BAHAN-BAHAN KEJURUTERAAN - KAYU

PENYIMPANAN KAYU

CHESAPEAKE WOODCRAFT
WOODWORK
STANDARD SIZE

Medium-density fibreboard
From Wikipedia, the free encyclopedia

Medium-density fiberboard output in 2005

Medium-density fiberboard (MDF or MDFB) is an engineered wood product formed by breaking down softwood into wood fibers, often in a defibrator, combining it with wax and resin, and forming panels by applying high temperature and pressure. It is a building material similar in application to plywood but made up of separated fibers, not wood veneers. It is denser than normal particle board.
Large-scale production of MDF began in the 1980s. Its name derives from the distinction in densities of fiberboard. MDF typically has a density of 600-800 kg/m³, in contrast to particle board (160-450 kg/m³) and to high-density fiberboard (600-1450 kg/m³). Similar manufacturing processes are used in making all types of fiberboard.
MDF is also known as Customwood or Craftwood.[citation needed].
MDF has been controversial in regard to its use of formaldehyde resins and the associated health risks. Thus, other resins are being considered and used instead of formaldehyde.
MDF is often used in school projects because of its flexibility.

A sample of MDF

Hollow extruded MDF decking boards, which appear to have the colouring/preservative in the manufacture
Contents[hide]
1 Manufacturing
2 Comparison to natural woods
3 Different kinds of MDF
4 References
5 External links


Manufacturing
MDF is a wood product created by breaking down a softwood into a powder, which is then mixed with wax and resin. The final finish is created by submitting the boards to high pressure and temperatures.
In Australia the main species of tree used for MDF is plantation-grown radiata pine. However a variety of other products have also been used including other woods, waste paper and fibers.
The trees are debarked after being cut. The bark can be sold for use in landscaping, or burned in on-site furnaces. The debarked logs are sent to the MDF plant where they go though the chipping process. A typical disk chipper contains 4-16 blades. Any resulting chips that are too large may be re-chipped; undersized chips may be used as fuel. All chips are then washed and checked for defects.
The chips are then compacted using a screwfeeder, and will be heated for 30-120 seconds to soften the wood; they are then fed into a defibrator which maintains high pressure and temperature. The pulp that exits from the defibrator is fine, fluffy, and light in weight and in colour.
From the defibrator the pulp enters a blow line where it is joined with wax (to improve moisture resistance) and resin (to stop the pulp from forming bundles). The material expands in size and is then heated by heating coils. When it comes out it may be stored in bins for an indefinite length of time.
After this drying period the board goes through a "Pendistor" process which creates 230-610 mm thick boards. Then it is cut and continues to the press. Here it is pressed for a few minutes, to make a stronger and denser board.
After pressing MDF is cooled in a star dryer, trimmed and sanded. In certain applications boards are also laminated for extra strength.
The Environmental Impact of MDF has greatly improved over the years. Today many MDF boards are made from a variety of materials. These include other woods, scrap, recycled paper, bamboo, carbon fibers and polymers, steel, glass, forest thinning and sawmill off-cuts.

Comparison to natural woods
Benefits of MDF:
Some varieties are less expensive than many natural woods
Isotropic (no grain), so no tendency to split
Consistent in strength and size
Flexible. Can be used for curved walls or surfaces.
Shapes well with a router.
Drawbacks of MDF:
Heavier (the resins are heavy)
Swells and breaks when waterlogged
Warps or expands if not sealed
Contains urea-formaldehyde which may cause eye and lung irritation when cutting and sanding
Dulls blades more quickly than many woods
Though it doesn't have a grain in the plane of the board, it does have one into the board. Screwing into the edge of a board will generally cause it to split in a fashion similar to delaminating.

Different kinds of MDF
There are different kinds of MDF, which are sometimes labeled by color:
Moisture-resistant is typically green
Fire-retardant MDF is typically red
High finition for powder lacking
Lighter densities of fiberboard are commonly marketed as ultralight or LDF boards.

References

External links
A video podcast from podcastschool.net
The Production Process of Humewood MDF (Humewood is a product of Hume Fiberboards Sdn Bhd, a Malaysian fiberboard manufacturer)
Wood Dust - dangers of exposure to wood dust, including MDF dust (from the Worker's Health Centre)
Medium Density Fiberboard - from Investment New Zealand, a division of New Zealand's economic development agency.
A personal experience of MDF toxicity
Retrieved from "http://en.wikipedia.org/wiki/Medium-density_fibreboard"
Categories: All articles with unsourced state


KAYU

Botanical Names: Hevea brasiliensisFamily
Name: Euphorbiaceae
Others Name: Rubbertree ( Malaysia ,Singapore ), para rubber , Arbol de caucho (Venezuela), Sibi-sibi (Guyana), Mapalapa (Surinam), Seringa, Seringueira (Brazil), Capi, Jeve, Shiringa (Peru). Jebe, Arbre De Para ( French), Parakautschukbaum, Cauchotero de Pará ,Siringa , Seringueira-branca, rapa (Fiji)
Working Properties:Obtained by tapping the trunks of the trees , good strength characteristic, easy machining and processing properties. Additionally, The wood is reported to saw without difficulty, planes easily to a smooth surface; tends to split in nailing. Therefore it can easily be stained and finished to meet various market requirements.
Durability: The wood is perishable and stains readily. Also highly susceptible to borer and termite attack as well as powder-post beetles.
Wood Appearance: high color ( This wood is whitish yellow when freshly cut and seasons to cream, straw or light brown, often with a pinkish tinge.)
Rubberwood story:The rubber tree was originated came from Brazil named Hevea brasiliensis from the species family of Euphorbiaceae and widely planted for the production of latex in South East Asia country, mainly in Indonesia, Malaysia and Thailand.At the begining stage, rubber trees just for use in produce milky liquid known as latex that circulates through small tubes or veins for every 5- 7 years of growing. And these trees will discontinue for produce latex after 21 - 25 year, so at this moment, due to unproductive, therefore this trees are demand to fell (either replanting or other planning). Initially the felled trees were of low commercial value and mainly used as firewood, hence, due to worldwide technological developments & environment hazard, All these threes became valuable sources especially for furniture industrial. Today, Rubberwood becomes one of the most demanding and popular timbers for furniture maker (for both local & oversea market), therefore, this wood now can have categorised as environment-friendly due to hazard free to the environment and the supply is sustainable. In the sense that we are now using what was going as waste. Today Malaysia become one of the major resource and country who successful for supplying & exporting rubberwood ( for both sawn wood, raw, semi-finished, finished good and furniture accessories ) and for the production of panel products such as particleboards, woodfibre cement-bonded particleboards ,fibreboards (MDF), plywood and other products for both local and oversea market demand.
Perabut Seong Aik (or known as PSA ) is one of the manufacturer who leading to produce rubber wood furniture. click here for product view

