TY - CHAP A1 - Binninger, Karsten A1 - Kortüm, Christian A1 - Scholz, Frieder ED - Schajer, Gary T1 - Investigation of tool wear of the trimming unit and resulting quality in the edgebanding process T2 - Proceedings of the 25th International Wood Machining Seminar N2 - The edgebanding process, i.e. the covering of the raw edge of the laminated particleboard by means of decorative plastic or real wood veneer bands, is an important process step in the manufacture of furniture components. The quality of the final product is significantly influenced by this production step. The manufacturing process step within the edgebanding machine begins with the milling of the raw edge. The quality of the edgebanding process is determined by a large number of process input variables, such as the tool used and the cutting geometry, the type of laminate used for the wood-based material, adhesives, etc. The quality of the edgebanding process is also determined by the type of material processed. Particularly with regard to the materials, the increased use of recycled wood in the particleboard sector and different types of adhesives (with reduced formaldehyde emissions) results in increased demands on the milling process. Due to this developments, most of the earlier investigations (in the years 1990 - 2000) are not comparable with today’s general conditions. The mechanical and optical properties of the edge applied to the end product are decisively influenced by the quality of this joint. The milling technology used, as well as the tool used for this purpose and its condition, is a decisive influencing factor in the formation of quality. Tests on the indication of various influencing variables in the edgebanding process at the Rosenheim Technical University of Applied Sciences showed that in the case of chipboard milling, a decrease in the electrical power required for the cutting process can take place with increasing tool wear. It was also demonstrated that previous process steps in furniture production, such as panel dividing by means of sawing or milling/nesting, generally have a significantly different influence on the subsequent joining process during edge banding process. Furthermore, a direct correlation was determined between the mechanical properties of the end product and the condition of the tool used, which can be used as a measurable indicator. In addition to the effect of the tool condition on the mechanical properties of the edge banding, this also has an impact on the optical quality characteristics. Accordingly, it could be demonstrated here that an increase in the size and number of chippings takes place in the laminate of the board material to be processed. KW - edgebanding process KW - tool wear KW - trimming KW - product quality Y1 - 2023 ER - TY - CHAP A1 - Kortüm, Christian A1 - Riegel, Adrian T1 - Geometric Dimensioning and Tolerancing of Furniture Components T2 - Proceedings of the 24th International Wood Machining Seminar N2 - The machining of furniture components requires a complete geometrical specification of dimensions with associated tolerances to define in the first step appropriate manufacturing processes and to carry out the design and setup. Furthermore, a verification of the defined specification after production is a next step to check the quality and related to the production equipment, to calculate process capability and effectiveness. In 2011, the system of Geometrical Product Specification (GPS) has been published completely. The system is built for a distinct range of geometrical quality characteristics and consists of chains of standards referring to each other. With three elements of these chains, the product can be specified. With three additional elements, the verification of the product and the measuring system is possible. It does not contain the verification of the production processes, the process qualification. The German standard DIN 68100 provides a frame for dimensioning and tolerancing lengths and also angles, parallelism and straightness for furniture components. It includes a method to consider swelling and shrinking of wood and wood-based materials. Apart from its benefit of specifying products in a supply chain, it is rarely used in the branch nowadays. DIN 68100 is currently far away from GPS. To gain all benefits arising from GPS the branch needs a consolidated action. New symbols for drafts and an updated method for tolerancing with moisture consideration have to be developed as well as measuring dimensions of flexible work pieces, like most parts in the furniture industry. In GPS, the link between product verification and process specification is not that consistent. In other branches SPC and methods of process qualifications are established. At the moment the kitchen industry is