• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 7
  • 5
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 34
  • 34
  • 8
  • 6
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Model based simulation of broaching operation: cutting mechanics, surface integrity, and process optimization

Hosseini, Sayyed Ali 01 April 2013 (has links)
Machining operations are widely used to produce parts with different shapes and complicated profiles. As a machining operation, broaching is commonly used for the machining of a broad range of complex internal and external profiles either circular or non-circular such as holes, keyways, guide ways, and slots on turbine discs having fir-tree shape. Broaching is performed by pushing or pulling a tapered tool through the workpiece to remove the unwanted material and produce the required profile. Broaching is also acknowledged because of its high productivity and attainable surface quality in comparison to the other machining processes. The objective of this thesis is to simulate the broaching operation and use the results to present a methodology for optimum design of the broaching tools. In the course of the presented thesis, a new B-spline based geometric model is developed for broaching cutting edges followed by model validation using 3D ACIS modeller. To study the mechanics of cutting and generated cutting forces during broaching operation, an energy based force model is presented which can predict the cutting forces based on the power spent in the cutting system. An experimental investigation is conducted in order to confirm the estimated forces. The integrity of the broached surface is also investigated by focusing on surface roughness, subsurface microhardness, and subsurface microstructure as three major parameters of surface integrity. An optimization procedure for broaching tools design is presented in this thesis. A mathematical representation of broaching tooth geometry is also presented which is used to simulate the tooth as a cantilevered beam subjected to a distributed load. The beam is solved considering the given design constraints to achieve optimum geometric parameters for maximum durability and performance. / UOIT
12

Applying ergonomics to dental scalers

Ahern, Stacey January 1900 (has links)
Master of Science / Department of Industrial & Manufacturing Systems Engineering / Malgorzata J. Rys / The current state of the dental industry shows an increasing number of dentists and dental hygienists who are reducing hours and retiring early due to the injuries sustained while working. These injuries, or cumulative trauma disorders, can be reduced by applying ergonomics in dental tool design. The goal of ergonomics is to reduce current injuries but also prevent future ones. In addition, population demographics have shown an increasing trend in female dentists. With a shift from the male dominated field, design for different anthropometric measurements needs to be investigated. In order to pinpoint sources of pain, a survey was designed and distributed to dentists in Kansas, Missouri, and Texas. Even with a small sample size (n=24), results confirmed past studies in the dental industry of pain originating in the neck, shoulder, lower back, and wrist/hand region. The reasons stemmed from the repetitive motions and forces applied during dental procedures. Responses also found that ergonomic principles need to be applied to the handle and grip portion of dental scaler design. Dental scaling is the procedure to remove deposits on teeth, such as plaque and calculus, most commonly performed by dental hygienists. First, the history of dental tools, angulation, tool weight, and materials currently utilized were researched before looking into specific design factors for modification. Currently, the handle grip area on all dental tools range in size, but a 10 mm grip has been proven to be optimal. The optimal tool weight has yet to be determined as 15 grams is the lowest weight to be tested. Most tools are made of stainless steel and resins, which are not compressible. An experiment was designed to test a new dental scaler (A) made of a titanium rod with added compressibility in the precision grip area. The aim was to help reduce pressure on the fingers and hand muscles and increase comfort during scaling. The experiment utilized a Hu-Friedy sickle scaler (B) and a Practicon Montana Jack scaler (C) as controls to show two design spectrums, weight and material. The subjects (n=23) were taught the basics of scaling and required to scale using a typodont. The change in grip strength (Δ GS), pinch strength (Δ PS), and steadiness of the subjects hand were tested. An absolute and relative rating technique was utilized pinpointing that the new dental scaler was preferred with the eigenvector (A=0.8615, B=0.1279, C=0.0106). Statistical analysis confirmed this tool preference while also finding the interaction of gender and tool and Δ GS Tool A versus Tool B for males to be significant.
13

