Name: common wood flaws in lumber
Uploaded: 2024-09-12T16:16:32.000Z
Duration: 1 min 23 s
Channel: JoVE

나무의 성장 결함에는 가지가 나무 줄기에 연결되는 곳에 형성되는 매듭, 느슨한 매듭이 빠져서 생기는 매듭 구멍, 부패 및 곤충 피해가 포함됩니다.
흔들림은 연간 나이테를 따라 또는 가로지르는 경미한 골절이며 일반적인 목재 결함입니다.
Wane은 나무가 없거나 보드 가장자리를 따라 나무 껍질이 있는 것을 나타냅니다.
체크는 통나무에서 발생하는 방사형 균열이며 조미료 과정에서 수축으로 이어지는 원주 수축으로 인해 발생하는 제조 결함입니다.
뒤틀림은 보드의 평평하고 정확한 표면에서 벗어나는 것을 나타냅니다. 날실 유형에는 목재의 구부러짐, 구부리기, 비틀기 및 부항이 포함됩니다.
벌집은 부적절한 조미료로 인해 발생하는 보드의 내부 균열을 말합니다.
찢어진 곡물은 절단 또는 대패질로 인해 보드 표면에서 나무가 부서지거나 퍼져 나옵니다. 이러한 결함은 목재의 강도에 영향을 미칩니다.
목재로 가공된 후 목재에 표면 얼룩이 나타날 수 있습니다. 이러한 갈색, 녹색 또는 파란색 얼룩은 일반적으로 외관에 영향을 미치지만 목재의 강도에는 영향을 미치지 않습니다.

목재 결함

Lumber Defects

목재의 외관과 구조적 무결성에 영향을 미칠 수 있는 목재 결함에는 다양한 성장 및 제조 결함이 포함됩니다. 성장 결함은 옹이와 옹이구멍 등으로 나타납니다. 이는 가지가 나무줄기에 붙어 있던 곳에서 발생하고, 옹이가 떨어지면 옹이구멍이 형성됩니다. 또 다른 자연적 결함에는 부후와 곤충 피해가 있으며, 이는 목재의 강도와 내구성을 손상시킵니다.

윤할은 목재의 연륜을 따라 또는 가로지르는 사소한 균열을 말하며, 피죽은 목재의 결이 없거나 판자 가장자리를 따라 나무껍질이 있는 것이 특징이며, 일반적으로 목재를 자르는 방식으로 인해 발생합니다. 할렬은 목재 내부의 방사형 균열로, 목재가 건조되어 수축하면서 나타납니다.

틀어짐은 목재 표면에 평평하지 않고 구부러짐, 휘어짐 또는 컵 모양으로 나타날 수 있으며, 목재의 사용성에 영향을 미칩니다. 내부할렬은 부적절한 건조로 인해 발생하는 내부 균열을 말하며, 목재를 내부적으로 약화할 수 있습니다.

찢긴 결은 절단 또는 평면화 과정에서 발생하는 결함으로, 목재 조각이 떨어져 거친 표면으로 이어집니다. 마지막으로 갈색, 녹색 또는 파란색 변색과 같은 표면 얼룩이 가공 후에 발생할 수 있습니다. 이러한 얼룩은 일반적으로 목재의 외관에만 영향을 미치고 강도에는 영향을 미치지 않습니다.

이러한 결함을 이해하는 것은 목재의 품질을 관리하고, 목재가 건설 및 제조 용도에 필요한 표준을 충족하는지 확인하는 데 중요합니다.

나무의 성장 결함에는 가지가 나무 줄기에 연결되는 곳에 형성되는 매듭, 느슨한 매듭이 빠져서 생기는 매듭 구멍, 부패가 포함됩니다.

Education

교육

JoVE Core

Civil Engineering

토목공학

Unit 1

제1단원

Wood

나무

KEY TERMS AND CONCEPTS

주요 용어 및 개념

common wood flaws in lumber

Lumber defects are flaws in wood that can change both its appearance and its strength. These defects come from tree growth and from the way lumber is processed. Knowing the main defects helps explain why some boards are better for construction and manufacturing than others.

Some defects begin in the tree itself. Knots form where branches were once attached to the trunk, and knotholes appear when those knots fall out. Decay and insect damage are also natural defects that can weaken wood and reduce its durability.

Other defects come from splitting, cutting, or drying the lumber. Shakes are small fractures that run along or across the annual rings. Wane is the missing wood or bark left along a board edge after cutting. Checks are radial cracks that form as wood dries and shrinks during seasoning, and honeycombing is a set of internal cracks caused by improper seasoning.

Warping changes the flat shape of a board. It can show up as crooking, bowing, twisting, or cupping, and each form can make the lumber harder to use. Torn grain is another processing defect, where the wood chips away during cutting or planing and leaves a rough surface. Surface stains, such as brown, green, or blue discoloration, may also appear after processing. These stains usually affect appearance more than strength.