establishing SPC or similar procedures. An action towards GPS can also accompany these efforts. Due to a shift in the tolerance principles, the GPS system is hardly directly applicable to the furniture industry, e.g. DIN 68100. But there is a real threat that the system is called up accidentally and out of ignorance. This paper sketches a comprehensive system of product specification, verification for furniture components and process qualification. It will share experience gained in the kitchen furniture industry and will add a theoretical analysis of a possible application of GPS-chains for important examples of quality characteristics. The activities are part of a process (VDI 3415-2) carried out in the working group 102 of the Society of German Engineers (VDI). KW - Geometrical Product Specification (GPS) KW - Tolerances KW - Specification and Verification KW - Process Qualification, Furniture Components Y1 - 2019 ER - TY - CHAP A1 - Böhm, Stefan-Andreas A1 - Kortüm, Christian ED - Schajer, Gary T1 - Machining Feature Recognition in Furniture Parts based on a Graph Neural Network T2 - Proceedings of the 25th International Wood Machining Seminar N2 - Due to the increasing customer demands, companies face the challenge of adapting their manufacturing facilities to produce batch size one parts. In this context, each component comes with specific customer requirements, significantly increasing the complexity of its manufacturing process. Traditional process planning done by employees is no longer feasible in the face of the growing complexity and diversity of batch size one parts. Therefore, there is a need for novel computer-aided process planning methods capable of autonomously learning and identifying the necessary machining features of these parts. We propose a configurable automated feature recognition framework tailored to batch size one parts to address this need. This framework comprises two main components. First, a customizable data generator is developed to create a dataset of computer-aided design models incorporating user-specific machining features. Second, a graph neural network is employed to learn these user-specific machining features by leveraging the graph structure represented by the vertices and edges in each computer-aided design model. We evaluate the effectiveness of our framework using a real-world example from the furniture industry. Specifically, we construct a dataset comprising over 7000 computer-aided design models of wooden boards using our framework's data generator. Each wooden board contains up to 30 randomly placed machining features for the application of connectors and fittings, randomly selected from 14 standard machining features commonly used in the furniture industry. An optimization algorithm adapts a graph neural network for classifying these specific machining features. The results demonstrate that our framework addresses the automated feature recognition problem without requiring data conversions, such as pixels or voxels, as other approaches often do. By introducing this configurable automated feature recognition framework, we solve the challenges posed by batch size one manufacturing. The framework's effectiveness and accuracy are demonstrated through extensive testing on the example of the furniture industry, showcasing its potential for enhancing manufacturing processes in various domains KW - Furniture Industry KW - Automatic Feature Recognition, KW - Machining Features KW - Machine Learning, Graph Neural Networks Y1 - 2023 ER - TY - CHAP A1 - Kortüm, Christian A1 - Böhm, Stefan-Andreas ED - Schajer, Gary T1 - Holistic approach for geometric and technological similarity search in the production for profiled elements in the wood working industry for a more efficient production T2 - Proceedings of the 25th International Wood Machining Seminar N2 - In the whole field of woodworking, from carpentry to industry, new products are created and designed every day and manufacturers wonder if similar workpieces have already been produced in the company and if corresponding drawings, information, tools, jigs, etc. can be reused. Under certain circumstances, considerable duplication of work can be avoided and a more efficient production is possible. In order to find similar workpieces, it must be clarified what exactly is meant by similarity. The different fields of knowledge do not provide a clear definition. However, similarities are always used to compare objects. In woodworking, objects can be a wide variety of components and products, such as carcase sides, furniture fronts, fittings, tools or profile strips. The search for similar profiled elements – related to the potential, data structure and algorithms – is the focus of this paper. There is a wide range of different profiled elements, which