Heat development at the knife roller during leather shaving / Tilman Witt in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 3 (Année 2021)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 3 (Année 2021) . - 11 p. Titre : Heat development at the knife roller during leather shaving Type de document : texte imprimé Auteurs : Tilman Witt, Auteur ; Anke Mondschein, Auteur ; Jens-Peter Majschak, Auteur ; Michael Meyer, Auteur Année de publication : 2021 Article en page(s) : 11 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux Cuirs et peaux -- Analyse Cylindre à couteaux Dérayage Eléments finis, Méthode des Thermocinétique Thermographie Thermométrie Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Leather, which is regularly tanned from whole hides of up to 5 m2, needs a constant thickness over the entire surface in order to be processed into high-quality consumer goods such as shoes, furniture and car interiors. Precise adjustment of the thickness is achieved by shaving. On an industrial scale, rotating knife rollers are used to remove chips from the flesh side of semi-finished leathers whereby adjusting the specified thickness and generating a smooth surface. Care must be taken to prevent the temperature from rising above the denaturation temperature of the leather during shaving in order to avoid any loss of quality. Beside this, temperature rise is always a sign of friction showing avoidable energy expenditure. In order to localize the source of friction during shaving, actual temperature development at the roller knife is studied. Different measuring methods are used to evaluate the temperature increase at the blade roll of the shaving machine. The finite element method is used to thermally simulate the process. Measured temperatures, the geometry of the blade roll and process data are taken into account for modelling the temperature development close to the blade edge. The obtained results enhance the understanding of temperature generating processes during machine operation and allow conclusions about potential improvements in the design of the machine and blades. Note de contenu : - INTRODUCTION : Leather reactions to thermal stress - The shaving machine - Cutting principle and energy consumption - MATERIALS AND METHODS : Pre tanned leathers and shaving - Analysis of shaved hides - High speed infrared imaging - Temperature measurement of the cutting tool - Measurement of the roller turning speed - Thermal modelling with finite element method - Calculating the heat transfer coefficient - RESULTS : Thermography - Thermistor measurements - Transient finite element simulation - Analysis of shaved hides - Table 1 : Rizzi LW 3200 Shaving Machine Characteristics - Table 2 : Relevant material properties of steel - Table 3 : Selected material values for the surrounding fluid DOI : https://doi.org/10.1186/s42825-021-00057-0 En ligne : https://link.springer.com/content/pdf/10.1186/s42825-021-00057-0.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37543 [article]

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A study on characteristics of low-density regenerated leather using chromium-tanned shaving waste / Eun-Chul Shin in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 107, N° 2 (03-04/2023)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 107, N° 2 (03-04/2023) . - p. 43-48 Titre : A study on characteristics of low-density regenerated leather using chromium-tanned shaving waste Type de document : texte imprimé Auteurs : Eun-Chul Shin, Auteur ; Young-Woo Kim, Auteur ; Won-Ki Lee, Auteur Année de publication : 2023 Article en page(s) : p. 43-48 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuir reconstitué Cuirs et peaux -- Déchets -- Recyclage Dérayage Matériaux expansés Microsphères Moussage (chimie) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Shaving scrap is collagen fibre, that is the leather waste occurring during thickness adjustment during the natural leather manufacturing process, and may cause problems such as environmental contamination because of the chromium (Cr) contained when it comes to reclaiming processes. Various studies applying to shaving scrap are currently being conducted in many countries across the world with an initiative by the EU. Amongst those applications, the regenerated leather is being highlighted as a substitute for natural leather. However, since the regenerated leather uses latex as a binder, it accordingly entails a high weight, which is deemed as a disadvantage due to its dense internal tissues compared to other synthetic leathers. To address such disadvantages, this study employed the thermally expandable microspheres (TEMs) to improve its density and light weight by alleviating the internal structure. This is a study on the manufacturing of foamed regenerated leather using shaving scraps. In the study, the shaving scraps were forced to foam at under 100~120°C with consideration for the heat resistance of collagen fibre after applying the thermally expandable microsphere, and then the effect was analysed. In the analysis results, the most effective foaming rate was exhibited when the shaving scraps were treated at under 110°C for 8 minutes using TEMs T110. Note de contenu : - EXPERIMENTAL PROCEDURES : Materials - Manufacture of regenerated leather - Measurements - RESULTS AND DISCUSSION : Optimisation of foaming conditions - Foaming studies by microsphere content - Table 1 : Microsphere used in this study - Table 2 : SEM images of foaming conditions - Table 3 : Physical properties according to content of microsphere - Table 4 : WVP* and density according to content of microsphere En ligne : https://drive.google.com/file/d/11Uz81wHKO5x9AAvLwpedwpNOepWJST2F/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39063 [article]

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The behaviour of pieces in machine operations as a function of temperature and moisture content / Richard Daniels in WORLD LEATHER, Vol. 18, N° 8 (12/2005 - 01/2006)  

[article]  inWORLD LEATHER > Vol. 18, N° 8 (12/2005 - 01/2006) . - p. 36-37 Titre : The behaviour of pieces in machine operations as a function of temperature and moisture content Type de document : texte imprimé Auteurs : Richard Daniels, Auteur ; Walter Landmann, Auteur Année de publication : 2005 Article en page(s) : p. 36-37 Langues : Anglais (eng) Catégories : Cuirs et peaux -- Effets de l'humidité Cuirs et peaux -- Effets de la température Dérayage Echarnage Essorage Mise au vent Opérations mécaniques Refendage Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In the early mechanical operations much of the focus is on cutting, and for optimum effect the skins must be held flat against the cutting blade or knife. This requires a stretching action for good presentation, which is mainly provided within fleshing and shaving operations by spiral cutting blades on the rotating cylinder. In the splitting operations this is achieved by the helically-grooved gauge roller, and, in part, by the movement of the knife blade, as well as in presentation to the samm/setting operation by the setting cylinder. Over and above the objective of the operation, stretch is involved at the point of contact between the hide and blade. This action can be considerable, and the physical properties of the skin at that time—especially the ease and degree of extendibility, compression and recovery—strongly affect the outcome of the operation. Adjustments are made, both to machine settings and presentation, to achieve the best balance of results. But success is a balance between the way force is applied by the machine and received by the skin. It is an equal partnership, but however sophisticated the machine or perfect the application, variations still occur. The following diagrams provide an insight into the behaviour of mechanically-stressed pieces dependent upon skin condition. Over and above inherent skin variations, as hides and skins progress within manufacture the permutations that generate change increase enormously. Note de contenu : - Panel E10/1 : Presentation of hides and skins to operation versus effect : raw to tanned samm/set condition - Panel E10/2 : Presentation of hides and skins to operation versus effect : splitting ahd shaving En ligne : https://drive.google.com/file/d/1V_MmIOJ6_GLHbKQvRevicU4XfplK8UYc/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32504 [article]

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