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Subject: Forest Product and Utilisation × Author: KAU × End date: 2022 × Start date: 2021 × Type: Thesis ×
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    ThesisItemOpen Access
    Development of experimental kiln-drying schedules for different types of coconut (Cocos nucifera L.) palm wood flooring
    (Department of Forest Products and Utiliztion, College of Forestry, Vellanikkara, 2021) Shibu, C; KAU; Anoop, E V
    In India, there is a significant gap existing between supply and demand for wood and wood products. Several factors influence wood consumption. For example, the construction sector is witnessing a shift to eco-friendly furnishings. Indeed, the eco-friendly amenity of wooden flooring in hotels and houses has contributed to an upswing in commercial wood consumption. In the current scenario, effective utilisation of existing lesser-known species such as Cocos nucifera L. (Coconut palm tree) is gaining prominence. The lesser known wood species will help to meet the domestic demand and may help to bridge the gap between supply and demand of timber. Seasoning of wood is a crucial step for producing defect-free timber for the ease of doing timber work and potential use of available timber. The purpose of this research is to develop experimental kiln-drying schedules for Cocos nucifera L. (Coconut palm tree) for various flooring methods (Tongue & Groove flooring (T&G flooring), Parquetry flooring, and Engineered overlay flooring). The substructure, base kiln-drying schedules were developed based on the Terazawa method (1965), and optimised using Rasialy (1993) classification. The critical conditions of equalizing treatment and conditioning treatment were established in relation to the product's desirable moisture content, which is 12% for general wood flooring products in climatic zone IV (Kerala). High-density wood samples with thicknesses of 25 mm and 50 mm (20 cm x 10 cm in length and width) were used to investigate drying defects under drastic conditions, and schedules for both thicknesses were developed. Similarly, schedules were developed using medium-density wood samples of 25 mm and 50 mm. The moisture content of the experimental samples (2 cm x 2 cm in length and width) was determined using the oven-dry method, and the basic density was determined based on the water displacement method. 83 The experimental kiln drying schedule recommended for 50 mm thick high-density coconut palm wood Tongue and Groove flooring and Parquetry flooring was MT4-B1 (schedule code). Initial Dry Bulb Temperature 39°C (Relative humidity 89%), Initial Wet Bulb Depression 2°C, and Final Dry bulb Temperature 57°C were the critical conditions for MT4-B1. The highdensity coconut palm wood (25 mm thick) is also suitable for Tongue & Groove flooring and Parquetry flooring and the schedule was MT6-B1 with Initial Dry Bulb Temperature 45°C (Relative humidity 90%), Initial Wet Bulb Depression 2°C, and Final Dry Bulb Temperature 62°C. The recommended experimental kiln drying schedule for medium-density coconut palm wood of 50 mm thickness was MT6-D2 as follows: Initial Dry bulb Temperature 42°C (Relative humidity 87%), Initial Wet Bulb Depression 2°C, and Final Dry bulb Temperature 57°C. The schedule for 25 mm thickness medium-density coconut palm wood was MT6-E1, which includes an Initial Dry bulb Temperature of 42°C (Relative humidity 87%), Initial Wet Bulb Depression of 2°C and a Final Dry bulb Temperature of 45°C. The medium-density coconut palm wood only can be used for overlay flooring because of its low strength. All the schedules are made, considering the desired moisture content (12%) for general flooring purposes under the prevailing conditions of Kerala (Relative humidity > 67%) as prescribed by the Bureau of Indian Standards (BIS).
