Automatic re-contouring of repair-welded tool moulds

The process of repairing damaged tool moulds is conducted manually in the industry. This results in long process times as well as a high dependence of the repair result on the experience of the worker. After a visual inspection, the detected damages are removed by metal cutting and the missing material is filled by a build-up welding process. Afterwards, the target geometry is restored via machining re-contouring process. Because of the individual tool mould surface and welded seam, each repair case requires an individual machining strategy as well as toolpaths and process control parameters to ensure high surface quality and shape accuracy. This paper introduces an innovative design for re-contouring of repair-welded tool moulds, which takes into consideration the individual mould surface, repair welding and material properties. For that purpose, the actual geometry of the tool mould is measured directly in the CNC machine using an optical profile line sensor. Based on the measurement, the re-contouring process is planned automatically by means of a computer aided manufacturing (CAM) software. A material removal simulation with cutting force prognosis is carried out to adapt the process parameters individually with regard to repair time and surface quality. To set up the force and surface simulation model with high model quality, re-contouring experiments are carried out on welded seams made of 1.2343 (AISI H11) as well as on Toolox 44 and 1.2343 workpieces for comparison

Kierrätettyjen ja biopohjaisten muovien elinkaariarviointi ja tekninen toimivuus

Environmental impacts of products can be reduced, for example, by reducing materials or by selecting materials, whose production causes low environmental impacts. In this thesis is studied, whether it is possible to reduce environmental impacts of a plastic product by using recycled or bio-based plastics. In this case, the environmental impacts refer to the greenhouse gas emissions and primary energy demand. Essential recycling methods of plastics are presented. The definitions and manufacturing of bio-based plastics are also discussed. Environmental impacts of recycled and bio-based plastics are assessed with life cycle assessment (LCA) method. In addition to the LCA, material tests are used to evaluate suitability of the plastics to be used in base stations of mobile networks. Testing included 6 months outdoor exposure in Finland, Greece and Kenya and also a long-term accelerated aging test at 85 °C and 85 % relative humidity. Testing samples were made with an actual production mould. Studied materials were polycarbonate (PC), polycarbonate-polyethylene terephthalate (PC/PET) blend, bio-based polyamide (PA) 410 and bio-based glass fibre reinforced polytrimethylene terephthalate (PTT). Results of LCA show that recycling of plastics reduces significantly environmental impacts of material production. If the plastic cover of a base station contains 100 % recycled PC, emissions and primary energy demand of plastics production are reduced by 86 %. Substituting 30 % of virgin PC by recycled PC reduces the environmental impacts of plastic production by 23 %. The effect of bio-based material content on the environmental impacts is not as straightforward. Depending on the plastic grade, the environmental impacts of the production of bio-based plastics are higher or lower than those of virgin PC. Based on the material testing, the properties of recycled PC are comparable to those of virgin PC. The bio-based plastics also performed well in the testing, and based on these results they provide sufficient properties to the plastic cover.Tuotteiden ympäristövaikutuksia voidaan pienentää esimerkiksi vähentämällä materiaalien määrää tai valitsemalla materiaaleja, joiden valmistus tuottaa pienet ympäristövaikutukset. Tässä työssä tutkitaan, voidaanko kierrätysmuovien tai biopohjaisten muovien käytöllä vähentää muovituotteen ympäristövaikutuksia. Ympäristövaikutuksilla tarkoitetaan tässä tapauksessa kasvihuonekaasupäästöjä ja primäärienergian kulutusta. Työssä esitetään keskeisimmät muovin kierrätysmenetelmät sekä selvitetään, mitä muovien biopohjaisuus tarkoittaa ja miten biopohjaisia muoveja valmistetaan. Kierrätettyjen ja biopohjaisten muovien valmistuksen ympäristövaikutuksia selvitetään standardisoidulla elinkaariarviointi-menetelmällä. Elinkaariarvioinnin lisäksi muovien soveltuvuutta mobiiliverkkojen tukiasemien kuorimateriaaliksi arvioidaan testien avulla. Testiohjelmaan kuuluu esimerkiksi 6 kk:n ulkoilmatestaus Suomessa, Kreikassa ja Keniassa sekä pitkäkestoinen vanhennustesti 85 °C:n lämpötilassa ja 85 % suhteellisessa kosteudessa. Testejä varten tutkituista muoveista ruiskupuristettiin todellisen tukiaseman suojamuoveja. Tutkittavat muovit ovat polykarbonaatti (PC), polykarbonaatti-polyeteeni tereftalaatti seos (PC/PET), biopohjainen polyamidi (PA) 410 ja biopohjainen, lasikuidulla lujitettu polytrimeteeni tereftalaatti (PTT). Työssä todettiin, että muovien kierrätys vähentää selvästi muovinvalmistuksen kasvihuonekaasupäästöjä sekä energian kulutusta. Jos tukiaseman suojakuori tehdään kokonaan kierrätetystä polykarbonaatista, muovin valmistuksen päästöt ja energian kulutus vähenevät 86 %. Korvaamalla 30 % neitseellisestä materiaalista kierrätetyllä, muovin valmistuksen ympäristövaikutukset laskevat 23 %. Biopohjaisen materiaalin vaikutus ympäristövaikutuksiin ei ollut yhtä suoraviivainen. Riippuen muovilaadusta biopohjaisten muovien valmistus aiheuttaa suuremmat tai pienemmät ympäristövaikutukset kuin neitseellinen polykarbonaatti. Tehtyjen testien perusteella kierrätetty PC on ominaisuuksiltaan lähellä neitseellistä PC:tä. Myös biopohjaiset muovit suoriutuivat testeistä ilman suuria ongelmia ja tarjoavat suojakuorelle vaadittavia ominaisuuksia

