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Introduction Safety Precautions Operating the Soldering Station 1- Preparing the Tools Operating the Soldering Station 2- Steps to Solder Professional PCB Production Soldering & Assembly
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References
Introduction
Tasnim Hussain | FAB Engineer 06 | 25 | 2018
Q7| Q7-6| HAKKO FX-888D | Soldering Iron Station type DESIGN SOFTWARES (OPEN SOURCE | LICENCES) : PLATFORMS: FAB FOUNDATION REFERENCES:
MACHINE DESCRIPTION The HAKKO FX- 888D is a safe digital soldering iron station with adjustable temperature control. Moreover, it has a compact body and requires a space of only 100(W) x 120(L) mm. Additionally, it has very simple and easy operation only using the UP and ENTER buttons to adjust the temperature of the iron tip.
It is very IMPORTANT to note that the operating voltage of the soldering station is 120V while the voltage from the main is 240V, then it is crucial to use a step down transformer (220V - 110V). Otherwise, the machine will immediately get damaged once connected to the wall outlet and powered directly.
For more details refer to the following datasheet: https://cdn.sparkfun.com/datasheets/Tools/fx888d.pdf
SOLDERING BASICS
Soldering is the a process where two or more metallic items are joined together by melting and then reflowing a filler metal into the joint. Soldering is used to establish almost permanent connection between electronic components.
The metal to be soldered is heated with soldering iron and then the solder is melted connected parts being soldered. Therefore, the solder is considered to be a metallic glue that holds the parts together and forms a connection that allows the flow of an electrical current.
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Digital Display: The digital display of FX-888D makes it very easy to check the set temperature. Once the temperature is adjusted, the settings are locked by pressing “ENTER”. Present Mode: The present mode is a very convenient feature that allows you to change the set temperature to suit a particular workpiece, component or tip chape. This is done by selecting the desired temperature from a selection of pre-saved present temperatures. Up to five present temperatures can be registered.
Adjustment Mode: This allows the temperature adjustment by either entering a particular desired temperature or switching to another present mode temperature. The default temperature is 750 °F. The following diagram shows the steps to do a manual adjustment for the temperature.
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Safety Precautions
Tasnim Hussain | FAB Engineer 06 | 25| 2018
SAFETY PRECAUTIONS: ●
CAUTION: The soldering iron can heat to around 400°C which can burn or establish small fire. USE IT CAREFULLY and ALWAYS KEEP THE IRON IN ITS STAND WHEN IT IS HOT.
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Always switch OFF the iron when it is not used.
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Keep hands away from the soldering tip and avoid touching the soldering iron on a power line.
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Never put the soldering iron down on the work bench even for a moment!
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Work in a well-ventilated area and keep the smoke absorber open while soldering to ensure the suction of the toxic fumes.
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The smoke produced from the soldering is mostly flux which can be irritating. Avoid breathing it and work from the side not directly from above the circuit.
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Solder contains lead, which is poisonous metal. Wash your hands well after soldering.
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Operating the Soldering Station 1. Preparing the Tools
Tasnim Hussain | FAB Engineer 06 | 25| 2018
Items Needed to do Soldering:
● A soldering iron The soldering iron is used to melt soldering wire over the electronic connection to be soldered. ● Soldering wire The soldering wire is a wire that has a melting point lower than that of metals being connected. This special wire melts when heated by the soldering iron; however, the metals being connected will not melt. The soldering wire core acts as a flux and prevents oxidation of the metals that are being connected. For most of electronics work, a soldering wire with a diameter of 0.75 mm to 1.0 mm is usually used. Thicker soldering wire makes soldering small joints difficult and increases the chances of creating solder bridges between connected copper pads which might lead to short circuits and damaging the electronic ICs. It is very IMPORTANT to deal with the soldering wire with care as it consists of an alloy of 60/40 (60% tin, 40% lead) which are toxic materials. Thus, always use the fume/ smoke absorber to avoid inhaling the toxic fumes and wash your hands once done with soldering. ● Soldering Stand It is important to keep the soldering iron in its stand when it is not used. DO NOT put the soldering iron on any surface as it can melt and damage it. ● Sponge The sponge is used to clean the tip of the iron. ● Solder Braid This is used to remove solder in case any connection needs to be fixed or removed. To do this simply place it over the solder to be removed and heat it from the side over the braid until the solder flows into the braid and the connection is removed. Moreover, the solder braid is used to reduce the amount of solder on a connection. ● Prototype Board A prototyping board is used to assemble the circuit and has a copper tracks and pads for connecting components. ● Cutter To cut the soldering wire and components leads after soldering is finished. ● Fume/ Smoke Absorbing Fan This is used to extract the smoke produced from the melting of the soldering wire.
