Advantages of Robotic Cutting Over Manual Cutting in GRP Materials

Summary

Rapidly growing population worldwide and expanding industrialisation have made more efficient use of limited natural resources and sustainability among the most important objectives of our time. Technological advances ease life and enable globalisation while causing competition to spread across the world and every sector. Due to these new conditions created by competition, producing more with fewer resources is no longer a choice for companies but a necessity for their continued existence. Our company, competing in the global arena, develops projects with this awareness. Operating with this perspective, our company is ranked among the top 3 firms active in the water parks and entertainment sector worldwide, having carried out more than 3,000 projects in 103 countries.

1. Introduction

Cutting, drilling and edge trimming operations of CTP materials are performed manually across the entire composite sector, with the exception of aviation and aerospace. The variable nature of part shapes, complex surfaces and multiple angles make automation quite difficult. Edge trimming and drilling operations of CTP materials comprise two of the most important stages in our facility's processes. Prior to robot cutting, these operations were performed entirely by manual labour using stone motors and drills. With the transition to automation, edge trimming and drilling operations began to be performed with robot assistance in a controlled environment. With the robot project we implemented, we have demonstrated to the entire CTP sector that trim and drilling operations can be performed under suitable conditions through automation. The project objectives can be stated as making more efficient use of resources in production, reducing production costs and creating a healthier and safer working environment for employees. For this purpose, the product is transported using a specially designed rail-based part holder fixture for the robot's cutting area. There are approximately 400 types of parts in terms of product variety. Therefore, the system must be informed and introduced to which part will be cut. The operator places the part in the fixture by setting a specific zero point and reads the barcode on it to identify the part for cutting. As the part enters the cutting area with the aid of the rail fixture, the finished cut and drilled part exits through another fixture. Two loading fixtures working simultaneously ensure that while one part is being processed, another is being loaded into the system. This reduces part loading and unloading time to zero. With the automation system, cutting is performed in a closed area. Loading and unloading operations are performed outside the cutting chamber, and the parts to be trimmed and drilled are automatically transported to the processing area with the aid of the developed fixture. Thus, workers using the automation system work outside an environment with dust exposure. This reduces occupational accidents and exposure. Beyond all these benefits, CAD data designed in a computer environment and CAM programs ensure cutting and drilling operations are performed at desired dimensions with zero errors, resulting in a 10% reduction in the subsequent finishing station.

Figure 1. Post-mould manual operations on CTP materials, cutting.

Figure 2. Post-mould manual operations on CTP materials, drilling.

Figure 3. Modelling of CTP robot cutting and drilling automation system.

Figure 4. CTP robot cutting and drilling automation system.

Figure 5. Comparison of CTP material robot and manual cutting time.

Figure 2 compares robot and manual cutting times for CTP materials, and Figure 3 compares robot and manual cutting times on a part basis. The graph shown in Figure 5 compares slot opening times for CTP materials between robot cutting and manual cutting. Figure 6 shows an example of a slotted mould part.

Figure 6. Slot opening in example mould part using robot automation system

Figure 7. Part-based time comparison of CTP material in robot and manual cutting.

The graph shown in Figure 6 provides comparisons of total times for cutting and drilling operations for several example mould types between robot and manual cutting. In conclusion, a filter with 100 slots can be opened with a robot in 100 minutes, while this time reaches 900 minutes in manual operation. Additionally, with robot cutting, operations are completed in shorter times and smoother results are achieved.

2. General Conclusions

With the transition of edge trimming and drilling operations from manual cutting to robot cutting with automation system, the area allocated for these operations has been reduced from 848 m2 to 60 m2, achieving a 93% reduction. Since operations in this area are performed by operators, ventilation runs 50 cycles per hour. Nevertheless, while the legal occupational exposure limit (OEL) for personal dust exposure is 5 mg/m3, process measurements can reach 24 mg/m3. For this reason, in addition to ventilation, personal protective equipment (PPE) must also be used. With the automation implemented, cutting is performed in a closed space of 60 m2 area and 5 m height, and since there is no operator inside, 20 cycles per hour of ventilation is sufficient. This reduces total ventilation volume from 42,440 m3 to 6,000 m3. Solely due to volume reduction and the absence of operator presence in the process environment, annual energy savings amount to TRY 202,000. Additionally, when the reduction in illuminated area and consumption of other equipment are included, annual savings reach TRY 232,000. Particularly the cutting operation is performed in an environment with considerable occupational accident risk and heavy dust. As dust exposure values can reach 24 mg/m3 and the legal exposure limit is 5 mg/m3, workers are provided with PPE. In 2013, at considerable cost, equipment including full-face masks, special suits, special gloves, shoes and other items were allocated to workers as PPE. With transition to the automation system, a 92.3% improvement in annual PPE costs was achieved at the department level. Additionally, our facility has experienced a total of 7 occupational accidents in the cutting operation to date: 1 major and 6 minor. Although our facility provides necessary training and supplies PPE, deploying operators in dangerous work leaves the door open to accidents. For this reason, following the principle of reducing hazards at their source, in the new process operators remain outside the cutting area and PPE requirements are minimal. Summarising the improvements achieved: in 2014, man-hours spent per ton in the trimming operation decreased by 50% compared to 2012. PPE costs were improved by 92.3%. The average time spent per part in trimming was reduced from 14 minutes to an average of 4 minutes. The scrap rate resulting from faulty trimming improved by 99%. The area required for the trimming operation improved by 93%. The number of operators working in the trimming operation was reduced from 8 to 4. There was a 100% improvement in occupational accidents resulting from trimming operations. Mehtap Türkmen Research and Development Specialist Polin Waterparks       Çağla Yarmacı Process Engineer Polin Waterparks     Mehmet Ekmen CAD - CAM and Robotics Programming Engineer Polin Waterparks