ton

5

1, 10, 11, 12

160 Short ton

7.5.1.2 Line Balancing
Line reconciliation is a particular job for assorted type of production ( Schonberger, 1982 ) . The imperativeness store under consideration was analyzed for available and needed figure of shots. The analysis is presented in Table 7.9 for the month of January. It can be observed that the shots remain unutilized or balanced. The analysis for all the seven months showed similar tendencies except for the month of February and March. For the intent of computations, the overall minimal shots available were considered which are well lower than available for high volume occupations like J1 and J2. So, line reconciliation was besides non a concern for the imperativeness store.
Table 7.9 Capacity analysis for the month of January

Imperativeness

Jobs utilizing imperativeness and corresponding measure

Min. Capacity

Min. parts / twenty-four hours

Required shots

Balance shots

Occupation

Qty

Occupation

Qty

Occupation

Qty

Occupation

Qty

P1

J2

1128

J3

245

250

3500

1373

2127

P2

J1

2246

J2

1128

250

3500

3374

126

P3

J2

1128

J3

245

J4

316

J7

72

333

4662

1761

2901

P4

J8

157

J8

157

303

4242

314

3928

P5

J3

245

J3

245

J5

408

400

5600

898

4702

P7

J4

316

J5

408

J8

157

303

4242

881

3361

P8

J1

2246

J2

1128

J7

72

385

5390

3446

1944

P9

J1

2246

J4

316

J9

101

J9

101

286

4004

2764

1240

P10

J5

408

J9

101

J9

101

250

3500

610

2890

P11

J2

1128

J3

245

J9

101

J9

101

250

3500

1575

1925

P12

J2

1128

J6

273

J6

273

200

2800

1674

1126

7.5.1.3 Production Sequence
The constituents to be produced by imperativeness store includes some high volume occupations such as J1, J2, and J3 and some low volume occupations such as J7, J8 and J9. The sequence in which these occupations are scheduled affects the public presentation of imperativeness store. The simulation was carried out by scheduling the production from high to low ( on the footing of production volume ) and from low to high. The consequences indicated that in both the instances production lessenings and WIP increases drastically. So, the current attack of assorted type sequencing was maintained for ‘push’ and ‘pull’ theoretical accounts.
7.5.1.3 Raw Material Procurement Schedule
In the initial experimentation of ‘push’ type simulation theoretical account, some cases of ‘stock out’ state of affairss were observed. If the natural stuff measure in the shop was less than the twenty-four hours ‘s demand, the theoretical account calculated the figure of full bins that could be produced utilizing the bing natural stuff in the shop. The balance was added to the following twenty-four hours ‘s order.
Current procurance of natural stuff is in immense tonss bring forthing higher RMI.The public presentation of the sellers in footings of adhering to the measure and clip of bringing is really good. Average ‘On clip delivery’ public presentation is 99.24 % and the ‘right quantity’ public presentation is 95.50 % . Even though, the seller public presentation is moderately good, the works experienced arrests due to ‘non-availability of material’ on the one manus and high stock list of natural stuff on the other.
So, the new procurance agenda was developed to avoid the ‘stock out’ state of affairs with minimal possible natural stuff stock list. Assorted options such as agenda bringings after 5 yearss with and without opening RMI were considered. Still, some occasions of ‘stock out’ were observed. So, 5 % extra stuff was added to the procurance measure in order to counterbalance for possible rejections. Opening natural stuff stock list at the beginning of the simulation was assumed. The bringing public presentation in footings of quality and bringing timing was modeled as per paradigm execution.
7.5.1.4 Setup Time
Setup clip decrease is the most of import technique that enables JIT refillings. The set-up clip is the elapsed clip from when the last portion of the current tally is completed until the work centre starts running the first good piece of the following tally. Entire setup clip consists of the clip required readying, mounting and unhorsing, focus oning, dimensioning and puting measure, and test tallies and accommodations. For the imperativeness store under consideration, the mean set-up clip is 14.4 proceedingss, the maximal being 30 proceedingss and the lower limit is 10 proceedingss. Along with the other parametric quantities related to the apparatus procedure, apparatus clip depends on the tunnage capacity of the imperativeness and weight of the dies. Some larger machines like 3,000 dozenss with 35 ton dies, the universe criterion for set-up is 10 proceedingss, whereas Toyata was able to accomplish the set-up for similar machines in 3 proceedingss. The maximal capacity of the imperativeness in the imperativeness store is 160 tones and lower limit is 40 tones. Compared to the criterions, presently the set-up clip is really high.
