Have you ever tried to form a seal using an epoxy where you dispense the material, clamp the seal shut, and VOILA! It’s attached!?
You can do the same thing with indium in a wire, washer, or frame form. The process is no more difficult, it’s cleaner, and with some control, the seal is hermetic.
Alan Fairbairn
Guest Blogger
European Business Development Manager
Engineered Solders Materials
I hope I can bring a European flavour to Engineered Solders and give you a taste of the activities that are happening in this vibrant and diverse area. It is difficult to look at Europe as a whole because although the European Community is a strong economic and political union (in their 51st year), the many countries of Europe still have their own long-standing identities and industries.
For example, watch making is a key industry in Switzerland but really nowhere else in Europe. Germany is known for their medical and automotive markets. Even the small countries have their focal points. The Netherlands is the home to a major electronics manufacturer; Sweden and Finland both have cell phone manufacturing as major industries. Even Denmark hosts a major wind turbine manufacturer.
All of these industries can use Engineered Solders. The addition of preforms to solder paste gives joints the added solder volume they need. This solder fortification application is widely used by a variety of circuit board makers. Thermal applications are also growing as the dissipation of heat becomes more and more important. Indium metal has a thermal conductivity of 0.87W/cm-C making it an excellent thermal interface.
The applications are virtually endless as we find new and growing applications every day.
The European office, based in the UK, was opened in 1990 and has been growing ever since by supporting the European Community with manufacturing and technical support.
]]> Have you ever had to hand-place solder washer preforms on the pins of a connector and found it to be very labor intensive? Indium Corporation has a product called InTEGRATED Preforms which enable the user to place multiple preforms at one time in less than 15 seconds.
InTEGRATED Preforms are joined in a matrix by fine, precise strands of solder which, during the soldering process, melt and flow to adjacent pads to give complete preform separation.
In addition to time saved, the quality of the joint is assured because only one preform is delivered to each joint eliminating the chance that a pin will be missed or two washers placed on the same pin. Each scenario will create a quality problem that reduces the yield and increases the time spent on rework.
Unique preform designs and complicated configurations can simplify difficult soldering jobs. An example is a thru-hole connector with multiple rows of long pins that are difficult to reach in the center with hand soldering. InTEGRATED Preforms eliminate the need to reach these remote areas. The connected washers can be placed on top of the board, under the connector. After reflow, equal volumes of solder are delivered to each of the pins in the connector.
In order to get the full benefit of InTEGRATED Preforms they must be uniformly fluxed on both sides including the connecting strands. Also, they need to be flat in the application and uniform heat must be used to reflow them.
Many printed circuit boards have mixed technology. The surface mount components can be placed in the paste first followed by the thru-hole components using InTEGRATED Preforms. The board can then be reflowed and cleaned once, eliminating time consuming steps.
To learn more about this time saving product patented by Indium Corporation, please contact the Applications Engineering Staff at Indium Corporation.and we would be happy to design an InTEGRATED Preform to fit your solder requirements.
For additional information regarding reflow methods using InTEGRATED Preforms, check out the June 2007 issue of SMT Magazine.
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When considering the choice of flux for preforms, in addition to factoring in the amount of flux required on a preform, the type of flux is also important. Fluxes are categorized using the nomenclature given by the IPC, the Association Connecting Electronics Industries.
In the Joint Industry Standard 004A, the IPC specifies the testing methods used to categorize a flux. The end classification includes a designation for the type of ingredients used, the flux residue activity level, and the amount of halides included in the flux. A sample designation would be ROL1, indicating that the flux is a rosin-based flux with low residue activity, and does contain halides.
Fluxes are specified for their use based on this nomenclature. The correct flux is chosen based on the method of cleaning to be used post-soldering, the method used for reflowing the solder, the method in which the flux is to be applied, the reflow temperature it will be exposed to, and the substrate it is intended to be used on.
The ideal flux for an application will activate during reflow and any residue left at the end of solder processing (including any required cleaning) will be inert. The flux will be deposited in a repeatable way and the flux chosen will be the least active flux possible which can remove oxides from the substrates soldered.
For use with preforms, flux options include liquid fluxes which are water-soluble, rosin-based, or no-clean, Tacfluxes with similar options, or pre-fluxed preform coatings including no-clean and rosin options.
I recently read an article at Development Monkey by Karen Field about how Development Kits are growing in popularity with Design Engineers. She reports that 95% of the Design Engineers surveyed by EDN magazine reported that they had bought at least one development kit in the past year.
As Karen says, kits are a great way to test out some possible solutions to the wide variety of issues facing Design Engineers today without having to commit to a minimum order quantity.
At Indium we have long subscribed to this process and have several kits available. We identified the most popular alloys in our wire, ribbon and preform product lines and offer them in 3 foot quantities in kits. Because preforms are highly customized parts, the ribbon kit fills in nicely and allows users to cut the ribbon to the size they need.
