Catheter ablation has become more prevalent in recent years because it has successfully modified or eliminated certain heart rhythm disorders. The device is used to reach the heart through a venous blood vessel with a size of 2.0-3.5 cm; hence the design of the device's motion mechanism parts must be compact and delicate. This project focuses on improving the motion control of wire assembly device for making catheter ablation. The main contribution of this manuscript is to design a new device for the assembly of the wire of catheter ablation by considering effect solving method for product development. Because the existing design has a problem in the difficulty for assembly of the small workpiece, then production process takes longer time and larger workforce demand. At the early step, TRIZ theory was applied to renew the design of the wire-cutting machine by analyzing adverse factors impacting the production process and improving opportunities, including the assembly process of motion control line components. Afterward, Analytic Network Process (ANP) method was adopted to select the best conceptual design with the lowest weight in some parameters. According to the ANP result, the best concept is given in scenario 3 with the lowest score at design difficulty, process difficulty, cost demand, equipment cost, and manufacturing cost by 0.9, 0.9, 0.45, 0.3, and 0.35 respectively. Finally, it is conducted by adding an axis function with an upper and lower cover. Lastly, after applying the new device according to the effect-solving method analysis, it impacted the efficiency percentage of assembly cycle time, equipment demand, and labor by 55%, 57%, and 57%, respectively.
Research Article
Performance Improvement for Catheter Ablation Assembly Using an Effect Solving Method
https://doi.org/10.21203/rs.3.rs-3084811/v1
This work is licensed under a CC BY 4.0 License
Journal Publication
published 28 Feb, 2024
You are reading this latest preprint version
Catheter Ablation
Workload requirement
TRIZ Theory
ANP
Effect Solving Method
Catheter ablation demand has dramatically improved because it is successfully used to modify or eliminate certain types of heart rhythm disorders [1] . It involves the introduction of one or more catheters into the left atrium of the heart by reaching via the venous system. It requires a puncture through the inter-atrial septum, controlled by radioscopic control [2] . Therefore, it is a safe and effective treatment option for patients with arrhythmias when the symptoms are sufficiently severe to affect their quality of life, such as when they interfere with work or normal daily activities and when they do not respond to other treatments, such as medication or cause side effects (fatigue, increased palpitations, dizziness or stomach problems) [3]. Conceptually, it works with the high-frequency or freezing energy through the wire as a conductor which is put into the thermoplastic, then delivered into abnormal heart rate. Rottner et al. [4] predicted that catheter ablation would have increased demand over the recent year due to its effectiveness in inpatient treatment. In recent years, Cardiac Ablation Technologies Market Size accounted for USD 4.8 Billion in 2021 and is projected to occupy a market size of USD 12.6 Billion by 2030, growing at a Compound Annual Growth Rate (CAGR) of 11.6% from 2022 to 2030 [5] . In contrast, regarding the manufacturing process, because of the small size of each part and tight assembly in order to provide a safe, easy, and reliable part for the therapeutic device, then it should be manufactured with strict quality by deciding materials, design, and processes [6] therefore, while the market demand is growth continuously, it needs the high cost of the procedure with skilled professionals.
There are four key parts that are required to develop a catheter product, including an ergonomic handle, an adjustable wheel or slider that, when manipulated, controls the deflection of the distal tip. This shaft comprises a flexible, braid-reinforced polymer tubular body and the distal tip, which deflects according to the user's input and through which the therapy is deployed [6]. Although the existing motion control line component assembly line has been improved many times by the development unit, by contrast, it still cannot be separated from the manpower and technical capabilities of the operators. The total operator demand for wire assembly is two operators. If the demand increases, the employee demand rises, then the next problem is an individual skill that needs longer time in practice. Furthermore, with the increasing demand for shipments, the production capacity has been in a tight state.
Effect solving method as a fundamental for improving the product is the alternative way to improve product quality as well as interface’s revenue growth. Some previous studies used various tools and methods according to effect solving method is successfully improve the quality of the new concept product as well as efficiency during manufacturing process, such as Quality Function Deployment (QFD) [7], Failure Mode and Effects Analysis (FMEA) [8], and TRIZ theory [9] [10]. Wang et al. [11] and Gao et al. [12] reported that by analyzing the effect to solve the problem, could help to improve product development by using problem identification, function analysis, key problem determination, effect solution, structure mapping, and scheme evaluation. In fact, the effect can connect the existing problem with potential solutions [13]. Hong et al. [14], Kremer et al [15] and Cooper [16] reported that the effect customer response can be used as a fundamental concept for product development. Therefore, as a basic concept for new design, we adopted a method of product development that consider effect as a guidance to redesign new device.
TRIZ theory (Teoria Reszenija Izobretatielskich Zadacz - Rus., Theory of Inventive Problem Solving - Eng.) is the product development tool that is commonly used to solve complex problem type [17]. It used for product design and development in order to fit with customer and enterprise requirement [10] [18] by considering environment effect and technology [19]. TRIZ theory can be used to analyze an effect in improving the effectiveness of a team because it links technical solutions and physical contradiction [20]. TRIZ theory was successful in helping for several design cases according to the problem experienced by user, such as a digital twin [19], design for additive manufacturing (DFAM) [21], environmental impact because of phosphorus [22], multi-operations creep flexural test rig [23] and deburring problem analysis [24]. In addition, TRIZ theory is also widely applied to improving medical equipment with a fairly complex production process, such as medical infusion therapy [25] [12]. It will work when there is a need to solve ‘wicked,’ complex problems that lead to a situation where the available knowledge does not provide an efficient and transparent solution [22]. Sojka et al. [26] reported that conceptually TRIZ is a good tool to improve the product development process, but it would be better if it could be combined with the other tool. One of the effective combination tools is the TRIZ tool combined with Q.F.D. (Quality Function Deployment) [27] [28] [29]. Conceptually TRIZ used an effect as a basic concept to improve the product design [11].
