Behind the Braille

The world of ADA-compliant signage is a complex aspect of the public signage industry. Being able to produce even the smallest of ADA-compliant signs requires adhering to myriad government regulations. And although the federal rules governing over ADA compliance haven’t changed since 1991, states such as California have enacted their own rules that are more stringent than what are required to meet federal guidelines

There are many companies that take on the challenge of creating ADA signage on the wholesale level, and each has its own method of achieving fantastic results. One of those companies, Advance Corp. of Cottage Grove, Minn., has given us a behind-the-scenes look at how it creates ADA-compliant signs from the processing of raw materials to the decorating.

We will also take a look at some significant questions about ADA signage in general.

Behind the Scenes

The first step Advance uses in the manufacturing of its ADA Braille signs is the actual processing of the raw material. For this example, we will look at how the company works with most prevalent ADA-signage substrates: magnesium, zinc and photopolymer.

The processing of magnesium and zinc is very similar, yet each has been confronted with considerably different reputations in the marketplace. “Three or four years ago, magnesium was supplied to the sign industry by a few other manufacturers. Their product failed in the field,” says Kathy Wilson, Sales and Marketing Manager of Advance Corp. “Architects and distributors began to shy away from magnesium altogether because of their limited bad experiences from certain sources. We have been very successful with our magnesium products, and we desire our market to understand that the performance of ADA products should be tied to the manufacturer, not the raw material.”

Wilson says that with proper manufacturing, magnesium performs as well as zinc and photopolymer, and they can often produce finished magnesium signs for lower cost than the other substrates. Advance Corp. offers the same warranty for both zinc and magnesium signs. There are many steps in the production process that must be tightly controlled in order to turn out acceptable products. Both zinc and magnesium signs are one-piece metal signs in which all components are integral.

Characters and Braille are produced on a film negative. The negative is a clear material with emulsion on one side. The emulsion prevents light from passing through and curing the photo-resist coating. The exposure process involves placing the plate in a clean exposing unit with the resist side up. Once the protective covering is removed, the negative is placed emulsion-side down on top of the plate. The exposing unit is computer controlled and exposes the plate with a constant amount of UV light for a predetermined amount of time. The photo-resist coating cures when it is exposed to ultraviolet light or high heat. The area that is not exposed to light doesn’t harden, and the resist coating is cleared off the metal in the plate-development process.

In this next process, the exposed photo-resist is removed from the plate via a chemical stripping process. This takes place in the developer machine where a conveyor of rollers transports the plate through the developer. The metal is now protected from acid where the resist is still present, and the area that is exposed to the acid will be chemically etched away. The exposed photosensitive image on the metal is then developed and chemically machined with acid to create raised and recessed areas on the metal plate.

Next, the plate is inserted into an etching machine specific for its own raw material. The base of the machine holds a chemical bath consisting of nitric acid. The chemical reaction between the acid bath and the metal of the plate causes all exposed metal to etch away. Areas of the plate that were not exposed and developed remain intact, creating an etched image that may appear to be either a recessed or raised copy of the original film.

The processing of photopolymer (interior-grade and exterior-grade) has several similarities to that of etching magnesium and zinc. There are also many steps in the production process that must be tightly controlled in order to turn out acceptable products. This raw material is designed with a photopolymer layer and a phenolic base. The material is considered a seamless single-piece construction. The photopolymer is kept in a controlled environment to protect it from excessive heat and humidity as well as light sources.

The processing begins with exposure from fluorescent tubes located in the processing unit. A film negative is placed on the photopolymer side of the sheet and exposed to UV light, which transfers the images from the negative to the material. The photopolymer is developed in an aqueous solution called a washout process. The sheet is set onto the bed of the machine, which includes a set of brushes that sweep against the material during the processing. This step generates the raised and recessed areas on the photopolymer sheet. The sheet is then put through another process to achieve maximum moisture evaporation by drying it. A final baking cycle is completed to set and fully cure the photopolymer.

Regardless of the raw material–magnesium, zinc or photopolymer–the sheet is then trimmed to size. For these examples, Advance Corporation uses an Onsrud dual process CNC three-axis router. Other options include using a C02 laser to vector cut photopolymer and a Haas three-axis vertical machining center for zinc.

The final step in producing the ADA Braille signs is the decorating process. Here you will find a number of options that all share a main purpose of protecting each of the raw materials with a coating that withstands its intended environment. For these examples, Advance uses Matthew’s acrylic polyurethane paint as the base coat combined with its specialized screening ink, of which both are thermal set. Advance says the additional step of baking the decorating ingredients provides a superior finish that withstands graffiti-remover, most cleaners and chemicals, and rugged environments. Industrial ovens allow for controls over the parts and provide a dust-free environment and temperature controls. Other manufacturers may use foil stamping in place of screening ink.

1. Why should the signs I am purchasing incorporate domed Braille?

The ADA and ABA Accessibility Guidelines for buildings and facilities have made domed Braille part of its guidelines and are required. The Department of Justice is the enforcing agency.

“The reason ADA has required domed Braille is because this allows someone to read Braille with their fingers smoothly, flowing over the domed shaped characters without getting caught on edges,”says DeeAnn Barker, president of Etchcraft. “The fingertips become sensitive to the shapes of these characters and many push their fingers into the shapes as they read them. You can imagine how painful this would be if the Braille characters had straight edges and were not rounded domes.”

2. Are magnesium, zinc and photopolymer each capable of producing domed Braille?

Yes. It is actually the responsibility of each manufacturer to produce domed Braille according to Kathy Wilson, Sales and Marketing Manager of Advance Corp. The raw material is capable of being processed in such a way that a manufacturer can meet minimum guidelines if they take the proper steps in their manufacturing process.

3. What is “interior-grade” photopolymer and can it be installed in any environment as long as it is “interior”?

The term “interior-grade” is a term that is used by suppliers of raw material. Buyers should be aware that each manufacturer uses different decorating ingredients that protect their final products. Therefore, each manufacturer should educate their customers on appropriate use of their Photopolymer ADA Braille sign products.

“The intended use of interior photopolymer is in an environment that does not present excessive moisture and drastic swings in temperature,” says Dave Miller of Novapolymers. “Often, it is the fabricator who is left to make this final determination.”

4. If I receive photopolymer ADA Braille sign products that have Braille or letters that appear to be falling off, what should I do?

According to Wilson, you should contact the manufacturer immediately. The product is failing. Failure of photopolymer can stem from various causes including inappropriate installation methods, such as drilling holes in the product and breaking the seal of the paint; and the inappropriate placement of interior-grade material in an environmental setting not conducive to the manufacturers suggested warranty instructions. There is a possibility that the manufacturer processed the material incorrectly. However, most manufacturers would see visible signs of the product failing before it completed its final manufacturing cycle.

5. Once I purchase an ADA Braille sign product, what should I expect in terms of performance and longevity, and does the product come with a warranty?

The performance and warranty must be addressed by each manufacturer says Wilson. Although it is commonly thought that all photopolymer, magnesium and zinc products can be treated equally, they should not be treated equally. Each manufacturer uses different brands of raw materials, processing techniques and procedures and each have their own quality levels. Therefore, buyers must be aware that they must research each manufacturer that they wish to partner with when re-selling ADA Braille sign products