**3.5 Part five: Finishing in leather products manufacturing**

Finishing is the final process given to a garment or goods in order to achieve good appearance, desirable feel and look and to impart some important, and durable and functional properties.

*Significance of "Quality Control" in Leather Goods and Garment Production DOI: http://dx.doi.org/10.5772/intechopen.104494*

#### *3.5.1 Classification of finishing*

Finishing in leather products manufacturing can be classified according to the nature of the finish such as Kawabata's Evaluation System for Fabric-KES-FB and the degree of performance (ISO11644:2009). **Figure 3a** and **b** show these classifications.

#### *3.5.2 Edge coloring*

**Sand edges:** this is done by using emery paper to sand the edges and to arrange many belts/straps of the same size side by side on a flat table and sand simultaneously. This will ensure that all the leather layers are even and square and that any residual glues or finishes have been removed. **Figure 4** shows edge coloring in industry.

**Applying color:** this is done either by using *a* machine or manually. For manual operation, *the* use of dye box like Fiebing's dye will make it simpler. Keeping the dyed edge by facing up for air*-*drying before applying on the opposite edge is worthy. After the other side got dried, one can paint the opposite one and keep the same way one has done previously. It can also be applied during the second round if necessary. This method is used everywhere globally even though manual coloring is preferably practical in Ethiopian leather products manufacturing firms. **Figure 5** indicates the application of color with the aid of a machine.

**Applying filler:** the leather filler paste is a white compound that can be air- or heatdried and requires re-coloring with a leather repair pigment after its application. The

#### **Figure 3.**

*Classifications based on (a) the nature of finish (KES-FB) and (b) the degree of performances as per ISO11644:2009.*

leather filler remains flexible, durable, and natural to the existing leather surface. It is used to fill the edge surface and results in smoothness to the edge's surface (see **Figure 6**).

**Wet and soap:** the edge of the leather can be wetted using a sponge or piece of trimmed woolskin. The outcome will be a slick/polished rounded edge.

**Burnishing:** this is accomplished by briskly rubbing the canvas against the edge of the belt until the edge is smooth. A canvas wrapped around a motorized wood

**Figure 4.** *Edge coloring in practical.*

**Figure 5.** *Applying color with machine.*

**Figure 6.** *Leather filler paste.*

*Significance of "Quality Control" in Leather Goods and Garment Production DOI: http://dx.doi.org/10.5772/intechopen.104494*

**Figure 7.** *Scissors for trimming.*

**Figure 8.** *Soldering iron used for thread burning.*

burnishing wheel which speeds up the process could be used herein. However, care should be taken not to over-burnish, which will result in a rough edge.

**Hand burnishing:** this is done by means of a clean cloth that rubs the edges removing hence, any residual dye and determining thus, if the second coat is necessary.

**Polish:** at this point, paraffin is applied to the edge of the belt and burnished again and again. Denim works well here if burnishing is done by hand. Once one is satisfied with the finish, one can polish to a high luster with a dry cloth [9].

**Finish:** after the edges are polished, final finish is applied.

#### *3.5.3 Trimming: Hand trimming and trimmer machine*

It is preferred to use thread trimmer machines as it reduces trimming costs, increases production, uses unskilled help, eliminates scissor damage, keeps trimming area clean, and reduces cleanup cost. One can choose between different clipper blades and motor control for diverse material. Scissors can be used for trimming (**Figure 7**).

**Thread burning:** it can be manual with a candle or by means of soldering iron (**Figure 8**).

#### **4. Discussion**

The quality control concept is very useful especially for exports of branded products. Apart from the general knowledge and experience of the author in the sector, secondary sources were used from institutions such as the Ethiopian Leather Industry Development Institute (LIDI), Ethiopian Leather Industry Associations, and medium- and large-scale leather products manufacturers. The LIDI laboratory

was accredited from SANAS (South African National Accredited System) so as to support the leather sector with various laboratory testing (i.e. physical, mechanical, and chemical) services in 2012. Furthermore, the LIDI laboratory was also accredited from the Ethiopian National Accreditation Office (ENAO) in the same year.

With this responsibility, LIDI has been serving Ethiopian leather manufacturing firms by laboratory testing, technical training, quality management system (QMS), and quality control and quality assurance tools implementations. Under the Twinning program, which was made between LIDI and the Federal Democratic Republic of Ethiopia, FDRE, Ministry of Industry on Ethiopian side, and CSIR – Central Leather Research Institute-Council of Scientific and Industrial Research, India, in association with Footwear Design and Development Institute (FDDI), India, LIDI's R&D laboratory state of the art was created to meet the requirements and demands of leather and leather products in order to meet and ensure international quality standards [10].