Due to the flexibility requirement of product design quality with shortened quality then, this research used the TRIZ tool to identify what customer needs, then it combined with Q.F.D. Finally, the purpose of this study is not only to introduce the design of the fast-threading mechanism used in wire-cutting equipment into the assembly fixture but also to use TRIZ theory to examine the entire assembly process, find out the improvement points that can reduce the process, and hope to reduce the demand for workforce and equipment investment.
2.1 Definition of the problem
There are two materials used for making the catheter, including thermoplastic tubing and heat shrink tubing. Because of the material used, then the customer identified catheters with good quality are strong, smooth, and flexible. And to meet that specification, it depends on material, tool, and delivery [30]
Catheter ablation, as we can see in Figure 1, it is a small flexible tube called a catheter that is passed through a small incision in the groin and up through the blood vessels to the heart. During the mapping process, the electrophysiologist uses a specialized catheter to create a three-dimensional image of the heart to identify areas of abnormal electrical signals that may be causing the arrhythmia. It can be seen in Figure 1b the cable has a small size, and it is conducted by three components which are detailed in Figure 1a, Spacer, small tube, and conductor. The material used for Spacer is SUS 304 stainless steel with a thickness is 0.10mm, and it is assembled with the 0.11mm square groove of the small tube. The height and width are only 0.01mm for assembly.
The material used for the small tube is SUS 304 stainless steel, the inner diameter of the red area is 0.2mm, which is used as a feature for assembly with the baffle; the height of the square groove in the green area is 0.11mm, which is a feature for assembly with the baffle. The material for the conductor is SUS 304 stainless steel wire, the green part is coated, the outer diameter = 0.18mm, the length = 1500mm, and the assembly gap with the small tube inner diameter of 0.2mm is only 0.02mm. The cable has small size, and for this reason it will be difficult to produce the part. Besides that, it will take more time. In recent days, due to its benefit, production has been rising daily, and production time and human resource numbers are also necessary considerations for its manufacturing process.
This study uses the TRIZ theory contradiction matrix to analyze the opposite parameters to find out the improvement of the welding jig design and assembly process, to solve the engineering parameters and to avoid deterioration of the engineering parameters and methods, redesign the assembly welding jig, and plan the assembly process, and invest in after delivery, statistical methods by using Minitab software were used to validate and also analyze the efficiency of improvement. Figure 2 is the detailed step of this study.
The four tools of TRIZ, evolution trend, resources, idealized design, and material-field method, are biased toward the product development market. By following research that used the TRIZ tool for product development [31], this research focuses on the improvement of the assembly process, it used 39 general characteristic parameters, 40 Invention Principles, which is linked into Contradiction Matrix. Therefore, the main goal of using TRIZ theory as fundamental concept improvement is reducing production cycle time, manpower demand, and equipment for the operation. Before identifying the problem for reaching the goal, firstly, we examine the design of the fast-threading mechanism used in wire-cutting equipment into the assembly fixture.
First problem, in the existing problem, there are two welding processes for manufacturing the motion control line, and there are two operators with 16 total processes, and it needs 165 secs to make per product. The welding jig must be disassembled and assembled three times, as well as the upper and lower machine tables, to complete a component. This is due to the small size of the workpiece, the limitations of multi-zone welding processing, and the characteristics of the laser welding process. During the process of laser welding stainless steel, nitrogen must be continuously blown for protection to prevent the weld pool from being oxidized due to contact with oxygen in the atmosphere, resulting in a decrease in bonding strength, therefore the workpiece with light weight is processed. In addition, it must be properly clamped to prevent the workpiece from being blown away or displaced by nitrogen.
Second problem, positions of the solder joints are almost spread in the area of the workpiece. Therefore, in order to handle the problem, it requires clamping area. The processing area must be divided into three places and processed three times, as shown in Figure 3a. We can see zone 1, then it followed by zone 2 and zone 3 as one group (denoted with red line). Zone 1 is worked by operator 1, then zone 2 and zone 3 are worked by operator 2.
Third problem, due to the consideration of clamping stability in the design of the existing assembly welding jig, the second stage of welding cannot be directly welded on the original welding jig. The workpiece must be removed and turned over, and the Zone 3 on the back of the semi-finished product is facing upwards before reinstalling the welding jig. This operation is also a part that tests the operator's eyesight and handholding stability.
Fourth problem, regarding the workpiece size, as we can see in Figure 3b, the diameter of the wire is only Φ0.18mm and must penetrate into the inner diameter of a small tube of Φ0.20mm. Although it has been assisted by a 20x optical microscope, it is still a test of the operator's vision and handholding stability.
Because not every invention principle can provide an effective solution to the corresponding problem, it is possible to screen out the most critical and contradictory fundamental factors so as to reduce the number of filtered and suggested invention principles [32]. Then those 4 problems point can be summarized into the following 2 points before analysis, first until third problem are denoted as light in weight and the clamping area is insufficient, and the second problem is fourth problem, denoted as difficult assembly of small workpieces.
