Engineered Solders Blog
Recent Entries
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When the Bargain Bin is Not What You Bargained For
Posted by Amanda M. Hartnett
20 hours ago
Jim Hisert's Dad demonstrating a jar of old flux which pales in comparison to Indium's new advanced flux technologies.
I’ve learned this lesson time and time again that a lower price does not make for a better deal. I learned this lesson yet again as I bought my cedar summer
This lesson should go without saying, but it applies to products of all types. That is, it also encompasses solders and their fluxes.
Jim Hisert recently posted this image of his dad with some OLD flux in his July blog posting titled, “Juxtaposition.” This got me thinking because just the other day I was shopping at my local home store and saw the rack of fluxes and solders made for soldering home water pipes. A jar of flux was in the $10 price range.
Coming from the industry of electronic-grade solders, this at first seems like the bargain of a lifetime. When investigated further however, it is quickly realized what technology went into making this versus the attentiveness we put into our materials and it is apparent that this bargain is not a bargain at all outside the old pipe soldering industry. There is no comparison
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Why use flux?
Posted by Paul Socha
June 10th, 2008
Flux & Substrate Compatibility
Flux is a liquid, solid or gaseous material which, when heated, speeds up and/or promotes wetting of the base material(s) by the flux’s removal of any surface oxides on the base material. Flux will protect against further oxidation during the soldering process.
Flux is an important component of most soldering operations. Using the correct flux for the application is essential to insure that a reliable joint is made.
To the right is a chart to help you choose the correct flux type for your application. Most post reflow flux residues need to be removed either to avoid corrosion or for reasons of appearance.
Reducing Gas Atmosphere is a gaseous atmosphere comprised of one or more gases, generally hydrogen and inert filler gas, such as nitrogen. Used where standard fluxes are ineffective at removing and preventing surface oxides. Hydrogen, for example, reduces the oxides, while nitrogen remains inert. It is recommended that both gases be present to effect a “fluxing” action. About 350°C is best. -
Indium Compressed into Hermetic Seals
Posted by Amanda M. Hartnett
May 16th, 2008
Compress indium between the arrows to form a hermetic seal
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.
This process has been used by many who have looked for a high reliability seal that doesn’t leak yet many of you are still asking questions about it. If you have a sealing application and would like more information on this process, feel free to contact me or look over our indium sealing application note.
Image from penforhire.wordpress.com/.../ -
Engineered Solders with a European Flavour
Posted by Carol Gowans
April 30th, 2008
Alan Fairbairn
Guest Blogger
European Business Development Manager
Engineered Solders MaterialsI 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.
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InTEGRATED Solder Preforms
Posted by Paul Socha
April 18th, 2008
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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Preform Flux Types
Posted by Amanda M. Hartnett
April 7th, 2008
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.
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Research Solder Kits
Posted by Carol Gowans
April 7th, 2008
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
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Flux coated preforms are like a snowball….
Posted by Seth Homer
April 1st, 2008
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.
When a flux is required to facilitate a bond in an engineered solder application, the flux type depends on the alloys involved, the temperature range and the surface you’re dealing with. Herbert Ludowieg is one of our manufacturing engineers involved with engineered solders and flux coated preforms, he has this advice;
“Since most surfaces involved are in good shape, starting with a low percentage of flux is best. Larger quantities can result in excessive cleanup after reflow and can change the dimensions on through holes by reducing the size of an opening. Ultimately, more is not always better. We have several customers who have reduced their flux percentage from more than 2% to 0.5% with excellent results, the parts are easier to handle and have a better overall experience.”
These issues along with possible voiding can really make your flux coated preform experience a bad one. For further support and information, please use the following links:(Flux Coatings for Preforms) and (World Class Tech Support) -
Soldering to Stainless Steel
Posted by Paul Socha
March 20th, 2008
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.
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Solder Troubleshooting
Posted by Amanda M. Hartnett
March 12th, 2008
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
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