Daniel Koutny

Pilot study of the wrist orthosis design process

Purpose – The purpose of this paper is to describe a manufacturing methodology for a wrist orthosis. The case study aims to offer new approaches in the area of human orthoses. Design/methodology/approach – The article describes the utilization of rapid prototyping (RP), passive stereo photogrammetry and software tools for the orthosis design process. This study shows the key points of the design and manufacturing methodology. The approach uses specific technologies, such as 3D digitizing, reverse engineering and polygonal-surface software, FDM RP and 3D printing. Findings – The results show that the used technologies reflect the patients requirements and also they could be an alternative solution to the standard method of orthosis design. Research limitations/implications – The methodology provides a good position for further development issues. Practical implications – The methodology could be usable for clinical practice and allows the manufacturing of the perfect orthosis of the upper limb. The usage ...

Use of digital technologies for nasal prosthesis manufacturing

Background and aim: Digital technology is becoming more accessible for common use in medical applications; however, their expansion in prosthetic and orthotic laboratories is not large because of the persistent image of difficult applicability to real patients. This article aims to offer real example in the area of human facial prostheses. Technique: This article describes the utilization of optical digitization, computational modelling, rapid prototyping, mould fabrication and manufacturing of a nasal silicone prosthesis. This technical note defines the key points of the methodology and aspires to contribute to the introduction of a certified manufacturing procedure. Discussion: The results show that the used technologies reduce the manufacturing time, reflect patient’s requirements and allow the manufacture of high-quality prostheses for missing facial asymmetric parts. The methodology provides a good position for further development issues and is usable for clinical practice. Clinical relevance Utilization of digital technologies in facial prosthesis manufacturing process can be a good contribution for higher patient comfort and higher production efficiency but with higher initial investment and demands for experience with software tools.

Influence of Scanning Strategies on Processing of Aluminum Alloy EN AW 2618 Using Selective Laser Melting

This paper deals with various selective laser melting (SLM) processing strategies for aluminum 2618 powder in order to get material densities and properties close to conventionally-produced, high-strength 2618 alloy. To evaluate the influence of laser scanning strategies on the resulting porosity and mechanical properties a row of experiments was done. Three types of samples were used: single-track welds, bulk samples and samples for tensile testing. Single-track welds were used to find the appropriate processing parameters for achieving continuous and well-shaped welds. The bulk samples were built with different scanning strategies with the aim of reaching a low relative porosity of the material. The combination of the chessboard strategy with a 2 × 2 mm field size fabricated with an out-in spiral order was found to eliminate a major lack of fusion defects. However, small cracks in the material structure were found over the complete range of tested parameters. The decisive criteria was the elimination of small cracks that drastically reduced mechanical properties. Reduction of the thermal gradient using support structures or fabrication under elevated temperatures shows a promising approach to eliminating the cracks. Mechanical properties of samples produced by SLM were compared with the properties of extruded material. The results showed that the SLM-processed 2618 alloy could only reach one half of the yield strength and tensile strength of extruded material. This is mainly due to the occurrence of small cracks in the structure of the built material.

PROCESSING OF NEARLY PURE IRON USING 400W SELECTIVE LASER MELTING – INITIAL STUDY

e-mail: palousek@fme.vutbr.cz The proposed article deals with development and initial tests of nearly pure iron powder ATOMET Fe AM (Rio Tinto, QMP) using 400W selective laser melting technology. Magnetic properties in conjunction with 3D printing possibilities of metals could be used in many applications. Metal powder was analyzed for verification of distribution and shape of particles. The main laser parameters such as laser power, laser scanning speed and hatch distance were tested to achieve low porosity and sufficient, high building speed. Laser scanning speed was tested in the range from 200 mm/s up to 1400 mm/s and laser power from 100 W to 400 W. The hatch distance was set to the values of 90, 120 and 150 μm. Porosity was evaluated via microscopy image analysis and micro CT. To obtain mechanical properties the tensile testing was performed.

IMPACT RESISTANCE OF DIFFERENT TYPES OF LATTICE STRUCTURES MANUFACTURED BY SLM

The presented paper describes the impact resistance of lattice structure samples made by Selective Laser Melting with the use of AlSi10Mg powder material. The samples with five types of different unit cells of lattice structure were used in this study. The topology of the unit cells structure was changed to describe various impact resistance behavior while the relative density of lattice structure was kept constant. The samples were tested by drop-weight impact testing device with spherical shape of indenter. During the test the maximum reaction force, deceleration and position of load element (indenter) were measured. The results showed, that samples with the same relative density, but with a different shape of unit cell had a different impact resistance. It is because the mechanical properties are significantly influenced by the cell topology which determined the type of failure under loading – bending or buckling. The FBCCZ had the highest impact resistance, but the energy was absorbed with very high reaction force during absorption.

COMPARISON OF SELECTIVE LASER MELTING OF 18NI MARAGING STEEL BY PXL AND M2 CUSING

e-mail:daniel.koutny@vut.cz This study compares 18Ni maraging steel processing on two competitive SLM machines, PXL and M2 Cusing. For the production of samples, powder material from original machine supplier was used on each machine separately. Process parameters for the production of small thin-walled parts were set individually on each machine according the recommendation of the device manufacturer. The basic mechanical properties of the produced materials were determined using tensile tests and hardness measurement. Metallographic and fractographic analyses were conducted by means of a lightand scanning electron microscopes. In comparison to M2 Cusing, higher relative density achieving 99.9% in the volume of material, was measured on the thin walled samples of PXL. The reason is probably higher energy density during material processing. As a consequence, the specimens from PXL had slightly better mechanical properties.

Project-Oriented Learning of Mechanical Engineering Design

The article explains a newly utilized project-oriented curriculum at the Institute of Machine and Industrial Design. In addition to digital technologies, the curriculum focuses on practical tasks with the utilization of advanced technologies in the area of mechanical design processes, such as Rapid Prototyping, Vacuum Casting etc. The paper describes a new approach to teamwork, where groups of students manage project tasks from the design phase up to the manufacturing of the real product.Copyright