Installation of printed circuit board etching

Contents

Contents

Task

Paper

Setting the task

Structural Layout Analysis

1. karomysl mechanism

2. Pneumatic mechanism

3. Reversing mechanism

4. Through mechanism

5. Hydromechanical mechanism

Bath materials

1. Polypropylene

2. Steel

3. Stainless steel

4. Fiber glass

Bath structures

Bath fabrication methods

Heating of chemical solutions

Introduction to pneumatics

Calculation of heating elements

Hydrostatic bath calculation

Design parameters of pneumatic cylinder

Calculation of lifting weight

Design diameter of pneumatic cylinder

Selection of pneumatic cylinder

Lift of selected pneumatic cylinder (check calculation)

Pneumatic equipment parameters

Design diagram of pneumatic system

Calculation of consumed air

Selection of pneumatic distributor

Selection of pneumatic valve with check valve

Pipeline Selection

Selection of air silencer

Selection of components of air treatment system

Compressor selection

Receiver Volume Selection

Calculation of Etcher Solution

Conclusion

List of used literature

Paper

The course project on the subject "Calculation and design of drives" contains 5 sheets of A1 format, made in the Corel Draw X3 software package and V8 Plus Compass, as well as a 42-sheet explanatory note made in the Word 2003 text documentation environment using the Microsoft Equation formula creation environment, all calculations were made in the mathematical software system MathCAD 13 Professional, the information section was prepared in the Microsoft Power Point environment.

The course project includes the following stages:

Analysis of initial design data;

Process analysis of the product;

Development of drawings in accordance with TA.

Calculation of pneumatic system and drive

Selection of pneumatic actuator

Selection of main elements of pneumatic system

Introduction to Pneumatics (Overview)

Any object in which a gaseous substance is used can be classified as a gas system. Since the most accessible gas is air consisting of a mixture of a plurality of gases, its wide application to various processes is due to nature itself. Translated from Greek pneumatikos - air, which explains the etymological origin of the name pneumatic systems. In the technical literature, a shorter term is often used - pneumatics.

Pneumatic devices began to be used in ancient times (wind engines, musical instruments, blacksmith furs, etc.), but they became widespread due to the creation of reliable sources of pneumatic energy - superchargers capable of giving gases the necessary supply of potential and (or) kinetic energy.

The pneumatic drive, consisting of a set of devices for driving machines and mechanisms, is far from the only area of ​ ​ using air (in the general case gas) in human technology and life. In support of this provision, let us briefly consider the main types of pneumatic systems that differ both in their intended purpose and in the manner in which the gaseous substance is used.

Due to the presence and cause of gas movement, all systems can be divided into three groups.

The first group includes systems with natural gas convection (circulation) (most often air), where the movement and its direction are due to gradients of temperature and density of a natural nature, for example, the atmospheric shell of the planet, ventilation systems of rooms, mine workings, gas ducts, etc.

The second group includes systems with closed chambers that do not communicate with the atmosphere, in which the state of the gas can change due to changes in temperature, volume of the chamber, pressurization or suction of the gas. These include various storage tanks (pneumatic balloons), pneumatic braking devices (pneumatic buffers), all kinds of elastic inflators, pneumohydraulic systems of aircraft fuel tanks, and many others. An example of devices using vacuum in a closed chamber may be air grips, which are most effective for moving piece sheet products (paper, metal, plastic, etc.) under automated and robotic manufacturing conditions.

The third group includes such systems where the energy of pre-compressed gas is used to perform various works. In such systems, the gas moves along the lines at a relatively high speed and has a significant energy reserve. They can be circulation (closed) and circulation-free. In circulation systems, exhaust gas is returned along the lines to the supercharger for reuse (as in a hydraulic drive). The use of systems is very specific, for example, when gas leaks into the environment are unacceptable or the use of air is impossible due to its oxidizing properties. Examples of such systems can be found in cryogenic techniques where aggressive, toxic gases or volatile liquids (ammonia, propane, hydrogen sulfide, helium, freons, etc.) are used as energy carriers.

