Egyptian Electronic Technology Company (EETC) is an electronic manufacturing Company, which produces boards of telephone, switch central and many electronic boards using two technologies that are: Surface Mount Technology (SMT) and Through-hole Technology (THT) This Company also involved with producing any printed circuit boards that achieve the requirements of the market.
The EETC consists of two sections, Mechanical and Manual one. Each section has the ability to perform a certain stage in manufacturing and fabrication processes. In mechanical section, printed wiring board (PWB) of telephone come to this section, which enter into two processes: testing the (PWB) and placing the components on the board by using (SM) and (TH) technologies The manual section has three operations. First, the large components have been inserted in boards by manual (TH) technique because we can't use (TH) machines, due to large size and high weight. Then, the boards enter the soldering process using the wave-soldering machine. Finally, some tests performed. During the training period, the company started to produce a modified telephone called (BARQ 6).
Traditional through-hole Dual In-Line Package assemblies reached their limits in terms of improvements in cost, weight, volume, and reliability. Surface Mount Technology (SMT) allows production of more reliable assemblies with higher I/O, increased board density, and reduced weight, volume, and cost. The weight of Printed Board Assemblies (PBAs) using SMT is reduced because Surface Mount Components (SMCs) can weigh up to 10 times less than their conventional counterparts (PB) surface. SMT also provides improved shock and vibration resistance due to the lower mass of components. The smaller lead lengths of surface mount components reduce parasitic losses and provide more effective decoupling .The small size of SMCs and the option of mounting them on either or both sides of the printed board can reduce board real estate. A cost savings of 30°l0 or better can also be realized through a reduction in material and labor costs associated with automated assembly.
1.2.Definition of (SM) and (TH) Components:-
Surface Mount:- a type of electronic component package. Most electronic components can be divided into two categories - through hole (TH) and surface mount (SM). Through-hole components have been used for many years and are designed to be loaded on one side of a printed circuit board (PCB) and soldered on the other. SM components are designed to be loaded and soldered on the same side of the PCB.
1.3. Surface Mount Technology and SMT part types:-
The electrical and mechanical connection of parts to the surface of a conductive load pattern on a printed circuit board that does not use part lead holes or terminals. There are many types of (SM) component used manufacturing filed such as
- Chip resisters, capacitor.
- Leadless Ceramic Chip Carrier (LLCC).
- Gull wing flat packs.
- J leaded component.
- Small Outline Transistors (SOT).
(See Figure 1.1)
1.4. Types of Surface Mount Technology for assembling:-
Figure (1.1) Examples of Surface Mount Components
SMT replaces Dual Inline Packages (DIPs) with surface mount components. The assembly is soldered by re-flow and/or wave-soldering process depending an the mix of surface mount and through-hole mount components.
When attached to PBs, both active and passive (SMCs )form three major types of SMT assemblies, commonly referred to as Type I, Type II, and Type III (see figure 1).
Type I is a full (SMT)board with parts on one or both sides of the board. Type II is probably the most common type of (SMT) board. It has a combination of through-hole components and SMT components. Often, surface mount chip components are located on the secondary side of the Printed Board (PB). Active SMCs and DIN are then side: Multiple soldering processes are required. Type III assemblies are similar to Type II. They also use passive chip SMCs on the secondary side, but on the primary side only DIN are used. This is the type which used in (BARQ 6) in EETC.
The process sequence for Type III SMT is shown in Figure (1.3). Leaded components are inserted, usually by automatic equipment. The assembly is turned over, and adhesive is applied. Next, passive SMCs are placed by a "pick-and-place" or chip shooter machine, the adhesive is cured by special ovens, the assembly is turned aver, and the wave-soldering process is used to solder both leaded and passive SMCs in a single operation, but when we have sensitive SMCs such as some kinds of microcontrollers we use another different method of soldering. The LCD board of (BARQ 6) is a good example of this type of soldering which called paste-soldering. The steps of inspection, maintenance, testing, and quality insurance and packaging are performed later.
Figure (1.2): Surface Mount Technology Board Types
1.5.Flow chart of Electronics Manufacturing Process:-
The following flow charts illustrate briefly the steps of manufacturing process of both main board and LCD board of (BARQ 6) telephone which produced by EETC.
1.6. The Factory Structure in Block Diagrams:-
EETC consists of two basic sections as it wag mentioned, the automatic section which contains of the following mechanical production lines.
-Thefirst SMT production line.
- The second SMT production line.
- Production line with fine pitch components placer.
- THT. Production line which divided into two stages:
a) Axial stage.
b) Redial stage.
The following block diagrams illustrate the automatic production line and the production process sequence for type III SM production line.
THE FIRST SMT RODUCTIONLINE
FIGURE (1_7): The First SMT Production Line
THE SECONED SMT PRODUCTION LINE
FIGURE (1.8): The Second SMT Production Line
PRODUCTION LINE WITH FINE PITCH COMPONENTS PLACER
FIGURE (1.11): Radial Production Line