utorak, 3. prosinca 2013.

Use of carbon fiber in engineering

As technology progresses, we are looking for the increasing capabilities of machines, devices and elements that play a role in the functionality. Today the main task is greater efficiency that is more prosperity for some elements or second element. Hi gh tech materials will allow us to very purposefulness of an element and to the machine contribution. A negative factor which is most ruling in the case of selecting the second material is a high price. For the price of one supercar rim, carbon fiber is around 10,000 to 15,000 €. Possible applications are infinite, the basic structural elements in automobiles, mechanical constructions such ship and vessel onwards. The main feature of which is a winning short explanation for all this it has a high tensile strength and low weight. The main feature that made so many uses. Carbon fiber is mostly used in small-series production , a small application use in mass production .But if we interpret carbon fiber for functional side only as an element for weight reduction it is a mistake. During the development of these procedures and the processing and use of carbon fiber , these are  main priority because they get relatively easily formed into the desired final shape or appearance.

As each part of the machine is realized as a function of carbon fiber and its function is realized only if we reach some kind of conditions, as an example I will take brake discs in bikes that are used in moto-racing, in order to be fully effective, first we have to reach operating temperature , that is , neither less nor more than 400 Celsius. Gyroscopic effect is reduced due to the easyness and weight of material .One of the drawbacks of this material is that the majority is made to order, hand-made or manually , so there is small impact or use of this material in automation.Their density is much lower than the density of steel , so they are ideal for use in areas that require low weight and high strength material. A very important feature is that you also have a smaller linear expansion coefficient then most of materials .The material is a winning combination in all aspects of production, to the implementation in various elements and mechanisms and is expected to have a greater range of use in the near future .

utorak, 26. studenoga 2013.

Product assembly

The installation can speak with more facets, it all depends on what kind of assembly we work on, where we work, under what conditions are we working (temperature, position of workers, a way of connecting two functional elements).
In this case, I will describe the installation in effectiveness and efficiency way in certain specific situations.
As you know and assume, the skill of workers is one of most important factors and there is an adverse factor , and that is man. Robotization and automatization is one of increasingly factors that are targeted and there is increasing characteristics of  using such elements in the present time, but sometimes we dont need it when it comes to small-series production and part production of certain elements that are in most cases smaller dimensions .
As an example, I'll describe a hole in the casting furnace for heating elements .
When are we making a hole in which the number of holes is bigger than five, we are using machining centers (five axes, three axes) which prepares the elements for drilling (positioning , preparation tools for processing, cleaning up after previous operations), it takes more time than processing itself, and thus the requires of that production is reduced to man, as in the case of machining centers handling the elements in which the number of small holes are less than 5, the efficiency would not be so great, so more time would be taken away for nothing, bigger consumption of money, less durability of machine in processing would be answer. Just because it boils down to some conditions, standarded by which are settled when and what to choose . As a second example I will take as an example of welding together two elements where are we particularly careful and take into account the cost (the cost of the electrodes , the cost of electric arc , the cost of operating machines etc..). We have a different  procedures of welding , some of which are horizontal , angular , vertical-horizontal and overhead. The efficient costs itself in welding are complicated way down to the fact that there are more negative factors , such as skills of welders, cost, cost of elements for the realization of such compound. As one of the best elements of the indicator spent we have obtained horizontal welding which is today the most used and which is used in the light and in the massive building, while on the other hand we have the angular welding that we have in several versions , ruling factor in this all is engineer (planner) that has a major role to reduce costs and choose favorable conditions of welding.
The quality of materials is also crucial when choosing a welding method, which are more expensive alloys and materials with which it will be welded, and also welding skills of workers welders which unfortunately are not all the same. When we looked with every aspect of everything has its cost some who adjudicate in an element. A welding is used everywhere (steel halls , ships , rail cars , containers).

So alone costs and conditions of exploitation are ruling, and it is depended on many things, so we should look at all aspects, whether it was a massive production or serial or piece production. Everything is purposeful.

četvrtak, 11. srpnja 2013.

