Estudo da eficiência técnica na conversão de toros de mecrusse em madeira serrada e parquet num sistema de serras fita e circular

Abstract

The study was carried out at the sawmill “Madeirarte, Lda”, located in the province of Gaza. We tried to evaluate the technical efficiency of the production of sawn wood and parquet from mecrusse logs in a band and circular saw system. As a study methodology, 8 diametric classes were defined to allow the processing of 5 logs for each class, making a sample of 40 logs of Androstachys johnsonii. The logs were subjected to bark diameter, length and thickness measurements before sawing. After processing, measurements were performed on the sawn wood, as well as its classification. The volume efficiency indicators (volumetric yield, parquet yield, sawdust percentage and coastal percentage) as well as the value efficiency indicators (value per cubic meter of logs and value per cubic meter of the obtained products) were used to evaluate the technical efficiency of the sawmill. The relationship between the diameter of the logs and the indicators of technical efficiency in the production of parquet was also analyzed using regression equations. The results show that the efficiency indicators presented average values ​​of 56.8% for the total volumetric yield, of 51.7% for the parquet yield, of 5.1% for the percentage of sawdust, of 28.4% for the percentage of coasters, 5,746,762.36 MT/m3 for the value per cubic meter of logs and 9,797,118.98 MT/m3 for the value per cubic meter of the products obtained, using the cutting scheme 2. The results also show that the diameter and defects of the logs significantly affect the different parameters of conversion efficiency, recommending careful sawing of logs with small diameters and/or with defects. The study was carried out at the sawmill “Madeirarte, Lda” , located in the province of Gaza. We tried to evaluate the technical efficiency of the production of sawn wood and parquet from mecrusse logs in a band and circular saw system. As a study methodology, 8 diametric classes were defined to allow the processing of 5 logs for each class, making a sample of 40 logs of Androstachys johnsonii. The logs were subjected to bark diameter, length and thickness measurements before sawing. After processing, measurements were performed on the sawn wood, as well as its classification. The volume efficiency indicators (volumetric yield, parquet yield, sawdust percentage and coastal percentage) as well as the value efficiency indicators (value per cubic meter of logs and value per cubic meter of the obtained products) were used to evaluate the technical efficiency of the sawmill. The relationship between the diameter of the logs and the indicators of technical efficiency in the production of parquet was also analyzed using regression equations. The results show that the efficiency indicators presented average values ​​of 56.8% for the total volumetric yield, of 51.7% for the parquet yield, of 5.1% for the percentage of sawdust, of 28.4% for the percentage of coasters, 5,746,762.36 MT/m3 for the value per cubic meter of logs and 9,797,118.98 MT/m3 for the value per cubic meter of the products obtained, using the cutting scheme 2. The results also show that the diameter and defects of the logs significantly affect the different parameters of conversion efficiency, recommending careful sawing of logs with small diameters and/or with defects.