You can see more about Our Solder Kits
]]> For those of us who grew up in colder climates, snowball fights were a right of passage. As a child I fell victim to the misconception that a really big snowball would hasten the victory I desired. I realized quickly that too much snow was hard to throw and basically useless. Needless to say I was pummeled into oblivion by my adversaries. It didn’t take long for me to realize that there had to be “just enough” for optimal performance. When it comes to flux coating your engineered solder preform, the same rules apply. Have you ever had that sinking feeling when you tried soldering to stainless steel and found it to be very draining? You can join stainless steel, you know, and here’s how!
You need the correct flux, a solder with some tin (Sn) in it, a heat source, and the ability to clean the post reflow flux residue in warm water.
Indium Corporation’s Indalloy Flux #2 is especially formulated for removing the oxides from stainless steel. It has an activation range from 100-371°C. For high temperature applications, a forming gas (nitrogen and hydrogen) can be used.
Depending on the operational temperature of the device being soldered, Indium Corporation has a variety of tin containing alloys that will fit the requirements of the application. Indalloys #121 (96.5Sn, 3.5Ag) and #182 (80Au, 20Sn) are excellent solders for joining stainless steel. For other alloy choices please see our Alloy Property Chart for a complete selection of our solders.
The chosen solder can be reflowed using whatever heat source is available, as long as it is capable of reaching a temperature that is 20-40°C above the liquidus temperature of the solder. If a forming gas is used, it is best to use a temperature 350°C and above to activate the hydrogen so it will reduce the oxides.
Indalloy Flux #2 is corrosive, so it is necessary to clean any flux residue from the device being soldered. Because of the corrosiveness of this flux it is not recommended for electronic applications because it could cause problems if any residue remains after cleaning. If the application is for mechanical attach and not electrical, in certain applications, it may not require a cleaning.
If you have any questions please contact the Applications Engineering staff at Indium Corporation.
]]> Why doesn’t my solder flow?
The most common issue preventing good solder wetting on a substrate is oxidation. All metals are prone to some level of surface oxide formation when exposed to ambient conditions. Solders cannot wet substrates when they or the substrate they are soldering to is oxidized.
How can I be sure that oxidation is my problem? Well, is your solder balling up on the surface like the water droplet shown in this image? If so, you have an oxidation problem.
How do I remove this oxidation? Indium has over fifty fluxes formulated for removing oxides. Every Indium technical staff member is trained to identify the appropriate flux to suit your application and will be happy to do so. Feel free to contact us here.
Can’t use a flux? Other oxide removal techniques include chemical etches, plasma cleaning, ultrasonic soldering, or use of a reducing atmosphere.
image courtesy of www.malawicichlidhomepage.com
This question was posed to me while introducing a family member to the world of Engineered Solders this past weekend. While I was still reeling from the shock of what seemed like a ridiculous question, it suddenly occurred to me that solder is not part of everyone’s daily life. Actually it is, they just don’t know it.
Take a moment to run through the average day. Before you get through the morning you have probably taken solder for granted more often than you realize.
Usually the day begins with the dreaded alarm clock we all wake up to (Solder Paste) and the flat screen HDTV we watch the morning news on(Thermal Products). Need I mention the cell phone (Engineered Solders)?
Indium has over 200 alloys to choose from.(Alloy List) The list is always growing, but the diversity in solder types is exceeded only by the applications in the industry.
With close to 75 years of contribution to the ever changing world of solder, Indium has been a leader in technology and education. Right down to the correct spelling of the word.
Do you have a 2’ x 3’ area on the wall of your office or cubical for the latest new and improved Indium Corporation Wall Chart? Click here to email us your name and address so we can send you one.
We have updated the Table of Specialty Alloys and Solders, added new tables for fluxes and improved the graphics. And yes, the periodic table is still there, as well.
The wall chart is a ready reference for a quick check of the melting temperature of an alloy or one of its unique properties. The chart will help to compare different properties of alloys to narrow down your solder selection.
Indium Corporation is a quality supplier of preforms, Integrated Preforms, Informs, wire, ribbon and foil, as well as, solder pastes, liquid fluxes and epoxies. If you need assistance you can contact an Indium Corporation Applications Engineers anywhere in the world. Our location information is on the chart. Call us to discuss your application and we will help you determine which form of solder will give you the best performance in your application. We have very talented engineers that help dozens of companies each week with their soldering questions.
In the upcoming weeks, we will be discussing topics such as:
The proper alloy for the metallizations
Flux selection
Methods of reflow
Engineered solder packaging
Ways to improve quality and uniformity in your process
Step soldering
Indium as a cryogenic seal, as well as, vacuum applications.
Paul A. Socha
Principal Engineer
Engineered Solder Products
