Increasing Saw Resistance to Wear by Sharpening Interruption Abrasive Circles

Abstract

The existing method of sharpening steel saws with solid abrasive wheels is of low productivity and doesn't provide high level of wear resistance. Abrasive wheels with intermittent sharpening surface may be used to avoid this drawback. The purpose of the study is to identify the relationship between the teeth wear area, cutting path and the number of abrasive wheel interruptions, and to define the rational number of interruptions and circular saw replacement frequency during sawing wood. We used a circular saw blade with the diameter of 400 mm and 60 square top teeth on the blade. Experiments were conducted on circular sawing woodworking machines with crawler conveyor. Dried beech boards were sawn. Speed of conveying workpieces was constant – 24 m/min. Five series of experiments were carried out. The first series was with saw sharped by continuous abrasive wheels. The next series was with saw sharped by intermittent abrasive wheels with the number of interruptions – 3, 6, 9, 12. We used circles ceramic bond. For quantitative evaluation of saw blade teeth' wear we used the area of blade teeth' wear. Cutting path is determined as a function from the length of the cut, cutting arc length and filing for tooth. The wear area was measured using the integrated methodology and 'Compass' software. During the cutting process the blade teeth wear on the front and back sides. At the beginning the area of blade teeth ware increased rapidly; later ware intensity decreases and progressed into the phase of steady wear. After reaching a value of 15´103 μm2 sharp increase of wear area was observed and some teeth had broken down or bent blades. On the basis of the experiments and model analysis, it could be stated that as the number of interruptions increases the area of blade teeth ware decreases. Subsequent exploitation of the circular saw is impossible. To conclude, we have conducted for the first time comparative research of wear of steel circular saw blades teeth sharpened with continuous and interruption abrasive circles. Using abrasive wheels with intermittent grinding surface may increase wear resistance of circular saws to 1.67 times. This helps reduce expenses on circular saws, machines and replacement of instrument and increase their productivity.

Keywords

• sharpening
• steel saw blade
• interruption abrasive circle
• mathematical model of wear
• regression equation
• cutting path
• wear resistance