Development and Comparison of Structural Applications of Production Machine Nodes Ing., Jaroslav, Červenka V příspěvku se zabýváme návrhem změny technologie výroby posuvných stolů dřevoobráběcích strojů. V současné době jsou posuvné stoly vyráběny jako složité protlačované Al profily, což je značně nákladné. Nahradíme- li hliníkové protlaky ohraňovanými ocelovými profily výroba se značně zlevní a zjednoduší. V naší práci se zabýváme použitelností těchto technologií s ohledem na mechanické vlastnosti ohraňovaných profilů, především na jejich tuhost. Při porovnávání protlačovaných a ohraňovaných profilů se vycházelo ze stejných podmínek zatížení a stejné funkce použitelnosti. Modely našeho řešeného problému určené pro výpočty pevnostní a deformační byly zhotoveny v CAD systému Solid Works. Výpočty byly provedeny za použití metody konečných prvků a softwarového prostředí Cosmos Design Star 4.0. Wood-working machines, Sliding tadle bearing, Linear course The contribution is focused on innovative development of production machines nodes. In this instance we deal with change of sliding work-tables arrangement, which has been used for woodworking machines so far. The table seated in rolling elements on the basic supporting profile, is used in construction of these machines for sliding of cut material. Nowadays extruded alluminium-based alloy profiles of various structural groupments are in common use. They are explicitely specified for every single production and they are designed and produced only for the individual producers use. There are some of used profile groupments on following figures.
Fig. 1. Possible shapes of produced profile groupment. In the upper part of groupment, there is the table and rolling elements in modified snap-rings. The supporting beam, made in accordance with requirements and the way of rolling seating, is situated in the lower part. Our aim was to replace such a complicated and expensive profile with other profile of identical parameters, while produced differently. Shape complicacy of aluminium-based alloy profiles is given by properties of used material; there has to be used great amount of reinforcement ribs and technological roundings. Manufacture of these extruded profiles is expensive and profitable only in batch production of the tabels. Consequently, thay are applied in other spheres as a fixed supporting element. Profiles of our design are made by technology of folding of sheet metal semi-product. Their shape is depicted on the following figure. The results, which are presented in contribution: Comparison of Strength Properties of Used Al Profiles on Work-Tables were used for comparison of properties, paticularly deformation and tension parameters. Fig. 2. One of designed profiles.
Fig.3. Total strain of sliding work-table bent of sheet metal. Fig. 4. Total tension of sliding work-table bent of sheet metal. It is evident on the figure, that maximum tension is in the punctal contact of rollers with hardened surface of sliding table. Along the rest of the profile the tension is minimal. Fig. 5. Tension progress along vertical section in contact place of rollers and hardened surface of sliding table.
Fig. 6. Strain of sliding table in edge loading position. Deformation of sliding table at the most distant place from the end support realized by roller. Fig. 7. Tension of sliding table in edge loading position. Maximum tension is located in the linear contact of rollers and hardened surface of sliding table and in the place of the end support realized by roller of guiding way, where the sliding table is bent due to maximum protrusion and load. Fig. 8. Strain of sliding table in rear edge position. Deformation of sliding table at the most distant place from the end support realized by roller.
Fig. 9. Tension of sliding table in rear edge position. Maximum tension is located in the linear contact of rollers and hardened surface of sliding table and at the place of the last support realized by roller of guiding way, where the sliding table is bent due to maximum protrusion and load. Tables made of bent sheet metal semi-products are approximately half price of tables made of aluminium-based alloy extruded profiles not only due to high acquisition costs of extruding mould, but also regarding operation costs of extruding line and folding brake. Acquisition costs of sheet metal semi-product are lower than acquisition costs of aluminium-based alloys, as well. Other indisputable advantage is variability and flexibility of production with minimal costs of change of the table shape complying with the customers request. 2. Conclusion Considering the comparison above, it is evident, that the sheet metal profile conceptually created and designed by us is simplier in shape and reaches similar values of strain and tension in comparison with extruded aluminium-based alloy profiles.
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