In a recent blog, we mentioned using projections as “energy directors” to achieve weld joints at specific, pre-defined locations. Ring projections - also known as annular projections - are commonly utilized in the electronic packaging industry to achieve hermetically sealed electronic packages, for transistor outline (TO) packages and, more recently, rectangular packages. Following are some tips for successful design of these ring projections and possible solutions to help you overcome less-than-perfect designs.
One of the great things about working for Miyachi Unitek Corporation is the company’s near-religious zeal for innovation. I feel like it’s really in our “DNA,” - and while it can be frustrating to ‘finish’ a new technical datasheet only to find out that the product has been tweaked/improved in the time it took to print it - it’s something that I’m proud to be a part of. As a company, we have always provided not only equipment, but also complete manufacturing solutions, which require an understanding of both equipment and process. We are always helping people answer the question, “Is there a better way to do this?”
That innovative spirit recently got its just rewards, as Miyachi Unitek was named one of 14 finalists in the Patrick Soon-Shiong Innovation Awards, presented by the Los Angeles Business Journal and NantWorks. We were honored as an organization that “expands the boundaries of its industry and leads the region in impactful innovation.” I have to admit it felt good to get kudos for some of the technical innovations we have spearheaded in the past decade, and recognition for the impact some of these innovations. I’d like to give our readers just a few examples.
- Application of three-dimensional laser cutting for production of arthroscopic surgery devices – This is a method of using a five-axis motion platform to achieve true three dimensional contour cutting for a shaver used to cut away and remove unwanted fragments of the cartilage from a joint during arthroscopic surgery. With this technique, the edge quality of the laser cut tube is nearly flawless, minimizing the extent of secondary manufacturing process steps. This means better shavers, better surgeries, lower risks and ultimately a better quality of life for many people.
- New welding technique enables crack free welding of high silicon Al-Si controlled expansion alloys and aluminum 4047 for aerospace electronic packages – Using a novel concept, we enabled crack-free welding of 70 percent silicon alloys, which are lightweight, high thermal conductivity alloys that are used for RF and microwave packages and other critical heat sinking applications. Miyachi Unitek modified the solidification process without using post weld heat treatment. By using a fillet weld geometry and moving the weld close to the edge of the package the isotherms around the weld are modified such that the thermal gradient is reduced and re-orientated. The result included crack-free welds in the highest silicon content alloy, CE7.
- Advances in laser welding systems and technology for medical device manufacturing – This innovation includes motion and laser control techniques beneficial to hermetic laser seam welding of implantable devices. Using special software to achieve “position-based firing” along the contour, we developed a method that fired the laser in response to its actual position along the contour at any point in time. We also developed new metals joining production methods using “green light” (532nm) pulsed welding lasers, which facilitates precision welding of copper and gold alloys. This offers a true metallurgical weld, consistent high-reliability electrical connections with no long term resistance drift, and a non-contact process that completely eliminates risks of electro-static discharge or physical damage to the parts being joined.
- New force-based bend align increases yield and throughput for manufacturing pump lasers for the telecom industry – This unique force-based algorithm is used for deforming pump laser diode packages back into alignment. The packages are part of fiber laser amplifiers used to boost a telecommunications signal as it’s transmitted over vast distances. With the force based bend align method, the signal is peaked faster and in many cases with increased coupling over position based systems. The increased coupling provides improved amplification of the signal and greater signal to noise ratio.
- Enabling high performance optoelectronic modules using novel gas-conserving resistance welding electrode system – This new projection welding technique dramatically reduces the amount of Xenon gas needed to backfill a package. Xenon has good thermal properties and does not enter into slow chemical reactions with other materials that can cause degraded performance and reliability. However, it is extremely expensive, and many existing processes waste the costly gas during backfilling. The new technique enables packages to be evacuated, and then filled with gas before being hermetically sealed using projection welding. This process consumes as little as 5 cubic centimeters of Xenon gas, costing only $0.75 per part.
If you read my recent blog on heat balance, you know that there are five different techniques that can be used to balance weld heat that don’t involve making changes to materials or part design. And at the end of the blog I mentioned that if you’re still having difficulty after trying all five of the techniques, you may want to consider adding projections to one of the parts.
Electronic package sealing is a tricky process. It may seem straightforward: place components in a metal package and seal, generally using projection spot welding (aka cap welding). It is very important, however, to prevent moisture and oxygen ingress to the package during sealing, which, over time, will damage the sensitive electronic components housed within. This zero-moisture requirement is most commonly achieved by heating the package in an oven and then moving it into a glove box backfilled with nitrogen, removing both moisture and oxygen. With increasing frequency, however, manufacturers are starting to use xenon to backfill the packages. Why? Xenon is a large molecule with good thermal properties, and, because the outer valence shell contains eight electrons, producing a stable, minimum energy configuration in which the outer electrons are tightly bound, it is inert to most common chemical reactions, including combustion.