Change of notch impact strength depending on radiation dose and test temperature

The main purpose of this paper has been determine the effect of radiation crosslinking on the notch impact strength of polyamides filled with fiberglass. These properties were examined in dependence on the dosage of the ionizing beta radiation (non-irradiated samples and those irradiated by dosage 66 and 132 kGy were compared) and on the test temperature (23–150 °C)

Case study research: Optical digitization, reverse engineering and rapid prototyping as a solution in pedal car development process

The motivation of this work was to find an appropriate manufacturing method for pedal car accessories. This study describes the application of optical digitization, reverse engineering and rapid prototyping in manufacturing process of accessories for handmade pedal car, which imitates an unique historic Czech car, a Škoda 1000 MB, type 990 Roadster. Two well-known design elements, rear light and front indicator, were digitized by non-contact 3D scanner. The digitized 3D models were used as an inputs for reverse engineering. Their shapes were modified due to technological limits of vacuum forming, scaled and used to design of the 3D printed vacuum forming moulds. The final parts were made of transparent foil, trimmed around the perimeter and airbrushed from the inside. The described process served to verify the manufacturability of these accessories before commencing works on a mass-produced pedal cars intended for sale to customers

Effect of Temperature Ageing on Injection Molded High-Density Polyethylene Parts Modified by Accelerated Electrons

The temperature ageing of high-density polyethylene (HDPE) modified by accelerated electrons was studied. Commodity plastic HDPE was used as a basic polymer material which was modified by radiation cross-linking. This polymer was used because of its excellent processability and chemical resistance. Plastic injection molding technology was used for the production of test specimens. These specimens were modified with the dose of radiation 33, 66, 99, 132, 165, and 198 kGy. The prepared specimens were tested to determine: gel content, degree of swelling, temperature stability, and changes in mechanical properties after temperature ageing. The results were determined by scanning electron microscopy (SEM) analysis on the fracture surfaces. The results of this study confirm that modification of HDPE by radiation cross-linking has a significant effect on increasing temperature stability. It has been shown that HDPE modified by radiation cross-linking can withstand temperatures exceeding the melting point of the original HDPE for a short-term

Improvement of handle grip using reverse engineering, CAE and Rapid Prototyping

The overwhelming majority of manual operations is even nowadays performed by using manual hand tools. These tools can be divided into 2 groups – hand tools designed for general use or a single-purpose hand tools for special operations. Tool described in this paper is used in assembling operation in the completion of electric motor. During the design of the existing tools the requirements for a functional part of the tool (lifespan, inability to damage the engine installation) were fully considered, demands for ergonomic grip area, however, were not taken into account. Long-term use of incorrectly designed tool causes carpal tunnel syndrome, hand-arm vibration syndrome, diminished sensitivity or tingling in the fingers of workers. These difficulties can be reduced or entirely eliminated due to proper design of the grip of hand tool. Most authors focus on adjusting the grip for optimum ergonomics at individual types of grips (cylindrical, palmar, lateral, etc.). However, as already mentioned, there are tools for specific operations when the working area is limited by space or a specific type of load on the grip is needed. In some cases, it is often necessary to change the type of grip or combine different types of grips. This paper describes the design of an optimal grip of hand tool used for specific operation when assembling motors. Design of prototype mold and production of functional prototypes for ergonomics assessment directly in the workplace were realized. New design of handle should reduce the risk primarily of developing carpal tunnel in long-term use

Flexural behaviour of ABS 3D printed parts on professional printer Stratasys Fortus 900mc

Nowadays, it is very desirable to obtain the low cost polymeric material with the best material properties. For the best modification of the commodity and construction polymeric materials it is firstly necessary to know the basic material properties. In this study the bending and Charpy impact test specimens were fabricated via a professional FDM 3D printer Fortus 900mc, from company Stratasys, processing ABS-M30 in three build orientation XY, XZ-H and XZ-V. The 3D printed test specimens were examined to compare the effect of layer thickness and building orientation. Tensile test machine Zwick 1456 and impact pendulum Zwick HIT50P were used for bending and Charpy impact tests. Optical microscopy was utilized to perform fractography on impact test specimens to explore the effect of the layer thickness and building orientation on the fracture surface morphology of the failed specimens. This study demonstrates the need for material testing for specific processing as additive manufacturing technologies

Mechanical properties and temperature stability of modified polybutylene terephthalate by beta rays

The presented article deals with the research of mechanical properties before and after temperature load and temperature stability of modified polybutylene terephthalate by radiation cross-linking. The mechanical properties were measured, at the ambient temperature, by the tensile test on samples which were non-irradiated and irradiated by different doses of the beta radiation and then were temperature loaded. Results demonstrate that PBT has higher values of tensile strength with the increased irradiation dose and it has decreased elongation at break sharply. The purpose of the article is to consider to what extent the irradiation process influences the resulting mechanical properties and temperature stability. The PBT tested showed significant improvement of temperature stability after irradiation. This behaviour leads to the expansion of these materials in the automotive and electrical industry

Mechanical properties change of thermoplastic elastomer after using of different dosage of irradiation by beta rays

Radiation processing of polymers is a well-established and economical commercial method of precisely modifying the properties of polymers. The industrial applications of the radiation processing of plastics and composites include polymerization, cross-linking, degradation and grafting. Radiation processing mainly involves the use of electron beams from electron accelerators. The Thermoplastic Elastomer (TPE) was used in this research and the mechanical properties were investigated at the ambient temperature. Results demonstrate that TPE has higher values of tensile strength with the increased irradiation dose and it has decreased elongation at break. This behaviour leads to the expansion of these materials in the automotive and electrical industry

Effect of Beta Radiation on the Quality of the Bonded Joint for Difficult to Bond Polyolefins

Bonding is increasingly being used, and it is an ever-evolving method for creating unbreakable bonds. The strength of adhesive bonds determines, to a significant extent, the possible applications of this technology and is influenced by many factors. In addition to the type of adhesive used, the characteristics of the surface layers play a significant role; therefore, significant attention is paid to their adjustment and modification. Radiation crosslinking is one of the most important methods for modifying polymer properties. Currently, the most frequently used type of radiation for polymer crosslinking is beta minus (β−) radiation, which affects not only mechanical but also surface properties, chemical and temperature resistance, and surface layer characteristics of polymers. This study investigated the effect of β− radiation on the surface layer properties of low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polypropylene (PP) and the effects of surface-layer modification on the ultimate tensile strength of bonded joints. Based on the results, we concluded that β− radiation significantly changes the properties of the tested surface layers, increases the surface energy, and improves the adhesiveness of bonds. Consequently, the final strength of the LDPE, HDPE, and PP bonds increases significantly

Micro-hardness of surface layer of irradiated Polybutene Terephthalate (PBT)

Using high doses of beta radiation for polybutylene terephthalate (PBT) and its influence on the changes of micromechanical properties of surface layer has not been studied in detail so far. The specimens of PBT were made by injection moulding technology and irradiated by high doses of beta radiation (0, 132, 165 and 198 kGy). The changes in the microstructure and micromechanical properties of surface layer were evaluated using WAXS and instrumented microhardness test. The results of the measurements showed considerable increase in micromechanical properties (indentation hardness, indentation elastic modulus) when high doses of beta radiation are used