Josh Ricketts says:
Josh out...
November 17, 2009
November 01, 2009
Sand Casting
Josh Ricketts says:
Sand Casting - Is the process in which a sand mould is used to create a product or component from metal.
The process is shown below. The pattern is separated into two halves. Firstly the pattern, usually made of wood, is placed down and sand is poured on top. This is then compacted and the other half of the pattern is processed. Once this is complete, the pattern is removed, and the mould is finished. A gating system is created to allow the liquid metal to pour in and then the mould is cooled. Removing the moulds leaves the product and the gating system (the spruces) is cut off, leaving the finished product.
Josh out
Sand Casting - Is the process in which a sand mould is used to create a product or component from metal.
The process is shown below. The pattern is separated into two halves. Firstly the pattern, usually made of wood, is placed down and sand is poured on top. This is then compacted and the other half of the pattern is processed. Once this is complete, the pattern is removed, and the mould is finished. A gating system is created to allow the liquid metal to pour in and then the mould is cooled. Removing the moulds leaves the product and the gating system (the spruces) is cut off, leaving the finished product.
October 09, 2009
Metals
There are 4 main types of metals;
Ferrous - These metals contain iron and carbon and therefore rust and can be brittle.
Non-Ferrous - As the name suggests, these metals contain no iron and corrode, not rust.
Ferrous Alloy - A ferrous alloy is a mix of metals which contain iron and carbonNon-Ferrous Alloy - An alloy which is a mix of non-ferrous metal and contains no iron or carbon.
An alloy is a mix of metals to create and combine properties to suit the function or form. An alloy is usually to keep one property, strength for example, and get rid of another, like rust, an example of this is stainless steel.
By combining them you can change the:
-Resistance to corrosion
-Melting Point
-Colour
-Strength
-Electrical properties
-Thermal properties
-Flow of the melted metal
Rust is a huge problem when concerning ferrous metals. The metal oxidises with the air and then flakes off the metal, which exposes more metal for rusting. Another way to avoid rusting is galvanising. This covers the metal in a thin layer of more reactive zinc which corrodes rather than the iron.
Ferrous MetalsMild Steel - Has a 0.3% carbon content and as a result is strong but rusts easily. The metal is tough and can't be hardened.
High-Carbon Steel - Is brittle but strong. The high carbon content means it is tough to impact, but easier to break. High-carbon steel can be hardened and tempered.
Cast Iron - Is hard but brittle. It has a hard skin but a soft core. Used for manhole covers and other applications which the weight of the product is not very important as cast iron is very heavy.
October 08, 2009
Man-made Boards
Josh Ricketts says:
There are various types of man-made board. The main size of the board bought is 2440 mm by 1220 mm, and then the thickness is decided by the designer and/ or manufacturer, which can be made to order in steps of 3mm thickness, 3mm being the smallest. The types of man made board mainly used today are listed below and described.
Plywood - Is strong because of the layers of wood arranged in such a way that makes the board tough in both directions. The grain is aligned so that each layer counteracts the other and makes it strong, because of how wood is weak along the grain. Marine plywood, aptly named, has a plastic based layer coated onto the outside of the wood to make the wood more water resistant.
Medium Density Fibreboard (MDF) - Is made from wood chippings from the conversion process (mentioned in earlier post). These waste chips then have glue added to them and then pressure is applied to squash the bit together to create the finished product. High Density Fibreboard has had even more pressure applied to it and so therefore costs more. The hardened glue in MDF gives the board blunting properties and so in manufacture of large quantities, the cost efficiency of having broken or just blunt saws can be serious when dealing with thousands of products.
Hardboard - Or HDF (mentioned above), is mainly for filling gaps. The weak, brittle material is useless for products and is mainly used for the backs of furniture. Hardboard absorbs liquid easily and can hence become rotten and useless. As a result of this, hardboard is very cheap.
