Автор: Valentin Atanasov
- ADDITIONS TO THE SOLUTION OF THE STATICALLY INDETERMINATE PROBLEM OF TENSION IN BANDSAW BLADE
At the Faculty of Forest Industry, seemingly for the first time in the bandsaw studies history, the statically indeterminate problem of spring mechanism tension in bandsaw blade sections was set up and solved. The solution, transferred and generalized for a horizontal bandsaw, was defended in a Ph.D. thesis. Questions and discussions arose necessitated additions and details to the solution spared in previous papers for their limited volume. Now, the following points are detailed: the concentration of distributed loads, the subcritical friction, and the application of L'Hôpital's rule for obtaining the tension of the blade in the state of idle running (without cutting).
Ключови думи: bandsaw, bandsaw blade, tensioning spring mechanism, statically indeterminate problem
- SAWING OF DOUGLAS FIR LOGS WITH NARROW BAND SAW BLADES IN WINTER CONDITIONS
The report presents some experimental studies carried out by sawing of logs with narrow band saw blades in winter conditions. The experiments were carried out in manufacturing conditions in February. For the purpose a horizontal band saw "Wirex CZ-1/ZM" was used.
Operating conditions were established and the quality of sawn lumber from semi frozen logs of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) was tested. The quality preparation of the band saw blade with the used horizontal band saw provides good parameters of the sawn lumber: surface roughness R̅m = 190 μm; variation in the accuracy of the size and shape of 1.5 mm and 1.8 mm at a feed speed of U = 11.5 m.min-1.
Ключови думи: logs, Douglas fir, sawing, narrow band saw blades, winter conditions
- RESEARCH ON THE QUALITY OF PROCESSING WITH A HORIZONTAL BANDSAW
Experimental studies related to the influence of some factors on the quality of the resulting lumber were carried out. The venue of the research is the manufacturing conditions in Experimental and Training Forest Ranges in Barziya. As a work station a horizontal bandsaw for logs Arsov 90 Ltd. (Bulgaria) was used. The results were analyzed and compared to some earlier obtained with other machines of this type. They show that it is not advisable feed speed to exceed 16 m.min-1– due to the risk of unacceptable size deviations. Some recommendations for a more efficient usage of this type machines were proposed.
Ключови думи: horizontal bandsaw, logs cutting, surface roughness, quality of processing
- STUDY ON THE POWER – ENERGETIC INDICATORS OF A UNIVERSAL MILLING MACHINE
Experimental studies during milling of solid wood were carried out. The current study was performed at the Laboratory of Woodworking Machinery, University of Forestry, Sofia. The measurements were carried out using universal milling machine FD – 3 (ZDM – Plovdiv). The correlations between fundamental factors influencing the milling process and target functions, such as cutting force and power, specific cutting work, specific power consumption have been investigated. On the basis of the analysis of the obtained results, practical recommendations have been proposed.
Ключови думи: universal milling machine, cutting power, cutting force, specific cutting work, wood milling