Development of a design feature database to support design for additive manufacturing (DfAM)

Maidin, Shajahan January 2011 (has links)
This research introduces a method to aid the design of products or parts to be made using Additive Manufacturing (AM), particularly the laser sintering (LS) system. The research began with a literature review that encompassed the subjects of design and AM and through this the need for an assistive design approach for AM was identified. Undertaking the literature review also confirmed that little has been done in the area of supporting the design of AM parts or products. Preliminary investigations were conducted to identify the design factors to consider for AM. Two preliminary investigations were conducted, the first investigation was conducted to identify the reasons for designing for AM, the need for a design support tool for AM and current challenges of student industrial designers designing parts or products for AM, and also to identify the type of design support they required. Further investigation were conducted to examine how AM products are developed by professional industrial designers and to understand their design processes and procedures. The study has identified specific AM enabled design features that the designers have been able to create within their case study products. Detailed observation of the case study products and parts reveals a number of features that are only economical or possible to produce with AM. A taxonomy of AM enabled design features was developed as a precursor for the development of a computer based design tool. The AM enabled design features was defined as a features that would be uneconomical or very expensive to be produced with conventional methods. The taxonomy has four top-level taxons based on four main reasons for using AM, namely user fit requirements, improved product functionality requirements, parts consolidation requirements and improvement of aesthetics or form requirements. Each of these requirements was expanded further into thirteen sub categories of applications that contained 106 examples of design features that are only possible to manufacture using AM technology. The collected and grouped design features were presented in a form of a database as a method to aid product design of parts or products for AM. A series of user trials were conducted that showed the database enabled industrial designers to visualise and gather design feature information that could be incorporated into their own design work. Finally, conclusions are drawn and suggestions for future work are listed. In summary, it can be concluded that this research project has been a success, having addressed all of the objectives that were identified at its outset. From the user trial results, it is clear to see that the proposed tool would be an effective tool to support product design for AM, particularly from an educational perspective. The tool was found to be beneficial to student designers to take advantage of the design freedom offered by AM in order to produce improved product design. As AM becomes more widely used, it is anticipated that new design features will emerge that could be included in future versions of the database so that it will remain a rich source of inspirational information for tomorrow s industrial designers.
14

The impact of tool performance on micromachining capability

Zdebski, Daniel January 2012 (has links)
Micro-milling represents a versatile and fast manufacturing process suitable for production of fully 3D micro-components. Such components are demanded for a vast number of industrial applications including safety systems, environmental sensors, personalized medical devices or micro-lenses and mirrors. The ability of micro-milling to process a wide range of materials makes it one of the best candidates to take a leading position in micromanufacturing. However, so far it does not seem to happen. By discussion with various industrialists, low predictability of micro-milling process was identified as the major limiting factor. This is mainly because of strong effects of the tool tolerances and process uncertainties on machining performance. Although, these issues are well known, they are not reflected by the current modelling methods used in micro-milling. Therefore, the research presented in this thesis mainly concentrates on development of a method allowing a prediction of the tool life in manner of tool breakage probability. Another important criterion which must be fulfilled is the method applicability to industrial applications. This means that the method must give sufficiently accurate prediction in reasonable time with minimum effort and interactions with day-to-day manufacturing process. The criteria listed above led to development of a new method based on analytically/numerical modelling techniques combined with an analysis of real tool variations and process uncertainty. Although, the method is presented in a relatively basic form, without considering some of the important factors, it shows high potential for industrial applications. Possibility of further implementation of additional factors is also discussed in this thesis. Additionally, some of the modelling techniques presented in this thesis are assumed to be suitable for application during designing of micro end-mills. Therefore, in the last part of this thesis is presented a systematic methodology for designing of micro end-mills. This method is based on knowledge and experience gained during this research.
15

