soldering lcd display manufacturer

Assuming the LCD is not going face down into the wave, wave soldering should not be a problem for this type of component. Make sure the wave system provides the correct preheat to the assembly prior to soldering and that you profile the assembly so that it meets the thermal characteristics of the component without exceeding them.

Ed Zamborsky is a Regional Sales & Technical Support Manager for Thermaltronics, located in New York. His position requires frequent customer visits throughout North America and the Caribbean and his position encompasses not only sales but the role of trainer and master applications engineer for all of Thermaltronics products. His expertise includes such specialties as hand soldering, convection and conduction reflow techniques, array rework, fluid dispensing equipment, and fume extraction. Ed has authored many articles and has presented many papers on topics such as; Low Volume SMT Assembly, Solder Fume Extraction, SMT Rework, BGA Rework, Lead-Free Hand Soldering, High Thermal Demand Hand Soldering, Lead Free Visual Inspection and Lead Free Array Rework.

Many of our customers wave solder LCD displays on their circuit boards without any problems of thermal damage. All of the devices I have seen are rated for wave soldering but the biggest concern I would have is over preheating. Typical topside board temperature as the board leaves the preheat is 210-220 F and I would avoid using topside preheat.

Depending on flux type, lead layout, orientation and lead length bridging could be a issue. If the leads are all inline keep them parallel to the conveyor. If you keep the preheat temperature in spec and dwell time in the wave to the minimum needed for good hole fill you should not have any issues with thermal damage to the LCD display.

Greg joined Electrovert in February 1984. Based out of the Electrovert applications laboratory in Camdenton Missouri, Greg has been in the process applications support role since 2000. His primary responsibilities include providing process and machine applications support for the wave soldering lines as well as process, machine and operations training. He also provides applications support for the reflow and cleaner lines. Greg is a PBET certified trainer and holds two patents on wave solder nozzle design.

There is another option other than wave solder. EFD developed a system that dispenses solder then uses a laser to heat the solder at the joint for reflow. This is much slower than wave solder, but should improve your quality and have even less thermal impact than hand soldering.

I would think selective wave soldering systems or selective soldering stations would be able to handle this application quite well. Spacers could be used to keep the LCD off the board and the board could be process through the equipment. Since this is a double sided board, I would not believe you would need too much top side preheat to get the solder to flow to the top side of the board, so this would be helpful in preventing the component from overheating during the soldering operation.

If you are currently manually soldering these components, you are applying more heat to each lead than they will see going over any wave solder system. Hence the heat from the wave or mass soldering system will be less than the heat from the solder iron, which should also help in improving the quality of the product. I say this because soldering irons are typically set at 650 to 750 F while soldering systems are typically set at 500F, quite a different.

This article about soldering techniques is the second on a series written by Barbara Dutra, an exchange engineering student from Brazil, currently attending Arizona State University, college of electrical engineering. She is currently an intern at Focus Display Solutions.

The majority of Liquid Crystal Displays require electronic components to be attached to the LCD Glass via a printed circuit board. These components are permanently attached using solder via LCD soldering techniques.

The soldering of electronic components is the act of joining two pieces mechanically by melting a combination of metals that becomes a permanent adhesive once cooled.

There are many types of soldering tools and methods used depending on the application. For example, there is the soldering of mechanical parts with special materials in large equipment such as aviation, or solders used in very small scale applications such as in Surface Mount Devices (SMD) components, and finally there is one extremely delicate type of soldering processes used in the case of the amendment in optical fibers.

A poor solder connection can seriously reduce or cut the flow of current causing the circuit to fail in its operation. ( Note: A poor LCD solder connection increases the amount of resistance. The higher the resistance the more heat that is generated and the more power required to operate the device. This is a critical concern in battery powered applications that have a LCD and a Liquid crystal module with a backlight.)

The soldering station is used for SMD components in the industrial manufacturing of some PCB assemblies used in such products as display modules, cell phones and computer boards.

Soldering irons have a hollow base with a heating element located inside. Its tip, which is typically copper covered by another material that allows the transfer of heat, becomes heated when the iron is turned on.