Most of leather goods and garment manufacturing companies in Ethiopia use smell test, function test, and color fastness check on leather accepting it as internal


**Table 2.** *Leather physical testing.*

#### *Significance of "Quality Control" in Leather Goods and Garment Production DOI: http://dx.doi.org/10.5772/intechopen.104494*

company policy, as it matches with some of global/international standards in this aspect (ASTM D1296, ISO 11640, ISO 11641, SLF 401, IUP 470).

Apart from common quality parameters, there are also other leather goods-specific quality parameters. Items made from real leather or imitations, such as PU, which are very popular, should be treated accordingly. However, leather goods and garment manufacturing companies prefer to use simpler (by observation and manual tests) methods, whereas other manufacturers in footwear subsectors could use more test methods as per international standards in order to check, for example, grain structure, thickness, apparent density, shrinkage, flex resistance, water resistance, and so on as per ISO 2589:2002, ISO 2420, ISO 5402, ISO 3380, ISO 5403. That is because, footwear products are highly vulnerable to damage, and hence, their suitability to use needs to be assured before reaching the end users. **Table 2** provides a summary of physical testing standards for leather that could be recommended by the author to be used so as to improve productivity and reduce defect rates, rework, and waste.

Regarding the effect of human factors in product quality, it is the author's view that most quality problems are caused primarily by a lack of interest or care on the part of the worker in the production department. However, it is usually not only the worker who is responsible for this but also the conditions necessary to carry out the work correctly often do not exist. For example, instructions may be inadequate, the incoming material may be defective, the machines may not be capable of producing goods of the required quality, and proper conditions for conducting inspection of the product are not given to the workers, and so on. The study done by joint consultancy of Ethio-Indian twinning project in collaboration with the Leather Industry Development Institute (LIDI) and the Footwear Design and Development Institute (FDDI) of India approves this fact [11]. **Figure 4** (in Section 4.1) shows that inadequate instructions, which accounts for about 28% caused the rest effects. Effective understanding of the worker to the instructions in every step of production will surely lead to more pleasant effects on the product quality. However, although workers may not have control over these factors, they may though lead to defective work. **Figure 9** shows Pareto analyses of one factory.

In Japan, it is generally believed that 40% of quality problems are caused by poor product design, 30% of quality problems are due to wrong or defective materials being purchased from suppliers, and the remaining 30% are due to errors made during the manufacturing process [12]. One could argue that any other quality problems

#### **Figure 9.**

*Result of Pareto analysis for ELICO-universal leather products unit. Source: Twinning report [11].*

in manufacturing are caused in equal proportion by managers (by not providing adequate training for workers) and by workers (by not paying adequate attention to machine settings).

Regarding defects observed in goods and in garments manufacturing listed in the following section are common examples of deficiencies in leather products manufactured in Ethiopia:

**Sewing defects:** open seams, wrong stitching techniques, non-matching threads and missing stitches, improper creasing of the garment, erroneous thread tension and raw edges are some of the sewing defects which can affect the garment quality adversely. Firms mitigate these types of defects by providing continuous on-the-job trainings for sewing operators.

**Color defects**: this category includes color variations between the sample and the final garment, wrong color combinations, and mismatching dyes' that should always be avoided. Leather issuers check this in store for every order with the help of leather sorter or in-process quality inspector.

**Sizing defects: this** refers to wrong gradation of sizes and difference in the measurement of various parts of garment-like sleeves of XL size for a body of L size garment that can deteriorate the garments beyond repair. Though tanneries use leather grading machine during production, Ethiopian leather goods and garment manufacturing firms usually identify and mitigate these defects by cross-checking cut components visually.

**Other defects:** this group entails broken or defective buttons, snaps, stitches, different shades within the same garment, dropped stitches, exposed notches and raw edges, fabric defects, holes, faulty zippers, loose or hanging sewing threads, misaligned buttons and holes, missing buttons, needle cuts or chews, pulled or loose yarn, stains, unfinished buttonhole, short zippers, inappropriate trimmings, etc. These defects, unless tackled at the very beginning, and/or quality assurance is undertaken in every step, could lead leather products manufacturing companies to be less competitive and affect in turn their existence. Due to globalization and acceptance of Ethiopian leather products to export markets, manufacturers of leather products are obliged to implement various quality improvement tools including QC/QA. Thus, respective process and final quality checking parameters have been posted in front of operators in each section along with visual defective and free cut components. This method encourages operators to think about quality issues in addition to their duties of – say – cutting, table work, sewing, and finishing.

Concerning defect control at the finishing section, various final quality control parameters are used that include trimming, thread burning, glue erasing, pattern vs. assembly correspondence, thread tension, leaving broken stitches and skipped stitches, and stitches too far or too close to the edge.

As for Ethiopian leather products manufacturers, the defect control parameters during the final inspection stage include aspects such as:


*Significance of "Quality Control" in Leather Goods and Garment Production DOI: http://dx.doi.org/10.5772/intechopen.104494*