Chipboard - Is commonly used for kitchen worktops and units. Chipboard is made of bigger wood chippings and usually has a laminate or other attractive material on top to 'hide' the chipboard. Made in the same way as MDF, using chippings with glue then compressed.
Blockboard - Uses a different method to attain a good finish. Strips of cheap wood are stuck together is rows and then are sandwiched between two veneers. Its the veneers which make board worth something, as the veneers are attractive and the blocks are hidden.
Aero-ply - Is, as the name suggests, used in the structure of plane wings. The material is made in such as way that in bends around an object or frame, by having many separated blocks with a flexible top layer.
Maplex - Is a higher grade board for furniture which is new and easier to machine. High density and made of pure wood fibres, Maplex is expensive and acts and looks like sheet metal. This ultra modern material is used as shown to the left, to make a variety of high quality products.
Veneers
A veneer is basically a 'slice' of wood. Usually thinner than 3 mm, they are typically glued onto core panels to produce flat panels such as doors, tops and panels for cabinets, parquet floors and parts of furniture. To produce these veneers 3 main types of processes are used; Slice, Rotatory and '3D' Veneering.
Slice Veneering - Involves a piece of log that is raised and lowered against a blade and slices of the log are made. This yields veneer which looks like sawn pieces of wood, cut across the growth rings. This gives a decorative pattern for multiple uses and is cheap compared to the other methods.
Rotatory Veneering - Uses a rotary lathe in which the wood is turned against a very sharp blade and peeled off in one continuous or semi-continuous roll. Rotary-cut veneer is mainly used for plywood, as the appearance is not desirable because the veneer is cut concentric to the growth rings.
3D Veneering - Is a process in which a half-round lathe in which the log or piece of log can be turned and moved in such a way to expose the most interesting parts of the grain. This means you get the best results of veneer but waste material getting to the interesting grain.
Each slicing processes gives a very distinctive type of grain which is important for the aesthetic qualities the designer is looking for.
Finishing Wood
Wood protection is vital for any wooden product and come in both water and oil based composites.
Polyurethane Varnish - Seals and protects with a smooth finish. The plastic covers the wood like an extra layer and stops water and other chemicals getting to the wood. The varnish is usually uncoloured but still enhances the wood's natural colour and grain.
Wood Stains - May have a varnish with them, but if not then varnish must be added on top of stain. The stain colours the wood to many shades of brown and other colours like red and green.
Oils - Enhance the natural wood colours and protects the wood too. Oils can be for outdoors too, as the oil resists water molecules and therefore is perfect for outdoor use.
Preservatives - Are for outdoor use of wood. They enhance appearance and extend the wood's life by up to 5 times as long. This is extremely useful for long life wood products. Tanalised timber is a common timber product which is coloured green. The original timber is injected with tanalise so that 5mm into the wood is tanalised and the wood in protected greatly.
Paint - Is colouring and protecting. Emulsion paints have too much water in them and would warp the wood so special wood paints are used. Polyurethane paints are available for waterproofing and are tough at protecting but however, are more expensive.
There are various types of man-made board. The main size of the board bought is 2440 mm by 1220 mm, and then the thickness is decided by the designer and/ or manufacturer, which can be made to order in steps of 3mm thickness, 3mm being the smallest. The types of man made board mainly used today are listed below and described.
Medium Density Fibreboard (MDF) - Is made from wood chippings from the conversion process (mentioned in earlier post). These waste chips then have glue added to them and then pressure is applied to squash the bit together to create the finished product. High Density Fibreboard has had even more pressure applied to it and so therefore costs more. The hardened glue in MDF gives the board blunting properties and so in manufacture of large quantities, the cost efficiency of having broken or just blunt saws can be serious when dealing with thousands of products.
