Development ofbandsaw to control washboard during sawing

2001 Fiscal Year Final Research Report Summary

• Project/Area Number: 12556026
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 展開研究
• Research Field: 林産学
• Research Institution: NAGOYA UNIVERSITY
• Principal Investigator: KIMURA Shiro NAGOYA UNIVERSITY Graduate School of Bioagricultural Sciences Professor, 大学院・生命農学研究科, 教授 (30023443)
• Co-Investigator(Kenkyū-buntansha): RYOU Kokushin Chugoku Mokuzai Co.Ltd Chief Scientist, 開発課, 主任研究員 ; TUCHIKAWA Satoru NAGOYA UNIVERSITY Graduate School of Bioagricultural Sciences Research associate, 大学院・生命農学研究科, 教授 (30227417) ; YOKOCHI Hideyuki NAGOYA UNIVERSITY Graduate School of Bioagricultural Sciences Associate Professor, 大学院・生命農学研究科, 助教授 (60124723)
• Project Period (FY): 2000 – 2001
• Keywords: bandsaw / bandsaw / washboard / self-excited vibration / random piteh / transverse vibration mode / torsional vibration mode / surface

Research Abstract

The rugged sawn surface like washboard occurred, when the tooth passing frequencies were slightly higher than the natural frequencies of bandsaw. It was because when the tooth passing frequencies were slightly higher than natural frequencies of bandsaw, the direction of lateral component of the cutting resistance during sawing agreed with the direction which bandsaw instantaneously intended to vibrate in the moment. In the last study, the marketed bandsaw were remodeled in order to disturb the direction or the size of lateral component of cutting resistance during sawing. The tooth of one marketed bandsaw with uniform pitch teeth was randomly ground off. Then, a pitch was disarranged One side of set of one marketed bandsaw with uniform pitch swage set teeth was regularly or randomly ground off. The remodeled bandsaw remarkably controlled the rugged sawn surface like the washboard in comparison with marketed bandsaw with uniform pitch swage set teeth. However, all changed pitch is integ er multiples of the 19mm pitch of the uniform pitch swage set teeth. Therefore, it seemed to be able to not perfectly control the rugged sawn surface like washboard.
Then, in this study, we made two typed handsaws with swage set teeth of random pitch in which a pitch was not very long. These pitches of type-1 were decided to be the 10 levels from 15mm to 24mm in step of 1mm, and these pitches were assigned using table of random numbers. These pitches of type-2 were decided to be the 5 1evels from 17mm to 21mm in step of 1mm, and these pitches were assigned using table of random numbers.
The results of type- 1 bandsaw are follows. The rugged sawn surface like washboard occurred under the torsional vibration mode 2 or the torsional vibration mode 3.
The revolution speed of the bandsaw wheel is from 150rpm to 350rpm and the revolution speed range of the bandsaw wheel is from about lOrpm below to about 30 rpm above the speed at which the apparent tooth passing frequency becomes equal to the natural frequency of the bandsaw. In the above-mentioned range, the revolution speeds of the bandsaw wheel were varied in steps of 2rpm.
The results of type-2 bandsaw are follows. The rugged sawn surface like washboard did not occur under all transverse vibration modes and all torsional vibration modes.
At last, type-2 bandsaw with swage set teeth of random pitch perfectly controlled the rugged sawn surface like washboard.
We tried the numerical evaluation about the effective of vibration control.
When the direction of lateral component of the cutting resistance during sawing agrees with the direction which bandsaw instantaneously intended to vibrate in the moment, the depth of cut on the side is denned as plus value. And when the direction of lateral component of the cutting resistance during sawing inverses to the direction which bandsaw instantaneously intended to vibrate in the moment, the depth of cut on the side is denned as minus value. The depth of cut was integrated during one period of sawteeth vibration. The integration value of type-2 was minus value.