The problem of insufficient clamping area of the control part stems from insufficient "weight." Then, possibility problem-solving direction is to increase the clamping device. However, there is a limitation problem that needs to be considered when adding a clamping device. According to 39 characteristic parameters, we found that parameter of #6, the weight of the stationary object, is a match for dealing with the problem "area." Comparing the intersection point of the weight of the #2 stationary object and #6 stationary object, we found that the suggested invention principles are 30, 2, 14, and 18, shown in Table 2.
After interpreting and assessing the applicability of the 30, 2, 14, and 18 invention principles suggested by the matrix table one by one, use #2 & #14 two invention principles, and their respective meanings are #2 Separation: Separation of processed and non-processed areas and #14 Surface: Use a curved surface instead of a plane
The factor that needs to be improved for "difficult to assemble small workpieces" affected assembly difficulty". The problem of "small size" is found from 39 characteristic parameter tables-#12 shape parameter; the limitation problem "assembly difficulty" is found from 39 characteristic parameter tables #33 parameter of operation difficulty product.
Compare the two parameters with the contradiction matrix table and obtain the invention principle, and compare the intersection point of #12 shape and #33 operation difficult. Therefore, the suggested invention principles are 1, 28, 13, 17, as shown in Table 3.
After interpreting and evaluating the applicability of the 1, 28, 13, and 17 invention principles suggested by the matrix table one by one, use the two principles of #1 & #28, and their individual meanings are #1 Segmentation: Through segmentation, objects can be easily assembled and disassembled and #28 system replacement: replaced by visual, auditory, tactile and other systems
According to those two problems, the applicable invention principles obtained after the contradiction matrix analysis include (1) #2 separation, (2) #14 curved surface, (3) #1 division, and (4) #28 system replacement. Table 4 cites the definition of 40 invention principles by Mazlan et al. [33], and a more specific description of the 4 suggested invention principles to ensure that the subsequent chapter 4 can be considered based on this description and then designed an improvement solution for the motion control line component assembly line that is easy to operate and has a reasonable process.
2.2 Resource Analysis
By following Chunlong et al. [19] study, in order to construct a TRIZ functional model, we determined the different types of objects that are represented by different modes. After we have obtained four suggested principles from the 40 invention principles, we constructed three functional model schemes, which are used to consolidate the interaction of existing manufacturing processes and existing equipment capabilities Conditions and gaps are explored to identify resource constraints. From Table 5, we gained three aspects as a parameter for designing the product: (1) fixture cost, (2) equipment cost, (3) manufacturing cost, and the weight is (1)>(2)>(3). C.T. is the abbreviation of Cycle-time duty cycle.
Since the existing manufacturing process must be equipped with two-stage workstations for welding operations, it can be seen from Figure 4a that four manual transfer operations from the welding area Zone 1 to Zone 3, in this scenario, needs four material handling movement four times so that it takes more production cycle time, then it impacts in manufacturing costs and equipment.
The existing laser welding equipment illustration process has been shown in Figure 4b, the process equipped with the fourth axis. Without changing the equipment specifications, it would cause the welding area Zone 3 to be suspended after the completion of Zone 2. Zone 3 welding can only be carried out after the surface-changing work of the welding jig is performed, which is where the current resources are limited.
Figure 4c is the scenario if the process adds a fourth-axis device. It can be illustrated if the laser welding equipment is added with the fourth axis and the fourth axis bearing welding jig, then the manual operation process of the welding area Zone 2 and Zone 3 can be transformed into a mechanical action process, and the welding jig can be changed by the fourth axis to reduce the working time of waiting for downtime and changing personnel.
The Analytic Network Process (ANP) is the common method that is used by some design engineering to select the best concept improvement [34]. Each of the alternative (design concepts) was given a numerical score to rank based on the relative comparison [35]. The ANP was used to select the best scenario to improve the new design of wire assembly device. For the selected concept, firstly we conducted the weight of each concept with score from 1-10. By analyzing those three possibility model scenarios, also by considering a real case then we added two more indicators, including fixture design difficulty and fixture manufacturing difficulty.
The multi criteria by using ANP used expert judgement to construct the weight of each parameter. Because the process improvement is including professional skill (the welding process improvement), therefore the judgement index used qualitative method, used professional qualification [36]. Then it was compiled into five possibility improvements with three scenarios, that showed in Table 5. The left column evaluates the pros and cons of the three schemes with a score of 1 to 10, and this analysis finally uses cost sensitivity as the evaluation standard. After determine the weight of each scenario, we gathered some information from the experts to determine the weight of each parameter (all parameters are equal to 100%) [37]. The weight distribution of the five indicators is carried out from the perspective of cost, and the results are shown in Table 5. The right column uses the product of pros and cons*weight as the index value, and it is expected that the index value should be as low as possible.
Finally, the result of sensitivity curve and the radar chart are drawn in Figure 5a and Figure 5b respectively. According to the figure, it can be clearly seen that the five indicators of schemes 2 and 3 are compared with the existing process scheme of scheme 1. After determining the weight of all parameters of all scenarios, then as a result scenario 3 becomes the best choice, with design difficulty, process difficulty fixture cost, equipment cost, and manufacturing cost by 0.9, 0.9, 0.45, 0.3, and 0.35 respectively.
Based on the results of the TRIZ analysis in we started to improve the design of the motion control line component assembly welding jig. The improvement design is based on Items detailed in Table 6, in which the overall required items for designing improvement products are #2, #14, #1#28, it is shown in Figure 6.
