Cooling of injection moulds manufactured by machining has limitations because cooling channels are formed by conventional straight holes. With additive manufacturing, the cooling channels can be ...produced in the shape which is adjusted to the cavity and core surface of injection moulds. Those kinds of cooling channels are called the conformal cooling channels. Conformal cooling channels can significantly reduce cycle time of plastic injection moulding process and significantly improve the quality of products. Thus, in this work conformal cooling channels for industrial case study were constructed and analysed. Besides expected tests, cooling simulation has been performed, comparing conventional and proposed cooling technology. Results have been confirmed also by testing prototype with conformal cooling channels, showing significant improvement in reducing cycle time, more than 40 %.
3D cutting tool-wear monitoring in the process CerAee, Luka; Pusavec, Franci; KopaAe, Janez
Journal of mechanical science and technology,
09/2015, Letnik:
29, Številka:
9
Journal Article
Recenzirano
The tool-wear of cutting tools has a very strong impact on the product quality as well as efficiency of the machining processes. Therefore, it in-the process characterization is crucial. This paper ...presents an innovative and reliable direct measuring procedure for measuring spatial cutting tool-wear with usage of laser profile sensor. The technique provides possibility for determination of 3D wear profiles, as advantage to currently used 2D techniques. The influence of the orientation of measurement head on the accuracy and the amount of captured reliable data was examined and the optimal setup of the measuring system was defined. Further, a special clamping system was designed to mount the measurement device on the machine tool turret. To test the measurement system, tool-life experiment was performed. Additionally, a new tool-life criterion was developed, including spatial characteristics of the tool-wear. The results showed that novel tool-wear and tool-life diagnostic represent objective and robust estimator of the machining process. Additionally, such automation of tool-wear diagnostics on machine tool provides higher productivity and quality of the machining process.
A major problem that limits the use of biodiesel is maintaining the fuel at the specified standards for a longer period. Biodiesel oxidizes much more easily than diesel, and the final oxidation ...products change its physical and chemical properties and cause the formation of insoluble gums that can block fuel filters and the supply pipes. This instability of biodiesel is a major problem and has not yet been satisfactorily resolved. Recently, the use of biodiesel has increased quite a lot, but the problem related to oxidation could become a significant impediment. A promising and cost-effective approach to improving biodiesel's stability is to add appropriate antioxidants. Antioxidants work better or less effectively in different biodiesel fuels, and there is no one-size-fits-all inhibitor for every type of biodiesel fuel. To establish a suitable antioxidant for a certain type of biodiesel, it is necessary to know the chemistry of the antioxidants and factors that influence their effectiveness against biodiesel oxidation. Most studies on the use of antioxidants to improve the oxidative stability of biodiesel have been conducted independently. This study presents an analysis of these studies and mentions factors that must be taken into account for the choice of antioxidants so that the storage stability of biodiesel fuels can be improved.
This two part paper presents general issues, methods and a case study for achieving production sustainability on a machining technology level. In order to tackle these issues, the paper promotes ...sustainable production via the alternative machining technologies, namely cryogenic and high pressure jet assisted machining that have a high potential to cut costs and improve competitiveness by reducing resource consumption and thus creating less waste. The general issues of sustainable technologies pointed out with a comparative case study life cycle assessment performed for alternative machining processes are covered in part I of the work, concluding that future of sustainable production is going to entail the use of alternative machining technologies to reduce consumption rates, environmental burdens, and health risks simultaneously, while increasing performances and profitability. As an upgrade to this part, overall cost evaluation is covered by a case study in part II of this work.
The study presents a new distribution tariff methodology in Slovenia that will enter into force on 1 July 2024. Its main novelty is the introduction of five-time slots with substantially different ...charges, the introduction of an agreed capacity (apart from nominated) that can be changed upon request several times a year, and an increased weight of capacity (power) in the distribution tariff making it more cost reflective. It is expected that changes will substantially increase the capacities of the grid and help to adapt it to the challenges of the energy transition. The approach can be replicated only in countries where connected capacity charge represents a substantial portion of the distribution tariff.
