DEFECTS DETECTION IN THE FIRST MANUFACTURED MODULE-ENSURING ERRORS FLOW IN THE GARMENT MANUFACTURING PROCESS

Quality control is necessary quality management activity. It doesn’t create values but it contributes to more successful work in the company. It ensures that the tasks set out in the plan are accomplished in a timely, rational and cost-eff ective manner. In this paper an approach to assessing the quality of the fi rst manufactured module in the production of clothes is made. Defects that reduce the use value of clothes, and their frequency caused because of a poor quality were detected. With use of Ishikawa diagram, the causes for defects occurrence were identifi ed, and their elimination was initiated.


INTRODUCTION
In the past, quality was considered as a task of the fi nal control, which means that at the end of the production process the controllers separate the defective products from the quality ones. However, over the time this system proved to be slow and expensive, because controlling the products only at the end of the production process can result with a higher number of defective products, and that can lead to a quality products obtaining, but at higher price. The next stage in the control development is focused to prevent defects occurrence, which imposes control at all stages of the technological process. With this approach, any omissions related to machines, man, raw materials can be detected and actions for solving can be made. Contemporary control is focused on a defects prevention [1,2,3].
Because the quality of a product is created during the production process, it is necessary: To form a complex of business processes, starting from the entry of raw materials to a fi nished product; To select methods for examining the working process; To select methods and instruments for the working process; Determine the control, depending of the working process, in other words to fi nd the quality indicators -what should to be controlled; The standardization of the meaning of those indicators, the category of defects, etc; To determine the liabilities of the control, that are terms of the operators and controllers; To implement verifi cation method and methods for verifying regulations and measuring instruments. To indicate those places that are subject to statistical regulation by applying control cards as well as the type of control card; To determine the methods and measures for action if deviations occur; Prepare a control card for the quality of business processes in which all technological operations are given, each stage of production and the quality of work in it is considered, but taking care to choose the appropriate instrument to achieve proper control [4,5,6].
In this paper is made an approach to assess the quality of the fi rst production module, in the clothes production. Detecting certain defects, which reduced the use value of clothing, and have serious impact in the overall costs caused due to a poor quality, was also made. With the use of Ishikawa diagram, the causes of defects occurrence were determined, and their elimination was approached [7,8,9].

EXPERIMENTAL
The model of women skirt that is subject to this analysis is shown below (Fig. 1).

Figure 1: Front and rear part of the women skirt
In the process of the model production, was made an approach to quality control of the fi rst manufactured module. According to the company's standard operating procedures, when a new model gets in the production line, accessed to the so-called production of the fi rst module, which always amounts to 1.5% of the total order, which means one level below the specifi ed level of acceptable quality (AQL) in the company, which is 2.5%. During the production of this fi rst module, the technologist together with the line controllers have the task to detect possible defects in the performance of each technological operation. Based on the received information, the production technologist is obligated to analyze and eliminate the possible causes for the occurrence of the registered defects. Table 1 shows the work order, which defi nes the number of ordered pieces, the number of pieces from the fi rst manufactured module as well as other informations that are an integral part of the work order. Table 2 shows the plan of technological operations for the preparation of the model of women skirt.

RESULTS AND DISCUSSION
The obtained results from the control during the production of the fi rst module are shown in Table 3. Total 20 From the obtained results (shown in Table 3) can be noticed that the largest percentage of registered defects in the fi rst manufactured module, as much as 75% belong to the defect -holes on the side seam, which occurs at the preparation of the technological operation under serial number 7.1.  The defect holes on the side seam occur in almost all manufactured pieces of the fi rst module intended for testing. This is warning for an unstable fl ow of production and production of low-quality products. In order to eliminate this defect, the most important thing is to detect the causes that lead to his occurring, as well as fi nding an appropriate solution. For that purpose, the Ishikawa diagram ( Figure 3) has been applied, which presents all the factors that have an impact on the process of production of women's skirt, and are possible causes of the defects that have the largest role.

The number of defects in the technological operation 3.3 (belt ironing) is also high and it occurs imme-
One of the possible factors (for the occurrence of the defect holes on the side seam) is the machine, respectively adjustment and needle (Figure 3). For the preparation of the technological operation 7.1 (sewing side seams) was made the wrong choice of needle size as well as the wrong choice of transport gears during machine setup. The defect is shown on Figure 2.
To test whether the wrong choice of needle size and the wrong choice of transport gears are the main causes for the defect (holes in the side seam), new samples were sewn. It was selected a type of needle with a medium sphere head and needle with numeration Nm 65./9 , instead of the previously used needle with numeration Nm 75/11 with normal conic head. The transport gears with higher density and lower inclination were also applied ( Figure 4). The pattern of the seam sewn with a new machine settings is shown on Figure 5. For the other defects occurring, it was noticed that the main cause is the man. That indicates that the line controllers should pay more attention in controlling operators who are working on these operations, to achieve a stable and quality course of the production process without variations for defects repair.
In addition, Table 4 shows the registered defects in the fi nal production control. With the application of inter-phase control and control in the fi rst manufacture module, the detected defective products did not exceed 2% of the total produced pieces of women's skirt. This indicates a steady fl ow of production process, without additional operating losses due to poor quality, caused by machines, materials and man.

CONCLUSION
From the obtained results can be concluded that the inter-phase control can contribute to improve the course of the production process, in the meaning to provide a stable and no defective fl ow.
According to the results in the fi rst manufactured module several defects were detected, which reduced the value of the product, and represented potential complaint by customers.
The largest percentage of registered defects in the fi rst manufactured module, as much as 75% belong to the defect holes on the side seam, which occurs at the preparation of the technological operation under serial number 7.1.
Applying the Ishikawa diagram were detected the reasons (factors) for this defect occurring. According to the results from the Ishikawa diagram it was concluded that one of the possible factors that have impact of the defects occurring was the machine, respectively adjustment and needle. That means that was made the wrong choice of needle size as well as the wrong choice of transport gears during machine setup.
To test whether the wrong choice of needle size and the wrong choice of transport gears are the main causes for the defect (holes in the side seam), new samples were sewn.
The type of needle was changed-the previously used needle numeration Nm 75/11 with normal conic head was replaced for a needle with a medium sphere head and numeration Nm 65/9. The transport gears with higher density and lower inclination were also applied, so the number of defects was reduced.
For the other defects occurring, it was noticed that the main cause is the man, which indicates that the line controllers should pay more attention in controlling operators who are working on these operations, to achieve a stable and quality course of the production process without variations for defects repair.
With the application of inter-phase control the number of defects began to decline, and this refl ects in the fi nal control results, indicating a stable process, with 1.49% defective products. This means that the goal has been achieved, the quality is satisfactory, and operating losses due to poor quality were minimized.