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Operating the Soldering Station 2. Steps to Solder
Tasnim Hussain | FAB Engineer 06 | 25 | 2018
Power ON the 220/110 V transformer, then power ON the soldering station and the smoke absorbing fan.
Note that, selecting the right/ proper soldering tip is very essential. This is decided based on the type of components to be soldered.
The default temperature is 750°F.
The temperature is adjusted to suit the type of the soldering board -copper board or FR1 board- and the type of conductive traces used. When turning ON the iron, it starts with a temperature of 000°F and after few seconds it switches to the previously saved temperature.
Wipe the iron tip on the sponge to clean the tip.
Wait for the soldering iron to heat up and moisten the sponge using few droplets of water.
Melt a little solder on the tip of the iron. The soldering wire will melt over the tip and produce a bright shiny surface. When tip is tinned, excess solder is removed by wiping over the sponge.
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Tasnim Hussain | FAB Engineer 06 | 25 | 2018
The soldering iron tip should always has a shiny silver color. If its color got black, sink the tip over the solder paste and then clean it with the brass sponge.
Prepare the prototyping board and all components to be used in the electronics circuit.
Use the board holder to hold the prototyping board and assemble all components over the prototyping board.
Use the paper tape to hold the components ďŹ xed in their places. Bend out the long components leads to stay in places.
Turn the board down carefully.
Use the soldering iron tip to heat the pad of the component and hold it for few seconds. Then touch both the pad and the lead.
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Tasnim Hussain | FAB Engineer 06 | 25 | 2018
Now feed the soldering wire right under the tip of the iron. Then stop feeding for one second and the solder will ow properly to hold the lead.
Cut the leads off with cutter.
Final Result!!
A good connection covers the whole pad and holds the leads completely with solder.
The board after soldering and ďŹ nishing all the components.
Desoldering can be done simply using the soldering iron and the solder braid. It is a very good practice to enhance better soldering.
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IMPORTANT REMARKS:
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Tasnim Hussain | Electronics Engineer Intern 06 | 04 | 2018
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Professional PCB Production Soldering and Assembly
Tasnim Hussain | Electronics Engineer Intern 06 | 04 | 2018
Using Flux and Solder Paste: ● Flux is a chemical agent used to aid the flowing of the lead-free solder. Moreover it helps making the solder joints better looking and is highly recommended to be used with soldering SMDs especially due to their small pins and high sensitivity to the temperature. In fact SMDs can get overheated and damaged if their soldering is done like regular solder of regular components treating the joints’ connections one by one. Check the following link for more techniques to solder SMDs using the flux and soldering iron: https://www.youtube.com/watch?v=5uiroWBkdFY ●
Solder Paste is a form of solder used in PCB assembly when reflow soldering techniques are used. It is mainly a mixture of solder spheres and special type of flux. Solder paste works highly efficient with SMDs assembly rather than through hole components. http://www.radio-electronics.com/info/manufacture/soldering/solder_paste/how-to-use-solder-paste.php
Pick and Place: To assemble a large number of small ICs the Pick & Place machine is used as manual assembly can be difficult especially for the proper alignment of the very tiny ICs. The following video shows how to operate the Neoden 4 Pick & Place machine to assemble components.