Jenis kayu

Kayu dalam pasaran

papan buatan

MESIN

Terdapat beberapa jenis mesin yang digunakan di dalam bengkel. Antaranya:
- mesin yang menggunakan kuasa elektrik
- mesin yang menggunakan kuasa hidraulik
- mesin yang menggunakan kuasa pneumatik
- mesin yang menggunakan konsep tuas

ALAT TANGAN

Alat tangan merupakan alat yang digunakan untuk melakukan kerja-kerja ketukangan dalam menyiapkan kerja ataupun projek.
Terdapat banyak jenis alat tangan dengan pelbagai fungsi. Dalam mata pelajaran ini, alat tangan dikhususkan kepada kerja kayu dan logam. Bagaimanapun untuk tujuan pembelajaran dan pengayaan ilmu, beberapa tambahan diselitkan hasil sumbangan pelajar.

Alat tangan
Alatan tangan dibahagikan kepada beberapa bahagian mengikut fungsi dan kegunaannya. Antaranya:
- alat menanda
- alat memotong
- alat membentuk
- alat memasang dan
- alat menguji.
Latihan1 ( tarikh hantar 15/1/08 )
Namakan alat, jenis dan fungsi alatan tersebut.
Nama alatan: Tolok teleskop
Jenis alatan: Alatan mengukur
Fungsi: Untuk mengukur garis pusat gerek dan jarak-jarak lain

Machine Tool Accessories General
End Mill Holders
Shell Mill Arbor
Morse Taper Adapters
Collets Chucks & Collets
HSK Tooling
Quick change Tooling
Tapping Heads & Holders
Right Angle Heads
Boring Heads
Lathe Centers
Quick Change Tool Posts & Holder
Nama alatan: Pengaras spirit
Jenis alatan: Alatan Mengukur
Fungsi: Menguji ketegakan dan kerataan aras seperti tembok tiang dan lantai
Tools for the Dominant Hand
Form :-
claw hammer
pencil
chalk line
slip-joint plier
utility knife
Dominant-hand tools are the primary task drivers. A good, general-duty claw hammer should weigh 12 or 16 oz. and be a balance of comfort, control and maximum nail-driving power. A flat carpenter’s pencil won’t break as easily as an ordinary round one and works best for rough carpentry work. A chalk line is a must for snapping long, straight lines. It’s also essential as a plumb bob or string line. A slip-joint plier is a versatile tool for pulling nails and for simple electrical and plumbing work. The utility knife is a must for everything from cutting drywall to roofing work and should have extra blades, both straight and curved, stored in the handle.
Nama alatan : Andas
Jenis alatan : Alat memegang
Fungsi : Digunakan untuk menyokong benda kerja semasa kerja membentuk
Nama alatan : Perengkuh soket
Jenis alatan : Peralatan menyambung atau mengikat
Fungsi : Digunakan untuk memiuh atau memegang kepala bolt atau nat
Alatan bergabung
Nama alatan : Kunci Allen
Jenis alatan : Alatan memasang
Fungsi : Membuka dan memasang skru berkepala Allen
Nama alatan : Alat bergabung T
Jenis alatan : Alat memotong
Fungsi :Melakukan pemotongan untuk semua jenis dan saiz bahan yang kecil
Terdiri daripada : -tukul spring
-pemotong wayar
-pemotong wayar keras
-pisau
-gunting
-pemutar skru philiphs
Nama alatan : Alat bergabung tangan
Jenis alatan : Alat memotong
Fungsi : Memotong benda kerja seperti wayar
Terdiri daripada : -tukul spring
-pemotong wayar keras
-pemotong wayar
-pisau
-gunting
-pemutar skru philips
Nama alatan : Pisau pelbagai guna
Jenis alatan : Alatan memotong
Fungsi alatan : Membuka nat,memutar skru dan membuka tin
Penyimpanan alat
Nama alatan : Tool racks
Fungsi : Menyimpan dan mengelaskan alatan tangan
Nama alatan : WM369 super wrist magnet
Fungsi : Menyimpan alatan di tangan untuk memudahkan kerja
Nama alatan : Pegboard
Fungsi : Tempat menyimpan alat yang diletakkan di atas papan tergantung
Nama alatan : Meja kerja dan rak
Fungsi : Mengatur kedudukan dan mengelaskan bahan kerja serta alatan
(sumbangan Md Zuhairi Bin Md Saiaan Harry)

SUKATAN MATA PELAJARAN

REKA BENTUK DAN TEKNOLOGI I

Pensyarah : MOHD ALI BIN JEMALI
Sukatan mata pelajaran : Asas Binaan Awam
( 1 kredit – 15 jam teori )
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