The soldering gun contains an iron tip which heats almost instantaneously when the trigger is pressed. It also contains a small lamp to illuminate the place where soldering is taking place. This iron is suitable for heavier soldering applications or large components with thicker terminals that require more heat.

The majority of industrial countries now require ROHS approved solder and soldering techniques. The use of ROHS solder in Liquid crystal displays has not increased its cost or lead-time.

Before starting the soldering process, a bit of solder is applied to the tip of the soldering iron, this allows heat to be passed from the heating element to the copper contact.

The tip of the soldering iron is briefly placed simultaneously against both the leads of the component and the copper of the trace. The solder flows into the hole and forms a strong electrical bond as the solder cools down to room temperature.

Warning: This operation must be quick so that the soldering iron heat does not damage the track or electronic component. If there is excess solder or join is faulty, the solder can be reheated and removed with the use of the nozzle.

Soldering of SMD"s is more complex for a variety of reasons such as exposure to high temperatures and soldering conditions. The SMD components have very small terminals for soldering, and they are on the copper side of the board that will be exposed to heat. The risk of heat damages to the components is much higher than in a conventional method of mounting components with through-hole.

There are two welding processes: wave soldering and reflux soldering. The majority of Chip on Board (COB) LCDs contain a combination of both SMD (sometimes called SMT for surface mount technology) and through-hole.

In the wave solder process, the board should be reversed to receive the wave soldering, so it is required that the components are pre-pasted with an epoxy adhesive. On a conveyor belt, the board passes through a tub with solder alloy in liquid state.

In the case of reflux soldering, the components on the LCD are placed on the board that will be carried by a belt into an oven. A solder paste is applied to the plate and this paste is melted in the oven, soldering all components. This process will solder the components of the upper part of board. Then the plate goes to the soldering wave form, where the lower side components are soldered.

When a SMD component is defective or poorly welded, in some cases, the issue can be corrected using a soldering iron. However, an experienced person is required for this to be carried out due to the very precise work involved.

First remove the solder and then the soldering iron. Do not move the terminal until the solder cools and never "blow" on the solder. This may create air bubbles to form creating a poor solder joint and increasing resistance in the circuit or misalignment of the component.

Once the solder is cooled, tap the terminal with a wire cutter to make sure that soldering is secure and cut off the excess terminal with cutting pliers.

Note: "flow soldering" should not be used for soldering printed circuits due to their acidic nature which can corrode from their residues, thereby damaging the components.

A good LCD soldering joint will be shiny and even, a poor LCD soldering joint will have a dull appearance and be filled with holes or gaps that allow for the component to break free. Also, a poor solder joint will create more resistance.

The LCD soldering may have a good bond with the lead of the component, but a bad contact with the trace on the PCB. This can happen by insufficient heating of the lead, or the printed circuit board is dirty or rusty. Below is an image of this type of solder failure.

The image below shows a good LCD soldering contact with the trace, but little adhesion to the lead of the component. Note the lack of contact between the lead and the solder.

This can be a major headache since the LCD soldering will look good and you will have a difficult time locating which solder joint is causing the broken circuit.

The image below shows a poor LCD soldering weld that can occur on a solder joint for a LCD Display. The component will behave as if there is no connection at all.

Contact Focus Display Solutions for any questions or concerns you have regarding LCD soldering requirements for LCD displays. We are based in Chandler, Arizona and support customers in the US and Canada.

The Aven 30W temperature controlled soldering station features a compact design that takes up minimal bench top space, an LCD display with blue backlight, safety guard iron holder, and a high quality ceramic heater that heats quickly and is designed for reliable, long-lasting use. The temperature range, from 160º to 550º C, is suitable for manual mounting and reworking of SMD components, audio equipment, RC hobbies and more. Soldering iron features a long life replaceable fine tip (N9 series) and comes with a 1.2m (4-foot) heavy-duty power cord. This exceptional soldering station also includes a recessed tip cleaning area with solid sponge for cleaning the iron tip as well as a small drawer in the base of the station for storing spare parts such as replaceable tips.