Applied Mechanics and Materials Vol. 761

Abstract: Innovative developments of hollow cellular mat for lightweight structure must satisfy sustainability, fit for purpose and optimize design concepts. However, such materials necessitate appropriate cutting technology to allow trimming and shaping operations to be easily carried out on an excessive porous and perhaps non uniformity nature. This paper presents a work that aims at studying the machinability of porous cellular mat using a newly innovative cutting technology. A large structure of vertical bandsaw has been fabricated to cut the product with the size of 1m (width) x 1m (height) x 1m (long). The systems also equipped with a feeding table and strong structure frame to avoid product shifting during the cutting operation. The surface integrity showed minimum deformation with uniformed direction of surface removal marks. The cutting technology developed in this study is suitable for the hollow cellular mat for its simple trimming and shaping process and fine surface profile.

Abstract: A syringe is a simple piston pump consisting of a plunger that fits tightly in a tube. The plunger can be pulled and pushed along inside a cylindrical tube (the barrel), allowing the syringe to take in and expel a liquid or gas through an orifice at the open end of the tube. The open end of the syringe may be fitted with a hypodermic needle, a nozzle, or tubing to help direct the flow into and out of the barrel. Syringes are often used to administer injections, apply compounds such as glue or lubricant, and measure liquids. The reuse and abuse of syringe has led to cross-infection of diseases; thus, the need of single use safety syringe arises. Single use safety syringe is able to prevent the abuse of syringe. Many inventions have been produced; the most common are through-push retract breakable safety syringe, rotary plunger retractable safety syringe and release-ring breakable safety syringe. A new type of single use safety syringe Piston Break Safety Syringe is discussed in this paper. The new Piston Break Safety Syringe has similar design with the widely used safety syringe; hence, it makes it easier to be adapted by the users due to its similarity, since no extra training is required. The cost should be equivalently low due to the similarity in size, design and number of components.

Abstract: Life Cycle Assessment or LCA method is believed to be a good solution to improve sustainability in a manufacturing process. This method allows designers to identify opportunities to improve the environmental aspects of products at various points in their life cycle. In this paper, the implementation of LCA through the development of an Environmental Impact Assessment Tool (EIAT) is demonstrated via a case study of Volkswagen pulley crankshaft. EIAT is a tool that aids designers to improve the environmental impact in a manufacturing process by designing or producing products with minimal environmental impact and minimal use of resources, such as the material and energy. EIAT also offers the optimization of design solutions to reduce potential environmental impact of a specific product according to its design features. A pulley crankshaft was modelled in a CAD system where the form is fixed to maintain its function. Pulley crankshaft features, such as the type of material, diameter of pocket, stock thickness and diameter are the parameters that were optimized through the Genetic Algorithm encoded in EIAT. EIAT was validated with Eco-It (an established LCA tool) and with actual experiments. Results show a difference of less than 9% error between EIAT with the results produced by Eco-It and the actual experiments.

Abstract: Back pain is one of the prevalent injuries that occurs among Malaysian industrial workers. This is due to manual lifting task. Minimal studies have been conducted to determine the effects of manual lifting on psychophysical experience and heart rate of Malaysian population. The objective of this study is to analyze the psychophysical experience and heart rate of Malaysian in manual lifting task. The lifting task was experimented at various lifting heights (55 cm, 75 cm and 140 cm); loads with masses of 5 kg, 10 kg and 13 kg; and twist angles (0°, 45° and 90°). Six male and six female Malaysian students participated as subjects in the experiment. The Likert Scale was used to evaluate the psychophysical experience; meanwhile the heart rate monitor (Polar FT2, Finland) was applied to measure the heart rate. This study discovered that the psychophysical experience recorded the highest rating when performing lifting test at maximum load mass (13 kg), lifting height of 130 cm, and twist angle of 90°. Furthermore, the subjects experienced the highest heart rate after performing lifting test at maximum lifting height (130 cm) and load mass of 13 kg. This study concluded that the load mass, lifting height, and twist angle are proportional to the level of psychophysical experience. Additionally, when the load mass and lifting height were increased, the heart rate was also increased.

Abstract: In automotive repair facilities worldwide, technicians are exposed to various ergonomic risk factors such as excessive exertions, awkward and static postures. The exposure of several ergonomic risk factors can lead to work related musculoskeletal complaints. This study was set out to examine working postures encountered by automotive service technicians in a small medium industry automotive workshop. A total of 240 observations (n=240) were made, and five types of working positions were identified, namely the “Underneath Vehicle” (vehicle on floor),“Side of Vehicle” (vehicle on floor), “Under the Hood”, “Side of Vehicle” (vehicle on lift), and “Underneath Vehicle” (vehicle on lift). Two positions, which were the “Underneath Vehicle” (vehicle on floor), and the “Side of Vehicle” (vehicle on floor) recorded 69 and 60 occurrences respectively. These two positions posed a significant ergonomic injury risk since the upper limbs, shoulders, spinal flexion combined with static holding were present in those two positions.