Hardboard - Or HDF (mentioned above), is mainly for filling gaps. The weak, brittle material is useless for products and is mainly used for the backs of furniture. Hardboard absorbs liquid easily and can hence become rotten and useless. As a result of this, hardboard is very cheap.Chipboard - Is commonly used for kitchen worktops and units. Chipboard is made of bigger wood chippings and usually has a laminate or other attractive material on top to 'hide' the chipboard. Made in the same way as MDF, using chippings with glue then compressed.
Blockboard - Uses a different method to attain a good finish. Strips of cheap wood are stuck together is rows and then are sandwiched between two veneers. Its the veneers which make board worth something, as the veneers are attractive and the blocks are hidden.
Aero-ply - Is, as the name suggests, used in the structure of plane wings. The material is made in such as way that in bends around an object or frame, by having many separated blocks with a flexible top layer.
Maplex - Is a higher grade board for furniture which is new and easier to machine. High density and made of pure wood fibres, Maplex is expensive and acts and looks like sheet metal. This ultra modern material is used as shown to the left, to make a variety of high quality products.Veneers
A veneer is basically a 'slice' of wood. Usually thinner than 3 mm, they are typically glued onto core panels to produce flat panels such as doors, tops and panels for cabinets, parquet floors and parts of furniture. To produce these veneers 3 main types of processes are used; Slice, Rotatory and '3D' Veneering.
Slice Veneering - Involves a piece of log that is raised and lowered against a blade and slices of the log are made. This yields veneer which looks like sawn pieces of wood, cut across the growth rings. This gives a decorative pattern for multiple uses and is cheap compared to the other methods.
Rotatory Veneering - Uses a rotary lathe in which the wood is turned against a very sharp blade and peeled off in one continuous or semi-continuous roll. Rotary-cut veneer is mainly used for plywood, as the appearance is not desirable because the veneer is cut concentric to the growth rings.3D Veneering - Is a process in which a half-round lathe in which the log or piece of log can be turned and moved in such a way to expose the most interesting parts of the grain. This means you get the best results of veneer but waste material getting to the interesting grain.
Each slicing processes gives a very distinctive type of grain which is important for the aesthetic qualities the designer is looking for.
Finishing Wood
Wood protection is vital for any wooden product and come in both water and oil based composites.
Polyurethane Varnish - Seals and protects with a smooth finish. The plastic covers the wood like an extra layer and stops water and other chemicals getting to the wood. The varnish is usually uncoloured but still enhances the wood's natural colour and grain.
Wood Stains - May have a varnish with them, but if not then varnish must be added on top of stain. The stain colours the wood to many shades of brown and other colours like red and green.
Oils - Enhance the natural wood colours and protects the wood too. Oils can be for outdoors too, as the oil resists water molecules and therefore is perfect for outdoor use.
Preservatives - Are for outdoor use of wood. They enhance appearance and extend the wood's life by up to 5 times as long. This is extremely useful for long life wood products. Tanalised timber is a common timber product which is coloured green. The original timber is injected with tanalise so that 5mm into the wood is tanalised and the wood in protected greatly.
Paint - Is colouring and protecting. Emulsion paints have too much water in them and would warp the wood so special wood paints are used. Polyurethane paints are available for waterproofing and are tough at protecting but however, are more expensive.
October 06, 2009
Steam Bending
Josh Ricketts says:
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As shown to the left, the layers of wood make the product strong in one direction and weak in the other. Grains can be lined up so that the wood becomes stronger. Laminated wood is stable and good looking and is used on a variety of products from CD racks to furniture but also for structural items such as beams in buildings.
Josh out.
Steam bending uses the application of moisture to soften wood to become more pliable. Using steam on some woods such as plywood can be delaminated by the process. Once shaped, the wood is held in place by a former, and the moisture is taken out using air like normal seasoning. This technique can be used in large and small scale production lines, and the products range from wooden jewellery to producing ribs in a traditionally made boat hull.
Shown on the right, this picture shows the steam being applied to the wood and the bending process taking place. Once the wood is bent, it is clamped down and left till rigid.
