Metrigraphics Article in Today's Medical Developments

Invisible Parts
By Elizabeth Modic, Senior Editor
It sure is tough to promote your business when 95% of your customers won't let you talk about the work you do for them - mainly out of fear that their competitors might become your customer as well.

Well then, how do you grow and develop a company without customer testimonials and word of mouth?

Simple: you deliver quality and consistency, along with a process that no one else has - refining the art of electroforming to the highest achievable level - and you get customers coming from around the world to your Wilmington, MA, facility for precision manufacturing.

Metrigraphics, a division of Dynamics Research Corporation has grown into a worldwide supplier of high precision custom components for designers and builders of medical and analytical instruments and devices - applying their core technologies of electroforming, photolithography, and thin-film deposition - to help healthcare product vendors increase the performance, accuracy and reliability of state-of-the-art instruments and devices.

"The difference between us and other people who make small parts is our process is solely an additive process, where other technology is a subtractive process," says Randolph Sablich, vice president and general manager. There is no claim that one process is better than the other, but rather that each process has its own area of expertise that it addresses.

Metrigraphics lives in the 75µm or smaller world and this is where their process excels - routinely producing miniscule products that are practically invisible to the human eye - through implementation of their core technologies.

Adding Up
If you look at core technology, it can be divided into three levels of technology. Traditionally, small metal parts are made by stamping, taking multiple dies on a tool, a high-pressure press, and stamping out the parts. "You are able to get a high volume of parts that require minimal tolerances with not a lot of variety in terms of complexity of the part," says Luke Volpe, director of product development engineering.

Metrigraphics has their manufacturing facility and their development laboratories located in Wilmington, MA.
If you need a little more precision and the parts need to be a bit smaller, the next process to move to would be chemical etching - similar to electroforming. "Chemical etching traditionally uses photolithography to create a mask and replicate that pattern on a sheet of material that already has metal deposited on it through a variety of techniques," Sablich explains. "Then, a variety of acids are used to etch away the metal that they don't want - leaving them with the metal they do want. Etching yields more precision than stamping, but it can only go down to about the 75µm or 100µm range."

So, the next option is electroforming. Electroforming is somewhat a subset of electrochemical deposition; it is a typical cathode electrolyte system. "An automobile manufacturer will plate bumpers, and in the similar thought, this is what we do, but it is more refined because we are quite specific in the materials that we are depositing," Volpe says. "The materials we work with have been chosen because of their characteristics and because of our ability to control them in an extremely refined space."

In addition to choosing the right materials, it's the process they follow that differs from the blanket coating process used to plate a car bumper or bronze those baby shoes.

Beginning with photolithography, a pattern is formed that is placed on the surface that will eventually be electroplated. Then an electrolytic bath is used to deposit electroplatable metal onto a photographically-produced conductive patterned surface. Once the plating material has been built up - plated-up - to the desired thickness, the electroformed part is stripped away from the master substrate, yielding high-quality duplicates of the master.

As Volpe further explains, "Chemical etching literally etches down. The process is visually isotropic, meaning as you etch down to remove material you will also be removing material from the sides. So, when working on such the miniscule scales that electroforming does - for example a product with a width of 10µm and a height of 25µm - trying to reproduce a similar product using chemical etching would not work." The result would be that for every 10µm being etched down, you are also etching, or lifting,10µm off the height and in on the sides. With that ratio of material removal, by the time you got 10µm or 15µm deep, you would end up with no traces at all.

An RF coupling device that Metrographics manufacturers puts the precision of the electroforming process into perspective. It could be implanted in the body to transmit data from outside to inside the body, or vice versa. The size of the device has grooves at 10µm, widths of the lines at 10µm, while the height of the grooves are 25µm. "That is a 2.5 to 1 aspect ratio, which is incredibly thick compared to some parts we manufacture," Volpe explains. "The pad in the middle is what is used to make contact. Putting this device in further perspective, if you put a human hair across this, it would cover most of the diameter of the pad. This is small, very, very small." Surface quality is also delivered. For example, a jetting nozzle, perhaps used to atomize a pharmaceutical, can be produced with a 20µm diameter hole, which is actually large compared to some holes - where a human hair could not pass through the hole.

