Stronger than steel and a fraction of the weight, carbon fiber is a brilliant invention. Since its first use as a motor case on space rockets in the 1960s, it's often proclaimed as the ticket to better performance. It costs enough that it better. Despite 50 years of advancements carbon fibre remains expensively high end. But 50 years later, carbon fiber is still rare and expensive (starting at $10/pound.The rate of steel is $0.38/pound.)
FEW FACTS ABOUT CARBON FIBER:
1.)Carbon fiber -- sometimes known as graphite fiber -- is a strong, stiff, lightweight material that has the potential to replace steel and is popularly used in specialized, high-performance products like aircrafts, racecars and sporting equipment.2.)The next generation of carbon-fiber composites could reduce passenger car weight by 50 percent and improve fuel efficiency by about 35 percent without compromising performance or safety.
3.)Carbon fiber can be woven into a fabric that is suitable for use in defense applications or added to a resin and molded into preformed pieces, such as vehicle components or wind turbine blades.WHY CARBON FIBER IS EXPENSIVE:
The main reason for high cost of carbon fiber is its manufacturing process.Let us see how it is made and what makes it expensive.
Before carbon fiber becomes carbon fiber, it starts as a base material—usually an organic polymer with carbon atoms binding together long strings of molecules called a polyacrylonitrile(similar to the acrylics in sweaters and carpets).To get the carbon part of carbon fiber, half of the starting material's acrylic needs to be removed. "The final product will cost double what you started with because half burns off,"This is responsible for a big part of the costs.Then there are two major processing steps. The first is called oxidization stabilization. Here the fibers are fed through very long ovens with temperatures of several hundred degrees. The process takes hours to complete and is therefore a massive energy eater.
The second step is carbonization where the material is again placed in an oven, but this time the temperatures rise over thousand degrees. This step will also increase the power bill. It doesn’t end there.
Manufactures also have to take care of the off-gases to make sure they do not poison the environment, which needs lot’s of energy, real estate and large equipment. All steps are just for the manufacturing of the individual filaments themselves.To get to the final product, the fibers and the resin have to be shaped and cured in an autoclave, again a time and energy consuming process.
So,the process of manufacturing is time taking and energy eating also only half of the raw material is used in final product.This leads to the high cost of carbon fibre.
1.)AIR GATE – A vertical channel for the removal of gases from the mould;
checking of the filling of the mould cavity with metal and feeding up
the casting with metal during solidification.
2.)BACK DRAFT – Taper or draft which prevents removal of pattern from the
mould.
3.)BINDER – Material used to hold the grains of sand together in moulds or
cores. May be cereal, oil, clay, resin, pitch etc.
4.)BLEED – Molten metal oozing out of a casting stripped or removed from
the mould before solidification.
5.)CAVITY, MOULD or DIE – Impression or impressions in a mould or die
that give the casting its shape.
6.)CHILL – A metal object placed on the outside or inside a mould cavity to
induce more rapid cooling at that point and thereby produce hard zone
i.e., hard, unmachinable surface.
7.)COPE – The upper or top most section of a flask, mould or pattern.
8.)DRAFT – Taper allowed on the vertical faces of a pattern to permit removal
of it from the sand mould without excessive rapping or tearing of the
mould walls.
9)DRAG – The lower or bottom section of a mould or pattern.
10.)FLASH – Thin fin or web of metal extending from the casting along the
joint line as a result of poor contact between cope and drag moulds.
In mechanical engineering a fillet is a rounding of the interior or exterior corner of a part. On the inlet fillets are concave while on exterior corners these are convex.We generally use fillet on the edges of almost every product.In this article we will see why fillets are used at corners.
We generally use fillets due to following reasons:
1.)Fillets are mainly used to reduce stress concentration compared to chamfers. These can easily distribute stress more uniformly.
2.)Fillets give a part better flow and less resistance. Using a fillet also eliminates any sharp edges that can be easily damaged, or that could cause injury when the part is handled. This means there is less risk of failing an inspection for having a burr or sharp edge.
3.)Industrial designers tend to prefer fillets compared to chamfers as these are considered to be visually pleasing.4.)One of the other reasons is that protective coating like paint are more uniformly distributed over a fillet compared to chamfer. Thickness of coating is reduced on sharp corners of chamfers so coating is lost first on these spots. Fillets have no such issues due to uniform distribution of coating.
But when it comes to comparison with chamfer in terms of cost then fillet is costly due to following reasons:
1.)A chamfer requires less machining time that a fillet radius.
2.)For fillets different radii of tools has to be stocked to create different radii, but a single tool can be used for creating different chamfers.
Still fillets are more preferred as compared to chamfers by industrial designers due to its advantages.Comment down your views in comment box.