Laminated Wood
Laminates are made up of layers of material bonded together. This is extremely strong as the glue is stronger than the wood itself so binding the two substances together makes a very stable and strong engineeing material.
As shown to the left, the layers of wood make the product strong in one direction and weak in the other. Grains can be lined up so that the wood becomes stronger. Laminated wood is stable and good looking and is used on a variety of products from CD racks to furniture but also for structural items such as beams in buildings.Josh out.
October 01, 2009
September 15, 2009
Materials - Timbers
Josh Ricketts says:
Materials
Timbers - Are renewable, natural and sustainable.
Lumber - Wood that has just been felled, so hasn't had any treatment.
Timber - Wood that has been sawn and worked with.
The two types of timber are;
Softwoods - Have pines and are evergreen. They are green all year round and have a less complex cell structure, are fast growing and therefore more harvests.
Hardwoods - Have leaves and are coniferous. They shed their leaves in autumn and have a more complex cell structure, are slow growing and therefore expensive. They are larger which means when harvested more wood is available.
Structure of Timber
Wood is fibrous with fibres down the length of the tree, like lots of long tubes glued together to form a complex and strong structure, which is easy to 'peel' along the grain and hard to cut across the grain. The tree is made from 55% cellulose and 28% resin. Timber is therefore as natural reinforced polymer.
From Tree to Saw
Step 1 - Harvesting - Cutting down the tree. Either chainsaws or two-man saws.
Step 2 - Conversion - Cutting trunk and large branches into boards. This is either slab or quarter sawn.
Slab Sawing uses the whole tree so there is no waste product but is not as stable and also more likely for twists and knots to appear. Quarter Sawing is most common for expensive hardwood timbers. This means more waste but more stability, also less liable to warp and twist and also a more expensive grain structure.
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Another type of sawing is Rift Sawing. Riftsawn lumber is much more stable than plain sawn lumber. As shown in the drawing, each board has the same relation to the log, and therefore each board will have the same grain pattern. Rift sawing however has a very poor yield and leaves the trianglular wedges shown in the drawing.
Natural Seasoning uses air; the wood slabs are kept in a containers with openings which allow the air to flow over and under the wood to take the wood's natural water out slowly. Kiln Seasoning uses heat to physically force the water out of the wood using a kiln. Both techniques have advantages and disadvantages such as time and warping issues and quality.
Step 4 - Board Preparation - Wood is sawed to size and planning takes place to make the wood smooth. Wood can be planed all round (PAR) or just planed on two sides.
Aspects for Choosing Woods
Physical strength is very important; timbers are stronger along the grain than across it.
Aesthetic properties are important too; colour of the wood and grain structure change aesthetic qualities dramatically.
Moisture changes the warping of the wood.
Protection is essential to stop the wet getting in and also becoming too dry, also stops insect attack.
Operating Conditions are important to consider, such as outside or inside or central heating.
Costs such as expensive softwoods or rare timbers, or cheaper softwoods have to be considered for the product.
Sustainability is important, environmental issues are important for the new sustainable sources wanted from the public.
Sizes of boards are also important for the product you're making and cost issues which may come with this.
Josh out.
Materials
Timbers - Are renewable, natural and sustainable.
Lumber - Wood that has just been felled, so hasn't had any treatment.
Timber - Wood that has been sawn and worked with.
The two types of timber are;Softwoods - Have pines and are evergreen. They are green all year round and have a less complex cell structure, are fast growing and therefore more harvests.
Hardwoods - Have leaves and are coniferous. They shed their leaves in autumn and have a more complex cell structure, are slow growing and therefore expensive. They are larger which means when harvested more wood is available.
Structure of Timber
Wood is fibrous with fibres down the length of the tree, like lots of long tubes glued together to form a complex and strong structure, which is easy to 'peel' along the grain and hard to cut across the grain. The tree is made from 55% cellulose and 28% resin. Timber is therefore as natural reinforced polymer.