In addition to nano-sizes, the surface quality is also extremely fine because electroplating is capable of reproducing nanometer grain size. "It's a combination of grain size and of the substrate that we plate on that determines the surface quality," Volpe says.

Material Choice
"Almost any metal, any conductive metal, can be electroplated," according to Sablich. "Some are much more difficult than others to electroplate and it has to do with the inherent grain size of the material itself. So, when you distill it all out, it comes down to a handful of materials that electroplate really well - specifically nickel, nickel-cobalt, gold, and copper."

The chemistries used in the electroplating process are specifically designed to work with various metals to achieve the results they do. Standard electroplating runs a DC current through an electrolyte, you flip a switch, and you plate. Electroforming is not quite that simple. "We change current densities, we pulse it, we sometimes will go positive/negative to create various surfaces. So it's the process and the choice of material that results in the nano-size surface quality," Sablich explains.

Nickel-cobalt - being a laminategrowth material as opposed to a columngrowth material - is the material of preference when looking for fine-grain material finish. "What nickel-cobalt achieves, being a laminate growth material, is as we plate it up in the process, we get extremely fine molecular layers, resulting in the uniform process all the way through the fine product," Volpe says.

The other materials that Metrigraphics uses are pure gold, bright gold and copper, which is used in applications where conductivity is essential.

Unique Service
When working in the micron ranges and using materials that deliver the finishes required, Metrigraphics that can literally produce thousands, and sometimes millions of devices on one sheet.

A RF coupling is so small, a human hair could cover most of the center pad.
"Being able to produce millions of components from one sheet is just one area that allows us to consider our services unique, the other is way we work with our customers," Volpe says. "We are a custom manufacturer. We have no products of our own, so we manufacture to other people's specifications and requirements. However, we try to work with the client - typically the design engineer - in the early stages of a product lifecycle, long before they have made any parts for the FDA."

The companies that come to Metrigraphics know the product they want produced, but Metrigraphics knows their process and enlists their engineers to work directly with the customer's engineers in order to help optimize their design so customers can take full advantage of the electroforming process. "For example, to make the jetting nozzle for atomizing a pharmaceutical, the designer knows he needs a nozzle. It's a single hole, a funnel-shape, but he may not know how small the nozzle can be made, or the other characteristics to consider. Our designers can work from the beginning process to help determine size and materials so the best product is produced," Sablich says.

A jetting nozzle with a 20µm or less diameter hole.
Medical is just one area that requires small components, or components with miniscule features. The nozzles manufactured range from those used for jetting pharmaceuticals to nozzles in inkjet cartridges. And again, the minute size of the parts enables 5,000 jetting nozzles to be packaged in a single gelatin capsule - the same size capsule you might take as your daily vitamin.

"Then there are purely structural parts we produce, such as a spring used for testing probes in the semiconductor industry," Sablich says. "The spring is quite large compared to some of the springs and devices we make - and putting it next to the eye of a sewing needle really helps put its size into perspective. To think even smaller components, we also produce a device that would fit inside of the loops of those springs."

In the aerospace industry, Metrigraphics has done a range of things as well - from putting blanket coatings on devices to very precise pattern coating and other structural devices for satellite-based portions of the aerospace industry and test devices launched into space.

The space application mentioned included a solid gold sheet with very precise slits in it that were electroformed. "There was really no other way to create this device other than using the kind of technology Metrigraphics offers. The intended use is to filter out everything but gamma ray from deep space," Volpe says. "That device is key in a satellite that has been flying for about five years now and it has made a very significant impact on some of the deep space exploration that is going on."

Beyond the miniscule work that electroforming delivers, Sablich feels there are a few things to remember about their process. One is that offering design services really helps their customers optimize their product design against the electroforming process. Another is they really are unique because they do offer things that very few others in the industry or world can do - which is why customers come to Wilmington from all over the world. Third would be they have been around 45 years, so they have a built a reputation of delivery and quality. The last that Sablich and Volpe feel needs known, is that they recognize that when you start out with a desire you are not going to place an order for 10 million parts right away, so they are always willing to build as few as one and as many as billions.