This technical information has been contributed by
ChemArt Company

Ocean State Firm Specializes in Extremely Thin, High-Precision Parts

Photochemical Machining

Photochemical Machining, also Known as Chemical Etching, is Forte of Rhode Island-Based Company

The art and science of manufacturing ultra-thin, chemically-etched parts with close tolerances is an area that takes a great deal of expertise and attention to detail. ChemArt Company, a Veteran-Owned Small Business (VOSB) located in Lincoln, Rhode Island, specializes in just such an area, both for industrial and decorative applications. The company has become a recognized leader in the manufacture of precision etched parts using photochemical machining (PCM), commonly called chemical etching. ChemArt has been a pioneer and major contributor to the PCM industry since the company's creation in 1976.

Advantages of PCM are said to include low-cost tooling, fast turnaround times for prototypes, no stress to the material, ultra-thin parts, multiple design possibilities, and a burr-free finish. Because the process doesn't change the internal molecular structure of the metal, it has no effect on the metal's hardness, grain structure, magnetic properties, or ductility. A multiplicity of designs is available for jobs that require repeating patterns with tight tolerances. And partially-etched fold lines can be incorporated into the tooling to provide precise and easy secondary bending and forming of the parts.

Almost any metal or alloy available can be chemically-etched. Metals that are commonly processed at ChemArt include brass, copper, carbon steels, nickel, Kovar®, stainless steel, beryllium copper, phosphorous bronze, Inconel®, alloy 42, nickel silver, Invar, Monel®, tin, and Mu-metal, a nickel-iron alloy with high magnetic permeability. Very exacting tolerances can also be held, and metals can be 0.0005 inch to 0.0900 inch in thickness. Typically, the thickness will not exceed 0.0600 inch. The standard tolerances are 10% of the thickness of the metal or alloy used to produce the part. Typical tolerances held for most parts would be from +/- 0.0005 inch to +/- 0.0010 inch.

Because of the characteristics of this process, the industrial applications are varied and diverse. Some of the most typical parts include step lids for thermal management; heat enclosures for electronic equipment; shims and washers; heat shields and sinks; filters; screens; and grids. Additional examples are encoder disks, lead frames, EMI and RF shields, shadow masks, flat springs, gaskets, meshes, actuators, and apertures. The primary uses of the company's parts come into play in the aerospace, aviation, and military industries, mostly for electronic applications. But they are also used for applications in fluid dynamics, thermal management, fuel cells, communications equipment, computers, and semiconductor machinery, as well as the automotive, medical, and scientific areas. Most of the parts manufactured are precision subcomponents.

Our parts have to be very precise in order to fit in with all of the other high-tolerance parts in a given component," says ChemArt Director of Technical Services and Business Development, Joseph Beck. "And with today's movement toward smaller and smaller parts, like for nanotechnology, our industry is really coming to the forefront. I have parts on my desk that will fit on the end of a toothpick."

ChemArt's founder and CEO, Richard Beaupre, was the originator and pioneer of the aqueous dry film photo resist process, the basic process that is now used throughout the entire PCM industry. Beaupre helped design the process when he worked for DynaChem for many years. At that time, he came up with several innovations that were patented, one of which is for this process. He went on to start ChemArt in 1976. On the industrial side, ChemArt was reportedly one of the first photochemical machining companies in the United States to adopt ISO 9000 standards, and the first manufacturing company in Rhode Island to adopt and be certified to the ISO 9001:2000 standards for quality management systems.

The company has a decorative division and an industrial division. While most of the other companies doing this type of work rely heavily on their industrial manufacturing, a large portion of ChemArt's sales are for decorative work. The usual order for decorative work is about 250 pieces, custom-designed ornaments used for philanthropic and fundraising events, corporate gifts, holiday ornaments, keepsakes, and awards. ChemArt also licenses and produces a full retail line of Christmas ornaments for the Baldwin Hardware Company.

"One of our larger clients is the White House Historical Association (WHHA), Beck states proudly. "Because of the WHHA confidence in ChemArt, we were awarded an exclusive licensing agreement to market the annual program in the retail environment nationwide. We probably have the most market share of any PCM company in the U.S. in the decorative area."

Beck says that chemical etching is not a cutting-edge technology, but is best evidenced by how the etching companies tweak or modify the chemicals and process methodology. Each company will come up with its own unique way of doing things to create better quality, tolerances, and sheet yields. On the industrial side, Beck insists that everyone follows the same guidelines for production that have been tested and proven to work for the past 30 years. On both sides, providers are concerned with how to better wash, prepare, coat, and etch the metals for more precision. On the decorative side, concerns drift toward secondary design and processes, like silkscreen printing, plating, hand assembly, and specialty packaging.