are used constructively as well as decoratively, e.g. for baseboards, door frames, window frames or decorative moulding profiles. These profiles are manufactured in a multi-stage production process in which the workpieces are first machined with profiled tools before surface finishing takes place. Along this production chain, tools, machine settings and, in some cases, fixtures are used that are adapted to the respective profile and can be reused for the same or similar jobs. Inheritance of information offers the greatest potential of similarity search. Inheritance means that existing knowledge in the form of drawings, CNC programs, process parameters and setup specifications, etc., is transferred from existing profiles to a new profile. By inheriting existing information, for example, the effort required for process setting can be reduced by adopting spindle positions, positions of guides and stops, or feed and cutting speeds. However, this can only be done if the process knowledge and other technological information concerning a profile are sufficiently documented. This is the only way how all information is made available for the similarity search and inheritance, and also for setting the processes when the profile is manufactured once again. The profile data must therefore be stored in a meaningful structure without loss of information. Therefore, a holistic product data model was developed that combines the geometrical with the technological profile data. The developed model allows a combined search for geometrically and e.g. materially similar products – also with a weighted evaluation of the individual criteria. The research has shown that data modelling is the essential foundation for the implementation of modern AI algorithms to enable similarity search. In conclusion, the use of a search system for geometrically and technologically similar profiles represents a real innovation for wood processing companies. This paper presents a holistic approach for geometrical and technological similarity search presenting different algorithms KW - similarity search KW - profiled elements KW - product data model KW - multi-stage production process Y1 - 2023 ER - TY - CHAP A1 - Weber, Susanne A1 - Draxler, Clemens A1 - Achtenhagen, Frank A1 - Bley, Sandra A1 - Wiethe-Körprich, Michaela A1 - Kreuzer, Christine A1 - Can, Gürer T1 - Chapter 13 Measuring Apprentices‘ Intrapreneurship Competence in Vocational Education and Training (VET): An Interdisciplinary Model-Based Assessment T2 - Good Teachers for Tomorrow’s Schools N2 - Teachers should be able to balance content knowledge, pedagogical knowledge and technological knowledge (TPACK) in their various activities on curriculum, instruction, and assessment. Our Germany-wide study focused on measuring intrapreneurship competence. To ensure a valid and reliable assessment, we followed the three-step assessment triangle: cognition, observation and interpretation. We modeled the intended IP competence as an interdisciplinary and interprofessional team, designed a technology-based performance assessment tool that uses authentic work tasks, and analyzed apprentices’ behavior via a model-based IRT (Rasch model) approach. Our results identify the distribution of the IP competence of apprentices on four proficiency levels. Since these results are generalizable, single IP tasks can be used by teachers to support and guide apprentices individually with regard to these proficiency levels. Our approach is a blueprint for evidence-based teaching that tackles all areas of TPACK. KW - teacher education Y1 - 2021 U6 - https://doi.org/10.1163/9789004465008_014 SP - 257 EP - 279 PB - Brill CY - Leiden ER - TY - JOUR A1 - Engler, Benjamin A1 - Hoffmann, S. A1 - Zscheile, Matthias T1 - Rubber tracked bogie-axles with supportive rollers–a new undercarriage concept for log extraction on sensitive soils JF - International Journal of Forest Engineering N2 - Driving forest machines on wet soils causes irreversible soil compaction, often associated with intensive rut formation and inaccessibility of wheeled forest machines for future forest operations. The German forestry equipment manufacturer FHS, Forsttechnik Handel & Service GmbH, engineered a forwarder, the Trac 81/11, equipped with conventional, well-proved bogie-axles embraced by a closed rubber track. At the center of the bogie-axle, four additional supportive rollers are placed to increase the load-carrying section between the tires of the bogie-axle. The study aimed to characterize the principle concept and the trafficability of the forwarder by analyzing the footprint area, the contact pressure, the rut formation on forest sites and the slippage during driving. Therefore, the effective contact area was measured on steel plates and rut formation was analyzed