CMM Labratory

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Published on Sunday, 21 October 2012 09:29

Written by tisser

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CMM machine and measurement laboratory

Measurement and accurate measurement data are increasingly being used in manufacturing, control, and reverse engineering. Measurement is by definition, a process of comparing a standard and an unknown quantity, which is of utmost importance in mass production. One of the most advance measurement methods is three dimensional coordinate measurement, for which the Coordinate Measurement Machine (CMM) is the best solution. This machine has application in 3 dimensional measurement of parts and parameters like parallelism, perpendicularity, angles, dimensions, etc. This machine finds wide application in different industries such as automotive, aerospace, machinery making, etc.

Translated by: Ehsan Taghdiri

Air Bag

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Published on Sunday, 21 October 2012 07:28

Written by tisser

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The seat belt, being one of the so-called passive safety systems in cars, has resulted in reduction of fatalities in accidents by 36%. The seat belt prevents the passenger from hitting the hard parts of the front of the vehicle including the steering wheel, the dashboard, and the windshield. However, it cannot protect the passengers fully against all possible impacts. The air bag system was developed as a supplement to the seat belt system reducing the fatalities of dangerous accidents to an additional 18%. This system has mechanical and electronic components.

A number of different airbags can be used for each vehicle: the most widely used are driver and front seat passenger airbags. More luxurious vehicles benefit from side airbags (covering side windows) and rear seat passenger air bags which are installed on head rests front seats. Some cars such as some models of Mercedes Benz are also equipped with roof air bags operating at times of roll over.

Main components of the electronic system

     1-      Crash sensors: these calculate the intensity of impact from front of the vehicle and send the appropriate signal to the electronic control unit.

     2-      SAS control module: This unit processes the data sent from sensors and if rapid deceleration due to collision is detected, a current signal is sent to the airbag module.

     3-      Clock Spring: Since the airbag module is located on the steering wheel which rotates frequently to left and right, there needs to be a robust connection between the steering wheel and the inflator which is the role of the clock spring

     4-      Airbag module: the current sent from the SAS unit goes to the primer in the module creating heat. This heat produces spark and flames which ignite the explosive material which produce rapidly expanding gases. These gases pass filters which reduce its noise and temperature and the cover on the steering wheel is torn by the airbag which inflates towards the face of the driver. The holes on the airbag help some of the inflating gas discharge which reduces the intensity of the shock and creates adequate visual space for the driver.

Translated by: Ehsan Taghdiri

Industrial Design

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Published on Sunday, 21 October 2012 07:33

Written by tisser

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Industrial Design

The role of industrial design as a form of art conducting industry has been getting more and more evident in today’s life. Among all different branches of industry, the automotive industry, as a strategic industry in both developed and developing countries, has more significant relationship with industrial design. Designers from all over the world offer their views on beauty and form of products of the automotive industry. A wide variety of fields in art and industry are involved in auto making. Therefore, the automotive industry is one of the most important sectors influencing economy and welfare of nations.

Although in the not so distant past the number of people active in automotive design was small, now there are a large number of people from all different nationalities active in this business and the number is constantly increasing.

An automobile is viewed by the public not only as a means of transport but also as a means of pleasure which represents the owner’s personality and prestige. Every individual now wishes to own a good automobile corresponding to his standards of beauty and prestige

A good automobile can be defined as a combination of latest technologies in all aspects, along with balance and human compatibility in application, in addition to the most beautiful visual features both as a whole and in all details.

To summarize, a car can be considered as a useful, beautiful work of art benefitting from latest technologies.

Designing a car is one of the most important stages of its production which, although seemingly simple, requires various fields of expertise to work as a team until the stage of prototype making and mass production.