Wind energy

As new technologies move on, there are many approaches, inventions and solutions for making something more efficent but cheaper, I am asure that there are several or even dozens solutions what make energy of wind efficient, renewable and most of that all, useful.
Wind is form of solar energy. The term „wind energy“ describes the process by which the wind is used to generate mechanical power or electricity.
Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Wind flow patterns are modified by the earth's terrain, bodies of water, and vegetative cover. There are specialized turbines that convert kinetic energy of wind into a mechanical raw power. A wind turbine is constituted of three or two propeller-like blades called rotor. The rotor is attached at the top. As the wind blows it spins the rotor. As the rotor spins the energy of the movement of the propellers gives power to a generator. There are some magnets and a lot of copper wire inside the generator that make electricity. One wind turbine can generate enough electricity for a single house. As they are higher, they are better for producing more wind energy. It is very high and expensive investment, but it is one of the most efficient ways od producing energy by itself. Turbine is made of blade(rotor), drivetrain, “tower”.
Its all about pressure of wind and about heights in which rotor operates. Wind is clear source of renewable energy, and that is one of the main advantages of wind energy. 
Mass production and technology advances are making turbines cheaper, and many governments offer tax incentives to spur wind-energy development. It is one of the most reliable sources of energy and is booming more and more. A wind turbine creates reliable, cost-effective, pollution free energy. 
As years goes ahead will be seeing more and more types of this free-cost energy that will make our future productive even more and so even much greener in every part of it.
I support this type of energy and I hope it will spread even more.

ponedjeljak, 8. srpnja 2013.

Maintenance in engineering

As part in field of mechanical engineering maintenance doesnt sound so powerful like mechanical design, constructions or manufacturing but it has very important role for every of this part and its link to everyone of them.
Main role of maintenance engineering is to make some machine or some element that has role or is link to some other element durable and long lasting. Product lifecycle must be long and with dowsizing curve of maintenance product. Therefore we must observate all parameters in product and around product and make them more efficent, secure and properly prepared for everyday role of that product.
 Main objectives of maintenance engineering are:
-provide the required level of reliability
-minimize maintenance costs due to failures caused by teh. systems, leading to losses in production
-restrict and slow obsolescence of technical systems
-propose and implement modernization and modifications in order to improve performance and extend product life
-ensure safe operation
-ergonomic design of the workplace
-monitor and improve the safety equipment in order to reduce and eliminate adverse effects on the environment

Every product has its own lifecyle and there is no machine or product that will never be „ill“.
Its about making product more efficent, more productive and more longlasting.
To make that happen there are many fields of maintenace engineering that help us to do so.
Corrective maintenance is based on elimination of damage and failures after they occur.
Before we kick on about corrective maintenance we first must define meaning of word damage and failure.
Damage is change of state of the system or its components that are not bothering to function of system, but it can turn into a failure.
Failure is change of the state of the system or its components, which obstructs or impedes the normal functioning of the system.
Advantage of corrective maintenance in the better use of spare parts and components,
maintenance before the failure, construction of reliable components of technical systems.
Preventive maintenance is based on the performance of a series of interventions by its plans before the injury occurs or failures.
Advantages of preventive maintenance are in reducing time failures, plan and prepare is in advance.
It defines many operations what are in purpose of fulltime supervision and to take certain actions to reduce defects and failures.
CBM (Condition Based Maintenance) The basic approach to CBM depends on to control the level of reliability is reduced to the continuous use of components and technical systems as long as the actual level of confidence within the limits determined values​​.
Advantages are increased security, increased the output (quantity) of the production system, increased the availability and reduce maintenance operations, improved quality of products.

There are different approaches of maintenance and everyone of them is defined in different way for a different operation or type of operation. All type of maintenances have own advantages and disadvantages. In most ways and cases type of maintenance that will be using is defined of properties of elements and machines that will be used in some circumstances or specific situations.

Turbocharger vs. Mechanical compressor

We have a number of ways with which we can increase the power of the engine, as you add more air and fuel into the cylinders in the combustion process. Another option is to add more cylinders or increase existing cylinders, these changes are not always possible or very simple. The second and the most easiest way is using a turbocharger. Turbocharger, turbine turbocharger or whatever you like to call it. Turbocharger is actually the correct name because it is a device that consists of a turbine and compressor parts. When they say turbines, experts in the field would understand that we are talking about the exhaust gases of which energy is converted into mechanical energy. In the auto industry, there are several ways of so-called "boost".  The engine burns a mixture of air and fuel, the air entering the engine through the intake manifold of the engine pulled from the surrounding atmosphere pressure difference created by the engine. In order to maximize the amount of air forces we use methods such as superchargers and turbochargers and so. For people who can not deal with the car topics  the word 'turbo' is over the past decade mainly associated with diesel engines. The so-called "turbo" era ended in the late 90s and since then until today turbo really is what the vast majority of cases suggests that it is a diesel engine. The first thing we need to clarify the difference between the meanings of words turbocharger and compressor (mechanical compressor). Turbo compressor (turbocharger) are commonly referred to as just the turbo, and english literature is a term used "turbocharger", while the mechanical compressor can still call compressor (using the name Mercedes Kompressor), charger (G Charger - VW) while in england literature mechanical compressors called "supercharger". There are rotary wing compressors, root blower, compressor, screw compressor (G-compressor), turbocharger (turbocharger).
Turbocharger is not a "compressor", but rather a classic "turbo", "turbine", turbocharger. The turbocharger is the assembly consisting of the turbine (the device which rotates the pressure of exhaust gases) and compressors (equipment powered turbine and which presses intake air).
Turbocharger use energy of exhaust gases that are thrown away and the compressor use motor power and thats why turbo is an advantage. The lack of a turbocharger is turbo hole. It's hard to say which is better, but it is obvious that turbocharger founded greater application.
Turbo: turbo blower, turbo, turbocharger
Compressor: mechanical compressor, supercharger
The turbines are used in power generation, aerospace and automotive industries, and what makes it different, of course, performance due to their different tasks, but what connects them is certainly the same layout and working principle. In the auto industry, there are several ways of the so-called "boost" that additional give compaction more air than a natural pressure. The engine burns a mixture of air and fuel, the air entering the engine through the intake manifold of the engine pulled from the surrounding atmosphere pressure difference created by the engine.