Common Wood Flaws in Lumber

introduction to wood

Wood Structure and Uses in Building

Wood is a construction material made from trees. A tree trunk has several layers. The outside is a protective layer of dead bark. Under that is living bark, then the cambium, then sapwood. As sapwood matures, it becomes heartwood. The pith sits at the center of the trunk. The age of a tree can be read from its growth rings. These rings are concentric bands seen in a trunk cross-section. Wood strength also depends on grain. Grain refers to elongated, tubular cells that run along the length of...

softwoods and hardwoods

Wood Grain in Softwoods and Hardwoods

Softwoods and hardwoods come from different kinds of trees, and their leaf structures and cell makeup help explain how they are used. Softwoods come from cone-bearing trees with needle-like leaves. Hardwoods usually come from trees that shed broad leaves seasonally. Softwoods are made mostly of long cells called tracheids and a smaller number of rays, which are radial cells. This simpler structure gives softwoods a rougher grain. Because of this, they are often used in construction for...

lumber

Lumber Cutting Methods

Lumber is made from logs that are harvested, debarked, and processed into long pieces with a rectangular cross-section. The process starts when an automated saw slices a log into slabs. Those slabs then move on a conveyor belt to smaller saws, where they are cut into square-edged pieces of specific widths. Freshly cut lumber usually has rough surfaces. Its dimensions may also vary slightly from one end to the other. The way wood is cut affects both the lumber’s appearance and how it is used. <br...

structural properties and dimensions of lumber

structural-properties-and-dimensions-of-lumber

Wood Strength Tests and Lumber Sizes

Wood strength depends on how its fibers are aligned along the length of the tree. This alignment gives wood much greater tensile strength along the grain than across it, sometimes up to twenty times higher. Wood also tends to perform better under compression than under tension. Fiber length varies by wood type. Hardwoods have fibers about one twenty-fifth of an inch long. Softwoods have longer fibers that range from one-eighth to one-third of an inch. Laboratory tests help measure how wood...

seasoning of wood

Wood Drying for Stronger Construction

Seasoning of wood is the drying process used to lower and stabilize moisture content before wood is used in construction. Fresh wood can swell when it takes in moisture and contract as it dries. Seasoning helps reduce that movement so the wood stays more stable after it is built into a structure. The main goal is to reach equilibrium moisture content. This is the point where the wood’s moisture level matches the moisture in the surrounding environment. When wood is seasoned properly, it is...

wood surfacing

Wood Surfacing for Smooth, Safe Lumber

Wood surfacing smooths lumber, improves its size accuracy, and makes it safer to handle. It is a key finishing step in woodworking and construction. The process also helps correct small distortions that can form as wood dries. Before surfacing, the wood may be sized slightly larger to account for shrinkage during seasoning, which is the drying stage. A plane, a tool with rotating blades, is used to remove material and smooth the surface. The same tool can also round the edges a little, which...

lumber defects

Lumber defects are flaws in wood that can change both its appearance and its strength. These defects come from tree growth and from the way lumber is processed. Knowing the main defects helps explain why some boards are better for construction and manufacturing than others. Some defects begin in the tree itself. Knots form where branches were once attached to the trunk, and knotholes appear when those knots fall out. Decay and insect damage are also natural defects that can weaken wood and...

wood fasteners

Wood Fastener Types and Uses

Wood fasteners connect parts of a wood structure and help keep members in place. The strength of the connection depends mainly on direct bearing between the wood members. Different fasteners are chosen for different jobs and structural needs. Nails are the most common wood fasteners. They are sharp-pointed metal pins that are driven into wood with a hammer or a mechanical nail gun. Nails come in many diameters, head styles, and lengths. Nailing methods also matter. Face nailing places the...

veneer

How Veneer Is Cut and Used

Veneer is a thin sheet of wood that is usually about one-eighth of an inch thick or less. It is made to show the look of wood while using timber more efficiently. Veneer is common in furniture and other finished wood products. One common way to make veneer is rotary cutting. In this method, a log is mounted in a large lathe and spun against a knife edge. As the knife moves deeper into the turning log, it peels off a continuous strip of wood. This creates rotary-cut veneer. Other veneer...

wood products

Engineered Wood Products in Construction

Engineered wood products are made from wood strands, veneers, lumber, and even waste wood shreds. They are used in both structural and nonstructural building applications. These materials are designed to improve strength, durability, and versatility in modern construction. Glue-laminated wood, or glulam, is made by bonding several smaller pieces of dimensional lumber with adhesive. Cross-laminated timber uses solid lumber panels with layers placed so the grain direction alternates. This layer...

wood panel products

Types of Wood Panels in Construction

Wood panels are common construction materials used for flooring, siding, and roofing. They usually come in standard 4-foot by 8-foot sheets. Their thickness can range from one-quarter of an inch to one and one-eighth inches. Plywood is one of the most familiar wood panels. It is made by gluing thin wood veneers, or layers, under pressure. The outer veneer grain runs lengthwise, while the inner layers run widthwise. Plywood also has an odd number of layers, which helps keep the panel...

key terms and concepts

Learn the main lumber defects found in wood, from knots and decay to warping, checks, and stains, and how they affect strength and appearance.

Common Wood Flaws in Lumber | JoVE K12

JoVE Core Civil Engineering offers a foundational exploration of essential construction materials such as bricks, stones, steel, wood, and concrete, along with fluid mechanics topics like flow over immersed bodies, open channel flow, and dimensional modeling. It also covers key surveying concepts, including leveling, traverse adjustments, curve design, topographic mapping, and geospatial technologies (GPS & GIS). Science-in-action videos showcase laboratory research on materials, fluids, and surveying practices in real-world engineering systems.

civil engineering

Common Wood Flaws in Lumber

Description

Transcript

Tags