Features of pneumatic drive, advantages and disadvantages

The field and scope of application of the pneumatic drive are due to its advantages and disadvantages resulting from the peculiarities of air properties. Unlike liquids used in hydraulic drives, air, like all gases, has high compressibility and low density in the initial atmospheric state (about 1.25 kg/m 3), much lower viscosity and greater fluidity, and its viscosity increases significantly with increasing temperature and pressure. Absence of air lubrication properties and presence of some amount of water vapour, which in case of intensive thermodynamic processes in varying volumes of working chambers of pneumatic machines can condense on their working surfaces, prevents use of air without giving it additional lubrication properties and moisture reduction. Therefore, there is a need for air conditioning in pneumatic actuators, i.e., to impart operability and life-prolonging properties to the actuator elements.

Taking into account the above-described distinctive features of air, consider the advantages of the pneumatic drive in comparison with its competitors - hydraulic and electric drives.

Simple design and maintenance.

The manufacturing of parts of pneumatic machines and pneumatic devices does not require such high accuracy in the manufacture and sealing of connections as in a hydraulic drive, since possible air leaks do not significantly reduce the efficiency and efficiency of the system. External air leaks are environmentally friendly and relatively easy to eliminate. The installation and maintenance costs of the pneumatic drive are slightly lower due to the lack of return pneumatic lines and the use of more flexible and cheap plastic or rubber (rubber fabric) pipes in some cases. In this regard, the pneumatic drive is not inferior to the electric drive.

Fire - and explosion safety.

Thanks to this advantage, the pneumatic drive does not have competitors for mechanizing work in conditions dangerous for the ignition and explosion of gas and dust, for example, in mines with abundant methane release, in some chemical industries, in flour mills, that is, where sparking is unacceptable. The use of a hydraulic drive in these conditions is possible only if there is a centralized power source with the transfer of hydropower over a relatively long distance, which in most cases is not economically feasible.

Reliable operation in a wide range of temperatures, in dusty and humid environments

Under such conditions, the hydro and electric drive require significantly high operating costs, since at temperature differences the tightness of the hydraulic systems is disturbed due to changes in the gaps and insulating properties of electrical materials, which, together with the dusty, humid and often aggressive environment, leads to frequent failures.

Significantly longer service life than hydro and electric drive

For pneumatic devices of cyclic action, the resource is from 5 to 20 million cycles depending on the purpose and design, and for devices of non-cyclic action about 1020 thousand hours. This is 2-4 times more than the hydraulic drive, and 1020 times more than the electric drive.

Fast performance

This does not mean the transmission rate of the signal (control action), but the realized speeds of working movements provided by high speeds of air movement. The translational movement of the pneumatic cylinder rod is possible up to 15 m/s and more, and the rotation speed of the output shaft of some pneumatic motors (pneumatic turbines) up to 100,000 rpm. This advantage is fully realized in cyclic actuators, especially for high-performance equipment, for example in manipulators, presses, spot welding machines, in braking and fixing devices.

The possibility of transmitting pneumatic energy over relatively long distances through main pipelines and supplying compressed air to many consumers.

In this regard, the pneumatic drive is inferior to the electric drive, but significantly exceeds the hydraulic drive, due to less head losses in the extended main lines. Electric energy can be transmitted through power lines for many hundreds and thousands of kilometers without significant losses, and the transmission distance of pneumatic energy is economically feasible up to several tens of kilometers, which is implemented in pneumatic systems of large mining and industrial enterprises with centralized supply from a compressor station .

No need for pressure overload protectors for consumers

The required air pressure limit is set by the common safety valve located on the pneumatic power sources. Pneumatic motors can be completely braked without the danger of damage and remain in this state for a long time.

Conclusion

In the course design, structural layout options for the installation of etching printed circuit boards were analyzed. As a result of the analysis, a pneumatic drive was chosen, since it most satisfies the requirements for the drive.

Working drawings of the frame, bath and main attachment units of all unit elements have been developed.

The pneumatic system was calculated and the components were selected: a pneumatic cylinder, pneumatic nozzles with check valves, a pneumatic distributor, a pneumatic silencer were selected, the receiver volume and flow rate of the pneumatic cylinder were calculated, and a compressor and receiver were selected.

As a result of the work carried out, a vertical type etching unit with pneumatic drive was designed in accordance with the declared TA