Technology has now progressed very well. To be effective, turbocharger must be adapted to the specification and the purpose of the engine that is built, it is to take literally thousands of parameters. Why use turbo instead of a mechanical compressor? All kinds of techniques for increasing engine power have their advantages, but generally speaking, in my opinion, especially in regard to "Performance" engines, turbocharging is the best solution. The advantage of the atmospheric engine before turbo engines in their simple construction and good response to openness of damper forces. The disadvantage is the price and lag (attack power) that can be reduced if we reduce sluggishness that weight moving parts. But compared to the turbo assisted engines, the atmospheric engine is much harder to draw extra power and torque. Engines with mechanical supercharger have a similar response and give good power at all engine speeds, but they are driven directly from the crankshaft. All in all, though you will lose something in the throttle response, turbochargers bring huge benefits in performance, and the relatively easy installation, reliability, and lower costs. In pursuit of power and torque, turbo is „king“.

nedjelja, 7. srpnja 2013.

Materials for cylinders

In the wide field of new technologies and knowledge, the regular adaptation to new approaches to production and processing of materials for motors in motor vehicles many elements of functional and economical operation adapt to new technologies and strives so. Downsizing is one of the key factors in achieving this goal, the cylinders and high tech materials that are used when creating such. Cylinder as the element in a motor mechanism plays an important role, serving as a supporting element or piston rod that performs the function of the linear motion of the TDC to BDC. Large thermal expansion occurring within that element and the material from which the cylinders are made must also be good heat implementers. Temperatures are in the high ranges, and it is very important to maintain an optimum temperature range in order to avoid overheating and in order to make usable engine for longer period . New approaches in mixture injection are making more difficult situation to cylinder constructing and therefore gives more indication to adaptation and the development of a certain normal and optimal lifetime motor functionality period (most optimal does not exist, and never will be!)

When developing the designer has more choices for element cylinder/piston, but everything has its advantages and disadvantages.Some of the features are:
Steel liner, Cast Iron piston
Cast Iron liner, Cast Iron piston
Steel liner, piston Steel
Steel liner, piston Aluminium, Cast Iron ring (s)
As alone two elements are interrelated function play a very important role and it is therefore very important to maintain an optimal working relationship between these two elements, because such operating parameters are very important.
There are other possibilities, but these above are actually the nearest optimal and most cost.
Machining processes that help in this are honing and turning.
Honing is an abrasive machining process that produces a precision surface on a metal workpiece by scrubbing an abrasive stone against it along a controlled path. Honing is primarily used to improve the geometric form of a surface, but may also improve the surface texture.
Turning is a machining process in which a cutting tool, typically a non-rotary tool bit, describes a helical toolpath by moving more or less linearly while the workpiece rotates. The tool's axes of movement may be literally a straight line, or they may be along some set of curves or angles, but they are essentially linear (in the nonmathematical sense). Usually the term "turning" is reserved for the generation of external surfaces by this cutting action, whereas this same essential cutting action when applied to internal surfaces (that is, holes, of one kind or another) is called "boring". Thus the phrase "turning and boring" categorizes the larger family of (essentially similar) processes. The cutting of faces on the workpiece (that is, surfaces perpendicular to its rotating axis), whether with a turning or boring tool, is called "facing", and may be lumped into either category as a subset.Turning can be done manually, in a traditional form of lathe, which frequently requires continuous supervision by the operator, or by using an automated lathe which does not. Today the most common type of such automation is computer numerical control, better known as CNC. (CNC is also commonly used with many other types of machining besides turning.)

Steel liner, Cast iron piston
This combination gives the highest possibility of producing a runable and durable engine that will have expected working life under predicted quality. Enginners prefer this combination for small and medium size engines. Very important part when using this combination is that the bore should be pointed, wider below the exhaust ports.