"Since a lot of our etching is for decorative pieces, we're looking more at aesthetics in this area," according to Beck. "However, most of our industrial applications are about precision and quality. On the industrial side, it's usually a very thin, flat part, but on the decorative side, it's left up to the customer and the artist that designs it."

As far as industrial guidelines are concerned, the company's engineers first want to see a drawing upfront to determine how they are going to make production templates. ChemArt has engineers on staff that can edit a base drawing to make it more manufacturable and cost-effective. One concern is the required thickness of the material. "We look at how many critical points there are on the design, like breakthroughs or hole sizes," Beck explains. "Typically, we can hold about 110% of the thickness to hold a hole size. We look at what secondary operations are required, most of which we do in-house, whether it's bending, forming, plating, silkscreening, heat treating, laminating, or other processes. Anodizing and powder coating would be things we send to an outside vendor. We look at what delivery times are necessary, and we check out the CAD file to see if the part is easily manufactured."

On the decorative side, concerns are different depending on the complexity of the design. ChemArt artists will want to know if the design is 1D, 2D, or 3D, if plating or coloring is necessary, how much bending or forming is necessary, or if special packaging must be designed. Designs can vary from very basic to extremely ornate. Some of the ornaments for the White House are 15 to 16 silk-screened colors, all in tight registration. They're in 3D shapes, they sometimes spin around, and they usually have text messages embedded in them. ChemArt has a complete art department with a staff of about 15 artists and designers who create original designs or help their clients with their designs.

In addition, design guidelines have company engineers checking out bevels and cusps. A cusp is formed at the intersection of the top and bottom of the part, which is usually less than 20% of the thickness, based on how processes are altered. "We can make it a high, low, or even cusp, or eliminate it altogether," says Beck. "This is the same process used to make printed circuit boards; therefore, we can make parts that are very thin using many different types of metals. Mainly, we just need to know what properties are needed for the parts, how they will be used, and the material hardness that will be necessary."

Problem solving is high on ChemArt's list of value-added services. In one instance, a company that designs and manufactures golf clubs needed several prototypes. The OEM came to the etching company because it wanted to redesign the face of a particular club. It wanted to increase the "sweet spot" on the striking surface of the club, which is the club's exact center for maximum force on the ball. "Our challenge was to help them come up with a series of new designs, but not to go into full production runs, which are very expensive," Beck remembers. "We were able to come up with new designs that had different shapes and configurations very reasonably. We were able to do this for them because of our rapid prototyping, low-cost tooling, and adaptive technology that allow us to make changes on the fly. We probably saved them tens of thousands of dollars the first year getting the clubs into production quickly, easily, and inexpensively."

Another instance had the company making prototypes for a customer that supplies parts for fuel cell technology. The main task was to shrink certain components inside the fuel cell. ChemArt was able to make prototypes out of very thin material for the company's new designs, and perform small production runs with low-cost tooling. "Once again, we saved this company tens of thousands of dollars the first year of production with our cost-effective process," Beck maintained. "Our film photo tools were created in one day, and then changes were made very quickly, which allowed this customer to get into a production mode very quickly."

In a best case scenario, says Beck, turnarounds for prototypes are very quick if they have the metal in stock. A prototype can often be turned around from a CAD drawing in 48 hours. Some very thin, exotic metals and alloys that are specially made for this process, however, could take up to 22 weeks to receive. Regular production runs range from very small to very large, and photo tooling costs are usually very low--from $180 to $300 depending on the complexity of the part--compared to other processes that require dies or hard steel tooling.

"One of the performance expectations our clients have are material certifications to ensure that a specific metal or alloy has a certain temper or heat treatment, or is formed to their specifications," says Beck. "Tolerances are always critical in this business, as well as metal finishes. We've made parts for the semiconductor industry that must be very small and very precise. For example, if the part is going into an aperture that has to have a fault-free finish, without any microscopic scratches, it must be perfectly smooth. Packaging guidelines can even be very critical to our customers. Most of our performance expectations are to create a high-quality part at a reasonable cost."

ChemArt must also have the ability to recycle and regenerate chemicals and contaminated water. "We are very concerned about how we manage our waste management streams for the chemicals we use," Beck explained. "We try to be a green company as much as possible. Under a management initiative, we have created a "green team" to try and reduce our eco-footprint. We received a conservation award for our sustainability efforts, the Senator John H. Chafee Conservation Award in 2002."

Kovar is a registered trademark of Carpenter Technology Corporation
Inconel is a registered trademark of Special Metals Corporation
Monel is a registered trademark of Special Metals Corporation

This technical information has been contributed by
ChemArt Company

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