The detail of improvement according to TRIZ invention principles is shown in Figure 7. According to the separation principle of #2, before redesigning the assembly fixture, it is necessary to first Divide the welding and processing area that needs to be filled with nitrogen from the entire motion control line assembly and then find the clamping method from the separated non-processing area.
According to the principle of #14 and #1, using the curved surface principle, the clamping position points of the lower cover welding jig and the upper cover welding jig follow the shape of the workpiece to be clamped and made with a curved surface. This method has the effect of enlarging the area of the clamping area. In addition, the clamping design follows the characteristic curved surface of the workpiece. In addition to providing up-and-down clamping pressure, the circular arc surface can also limit the lateral movement space of the workpiece, making the clamping more stable. The improved welding jig adopts the design of the upper and lower cover plates, using the end of the small tube head and tail and the non-welding area of the bracket as the clamping points and the clamping points of the upper and lower cover plate welding jigs are processed with arc shapes to match the outer diameter of the small tube, so although the clamping area is not large, the workpiece can still be firmly wrapped between the upper and lower cover plates.
Considering principle #1, the eye guide mechanism is divided into two halves; one half is designed on the lower cover, and the other half is designed on the upper cover. When the upper cover is removed, there is an open space to take out the components, which overcomes the need for the long design problem of distance drawing and reclaiming.
Using the design concept of the eye guide, the guide features of the tapered hole are processed in half on the upper and lower covers, respectively. And a tapered guide hole can be formed between the lower cover plates, as shown in the red frame. Because the diameter of the guide hole opening is designed to reach 3mm, the wire of Φ0.18mm can be easily inserted at this time. In the opening of the guide hole, the guide wire through two sections of guide holes with reduced diameters, then penetrate into the inner diameter of the small tube.
By considering the #28 division principle, another purpose of the base auxiliary fixture mentioned in Table 4 is to be fixed on the work table for use with an electronic magnifying glass composed of a CCD+LCD screen so that the assembly and loading position can be fixed on the lens and visible Within the range, it saves the time to find the position of the workpiece first. The CCD+LCD electronic magnifying glass also greatly improves the discomfort of the operator's eyes when working under the optical microscope and will be able to carry out the loading operation more stably and intuitively.
Regarding the problem of turning over welding, the welding area of Zone 3 of the lower cover welding jig body only needs to exist when the small tube is placed. The purpose is to help prevent the small tube from falling when placing the small tube. When the upper cover welding jig is closed, a clamping force is generated. It is not needed after that, so it is considered to separate the features of this area from the lower cover welding jig, which is the key factor to realizing the welding of three areas in one process. First, separate the Zone 3 welding area features on the lower cover welding jig, and then add a "base auxiliary welding jig" and design a bump on the base auxiliary welding jig.
Cited Lee et al. [38] used the quality function deployment (Quality Function Deployment, Q.F.D.) table to examine the correlation between customer needs and service solutions and compared the objectives of this study with the design strategies adopted in Table 6 to make Table 7 and compare their correlations, if the average weight of the five solutions is 20% each, it can be seen that except DR4 and DR3 will be the main correlations, and DR2 is the lowest correlation.
4.1 Comparison of Process Differences Between Old and New Control Line Component Assembly Lines
The new design of assembly device can reduce production cycle time more than twice. Table 8 shows the difference in assembly operation before/after improvement. After improvement, operation time can be divided into 16 steps, and then it can be reduced into nine steps. Therefore, the less process worked, then the less cost of production demand. Before improvement, the welding zones are separated into three places with two operators, meanwhile after using new device, the welding zones are combined into one process, with all processes welding before and after are the same, by 30 secs.
4.2 Man-hour benefit analysis of old and new assembly lines
After introducing the improved motion control line component assembly fixture and assembly process into the production line and stabilizing production, the M.E.S. production management system determines production operation [39]. Then it was used to collect 100 work orders for the motion control line component assembly line before and after improvement (the number of productions for each work order is 300 groups). The actual production report data and the difference analysis and description are carried out one by one. Table 8 it showed the man-hours before and after improvement. Since the pre-improvement process is divided into two workstations, the total work cycle must be added to the man-hours of the two stations. The right column shows the integrated workstation after improvement.
Then to analyze the difference between two groups with different treatments, we used T-test analysis [40]. Minitab software to conduct T-test to analyze the average duty cycle difference value before and after improvement. The Mean value in the T-test table represents the average value (Table 9). The difference between the two = 98.6 seconds, which is better than the 60-second target set. In addition, the data is drawn into a box diagram, and the difference in the average duty cycle between the two can be clearly seen through the graphical display. Furthermore, Figure 8a shows the boxplot and normal distribution of comparative results before and after the improvement. It can be seen that after the improvement, productivity is significantly increases compared to before.
In fact, denoted by the normal distribution diagram in Figure 8a to observe the data distribution of the work cycle before and after improvement and the single factor variance analysis table test, the P-value is 2.45E-82 > F (shown in Table 10). Therefore, according to the hypothesis test principle, P-Value<0.05 means that the test result is significant [41], which can be used as evidence that the averages of the two groups are not all equal, and prove that the average duty cycle time value is different between the 100 batches in the two processes before and after the improvement.