In the first stage, the identity of the brand of the car and the aim of the company in developing a new product are taken into account. The relevant input comes from the strategic center of the company based on marketing input from which the lifetime of the product is evaluated in its target market. This information is finally used to determine the class of the product, leading to addition or removal of various features in engine, axles, chassis, etc. These decisions and investments made for them contribute to determination of the final cost of the automobile. Sometimes these decisions result in small changes in the appearance and body of the vehicle (Such as Iran’s Peugeot Pars compared to Peugeot 405), but as the market gets increasingly competitive, survival of a car maker requires frequent redesign of its products, in intervals of 3 to 5 years, to be able to satisfy customer demand.

Initially, based on the data from the marketing department and managerial decisions, key dimensions of the car including length, width, height, wheel base, front and rear overhang, front and rear track, along with data such as class of the product, age and gender of its users are announced to the design team. The design team decides whether to transform or “facelift” an existing product or start a new product development project. At this stage, decisions are made on the ratio of using new, creative ideas with respect to more conservative and simpler ideas used already in previous generations and the final decisions are announced to the design team. 

Initially, based on the data from the marketing department and managerial decisions, key dimensions of the car including length, width, height, wheel base, front and rear overhang, front and rear track, along with data such as class of the product, age and gender of its users are announced to the design team. The design team decides whether to transform or “facelift” an existing product or start a new product development project. At this stage, decisions are made on the ratio of using new, creative ideas with respect to more conservative and simpler ideas used already in previous generations and the final decisions are announced to the design team.

Stylist designers use all the above mentioned information to prepare initial hand sketches from different angles. At this stage traditional hand tools such as pencil, pen, marker, etc. are widely used. At this stage designs are carried out in exaggerated liberal manners. However, most of these exaggerations are balanced in later stages, although effort is made to retain them as long as issues involved in manufacturing allow. .

In the next stage, after approval is received from the teams of feasibility study, marketing, design, manufacturing, ergonomics, etc. industrial drawings are created in scales from 1/5 to 1/5 for the product. Various software tools are widely used for this stage. All ergonomic issues and dimensions are corrected until they reach their ideal values and later, the digital data are fed into CNC machines which create black box models in scales ranging from 1/5 to 1/1.

Various elements are tested on the model at this stage including aerodynamic behavior of the body, reflection of surrounding lights, etc.

At the next stage, prototypes are made for the vehicle where skillful technologists use different techniques including temporary dies and rapid prototyping to reproduce all components of the body. The prototype which is created with the utmost care can be sent to auto exhibitions where feedback from the public is evaluated.

Translated by: Ehsan Taghdiri

What is ABS?

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Published on Sunday, 21 October 2012 07:26

Written by tisser

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Antilock Brake System

Ongoing advance in car brake systems have resulted in reliable systems contributing to increased car safety.

In normal driving conditions, conventional brake systems (CBS) can provide effective and fast stopping for the vehicle. However, in the following driving circumstances, braking can result in locking of wheels which in turn leads to lack of steerability and slipping of the vehicle:

     1-      Slippery and wet roads

     2-      Frightened reaction of the driver

     3-      Errors of other drivers and pedestrians

The above are among the issues for addressing of which the Antilock Brake Systems have been invented.

History of ABS systems

The first instance of ABS system was designed for trains in 1900. After the Second World War, ABS systems were used for Jet planes. In 1960s, as brake systems of automotives were being revolutionized, brake manufacturers started to develop and use ABS systems for luxury cars such as Mercedes Benz.

Operational principles

When brake pedal is pressed with excessive force, there is the possibility that tires decelerate with a higher rate than the car itself. This leads to slipping of tires on the road surface. A way to prevent this is to prevent locking of brakes when the threshold of slipping is detected. This is exactly what the ABS does. At normal braking, ABS has no interference in the operation of the brake system. However, when brakes are applied with excessive force, ABS allows brakes to operate only until the threshold of locking of wheels. When possibility of slipping is detected for one wheel, ABS removes brakes pressure for that wheel. When this risk is removed, the brake fluid is pumped to that wheel again and this cycle is repeated so that deceleration is accomplished without slipping.