Cast Iron liner, Cast Iron piston
This is a little bit difficultier operation then the last one because of the brittle nature of thin walled cast iron turnings. The liner requires care and a bit of prior experince in workholding.
In this process, the cylinder is roughed out, then the bore is finished, but not honed. It is next packed with case hardening compound using a bolt and two large washers to cover the ends. It is not "case hardened" as such, and is significantly softer, but the results are worthwhile. This combination doesn’t give any specific advantage in regard to previous combination.

Steel liner, Steel piston
Both components must be hardened, with piston tempered to 10 Rockwell c points lower than liner to minimize gailing. Higher oil usage is preffered for this combination. Tolerances are very small.

Steel liner, Aluminium piston with Cast Iron ring(s)
This combination has a highest priority. Requires experencied workers for making this combination possible for combination in engine. Errors are not allowed. Ringed piston doesn’t need honing.
best suited for larger engines. If its created with precision and care, the combination will produce an excellent, long lasting engine

petak, 10. svibnja 2013.

High tech materials in F1

50s and 60s of last century, when F1 became a real competition, the cars were made from everyday materials who were available. The situation today is much different and Formula 1 has become a testing ground for new materials and their properties.
In order to achieve the best results it is necessary to lead every part of the car and engine to the highest level, and one of the most important factors are the materials. The materials should have the lowest mass, and thus greater strength and durability time and that they were less affected by the performance of the car.
New rules and restrictions in F1 have made technical (mechanical) side in F1 even more interesting, for several reasons, and one of them is major costs of the construction, maintenance and so. A good balance is the most important in all of this, so we are looking for materials that oscillate less and that are able to withstand the mechanical and thermal efforts, and also have the lowest mass. The very essence of F1, which was based on pure power is changed, today and for some time the most important factors are the materials by the aerodynamics of the car, the engine only carries about 15% of merit, most chassis and thereafter expected tires that are crucial for the performances on the track. F1 is mostly based on advanced materials. The most important materials for the realization of these objectives are carbon fiber, aluminum and kevlar. Carbon fibers appeared in the eighties of the last century and soon became the basis for construction of F1 cars as they had an exemplary way  of combinating light construction and exceptional strength, with a very broad spectrum when designing. Today, 75% of the car is made of carbon fiber and so the brakes where also used in the manufacture of carbon (or carbon brakes are very expensive and can consume up to 5 months to produce a single brake disc).

Why carbon fiber?
They are strong, waterproof, lightweight compared to conventional materials they require higher costs, but they last for a very long time. F1 cars are designed for a maximum load that is to speed up to 300 km / h and the use of ordinary materials would be difficult, the ability to achieve high performances, as well as excellent results. Surely you know the laws of physics, which is a lighter car has better acceleration and higher speeds achieved in less time. Materials in F1 must be selected to meet all the criteria, but reliability is the first place regardless of the performances (which sometimes does not do so, unfortunately). Carbon fibers are nearly perfect material for use in the preparation of composite materials. Due to its molecular structure with extremely high tensile strength, combined with epoxy resin composite material make substantial characteristics. The fibers are obtained special procedures at high temperatures and pressures, and they are produced fabrics. These fabrics have high tensile strength, as much as four times greater than steel.
The biggest mistake in explaining as carbon fiber is to emphasize that we use only to reduce weight or to look, which is not true.
Another of the essential material used in the F1 is kevlar. Kevlar is used when creating forks, headrest, shoulder blades. Otherwise Kevlar is an organic material that combines high strength with low weight. This material is five times lighter than steel, which means it can provide a lighter, more flexible and also more comfortable seat when protection unlike steel armor. One of the main factors why it is used in F1 is a high resistance to chemicals and fire. Among the essential materials include the aluminum of which probably know a lot more in relation to the above materials. Half the motor mechanism is made of aluminum, like cylinder heads, pistons and other mechanisms. With new casting technologies, and the development of improved material properties and the very weight of the same is reduced.

As technology progresses, the incremental improvements are not only in F1, but in the entire automotive industry.
It is increasingly being used as access to maximize what we already have, how to get from smaller resources more into technical field and in the economic part.
One of the important factors that will in the future play a role in the F1 is environment, and reducing emissions. Maybe with this F1 will lose some charm, but it certainly is a big step forward for civilization and only the preservation of nature, and so to ourselves.
When it comes to materials, and the very F1 must emphasize to us, to our field of engineering, which is after all the lights and magic of racing and fast cars and famous drivers play a crucial role together with engineers to achieve these same goals, and the very existence of such a sport that is today one of the best paid, as well most watched.