Since the assembly operation in this study still needs to be done manually, the work cycle cannot be as stable as mechanical work, and fixtures and techniques are also influencing factors. Therefore, this section will further analyze the differences in the stability of the work cycle. The work cycle time data of 100 work orders are drawn into a distribution probability map (Figure 8b). It showed the blue data is before improvement, and the red data is after improvement. In addition to the apparent differences between groups, the standard deviation will be used to explain the stability of the work cycle. Also, the slope is shown as black before improvement<after red improvement, which means that the standard deviation of the work cycle distribution before black improvement=27.66 (about 150 seconds), the reason is just like the problem point of “The small workpiece is difficult to assemble and the difference in experience, vision and hand stability of the operators" is caused by the standard deviation of the data distribution after the improvement compared to red = 11.36 (about 50 seconds), and the difference between the two distributions is about 100 seconds. Finally, it can be borrowed. The standard deviation ratio is 11.36: 27.66 to specifically describe the improvement through this study, which has an improvement effect of nearly 60% on the stability of the work cycle.
4.3 Comparison of the difference in resource requirements between the old and new assembly lines
Table 11 is the 75-second average production cycle. As can be seen from the table, the main improvement results come from: The precise threading action assisted by the tapered guide hole of the welding jig, and the working time is reduced from 20 seconds to 5 seconds. In addition, the original three times of loading and unloading + three times of loading and unloading are reduced to 1 time each, reaching 95 Seconds saved. Assume that the annual volume is estimated at 1 million groups. Compared with the resource demand before the improvement, after the improvement, 4 laser welding units can be reduced. Requirements for equipment and 12 operators (three shifts). Therefore, by improving the new design, it can reduce production cycle time, laser welding demand, and workforce by 55%, 57%, and 57% respectively (Table 12).
The product development method can improve the production cycle of catheter ablation manufacturing process. This research used the effect solving method to determine the concept of a new catheter ablation assembly device design. By analyzing the effect, as a fundamental step, we used TRIZ method and then combined it with ANP method to evaluate the improvement factors of the whole system. The contradiction matrix of the TRIZ theory to find out the principle of the proposed invention and then develop a design to solve the three problems, including (1) reducing production cycle time by up to 60 seconds, (2) reducing workforce capacity requirements, (3) welding 1 & 2, 3 integrated into one. Then for the effectiveness of those problems, including (a) Tooling + process integration to reduce 100 seconds; (b) Welding jig design + electronic magnifying glass to assist in achieving; (c) Fixture design + 4th axis flip machining.
Through the various improvement benefits mentioned, then we know that the new generation of motion control line component assembly line improved by using the TRIZ method not only achieves the three research objectives but also comprehensively counts the actual improvement benefits.
The main contributions of this research include the following three aspects, (1) Production cycle time result. To identify the required specification for product installation, three TRIZ inventive solutions were made up from the TRIZ contradiction matrix: Segmentation (#1), Taking out (#2), Speriodality/curvature (#14) and Mechanics substitution (#28). Then, scenario three was chosen as the final product design; we obtained total production time from 165 secs to 75 secs; (2) Operator demand. Due to the shorter time needed for processing the assembly, then for one workpiece (one operation, it needs three operators); (3) Equipment demand. The total equipment for scenario three can reduce from 7 to 3 equipment demand. Therefore, overall, with scenario 3, the performance improvement percentage is 55%, 57%, and 57% for production time, laser welding equipment demand, and human resources, respectively.
Author contribution: Weiliang Hsu: writing research result report, Conceptualization, methodology, data curation, investigation, formal analysis, supervision, and visualization. Intan Mardiono: Writing manuscript, data validation, arranging research result into manuscript draft. Imang Eko Saputro: data validation, arranging research result into manuscript draft. Yiin-Kuen Fuh: supervision, Conceptualization, methodology.
Funding: This research is supported and funded by INTAI Technology Corp, Taiwan.
Conflicts of interest: Authors declare no competing interests
Acknowledgements
This research is supported and funded by INTAI Technology Corp, Taiwan. Also, we thank colleagues and experts for their help and reviewers for the improvement comments
- "Catheter Ablation," Metropolitan Heart and Vascular Institute, 2018.
- The Belgian Health Care Knowledge Centre (KCE) , "Catheter ablation of atrial fibrillation," Minister of Public Health and Social Affairs, Brussels, 2002.
- R. Parameswaran, A. M. Al-Kaisey and J. M. Kalman, "Catheter ablation for atrial fibrillation: current indications and evolving technologies," Nature Reviews Cardiology, pp. 210-225, 2021.
- L. Rottner, B. Bellmann, T. Lin, B. Reissmann, T. Tonnis, R. Schleberger, M. Nies, C. Jungen, L. Dinshaw, N. Klatt, J. Dickow, P. Munkler, C. Meyer, A. Metzner and A. Rillig, "Catheter Ablation of Atrial Fibrillation: State of the Art," Cardiol Ther, 2020.
- "Cardiac Ablation Technologies Market Size Will Attain USD 12.6 Billion by 2030 growing at 11.6% CAGR - Exclusive Report by Acumen Research and Consulting," Acumen Research and Consulting, 28 November 2022. [Online]. Available: https://www.globenewswire.com/news-release/2022/11/28/2563323/0/en/Cardiac-Ablation-Technologies-Market-Size-Will-Attain-USD-12-6-Billion-by-2030-growing-at-11-6-CAGR-Exclusive-Report-by-Acumen-Research-and-Consulting.html. [Accessed 19 April 2023].
- "Critical components, technologies, and designs to consider for catheter delivery systems," Spectrum Plastics Group, [Online]. Available: https://www.spectrumplastics.com/contact-us/. [Accessed 13 04 2023].