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    ThesisItemOpen Access
    A technical evaluation of veneer cutting and boring of coconut (Cocos)
    (Department of Forest Products and Utilization, College of Forestry, Vellanikkara, 2022) Arjun, M S; KAU; Anoop, E V
    Increased usage of wood products and a decline in supply of wood creates a major gap in the demand and supply chain. Severe restrictions in the felling of trees from natural forests create pressure on the plantations. But the limited supply from plantations alone will not be sufficient for meeting the current demand. Here, the role of trees outside forest especially from the home gardens is significant. Coconut, widely cultivated in home gardens of Kerala is considered as “Kalpavriksha” since, the entire part of the coconut palm is used. However, the coconut palm stem is underutilized and even considered as waste and farmers have to pay high prices to remove the old, diseased and senile palms from their field. Coconut palm stem has huge potential to substitute the hardwoods and softwood, their use is limited to fewer applications like conventional furniture mainly. Conversion of the coconut palm wood is very difficult due to the hard fibrovascular bundle distribution and low recovery rate leads to avoiding this cheap wood material despite its tremendous potential to replace more conventional species. The wood industry, especially the small and medium enterprises are reluctant to saw the coconut palm stem due to the damage caused to their machineries due to the hard fibro vascular bundles. Veneers are thin sheets produced by sawing, slicing or the rotary peeling process. Veneer production is another method for better utilization of logs for enhancing the recovery percentage. Peeling of coconut palm is also not practically feasible using the conventional spindle peeler because of its soft core which does not have enough strength to hold the chunk of the conventional peeler machines. Spindle less peeler is the only option for peeling coconut logs in an efficient way. Veneers produced by peeling of coconut logs using spindle less peeler can be used for the production of veneer-based products like plywood, laminated wood etc. Veneer-based products has lots of advantages as compared to solid wood. They have better strength, dimensional stability, durability and low shrinkage as compared to solid wood and also have lower costs. 99 Our study shows that pre-treatment of coconut log using steam or boiling makes the fibers soft and reduces the cutting force and also enhances the quality of veneers produced. We also found that peeling temperature is an important factor for peeling of coconut logs to reduce the cutting force and enhance the veneer quality. Above 50-600C is considered necessary for peeling the coconut logs of high density and temperature will vary according to the density of coconut logs. Appropriate lathe setting is necessary for peeling operations and will be different from species to species. Peeling and sawing at 2.5 mm thickness is considered ideal for veneer production coconut stem wood. Peeling at 4 mm nose bar gap reduce the thickness variations within the sheets. The setting of saw blade is important for the sawing and for the coconut log it is about 20 degree for left and right and zero degree for straight which is considered ideal for reducing the saw marking and also to remove the saw dust from the log without jamming the blade inside. The green veneer recovery of coconut log on peeling was higher for the middle part (66 %) of the coconut palm stem and lower for the upper portion (49 %) and the lower part of coconut palm stem has about 49 % of recovery. The average green veneer recovery of the peeling and sawing as about 51 % and 35 % respectively. It is lower as compared to other timber species. But peeling of coconut log showed enhanced recovery as compared to sawing due to the low residue left after the process. The veneer defects classification is important for the determination of the end uses of the veneer sheets. The coconut veneer sheets show significant defects like roughness, collapse and handling splits. All of these defects can be reduced by appropriate lathe settings and pretreatment of the coconut logs prior to peeling. Veneer can be used for manufacture different veneer-based products and composites. Coconut plywood with 3-ply and 5-ply and coconut rubber wood plywood with 3-ply and 5-ply were manufactured using resorcinol formaldehyde adhesive. In this study we developed 8 types of plywood from coconut and coconut composites. The static bending test of coconut plywood with (IS 1734: 1983) shows the maximum MOR of 114.81 N/mm² for the 5-ply coconut rubber plywood of 100 density more than 700 kg/m³ in the perpendicular direction of the face veneer. The MOE of 8834.6 N/mm² is the highest MOE for the 5-ply coconut plywood of density more than 700 kg/m³ with parallel direction of the face veneer. On the other hand, the 3-ply coconut plywood with density 400-700 kg/m³ had lowest MOR and MOE of 12.93 N/mm² and 2964.95 N/mm². 5-ply plywood using both coconut and coconut rubber plywood showed good results and can be used for construction purposes like load bearing. All the plywood samples made of 5-plies meet the minimum requirement as per the Indian standard and also showed significant results compared to other plywood species. The boring of coconut log for the construction of hollow cylindrical prototype was not successful due to the failure in the holding of the log with larger dimension on the single chunk of the lathe. The coconut log was able to bore only up to 1meter length with 4 inches of bored diameter. The coconut log can be bored to longer dimension by appropriate modifications on the lathe by providing support for the log for holding during the rotation of the logs.