on a case study basis. Results showed that the supportive rollers increase the contact surface area by about 1/3. By this, a decrease of peak loads below the wheels and a more homogenous load distribution were observed. However, the contact surface area is still clearly divided into three parts; the area between the supportive rollers and the wheels does not take any load. Results of the rut formation were diverse: After 20 passes with 26,700 kg total mass, rut depth varied between 12.6 and 212.5 mm. Overall, the new undercarriage concept of FHS demonstrated a generally positive performance. The engineered forwarder contributes to reduce the environmental impact associated with log extraction. KW - Rut formation KW - rubber track KW - soil disturbance KW - ground pressure Y1 - 2021 U6 - https://doi.org/10.1080/14942119.2021.1834814 PB - Taylor & Francis ER - TY - GEN A1 - Ott, Holly A1 - Girata Sastoque, Lina Maria A1 - Brunsmeier, Martin A1 - Bayer, Claudia T1 - On the Cutting Edge of Wood Technology - Ensuring Sustainable Wood Flows T2 - Research in Bavaria - Spotlight KW - wood KW - sustainability KW - wood-based products Y1 - 2021 UR - https://www.research-in-bavaria.de/wood-technology ER - TY - JOUR A1 - Barth, Simon A1 - Schmid, Thomas A1 - Michanickl, Andreas T1 - TECHNICAL NOTE: A METHOD TO DETERMINE THE WETTING OF WOOD FIBERS WITH THERMOPLASTIC JF - Wood and Fiber Science N2 - This paper presents a method which allows to assess the wettability of thermomechanical pulp (TMP) with thermoplastic. The method is based on the usage of laboratory sheets made of TMP and plastic granules which form drops under heat. The contact angle of the drops after re-solidification on the surface of the laboratory sheets serves as the wetting characteristic. This method enables a direct and evaluable testing of wood fiber thermoplastic combinations. The exemplary results indicate that wood species, pulping temperature and mercerization influence the wettability of TMP with thermoplastic. KW - thermomechanical pulp KW - thermoplastic KW - wettability Y1 - 2021 UR - https://doi.org/10.22382/wfs-2021-16 VL - 53 IS - 2 SP - 157 EP - 159 ER - TY - JOUR A1 - Gretz, Markus A1 - Plank, Johann T1 - An ESEM investigation of latex film formation in cement pore solution JF - Cement and Concrete Research N2 - Environmental scanning electron microscopy (ESEM) and complementary methods were employed to study the time dependent film formation of a latex dispersion in water and cement pore solution. First, a model carboxylated styrene/n-butyl acrylate latex dispersion possessing a minimum film forming temperature (MFFT) of 18 °C was synthesized in aqueous media via emulsion polymerization. Its film forming property was at a temperature of 40 °C, studied under an ESEM. The analysis revealed that upon removal of water, film formation occurs as a result of particle packing, particle deformation and finally particle coalescence. Film formation is significantly retarded when the latex dispersion is present in cement pore solution. This effect can be ascribed to adsorption of Ca2+ ions onto the surface of the anionic latex particles and to interfacial secondary phases. This layer of adsorbed Ca2+ ions hinders interdiffusion of the macromolecules and subsequent film formation of the latex polymer. KW - Construction Chemistry KW - Cement KW - Cement Pore Solution KW - Latex-Particles Y1 - 2021 UR - https://doi.org/10.1016/j.cemconres.2010.11.005 VL - 41 IS - 2 SP - 184 EP - 190 PB - Elsevier ER - TY - JOUR A1 - Pavlitschek, Tom A1 - Gretz, Markus A1 - Plank, Johann T1 - Novel Core-Shell Hybrid Polymers Designed as Dual Functional Additives for Concrete JF - Advanced Materials Research N2 - Novel hybrid admixtures for construction applications were prepared by layer-by-layer deposition technique. Colloidal core templates consisting of styrene/n-butylacrylate latex particles were coated with multilayers of superplasticizers commonly used in concrete. This way, core-shell particles possessing both dispersing and film-forming properties were achieved. Incorporation of the latex@dispersant hybrid additive into a cement paste results in a slow release of the superplasticizer as a result of gradual shell disintegration which instigates prolonged plastification (long ”slump life”) of the cement slurry. Once the shell has been dissolved, latex particles are released into the pore solution and can coalesce into a polymer film which improves the mechanical properties of the hardened cement. Characterization of the templates and novel additives was performed by means of zeta potential measurement, dynamic light scattering and electron microscopy. Our method allows to synthesize multifunctional additives with time-controlled release effect. KW - Construction Chemistry KW - Cement KW - Concrete KW - Latex-Particles Y1 - 2021 UR - https://doi.org/10.4028/www.scientific.net/AMR.687.77 VL - 687 SP - 77 EP - 83 ER - TY - JOUR A1 - Pavlitschek, Tom A1 - Gretz, Markus A1 - Plank, Johann T1 - Microcapsules prepared from polycondensate-based cement superplasticizers via layer-by-layer self assembly on melamine-formaldehyde core templates JF - Journal of Applied Polymer Science N2 - Novel microcapsules were prepared from colloidal core–shell particles by acid dissolution of the organic core. Weakly crosslinked, monodisperse and spherical melamine-formaldehyde polycondensate particles (diameter ∼ 1 μm) were synthesized as core template and coated with multilayers of an anionic polyelectrolyte via layer-by-layer deposition technique. As polyelectrolytes, an anionic naphthalenesulfonate formaldehyde polycondensate that is a common concrete superplasticizer and thus industrially available, and cationic poly(allylamine hydrochloride) were used. Core removal was achieved by soaking the core–shell particles in aqueous hydrochloric acid at pH 1.6, resulting in hollow microcapsules consisting of the polyelectrolytes. Characterization of the template, the core–shell particles, and the microcapsules plus tracking of the layer-by-layer polyelectrolyte deposition was performed by means of zeta potential measurement and scanning electron microscopy. The microcapsules might be useful as microcontainers for cement additives. KW - Construction Chemistry KW - Cement KW - Construction Chemical Additives Y1 - 2021 UR - https://doi.org/10.1002/app.37981 VL - 127 IS - 5 SP - 3705 EP - 3711 PB - Wiley ER - TY - CHAP A1 - Wilhelm, Patrick A1 - Gretz, Markus A1 - Stephan, Dietmar A1 - Plank, Johann ED - Partec 2007, T1 - Synthesis and photocatalytic activity of magnetic core-shell nanoparticles T2 - International Congress of Particle Technology, Partec KW - Bauchemie Y1 - 2021 ER - TY - JOUR A1 - Gretz, Markus A1 - Plank, Johann T1 - Hybrid additives for construction applications, fabricated through layer-by-layer adsorption of polycondensate type superplasticizers on latex templates JF - Colloids and Surfaces A: Physicochemical and Engineering Aspects N2 - Novel hybrid admixtures for construction applications were prepared by layer-by-layer deposition technique. Colloidal core templates consisting of styrene/acrylate latex particles were coated with multilayers of polycondensate-based dispersants commonly used in concrete. This way, core–shell particles possessing both dispersing and film-forming properties were achieved. Incorporation of the latex@dispersant hybrid additive into a cement paste results in a slow release of the dispersant which instigates prolonged plastification of the cement slurry. Following disintegration of the shell, the latex core particles are released into the pore solution and coalesce into a polymer film which improves the mechanical properties of the hardened cement. Characterization of the templates and novel additives plus tracking of the layer-by-layer polyelectrolyte adsorption was performed by means of zeta potential measurement, dynamic light scattering and electron microscopy. Our method allows to synthesize multifunctional additives with time-controlled release effect. KW - Construction Chemistry KW - Construction Additives KW - Cement Y1 - 2021 UR - https://doi.org/10.1016/j.colsurfa.2010.05.014 VL - 366 IS - 1–3 SP - 38 EP - 44 PB - Elsevier ER - TY - JOUR A1 - Pavlitschek, Tom A1 - Gretz, Markus A1 - Plank, Johann T1 - Effect of Ca2+ Ions on the Film Formation of an Anionic Styrene/n-Butylacrylate Latexpolymer in Cement Pore Solution JF - Advanced Materials Research N2 - Several methods were employed to study the time dependent film formation of a self synthesized anionic latex dispersion in water and cement pore solution. First, a model carboxylated styrene/n-butyl acrylate latex dispersion possessing a minimum film forming temperature (MFFT) of 18 °C and a glass transition temperature (Tg) of 30 °C was synthesized via emulsion polymerization. Next, its film forming behaviour was studied at 40 °C, using an ESEM instrument. The analysis revealed that upon removal of water, film formation occurs as a result of particle packing, particle deformation and finally particle coalescence. Film formation is significantly hindered in synthetic cement pore solution. This effect can be ascribed to adsorption of Ca2+ ions onto the surface of the anionic latex particles and to interfacial secondary phases. This layer of adsorbed Ca2+ ions hinders interdiffusion of the macromolecules and subsequent film formation of the latex polymer. KW - Construction Chemistry KW - Latex-Particles KW - Cement KW - Film Formation Y1 - 2021 UR - https://doi.org/10.4028/www.scientific.net/AMR.687.322 VL - 687 SP - 322 EP - 328 