From Tree to Saw
Step 1 - Harvesting - Cutting down the tree. Either chainsaws or two-man saws.
Step 2 - Conversion - Cutting trunk and large branches into boards. This is either slab or quarter sawn.
Slab Sawing uses the whole tree so there is no waste product but is not as stable and also more likely for twists and knots to appear. Quarter Sawing is most common for expensive hardwood timbers. This means more waste but more stability, also less liable to warp and twist and also a more expensive grain structure.
Another type of sawing is Rift Sawing. Riftsawn lumber is much more stable than plain sawn lumber. As shown in the drawing, each board has the same relation to the log, and therefore each board will have the same grain pattern. Rift sawing however has a very poor yield and leaves the trianglular wedges shown in the drawing.Step 3 - Seasoning - Is reducing moisture content through two techniques;
Natural Seasoning uses air; the wood slabs are kept in a containers with openings which allow the air to flow over and under the wood to take the wood's natural water out slowly. Kiln Seasoning uses heat to physically force the water out of the wood using a kiln. Both techniques have advantages and disadvantages such as time and warping issues and quality.Step 4 - Board Preparation - Wood is sawed to size and planning takes place to make the wood smooth. Wood can be planed all round (PAR) or just planed on two sides.
Aspects for Choosing Woods
Physical strength is very important; timbers are stronger along the grain than across it.Aesthetic properties are important too; colour of the wood and grain structure change aesthetic qualities dramatically.
Moisture changes the warping of the wood.
Protection is essential to stop the wet getting in and also becoming too dry, also stops insect attack.
Operating Conditions are important to consider, such as outside or inside or central heating.
Costs such as expensive softwoods or rare timbers, or cheaper softwoods have to be considered for the product.
Sustainability is important, environmental issues are important for the new sustainable sources wanted from the public.
Sizes of boards are also important for the product you're making and cost issues which may come with this.
Josh out.
September 04, 2009
Josh Ricketts says:
I Should Never Have Purchased!
The young audience of new and exciting music is growing and the number of MP3 players is also rising. With all this music, earphones are essential so that you can listen to your favourite bands and artists. But while the earphone industry is buzzing with costs and hasn't been touched by the credit crunch, quantity is considered, not quality. Sony Ericsson has their own brand of earphones for their unique and numerous phones, so are in continuous demand, but not just because of the amount of phones. Sony Ericsson earphones are beautifully designed and the style looks great for all young people but the function is flawed. The normal life of earphones in teenagers today is around a month at best and the price tag means that every year you could be paying sixty pounds plus. The sound quality isn't that great and is greatly improved by the phone, just dampened by the earphones.
Headphones of today are generally better as prices rise, but as the prices get too high the boundary for form over function becomes flawed. Large headphone, the less stylish option, rather than earphones, have better function as the form has dropped. The headphones have a good volume and great quality and the life of them is usually a year or more. Earphones in general, even the expensive set, break too easily and have too little function, while retaining the unneeded form.
Earphones are essential and stylish, but a great alternative is a pair of headphones. With great quality and a small price, every teenager and music lover alike should own a pair!
Josh out.
I Should Never Have Purchased!
The young audience of new and exciting music is growing and the number of MP3 players is also rising. With all this music, earphones are essential so that you can listen to your favourite bands and artists. But while the earphone industry is buzzing with costs and hasn't been touched by the credit crunch, quantity is considered, not quality. Sony Ericsson has their own brand of earphones for their unique and numerous phones, so are in continuous demand, but not just because of the amount of phones. Sony Ericsson earphones are beautifully designed and the style looks great for all young people but the function is flawed. The normal life of earphones in teenagers today is around a month at best and the price tag means that every year you could be paying sixty pounds plus. The sound quality isn't that great and is greatly improved by the phone, just dampened by the earphones.
Earphones are essential and stylish, but a great alternative is a pair of headphones. With great quality and a small price, every teenager and music lover alike should own a pair!
Josh out.
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