Self-propelled rotary tool for turning difficult-to-cut materials

Parker, Grant 01 April 2011 (has links)
Hard turning of difficult-to-cut materials is an economical method of machining components with high surface quality and mechanical performance. Conventionally in the machining industry, generating a component from raw goods includes a casting or forging process, rough machining, heat treatment to a desired hardness, and then finished-machining through a grinding process. Given the relative disadvantages of grinding, which include high specific energy consumption and low material removal rates, a newer technology has been introduced; hard turning. After the heat treatment of a cast part (generally in a range of 50-65 HRC), hard turning allows for immediate finished-machining. Hard turning reduces the production time, sequence, cost, and energy consumed. In addition, dry machining offsets environmental concerns associated with the use of coolant in grinding operations as well as other common turning operations. Higher specific forces and temperatures in the contact area between the tool and workpiece lead to excessive tool wear. Generated tool wear affects the quality of the machined surface. Therefore, minimizing tool wear and consequently the generated surface quality become the status quo. Adverse effects associated with generated heat at the tool tip can be reduced by using cutting fluid or by continuously providing a fresh cutting edge. The latter method will be applied in this thesis. Rotary tool cutting involves a tool in the form of a disk that rotates about its axis. Different types of rotary tools have been developed, all with similar functional characteristics, however few are commercially available. Rotary tools can be classified as either driven or self-propelled. The former is provided rotational motion by an external source while the latter is rotated by the chip flow over the rake face of the tool. A prototype self-propelled rotary tool (SPRT) for hard turning was developed which provides economical benefits and affordability for the user. It was tested on a turret-type CNC lathe by machining AISI 4140 Steel that was heat treated to 54-56HRC and Grade 5 Titanium (Ti-6Al-4V). Carbide inserts with ISO designation RCMT 09 T3 00 (9.5mm diameter) were used during machining. Both the SPRT rotational speed and the workpiece surface roughness were measured. Also, chips were collected and analyzed for each of the cutting conditions. The same procedure was followed during machining with the same tool which was denied the ability to rotate, therefore simulating a fixed tool with identical cutting conditions. Comparisons were made between tool life, surface roughness, and chip formation for the fixed tool and SPRT. Tool rotational speed was also analyzed for the SPRT. In general, the designed and prototyped SPRT showed very good performance and validated the advantages of self-propelled rotary tools. A typical automotive component that is hard turned from difficult-to-cut materials is a transmission input shaft. These components demand high strength and wear resistance as they couple the vehicle‟s engine power to the transmission and remaining driveline. / UOIT
16

Technologie odjehlování tvářené součásti / On the deburring technology of a formed part

Žídek, Jan January 2015 (has links)
This diploma thesis was created in cooperation with Mubea company. It deals with proposal of alternative technology of groove deburring. A special tool was designed for this technology and was experimentally tested. There are also tests for finding suitable cutting conditions, tests for appropriate tool’s positioning against a workpiece and tests for comparison the alternative technology of groove deburring to grinding technology included in this diploma thesis
17

Návrh nástroje pro výrobu prolisů / Design of Tool for Louvers Production

Hejna, Jaroslav January 2020 (has links)
This thesis presents a tool design for production of embossments into the bottom part of the agricultural silo made of Dx51D material. The research analysis all technologies used for embossing, that is cutting and shallow drawing. This is followed by a chapter on simulation. The tool design itself is described. Its principle is based on tools for punching machines. The upper half of the tool is composed of a weldment to be clamped into pressing machine, into which are mounted functional parts in the form of inserts. The lower tool consists of several bolted plates, punches and a holding plate, which is located on the springs. In order to achieve correct design, necessary calculations were carried out and it was all confirmed by simulation in ANSYS. The two tool halfs are guided by pins attached at the edges of the lower tool. The technical - economical evaluation compares the work of the proposed tool with other possibilities of embossing.
18

Nástroj pro výpočet vnitřního výnosového procenta (IRR - internal rate of return) / Performance Calculations Breakdown (IRR) Tool