ER - TY - JOUR A1 - Gretz, Markus A1 - Plank, Johann T1 - Investigations on the interaction of cationic and anionic latex particles with Portland cement JF - Colloids and Surfaces A: Physicochemical and Engineering Aspects N2 - The interaction between organic latex polymers and the surface of hydrating cement was investigated by measuring the zeta potential and adsorbed amount of polymer on cement. First, differently charged model latex particles were synthesized in aqueous media by well-known emulsion polymerization technique. The latex polymers were characterized by differential scanning calorimetry (DSC), dynamic light scattering (DLS) and environmental scanning electron microscopy (ESEM). Electrokinetic latex surface properties were investigated by means of streaming potential measurements using a particle charge detector (PCD). It is shown that the anionic latexes adsorb a considerable amount of Ca2+ from the cement pore solution. Next, adsorption of the latex polymers on the surface of hydrating cement was confirmed by zeta potential measurements using the electroacoustic method. A water to cement ratio in the cement paste as low as 0.5 was studied, representing actual conditions in mortar and concrete. Additionally, adsorption isotherms were determined in a sedimentation test using the depletion method. For all latex polymers, Langmuir type adsorption isotherms were found. The latex dosages required to achieve saturated adsorption on the cement surface obtained from zeta potential measurements correspond well with those determined in the sedimentation test. Electron microscopy photographs confirm that the charged latex polymers adsorb selectively on surface areas of hydrating cement showing opposite charge. This way, domains of organic latex polymers exist on the cement surface. They provide adhesion between the inorganic cement matrix and the organic polymer film formed later on by particle coalescence as a result of cement hydration and drying. KW - Construction Chemistry KW - Latex-Particles KW - Cement Y1 - 2021 UR - https://doi.org/10.1016/j.colsurfa.2008.08.005 VL - 330 IS - 2–3 SP - 227 EP - 233 PB - Elsevier ER - TY - JOUR A1 - Engler, Benjamin A1 - Hoffmann, Stephan A1 - Zscheile, Matthias T1 - Rubber tracked bogie-axles with supportive rollers – a new undercarriage concept for log extraction on sensitive soils JF - International Journal of Forest Engineering N2 - Driving forest machines on wet soils causes irreversible soil compaction, often associated with intensive rut formation and inaccessibility of wheeled forest machines for future forest operations. The German forestry equipment manufacturer FHS, Forsttechnik Handel & Service GmbH, engineered a forwarder, the Trac 81/11, equipped with conventional, well-proved bogie-axles embraced by a closed rubber track. At the center of the bogie-axle, four additional supportive rollers are placed to increase the load-carrying section between the tires of the bogie-axle. The study aimed to characterize the principle concept and the trafficability of the forwarder by analyzing the footprint area, the contact pressure, the rut formation on forest sites and the slippage during driving. Therefore, the effective contact area was measured on steel plates and rut formation was analyzed on a case study basis. Results showed that the supportive rollers increase the contact surface area by about 1/3. By this, a decrease of peak loads below the wheels and a more homogenous load distribution were observed. However, the contact surface area is still clearly divided into three parts; the area between the supportive rollers and the wheels does not take any load. Results of the rut formation were diverse: After 20 passes with 26,700 kg total mass, rut depth varied between 12.6 and 212.5 mm. Overall, the new undercarriage concept of FHS demonstrated a generally positive performance. The engineered forwarder contributes to reduce the environmental impact associated with log extraction. KW - rut formation KW - rubber track KW - soil disturbance KW - contact surface area KW - ground pressure Y1 - 2020 UR - https://doi.org/10.1080/14942119.2021.1834814 ER - TY - CHAP A1 - Ott, Holly C. A1 - Heilmayer, S. A1 - Sng, S.Y. T1 - Granularity and Temporal Dependency of Forecast Accuracy in Semiconductor Industry T2 - 7th Economy and Efficiency Conference, Poznan University of Technology, Poland KW - Semiconductor Industry Y1 - 2012 ER - TY - GEN A1 - Ott, Holly C. T1 - Developing Local Leadership in Asian Operations KW - Case Study Y1 - 2020 ER - TY - GEN A1 - Ott, Holly C. ED - The Case Centre, T1 - Process Quality Monitoring at Altis Semiconductor KW - Case Study Y1 - 2020 ER - TY - GEN A1 - Ott, Holly C. T1 - Using the DMAIC Process Improvement Flow at Hanwag GmbH KW - Case Study Y1 - 2020 ER -