- M. Li and J. Zhang, "Integrating Kano Model, AHP, and QFD Methods for New Product Development Based on Text Mining, Intuitionistic Fuzzy Sets, and Customers Satisfaction," Big Data Modelling of Engineering and Management, 2021.
- C. I. Lorenzi and J. C. E. Ferreira, "Failure mapping using FMEA and A3 in engineering to order product development: a case study in the industrial automation sector," International Journal of Quality & Reliability Management, 2018.
- N. Şen and Y. Baykal, "Development of car wishbone using sheet metal tearing process via the theory of inventive problem solving (TRIZ) method," Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2019.
- J.-R. Chou, "A TRIZ-based product-service design approach for developing innovative products," Computers & Industrial Engineering , 2021.
- K. Wang, R. Tan, Q. Peng, Y. Sun, H. Li and J. Sun, "Radical innovation of product design using an effect solving method," Computer and Industrial Engineering, 2020.
- C. Gao, L. Guo, F. Gao and B. Yang, "Innovation design of medical equipment based on TRIZ," Technology and Health Care, pp. 269-276, 2015.
- B. Yong, D. Ma, . Y. Wang, H. Mi, C. He and P. Zhang, "Understanding the Design Principles of Advanced Aqueous Zinc-Ion Battery Cathodes: From Transport Kinetics to Structural Engineering, and Future Perspectives," Advance energy materials, 2020.
- Z. Hong and X. Guo, "Green product supply chain contracts considering environmental responsibilities," Omega, vol. 83, pp. 155-166, 2019.
- G. . O. Kremer, M.-C. Chiu, C.-Y. Lin, S. Gupta, D. Claudio and H. Thevenot, "Application of axiomatic design, TRIZ, and mixed integer programming to develop innovative designs: a locomotive ballast arrangement case study," The International Journal of Advanced Manufacturing Technology, pp. 827-842, 2012.
- R. G. Cooper, "The drivers of success in new-product development," Industrial Marketing Management, 2018.
- A. Czinki and C. Hentschel, "Solving complex problems and TRIZ," in Procedia CIRP, 2016.
- M. Li, X. Ming, L. He, M. Zheng and Z. Xu, "A TRIZ-based Trimming method for Patent design around," Computer-Aided Design, pp. 20-30, 2015.
- W. Chunlong, Z. Youcheng, M. V. P. Pessôa, Q. Peng and T. Runhua, "Conceptual digital twin modeling based on an integrated five-dimensional framework and TRIZ function model," Journal of Manufacturing Systems, 2020.
- I. V. Ilevbare, D. Probert and R. Phaal, "A review of TRIZ, and its benefits and challenges in practice," Technovation, pp. 30-37, 2013.
- S. N. H. Mazlan, A. Z. A. Kadir, M. Deja, D. Zieliński and M. R. Alkahari, "Development of Technical Creativity Featuring Modified TRIZ-AM Inventive Principle to Support Additive Manufacturing," Journal of Mechanical Design, pp. 1-49, 2021.
- A. Jama-Rodzenska, A. Bialowiec, J. A. Koziel and J. Sowinski, "Waste to phosphorus: A transdisciplinary solution to P recovery from wastewater based on the TRIZ approach," Journal of Environmental Management, 2021.
- M. Asyraf, . M. Ishak, . S. Sapuan and N. Yidris, "Conceptual design of multi-operation outdoor flexural creep test rig using hybrid concurrent engineering approach," Journal of Materials Research and Technology, 2020.
- C.-H. Cho, S.-W. Chae and K.-H. Kim, "Search for a new design of deburring tools for intersecting holes with TRIZ," International Journal of Advanced Manufacturing Technology, pp. 2221-2231, 2014.
- M. B. Mawale, A. Kuthe and A. Mawale, "Rapid prototyping assisted fabrication of a device for medical infusion therapy using TRIZ," Health and Technology, pp. 167-173, 2019.
- V. Sojka and P. Lepšík, "Use of TRIZ, and TRIZ with Other Tools for Process Improvement: A Literature Review," Emerging Science Journal, vol. 4, 2020.
- G. Caligiana, A. Liverani, D. Francia, L. Frizziero and G. Donnici, "Integrating QFD and TRIZ for innovative design," Journal of Advanced Mechanical Design, Systems, and Manufacturing, vol. 11, 2017.
- W. Yang, G. Cao, Q. Peng and Y. Sun, "Effective radical innovations using integrated QFD and TRIZ," Computers & Industrial Engineering, vol. 162, 2021.
- J. Weijie, "Research and Application of Mechanical Product Design Process Based on QFD and TRIZ Integration," Journal of Physics: Conference Series , 2020.
- "Catheter Bonding Technology Overview," Machine Solutions, 22 August 2020. [Online]. Available: https://machinesolutions.com/news-events/catheter-bonding-technology-overview/. [Accessed 13 04 2023].
- L. Fang, J. Ping, Z. Peng and T. Runhua, "Conceptual design process model for function and contradiction solving," in Proceedings of the 4th IEEE International Conference on Management of Innovation and Technology, ICMIT, 2008.
- H. P. Dave, "TRIZ: 40 Principles and Their Ranking by Contradiction Matrix," in 2nd International Conference for Convergence in Technology (I2CT), 2017.