Husák, Petr January 2015 (has links)
Diplomová práce se zabývá vytvořením softwarové aplikace IRR tool, pro společnost ABC s.r.o. IRR tool je nástroj sloužící k monitoringu vnitřního výnosového procenta investic, které jsou nabízeny v produktech společnosti. Cílem práce je s využitím Visual Studia rozšířit prostředí sloužící zaměstnancům společnosti o tento nástroj a nabídnout jim možnost nahlédnutí k výpočtu tohoto ukazatele. Nástroj poslouží k upřesnění informací pro zaměstnance, podpoří jejich analytické možnosti a povede k vyšší spokojenosti zákazníků.
19

Návrh kompaktního stroje pro třískové obrábění klíčů / Entwurf einer Kompaktmaschine zur Schlüsselbearbeitung

Žůrek, František January 2017 (has links)
This master thesis Design of a machine tool for a safety keys production deals with concept of a machine tool for production of safety keys. Solution variants are methodically elaborated, mainly concerning their achieved tact times and machine dimensions. A computation diagram for fast comparison of concepts in case of different customer key specification is presented. Chosen concept version is then detailed designed. The result fills a hole on the market of specific machine tools for machining of safety keys.
20

Budget Your Carbon Emissions : Interactive visualisation of an individual’s carbon budget / Budgetera dina koldioxidutsläpp : Interaktiv visualisering av individers koldioxidbudget

Raghunathan, Jayanthi January 2021 (has links)
Climate change is now more of a reality than ever. Carbon budget provides an upper limit on the amount of carbon that can be emitted, for the earth to be within an accepted temperature rise. People are aware that eating less meat, flying less and reducing product consumption would decrease their emission, but they are not sure on how much less. Existing studies show that people are quite willing to accept the concept of carbon budget but there is no tool that visualises this information at an individual level.  This study investigated the features that must be included in a carbon budget tool when visualising an individual’s information to create awareness. An exploratory design approach was used in this study where the design was iteratively developed from user feedback. Four preliminary designs were first developed and discussed in a focus group. With the feedback from the focus group, one design was finalised and redesigned as a carbon budget tool. This was tested in a one-on-one user testing where users had to complete tasks using the tool. The study results provided evidence that personalised information, effective text, labels, interactive features, and clear and simple layout are important features that must be included when designing a tool to visualise an individual’s carbon budget. The participants also rated an increase in awareness of carbon budget concept after using the tool. / Klimatförändringarna är nu mer verkliga än någonsin. En koldioxidbudget anger en övre gräns för mängden utsläpp av klimatgaser som kan släppas ut för att hålla ökningen av jordens medeltemperaturen inom en acceptabel gräns. Många människor är medvetna om att lägre köttkonsumtion, färre flygresor och en minskad konsumtion av saker skulle minska deras utsläpp, men de är inte säkra på hur mycket varje ändring påverkar utsläppen. Befintliga studier visar att människor accepterar begreppet koldioxidbudget i sig, men det finns idag inga verktyg för att visualisera en koldioxidbudget på individuell nivå.  Denna studie undersöker vilka funktioner som behöver ingå i ett verktyg för visualisering av en individuell koldioxidbudget, med syfte att skapa medvetenhet hos användaren. En utforskande designmetod användes där verktygets design utvecklades iterativt med feedback från användare. Först utvecklades fyra preliminära designprototyper som diskuterades i en fokusgrupp. Med feedback från fokusgruppen vidareutvecklades en av prototyperna till en slutgiltig version. Detta testades i en användartestning där användare utförde uppgifter med verktyget. Studieresultaten visade att personlig information, effektiv text, etiketter, interaktiva funktioner och tydlig och enkel layout är viktiga funktioner som måste inkluderas när man utformar ett verktyg för att visualisera en koldioxidbudget för individuell användning. Deltagarna bedömde också att de uppnått en ökad medvetenhet om konceptet koldioxidbudget efter att ha använt verktyget.

Page generated in 0.0493 seconds