Abstract: Optimum working conditions, such as body posture, body movement and working environment are commonly not directly known to the worker. In fact, the worker current working conditions are rarely provided. Although some may find it unnecessary, a mechanism to provide information on this situation is deemed to be useful. This paper presents a proposed framework for acquiring and monitoring ergonomic parameters. There are six potential useful parameters proposed in this study. The parameters include temperature, light, vibration, body posture, indoor air quality, and noise. In the proposed framework, the capturing device and signal converter are regarded as the main components. The framework is proposed to capture all parameters in the analog signal, and later convert it into the digital signal using the signal converter. At this stage, NI cDAQ-9188 is proposed to be used as the signal converter in the framework. The preliminary work of the proposed framework will be developed in the lab, while the implementation will be conducted at the chosen industry. It is hoped that the proposed framework will benefit industry and promote a safe working environment in the industry, especially for assembly tasks.

Abstract: In the recent years, Advance Manufacturing Technology (AMT) has been widely used in manufacturing industry to increase manufacturing process capability. However, Computer Numerical Control (CNC) machine designs have only focused on its operational capability. The harmonious coordination between users and CNC machines is often neglected, which can contribute to hazardous working practices that can affect the health of users. Bending posture while loading the work piece to the machine can cause fatigue and discomfort to the users. Thus, the focus of this preliminary study is to analyse the effect of CNC machine work piece loading on muscle activity levels and to determine the effectiveness of roller conveyor in reducing muscle activity levels. Muscle activity has been analysed using surface electromyography (sEMG) technique. Erector spinae, biceps and trapezius muscles were concurrently measured during the work piece loading. Five male subjects (n=5) participated in the pre-intervention study and two subjects (n=2) in the post-intervention study (roller conveyor implementation) participated to test the effectiveness of the roller conveyor. Result pre-intervention study found that muscle activity level of biceps was the highest followed by trapezius and erector spinae. Based on the post-intervention study involving the roller conveyor, muscle activity of the erector spinae was reduced meanwhile the muscle activity of biceps and trapezius increased for both subjects.

Abstract: Upper body discomfort has become one of the issues to drivers nowadays. In this modern era, majority of Malaysian workers drive to work daily. This paper aims to find the most uncomfortable upper body part, as well as the effect of time, body mass index (BMI) and length of arm towards upper body discomfort for drivers. Sixteen volunteers were requested to complete the questionnaire soon after they completed driving the car simulator for three duration of times (30 minutes, 60 minutes and 90 minutes). Time is proven to be the main factor affecting the upper body comfort level, with the upper arm and lower arm being the most affected part during driving, [F(2,237) =14.37, p<0.01] compared to BMI and length of arm. It can be concluded that the upper body discomfort can be caused by driving for a long time. Nevertheless, the BMI and length of arm is not the issue for upper body discomfort.

Abstract: Muscle fatigue and the development of hand-related musculoskeletal injuries can be caused by body positions that fail to accommodate control interfaces such as control knobs. There appear to be limited studies that investigate how different selections of body positions affect various selections of knobs, despite the fact that some articles have presented theoretical associations between different body positions and knob shapes. The goal of this paper is to determine the influences of body position selections on the knob selections of manual workers from several Malaysian manufacturing industries. A survey and observational studies were conducted, with over 70 responses collected for the survey and 79 responses collected for the observation. The survey responses were entered into Minitab 16 for the analysis, while the observation responses were sorted by frequency. The results show that the majority of the workers normally and preferably use the standing, seated and kneeling position for their manual work. The selections of the body positions that the workers assume also considerably affect the knob selections.

Abstract: The development of hand-related musculoskeletal injuries can be caused by pinch grips that fail to accommodate different control interfaces. One of the frequently used control interfaces in manufacturing industries is the knob. To date, there are limited statistical studies that investigate and support how different ways of executing pinch grips affect the selections of different knobs, even though there have been some studies theoretically suggesting a relation between different pinch grips and shapes of knobs. The purpose of this paper is to determine the roles of different pinch grips on the knob selections of a number of manual workers from Malaysian manufacturing firms. Regression analysis is used for this study. Survey responses were entered into Minitab 16 for analysis. The findings show that majority of the workers normally use the pulp pinch and lateral pinch, and prefer to use the lateral pinch for their manual tasks. The selection of these pinch grips also considerably affects the selection of the knobs that the workers control. The findings are valuable preliminary guidelines for identifying the ideal pinch grips that accommodate different knobs to potentially reduce hand-related injuries in Malaysian manufacturing industries.