Some Critical Issues for Injection Molding

This book is composed of different chapters which are related to the subject of injection molding and written by leading international academic experts in the field. It contains introduction on polymer PVT measurements and two main application areas of polymer PVT data in injection molding, optimization for injection molding process, Powder Injection Molding which comprises Ceramic Injection Molding and Metal Injection Molding, ans some special techniques or applications in injection molding. It provides some clear presentation of injection molding process and equipment to direct people in plastics manufacturing to solve problems and avoid costly errors. With useful, fundamental information for knowing and optimizing the injection molding operation, the readers could gain some working knowledge of the injection molding

Artificial Neural Network Model Based Setup Period Estimation for Polymer Cutting

The paper presents the results and industrial applications in the production setup period estimation based on industrial data inherited from the field of polymer cutting. The literature of polymer cutting is very limited considering the number of publications. The first polymer cutting machine is known since the second half of the 20th century; however, the production of polymer parts with this kind of technology is still a challenging research topic. The products of the applying industrial partner must met high technical requirements, as they are used in medical, measurement instrumentation and painting industry branches. Typically, 20% of these parts are new work, which means every five years almost the entire product portfolio is replaced in their low series manufacturing environment. Consequently, it requires a flexible production system, where the estimation of the frequent setup periods' lengths is one of the key success factors. In the investigation, several (input) parameters have been studied and grouped to create an adequate training information set for an artificial neural network as a base for the estimation of the individual setup periods. In the first group, product information is collected such as the product name and number of items. The second group contains material data like material type and colour. In the third group, surface quality and tolerance information are collected including the finest surface and tightest (or narrowest) tolerance. The fourth group contains the setup data like machine type and work shift. One source of these parameters is the Manufacturing Execution System (MES) but some data were also collected from Computer Aided Design (CAD) drawings. The number of the applied tools is one of the key factors on which the industrial partners’ estimations were based previously. The artificial neural network model was trained on several thousands of real industrial data. The mean estimation accuracy of the setup periods' lengths was improved by 30%, and in the same time the deviation of the prognosis was also improved by 50%. Furthermore, an investigation on the mentioned parameter groups considering the manufacturing order was also researched. The paper also highlights the manufacturing introduction experiences and further improvements of the proposed methods, both on the shop floor and on the quotation preparation fields. Every week more than 100 real industrial setup events are given and the related data are collected

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

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

Development, modelling and analysis of Vacuum Assisted Multipoint Moulding for manufacturing fibre-reinforced plastic composites

