**Figure 9.**

*Different problems in laser bone.*

From the point of view of laser hole cutting, the most important issue is to maintain the optimal parameters of the laser beam. After a detailed analysis of the problem, it was determined that the employee has only one right program to run, but the thickness of the material changes. Thus, the location of the beam focus changes, which is crucial for the effective impact of the laser. An example of solving this problem is shown in **Figure 10**.

The above example is also a confirmation that sometimes rigid adherence to five questions may not give a satisfactory result; in the analyzed situation, one more question, the sixth question, was needed.

*Identification of Defects Causes: Ishikawa Diagram and 5 Whys in Theoretical and Practical… DOI: http://dx.doi.org/10.5772/intechopen.113990*

#### **Figure 11.**

*5 Whys of the problem in PC & software area.*

In turn, the analysis of the PC & Software area made the team think about why the laser often fails to start, despite a working computer and the right program. The 5 Whys results for this problem are shown in **Figure 11**.

Analysis of the Ishikawa diagram and the results of 5 Whys made it possible to conclude that the overriding issue is the efficiency of the device. All employees associated with this position are required to maintain the laser in this state. The operator has the greatest contact with the laser. His knowledge and general condition, indicated by the Man area, are important in the context of determining technological parameters. In addition to him, an important role is played by service technicians, electronics engineers, and programmers as people interfering with the construction and operation of the device. People can also have an impact during transport (and thus suppliers), when damage to components may occur, during assembly and organization of the station. Fortunately, the problem that was finally identified was trivial and was quickly eliminated.

#### **4.3 Bonding of materials**

In the gluing operations, various substances are used, necessary for the proper preparation of the surface of the materials before gluing. This diversity results from the type of bonded material, surface condition, selected adhesive mixtures, and gluing technology (surface preparation baths, rinsing, method of preparing the mixture, method of applying the adhesive, and method of curing) (**Figure 12**).

The problem of waste can be perceived in different ways in a plant. The Ishikawa diagram drawn for this problem made it possible to identify a number of reasons why a lot of waste from various materials and packaging contaminated with various substances remains after gluing operations (**Figure 13**).

Reflecting on the problem, attention was first drawn to the considerable amount of total waste that comes from the gluing process. 5 Whys for this thought process are shown in **Figure 14**.

On the other hand, by emphasizing the fact that gluing waste is hazardous waste, and additionally paying attention to its accumulation at workstations, 5 Whys may have a different course and result in other management decisions (**Figure 15**).

#### **Figure 12.**

*The problem of a significant amount of waste after gluing: (a) used mixing containers and brushes for applying adhesives; (b) plastic and glass packaging from degreasers and rinsing liquids; (c) metal packaging for adhesives and hardeners; and (d) plastic, glass, and pressurized packaging with various applicators for washing, preparing, and activating the surface before gluing.*

#### **Figure 13.**

*Ishikawa diagram for gluing.*

#### **Figure 14.**

*The problem of the amount of waste after gluing.*

*Identification of Defects Causes: Ishikawa Diagram and 5 Whys in Theoretical and Practical… DOI: http://dx.doi.org/10.5772/intechopen.113990*

#### **Figure 15.**

*The problem of hazardous waste after gluing at workstations.*