The survey of set-up procedure at the imperativeness store under consideration reveals that it uses the traditional manner of puting dies. All the dies are stored in the rack built really near to the machine cell. Tooling needed for puting up is kept near to the rack. Forklifts, wires and ropes, and skidding methods are used to interchange the dies. Lot of accommodation work is performed to do a good portion during attempt outs. External set-ups are kept ready most of the clip, but still there are issues such as deficiency of be aftering due to some of import and pressing orders due to reshuffle of production agenda, unorganised readying and eventually, some hapless executing of the conversion. Sometimes, it is further deteriorated due to miss of preciseness equipment, no set control bounds, wear and rupture on tooling, fixtures, equipment, deficiency of criterions or mention points and non-documented work methods. The clip required for machine accommodations, trials to run into needed dimensions or quality facets is besides high. Other discretional clip taken by the compositors besides adds to the apparatus clip.
The set-up clip can be reduced significantly through focused and problem-solving low-priced attacks such as organizing a cross-functional squad ; separation of external and internal apparatuss ; standardisation of internal apparatus processs ; usage of standardised parts, tools and fixtures ; decease clamping system that works with a assortment of die sizes ; mounting line up blocks ; usage of preset-positions, gigues and fixtures, lasting mention lines and ram accommodations.
For the imperativeness store under considerations, the observation of current apparatus patterns and the setup clip required thereof, there exists a big potency to cut down the set-up clip based on the countries for possible betterment. For the intent of repairing the per centum decrease in apparatus clip, the simulations were conducted at 25 % less and 50 % less and 25 % more. With the 25 % decrease, alterations in production, lead clip and WIP was non much and discernible. Besides, the alterations reflected could be due to the random coevals of apparatus clip harmonizing to the exponential distribution. So, for the intent of change overing the system to JIT, the apparatus clip was reduced clip by 50 % , which is rather possible and practical.
7.5.1.5 Rejection Rate
The quality of the constituents being produced by the imperativeness machines is really of import public presentation index. For the imperativeness store under consideration, the mean rejection rate is 3.33 % , the maximal being 4.5 % and the lower limit is 2.0 % . The high per centum of rejection leads to decrease in concluding production measure, bit, rework and increased cost. Due to inability to run into the production agenda because of higher rejection rates, less handiness and higher MTTR, the company has to often run into the marks by overtime. In the imperativeness store, factors impacting reject rate are die quality ( design, wear and care ) , preventative care, proper apparatus, procedure monitoring and operator preparation.
Some minor undertakings related to constituents of brake pedal and door beam were successfully completed at the imperativeness store. It shows that some more continual betterment undertakings can be successfully executed to cut down the rejection rate. The simulation theoretical account was run by cut downing the rejection rate by 25 % and 50 % . The decrease in rejection rate provides seeable alterations in the end product. The betterment undertakings completed besides indicate that the decrease in rejection rate of 50 % is accomplishable by systematic analysis, betterment and control.
7.5.1.6 Supplier Quality Management
As mentioned above, the sellers are reputed and have a really good record of bringing clip and measure. On the quality forepart, the providers are executing moderately good. Out of 118 bringings over 7 months ; 69 times at that place was no rejection at inward subdivision. For staying 59 times, the mean credence was 91.54 % . The whole batch was rejected merely one time and was non considered in RM agenda. The natural stuff required for the imperativeness store is cut from the procured sheets. So, there are some rejections after shearing due to dimensional and geometrical issues. Supplier quality direction is ensured by puting rejection of inward stuff to zero.