Full version: Access restricted permanently due to 3rd party copyright restrictions. Restriction set on 12.11.2019 by SE, Doctoral CollegeMultipoint tooling is a mould making technology that enables the rapid reconfiguration of a mould to create individual components. It replaces the commonly used, elaborately designed, and costly manufactured solid die, with an array of individually adjustable pins. These pins can be set to represent a large variety of freeform surfaces. An elastic interpolation layer (IPL) is used to smoothen the pin array and forms the actual tooling surface. This technology is well established in sheet metal forming and other areas of manufacturing. However, only little research has been conducted in the area of fibre-reinforced plastic composites. In this thesis, a novel multipoint tooling technology is introduced, that is specifically designed for fibre-reinforced plastic (FRP) manufacturing. Different to existing solutions, this Vacuum Assisted Multipoint Moulding (VAMM) is capable of creating concave and convex geometries on a single sided mould. This enables the use of established FRP manufacturing processes without further adaptation. Two iterations of this technology are developed: A manually adjusted small-scale test bench is used to validate the VAMM concept and conduct experiments on, and a fully automated full scale manufacturing prototype then is used to demonstrate the feasibility of the technology for an industrial application. The elasticity of the IPL introduces two system immanent dimensional defects: the overall shape deviates due to the deformation of the IPL and the punctual support of the interpolation layer leads to a golf-ball-like surface effect. A process model was created to predict behaviour of the VAMM tool and the interpolation layer, and estimate the expected part quality. An iterative shape control algorithm was implemented, to improve the dimensional accuracy of the manufacturing process, by readjusting individual pins in the tool. On this model, a sensitivity analysis was conducted to quantify the influence of the process and pin array parameters on the dimpling of the tool surface. The most important parameters were identified and used in a Metamodel of Optimal Prognosis (MOP). This MOP enables the rapid estimation of the system behaviour. It was used to optimise the VAMM process and the interpolation layer in order to maximise the geometric part quality. With this method two IPL designs, one with a single, and one with two separate layers of silicone rubber, were evaluated. It turned out that the dual layer configuration can handle a 24 % higher process pressure, while using a 9 % thinner interpolation layer, to produce parts similar to the single layer configuration.Huber Kunststoff und Technik GmbHSGL Carbon SEPutzin Maschinenbau Gmb

METHODOLOGY FOR RESEARCH AND DEVELOPMENT OF NOVEL MEDICAL DEVICES FOR MINIMALLY INVASIVE INTERVENTIONS

The design of innovative medical device requires extensive and hard efforts to reach good results in terms of safety, efficacy and cost effectiveness. First of all the idea has to be set and a wide search of state of the art, both technological and academic, has to be developed. Then the materials, manufacturing processes and design constraints have to be understood. In this work three examples of innovative surgical devices for minimally invasive surgery and assistance have been presented. The Muneretto Beam catheter is a new device for atrial defibrillation. Starting from a catheter produced by Estech company for the treatment of atrial fibrillation by ablating cardiac tissue during surgery, a system for the magnetic guidance of the same has been implemented. Thanks to finite element analysis of various configurations of magnets and to several in vitro tests, a final configuration which allows a good balance between the sliding of the catheter on the tissues and the magnetic interaction and adhesion to tissues has been found. Further attention has been taken to the development of the cover and the right configuration and method of use of the device. The VideoDrain system is a new catheter for the monitoring of post-operative wound. After critical surgical procedures it is necessary to monitor the status of the surgical wound for avoiding second look surgical interventions. Therefore a new balloon catheter for allowing the vision of the abdominal cavity has been produced. Several in vitro and in vivo trials have been conducted and the device is at the pre-industrial stage. The FloSeal GI cath. is a new device for the gastrointestinal release of an haemostatic substance of the Baxter company: the Floseal thrombin matrix. It consists in a balloon catheter suited for the use in the lower and upper gastrointestinal tract in the occurrence of bleedings during endoscopic procedures. This device has been CE labelled and is now on the market. All the devices described in this work come from ideas of surgeons leader in innovation in the field of minimally invasive interventions. Their collaboration has been fundamental for the several phases of design and tests of the devices. This Ph.D. thesis is divided into five chapters. In the Introduction chapter the process of research and development of innovative MDs for minimally invasive surgery has been illustrated. The second chapter shows the efforts done to find a working configuration for the Muneretto Beam catheter and the subsequent first prototypes developed. The progress in the design of VideoDrain has been explained in the third chapter; the whole process goes from the idea to the animal test on prototypes and a preliminary risk analysis. The development of the Floseal GI Catheter is depicted in the fourth chapter; all the details of the materials used and tests done to ensure a CE mark have been reported. Finally, in the Conclusion chapter I have reported some lessons learned from the work in the field of MDs, as a student, researcher and engineer at close contact with the world of surgery and minimally invasive technologies. Some papers about a preliminary research activity in the field of minimally invasive surgery and robotic interventions have been also enclosed. These works have been very useful to start the understanding of the complex and amazing world of MIS