- S. N. H. Mazlan, A. Z. A. Kadir, M. Deja, D. Zieliński and M. R. Alkahari, "Development of Technical Creativity Featuring Modified TRIZ-AM Inventive Principle to Support Additive Manufacturing," Journal of Mechanical Design, pp. 1-47, 2021.
- M. R. M. Asyraf, M. Rafidah, M. Ishak, S. Sapuan, N. Yidris, R. Ilyas and M. Razman, "Integration of TRIZ, morphological chart and ANP method for development of FRP composite portable fire extinguisher," Polymer Composites, pp. 1-16, 2020.
- M. Asyraf, M. Ishak, S. Sapuan and N. Yidris, "Conceptual design of creep testing rig for full-scale cross arm using TRIZ-Morphological chart-analytic network process technique," Journal of Materials Research and Technology, 2019.
- J. Becker, A. Becker and W. Salabun, "Construction and Use of the ANP Decision Model Taking into ccount the Experts’ Competence," in International Conference on Knowledge Based and Intelligent Information and Engineering Systems, Marseille, 2017.
- K. Shahroudi and H. Rouydel, "Using a multi-criteria decision making approach (ANP-TOPSIS) to evaluate suppliers in Iran’s auto industry," International Journal of Applied Operational Research, pp. 37-38, 2012.
- C.-H. Lee, C.-H. Chen, F. Li and A.-J. Shie, "Customized and knowledge-centric service design model integrating case-based reasoning and TRIZ," Expert Systems with Applications, vol. 143, 2020.
- "What is an MES (manufacturing execution system)?," SAP, [Online]. Available: https://www.sap.com/insights/what-is-mes-manufacturing-execution-system.html. [Accessed 13 04 2023].
- T. K. Kim, "T test as a parametric statistic," Korean Journal of Anesthesiology, vol. 68(6), pp. 540-546, 2015.
- B. Wang, Z. Zhou, W. Hongyue, X. M. Tu and C. Feng, "The p-value and model specification in statistics," General Psychiatry, 2019.
Table 1. Existing production process
|
Item Number |
Notes |
Steps |
Name of action |
Time-Consumption (Sec) |
|
A-Operator |
|
spot welding 1 station |
Small tube & baffle welding |
|
|
Zone 1 |
1 |
Put the small tube into fixture 1 |
15 |
|
|
2 |
On the stage |
5 |
||
|
3 |
Spot welding |
10 |
||
|
4 |
Get off the machine |
5 |
||
|
5 |
Remove the workpiece |
10 |
||
|
6 |
Remove the workpiece and put it in the centralized area |
5 |
||
|
B-Operator
|
|
spot welding 2 station |
Small tube & wire welding |
|
|
Zone 2 |
7 |
Put the small tube into fixture 2 |
20 |
|
|
8 |
Threading |
20 |
||
|
9 |
On the stage |
5 |
||
|
10 |
Spot welding 2A |
10 |
||
|
11 |
Get off the machine |
5 |
||
|
12 |
Turn the workpiece over and put it back into fixture 2 |
15 |
||
|
Zone 3 |
13 |
On the stage |
5 |
|
|
14 |
Spot welding 2B |
10 |
||
|
15 |
Get off the machine |
5 |
||
|
16 |
Remove the workpiece |
20 |
||
|
Total working hours |
165 |
|||
Table 2. Contradiction Matrix of Insufficient Clamping Area
|
Improving Parameter |
Worsening Parameter |
Solution Parameter |
|
#2 Weight of the stationary object |
#6 Area of a stationary object |
#35 Change the parameters #30 Film utilization #13 Reverse thinking #2 separate |
|
#30 Productivity |
#2 separate #19 Periodic action #22 Turn harm into benefit #37 Thermal expansion |
|
|
#6 Area of stationary object |
#2 Weight of the stationary object |
#30 Film utilization #2 separate #14 Curved surface #18 Mechanical vibration |
|
#30 Productivity |
#27 Throw away #2 separate #39 Inert environment #35 Change the parameters |
|
|
#30 Productivity |
#2 Weight of stationary object |
#22 Turn harm into benefit #21 Fast action #27 Throw away #39 Inert environment |
|
#6 Area of a stationary object |
#22 Turn harm into benefit #1 partition #33 Homogeneity #28 Mechanical system replacement |
Table 3. Contradiction matrix table of feeding difficulties
|
Improving Parameter |
Worsening Parameter |
Solution Parameter |
|
#8 The volume of a stationary object |
#12 Shape |
# 7 Nesting # 2 separate # 35 Change the parameters |
|
#12 Shape |
#8 Volume of a stationary object |
#7 Nesting #2 separate # 35 Change the parameters |
|
#30 Difficulty of operation |
#32 Color change #15 Variability #26 Copying |
|
|
#33 Difficulty of operation |
#8 Volume of a stationary object |
#4 Asymmetry #18 Mechanical vibration #39 Inert environment #31 Porous material |
|
#12 Shape |
#1 partition #28 Mechanical system replacement #13 Reverse thinking #27 Throw away |
Table 4. Comparison Table of Principles and Meanings of Suggested Inventions
|
Item |
Principle |
Design strategy descriptions |
|
1 |
Segmentation |
Divide a system or object into independent parts Increase the degree of segmentation of objects or systems |