7.5.1.7 Equipment Development for Reduction in MTTR
Equipment design and development are really betterments to the production procedure itself as it has a direct and significant impact on the cost, quality, and production clip of merchandises. Simple equipment is easy to manage and later reduces the MTBF, MTTR and improves handiness. Few alterations were made in the bought out machines to ease easy care, to cut down MTTR and better quality of production. These alterations are as follows:

Power relays were often neglecting due to fluctuation in electromotive force. Relays were mounted inside the machine near the electric motor and were taking a long clip to mend. The location of the relays was changed and was brought outside of the machine. The replacing clip was reduced from 40 proceedingss to a few proceedingss.
For the safety of the operator and to avoid idle shot, exposure detectors were mounted. It reduced the opportunities of accidents and dislocations.
The jobs of hiting, cleft, thinning and furrows were reduced by utilizing a customized padding cylinder.
The breakdown frequence of the bracket of the stacker was reduced by developing new mechanism.
The shock absorber pins were responsible for doing the hole oblong and faulty. The bearing country was increased by replacing the earlier little home base with a bigger diameter. Once it was successful in one machine, it had been horizontally deployed to all the machines.
The review and care of the clasp assembly was hard and clip consuming because of its location and weight. The squad developed the keeping mechanism for 160T machine which was utile to skid the constituents, cut downing the clip for review and care.

Together with the above alterations, rapid motion of the random-access memory during the return shot could besides be implemented. The observation of the causes of dislocation showed that the happenings of electrical jobs were frequent. The failure of parts such as contactors, spiral, relays, coppice, fuse, switches, wires, etc. was the major beginning of dislocation. Depending on the frequence, the spares could be made available in the box attached at the back side of the machines. It would ease easy handiness of the same for look intoing and replacing.
Therefore, decrease in MTTR by 25 % and 50 % were simulated for initial tallies of the simulation. 50 % decrease in MTTR was selected for concluding experimentation to hold noticeable alterations in the public presentation indexs and to suit for random coevals of values.
7.5.1.7 Handiness
Similarly, the losingss in the production clip were due to decease dislocation job, machine startup, quality defect and rework losingss, velocity losingss, manpower deficits, apparatus and accommodation losingss, stuff related job, seek out and minor arrests, power inaccessibility, and interrupt down losingss. It showed that assorted grounds were lending to the loss in handiness. The apparatus and trial clip could be reduced as explained in apparatus clip decrease. The preventative care of imperativeness machines and dies would cut down the arrests due to machine dislocation and die failure. The breakdown losingss and other care related losingss could be reduced by implementing preventative care. The computerized care information system would bring forth the agenda of care for each hebdomad which included hebdomadally, half annual and annual care activities. This information would be helpful in put to deathing the scheduled care. The preparation of the operator, formation of care and development squads would assist in bettering the handiness the machines. So, it could be considered that the handiness could be improved by 25 % .
7.5.1.8 Loading and Unloading clip
In other patterns such as burden and unloading clip, independent care was besides looked in. Loading and droping was done manually. The mean loading clip was 3.70 seconds while droping clip was 3.58 seconds. Use of turn uping pins, pokayoke, proper workstation design, stuff provender and storage system could be used to cut down the burden and unloading clip. Therefore 25 % decrease was assumed in lading and unloading clip.
7.5.1.9 Autonomous Care
Care that is performed by the machine operator instead than the care staff is known as independent care. It includes undertakings such as lubricating and fastening machine parts, cleansing, and reviews to observe abnormalcies and possible malfunctions at the earliest. Extra 15 proceedingss of clip was provided while implementing this pattern in the simulation theoretical account.
The company location is about 7Km from the OEM site and has third party logistics for the bringing. After each displacement the finished constituents are delivered to the OEM. In the extra 15 proceedingss of clip provided, the operators are supposed to execute independent care. The operators can run any of the imperativeness machines and besides aid during the apparatus of machines. Therefore, operators are involved in a assortment of related undertakings stand foring multifunctional properties of workers. Design for fabrication pattern besides could hold been considered by uniting some operations utilizing progressive dies. Human related patterns, being intangible in nature, were excluded during the simulation survey.
After the initial experimentation, the patterns to be included in the concluding experimentation and the degree of fluctuation were finalized. Table 7.10 shows the patterns and matching alterations effected while implementing a peculiar paradigm.