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Soldering Surface Mount Components Surface Mount (SMDs) components are categorized by different standardized packages as illustrated below. -
Passive rectangular components
These SMT components are mainly resistors and capacitors. There are several different sizes which have been reduced as technology has enabled smaller components to be manufactured and used. The following table shows the different packages and their corresponding dimensions.
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Semiconductor SMD packages
There is a wide variety of SMT packages used for semiconductors including diodes, transistors and integrated circuits. The reason for the wide variety of SMT packages for integrated circuits results from the large variation in the level of interconnectivity required. Transistor & diode packages SMD transistors and diodes often share the same types of package. While diodes only have two electrodes a package having three enables the orientation to be correctly selected. The most popular transistors and diodes packages are listed below:
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SOT-23 - Small Outline Transistor: This is SMT package has three terminals for a diode of transistor, but it can have more pins when it may be used for small integrated circuits such as an operational amplifier, etc. It measures 3 mm x 1.75 mm x 1.3 mm.
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SOT-223 - Small Outline Transistor: This package is used for higher power devices. It measures 6.7 mm x 3.7 mm x 1.8 mm. There are generally four terminals, one of which is a large heat-transfer pad.
Integrated circuit SMD packages There are many forms of package that are used for SMD ICs. Although there is a large variety, each one has the areas where its use is particularly applicable.
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SOIC - Small Outline Integrated Circuit : This SMD IC package has a dual in line configuration and gull wing leads with a pin spacing of 1.27 mm
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SOP - Small Outline Package: There are several versions of this SMD package:
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TSOP - Thin Small Outline Package: This SMD package is thinner than the SOIC and has a smaller pin spacing of 0.5 mm
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SSOP - Shrink Small Outline Package: This package has a pin spacing of 0.635 mm TSSOP - Thin Shrink Small Outline Package: QSOP - Quarter-size Small Outline Package: It has a pin spacing of 0.635 mm VSOP - Very Small Outline Package: This is smaller than the QSOP and has pin spacing of 0.4, 0.5, or 0.65 mm.
QFP- Quad flat pack: The QFP is the generic type of flat package for ICs. There are several variants as detailed below.
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LQFP - Low profile Quad Flat Pack: This package has pins on all four sides. Pin spacing varies according to the IC, but the height is 1.4 mm.
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PQFP - Plastic Quad Flat Pack: A square plastic package with equal number of gull wing style pins on each side. Typically narrow spacing and often 44 or more pins. Normally used for VLSI circuits.
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Tasnim Hussain | Electronics Engineer Intern 06 | 04 | 2018
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CQFP - Ceramic Quad Flat Pack: A ceramic version of the PQFP. TQFP - Thin Quad Flat Pack: A thin version of the PQFP.
Read more about the QFP - Quad Flat Pack BGA - Ball Grid Array: A package that uses pads underneath the package to make contact with the printed circuit board. Before soldering the pads appear as solder balls, giving rise to the name.
Each package has a specific technique for soldering, in the following links are some tutorials for soldering different SMD components:
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https://www.sparkfun.com/tutorials/96 https://www.sparkfun.com/tutorials/100
To solder SMD components, soldering iron could be used; however, in most cases soldering is done using solder paste. To apply solder paste, the footprint of all components in the PCB layout should be cut as a stencil using vinyl cutter to ensure that the solder paste is applied directly over the footprints exactly.
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References
Tasnim Hussain | Electronics Engineer Intern 06 | 04 | 2018
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Soldering Through Hole Components:
https://learn.sparkfun.com/tutorials/how-to-solder-through-hole-soldering https://www.sciencebuddies.org/science-fair-projects/references/how-to-solder#soldering https://mightyohm.com/files/soldercomic/FullSolderComic_EN.pdf ●
Soldering SMD Components:
https://www.youtube.com/watch?v=It2eLGzGm_I ● Troubleshooting: https://www.sciencebuddies.org/science-fair-projects/references/how-to-solder#troubleshooting
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