Nanocomposites based on 13X zeolite (13XZ), calcium oxide (CaO) and metal zinc particles (Zn) were prepared. The resulting nanocomposites were characterized by different techniques. Then, a ...comparative study on catalytic and noncatalytic pyrolysis of biomass waste was performed to establish the influence of nanocomposites used as catalysts on the yields and characteristics of liquid and solid products. Residual rapeseed biomass (RRB) was employed for pyrolysis experiments and a fixed bed reactor was used. By introducing CaO and metal zinc particles into 13X zeolite mass, the surface area (SBET) of nanocomposites was reduced, and this decrease is due to the introduction of nano-calcium carbonate and nano-zinc particles, which occupied an important space into zeolite structure. By adding CaO to 13XZ, the pore structure was changed and there was a decrease in the micropores volume. The analysis of the pore area distribution showed a hierarchical pore structure for nanocomposites. The elements composition showed that the main elements contained in nanocomposites are Si, Al, Ca and Zn, confirming the preservation of the zeolite structure. Using these nanocomposites as catalysts in pyrolysis process, the residual biomass could be valorized, producing bio-oil and biochar for the management and sustainability of this low-value waste.
In this paper, the tool deflection is first analyzed analytically, based on a four-section cantilever beam representation of the tool. Contributions of different sections of the tool to total tool ...displacement are quantified. Then the influence of cutting parameters (width of cut, depth of cut, and feed per tooth) on tool deflection are investigated experimentally using precise laser-based measuring technique. Empirical modeling of tool deflection curves is based on a mixed full factorial (2
1
3
2
) design of experiments to find a functional interrelation between the tool deflection close to the tip and the cutting parameters. The results show that response surface model of tool deflection can be used to characterize the process behavior across a useful range of cutting conditions. Analytical and empirical model predictions are compared with experimental results and a good agreement is observed.
Machining with robots represents a promising, highly flexible and cost effective alternative to standard machining and hand labour applications when machining mid tolerance soft material end ...products. One of the most challenging issues is to know the vibration characteristics in milling with the robots which greatly affect tool life. In general the technological bases of tool life expectancy while milling with robot arms are not available or studied. That`s why the purpose of this paper is to investigate the influence of attained vibrations analysis during the milling process and correlated tool wear. Primarily the study is focused on tool wear according to the distance between the milling position and the robot`s base. Results show that increasing distance between the robot's base and the milling position significantly affects tool wear because of the attained vibrations in proportion to the increasing distance respectively. Tool wear has also proved to be greater in comparison to machining with CNC machine and applicable new information for woodworking industry.
This paper overviews the state-of-the-art in modern forms of organization, collaboration and flexibility, trends and forecasts of the automotive industry as a representative buyer of tools, machines ...and special equipment, as well as life cycle management, sustainability and possibility for added value creation in these industry sectors. Based on this, a framework called "smart tool, machine, and special equipment" is proposed. A part of the research done on Slovene manufacturers is presented, where the technological indicators important in the implementation of the proposed framework are identified and ranked regarding to their importance. Additional suggestions by the manufacturers are also provided, as well as critical analysis and discussion of the findings.Original Abstract: U radu se daje pregled najnovijih dostignuca u modernim oblicima organizacije, suradnje i fleksibilnosti, trendovima i predvidanjima u automobilskoj industriji kao reprezentativnom kupcu alata, strojeva i specijalne opreme, kao i upravljanje vijekom trajanja, odrzivosti i mogucnosti stvaranja nove vrijednosti u tim industrijskim sektorima. Na temelju toga predlaze se okvirno nacelo nazvano "pametni alat, stroj i specijalna oprema". Daje se dio istrazivanja provedenog na slovenskim proizvodacima kod kojih su prepoznati tehnoloski indikatori vazni za implementaciju predlozenog nacela, te su rangirani u skladu s njihovom vaznosti. Daju se i dodatne primjedbe koje su stavili proizvodaci, te kriticka analiza i rasprava rezultata.
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