|
2 |
Separation |
Separate distracting parts or properties from the target |
|
14 |
Spheroidicity/curvature |
The flat surface is converted to a spherical surface, and the part shape is converted from a cube (parallelepiped) to a spherical structure Instead of a straight surface or shape, use a curve or alter a flat surface Use cylinders, spheres, spirals, domes Change linear motion to rotary motion, using centrifugal force |
|
28 |
Mechanics substitution |
Replacing mechanical methods with sensory (optical, auditory, gustatory, or olfactory) methods or vice versa |
Table 5. Index benefit table
|
Index |
Scenario 1 |
Scenario 2 |
Scenario 3 |
Weight |
Scenario 1 |
Scenario 2 |
Scenario 3 |
|
|
|
|
|
|
|
|
|
|
Design difficulty |
2 |
6 |
9 |
10% |
0.2 |
0.6 |
0.9 |
|
Difficulty of processing |
3 |
8 |
9 |
10% |
0.3 |
0.8 |
0.9 |
|
Fixture cost |
1 |
3 |
9 |
5% |
0.05 |
0.15 |
0.45 |
|
Equipment costs |
9 |
3 |
1 |
30% |
2.7 |
0.9 |
0.3 |
|
Manufacturing costs |
9 |
3 |
1 |
35% |
3.15 |
1.05 |
0.35 |
Table 6. Invention principles and design response form
|
Item |
Principles of Discovery |
Design Policy |
|
2 |
Separation |
Separation of welded and non-welded areas |
|
14 |
Curved surface |
The clamping plane changes to a curved surface to increase the restriction effect |
|
1 |
Splitting |
Two-piece design for wire guide hole splitting to facilitate loading and unloading The loading aid features are split from the lower cover welding jig body to the base aid welding jig |
|
28 |
System replacement |
CCD+LCD electronic magnifier instead of visual optical microscope Fourth axis instead of manual flip |
Table 8. Comparison process before and after improvement
|
Before Improvement |
After Improvement |
|||||||
|
Operator |
Steps Number |
Name of activity |
Time-Consumption (Secs |
Operator |
Step Number |
Name of action |
Time-Consumption (Secs |
|
|
A |
1 |
Put the small tube into the fixture 1 |
15 |
A |
1 |
Put the lower cover plate to the base auxiliary fixture |
2 |
|
|
2 |
On the stage |
5 |
2 |
Put the small tube into the fixture |
15 |
|||
|
3 |
Spot welding Zone 1 |
10 |
3 |
Assemble the cover plate |
3 |
|||
|
4 |
Get off the machine |
5 |
4 |
Threading |
5 |
|||
|
5 |
Remove the workpiece |
10 |
5 |
Put on the line block |
5 |
|||
|
6 |
Remove the workpiece and put it in the centralized area |
5 |
6 |
On the stage |
5 |
|||
|
B |
7 |
Put the small tube into fixture 2 |
20 |
7 |
Spot welding zone 1-zone 3 |
30 |
||
|
8 |
Threading |
20 |
8 |
Get off the machine |
5 |
|||
|
9 |
On the stage |
5 |
9 |
Remove the workpiece and put in the centralized area |
5 |
|||
|
10 |
Spot welding Zone 2 |
10 |
||||||
|
11 |
Get off the machine |
5 |
||||||
|
12 |
Turn the workpiece over and put it back into fixture 2 |
15 |
||||||
|
13 |
On the stage |
5 |
||||||
|
14 |
Spot welding Zone 3 |
10 |
||||||
|
15 |
Get off the machine |
5 |
||||||
|
16 |
Remove the workpiece |
20 |
||||||
|
Total Production Time |
165 |
75 |
||||||
Table 9. T-test table
|
Two sample T-test and CI: Before Improvement, After Improvement |
||||
|
Sample |
N |
Mean |
StDev |
SE Mean |
|
Before improvement |
100 |
172.6 |
27.7 |
2.8 |
|
After improvement |
100 |
74 |
11.4 |
1.1 |
Table 10. One-way ANOVA result (analysis)
(a) Summary
|
Group |
Number |
Sum |
Average |
Variance |
|
Before improvement |
100 |
17260.65952 |
172.61 |
765.01 |
|
After improvement |
100 |
7404.1 |
74.04 |
129.02 |
(b) ANOVA result
|
Change source |
SS |
Degree of Freedom |
MS |
F |
P-value |
Critical value |
|
Between-group |
48758.94 |
1 |
48759 |
1086.66 |
2.4478E-82 |
3.889 |
|
Within the group |
88509.72 |
198 |
447.02 |
|||
|
Sum |
574268.7 |
199 |
Table 11. Before and after the improvement of the motion control line components
|
Estimate annual production capacity (pcs/year) = $1,000,000.00 |
|
|||||||
|
Part name |
Process name |
Processing time |
Daily processing (hr) |
Number of working days |
Number of weeks |
Number of units required |
||
|
Control line component (before improvement) |
Laser spot welding-1 |
50 |
22 |
6 |
50 |
1.89 |
||
|
Laser spot welding-2 |
115 |
22 |
6 |
50 |
4.36 |
|||
|
Total = |
7 |
|
||||||
|
Control line component (after improvement) |
Laser spot welding-1 |
0 |
0 |
0 |
0 |
. |
||
|
Laser spot welding-2 |
75 |
22 |
6 |
50 |
2.84 |
|||
|
Total = |
3 |
|
||||||
Table 12. Percentage of improvement
|
Number |
Productivity variables |
Before |
After |
Improvement |
|
1 |
Cycle time (s) |
165 |
75 |
55% |
|
2 |
Laser welding equipment (#) |
7 |
3 |
57% |
|
3 |
Workforce (#) |
21 |
9 |
57% |