It’s as simple as Addition and Subtraction
There are a variety of materials and manufacturing methods used to create compliant American with Disabilities Act (ADA) signage. There are pros and cons to each type; but for a beginner’s introduction you can break all types down to an integral process that either subtracts from a substrates background or is an additive process that applies raised material to the surface of a base substrate. This is a manufacturing outline to help explain differences in construction. Future newsletter articles will define more design options and the environmental conditions effecting the use of the various construction methods in greater detail. Before discussing the various sign types let’s look back at the original raised lettering and Braille choices for ADA signs.
History Lesson
Since its introduction in 1990, ADA signage with braille and raised text is a must for any building that is open to the public. At the time there were basically two types of compliant signage; photopolymer and raster braille with applied copy. These go-to products of the past are still very popular and are often called out in architectural specifications to this day.
Here is a quick summary of each. If you have additional questions our knowledgeable staff at Park Place Sign Systems can help guide you through these construction methods in greater detail.
Applied Copy and Raster Braille on Acrylic Substrates
This is an additive process of manufacturing using acrylic or other materials as the substrate background. The “raster braille” process is a rotary engraving method for creating tactile braille. It involves drilling high tolerance holes into the acrylic substrate then inserting spheres into the holes to create raised braille dots. The spheres, also called “rasters,” are produced from materials such as plastic, metal, or glass. Raised copy is accomplished by laser cutting engraving materials that are adhered to the surface of the acrylic substrate with Very High Bond (VHB) adhesive materials.
A rotary engraver is used to drill braille holes into the sign face. Raster braille beads are inserted in the holes creating a high tolerance, friction-fit bead which protrudes 1/32” above the sign surface.
A laser is used to cut lettering and numbers in the surface applied adhesive backed material. Excess material is removed leaving the 1/32” high raised text and numbers.
Examples of completed Raster Braille signage.
The overall process is efficient, and the resulting dots are uniform in size and appearance with the signs produced at an economical price point. Traditionally these products are found in offices and medical facilities where the buildings have less public access and sign vandalism is less of a concern
Because of the ability to paint both subsurface and first surface of the acrylic material along with the use of digital printing in the same manner, this method of sign production provides design options with maximum flexibility.
Photopolymer
This is a subtractive manufacturing process. The substrate is a ultra violet (UV) sensitive PETG plastic produced by Nova Polymers. A photographic negative of the sign copy and braille is created, then placed over the Nova substrate and exposed to UV light resulting in the removal of the background to a 1/32” depth. After the exposure process the sign is cleaned and prepared for finishing. This process produces raised text and braille elements that are integral with the sign surface making it more difficult to remove or vandalize the tactile components of the sign.
Film negatives are placed over PETG with polymer material coating and placed into the photopolymer processing machine to be exposed to UV light. The unexposed, water soluble material is washed away, leaving 1/32” high raised text and braille.
After removing the signs from UV exposure processing machine , the signs are flushed with water leaving the exposed and hardened raised text and braille.
Processed sign blanks are cut to size using a CNC router table with camera registration to achieve correct size and registration.
Individual signs are finished painted with surface applied Matthews brand polyurethane paint.
Raised text is “tipped” with catalyzed screen ink to provide a contrasting color to the sign background. A protective clearcoat finish is applied to the completed sign for added durability.
This product has been a mainstay in education facilities for decades where vandalism (“or picking”) at signs is a concern. Photopolymer materials remain clear after the processing of the raised graphics enabling the finish paint color and printed graphics to be applied to the sign face or subsurface for added durability.
Breaking the Mold
For decades raster braille and photopolymer signs were the go-to standards for the vast majority of all needed ADA signs. Just like the cassette player in your car turned to CD’s and then to streaming media; ADA sign making has also evolved. Today we have two new processes that provide options in manufacturing. These methods offer several durability and aesthetic design alternatives to the two traditional methods. Once again, one is integral/ subtractive construction, and the other is additive in the manufacturing process. The integral type is thermoformed acrylic and the additive process is UV tactile printing. Here’s the breakdown of each manufacturing method.
Thermoformed Acrylic
These signs are made of a single solid sheet of durable acrylic. A custom mold is machined with the raised copy and braille in a sacrificial phenolic material. This durable mold is capable of withstanding the extreme heat and the pressure applied as the acrylic is heated and pressed into the mold. This results in the acrylic forming into the copy and braille portions of the mold and the background compressing slightly.
CNC routers precisely mill out a phenolic mold material as the first step of the thermoformed process.
At the Thermoform press, the pre-cut phenolic molds and acrylic sheet are set in place. The press is heated and acrylic plate is pressed into the mold under extreme pressure.
Once cooled the acrylic is removed from the mold, leaving the one piece plate with raised copy and braille.
Examples of finished thermoformed signs with surface applied finish paint and contrasting screen ink applied to the top of the raised letters.
The formed product is an extremely durable sign that offers vandal resistance greater than photopolymer and can be used interior and exterior applications. Again, finish options are available in both first surface and subsurface versions.
UV Tactile Printing
The latest and perhaps most promising of ADA sign manufacturing is Ultra Violet (UV) tactile printing. Think of this as 2-½ D printing. Through a combination of proprietary software and inks, a flatbed UV printer is used to build up ADA compliant depths of ink for the raised copy and braille. This is not your standard flatbed digital printing process. Special inks are used to create the best bond to the base substrates that have been carefully pretreated with an adhesive promoter. The resulting raised graphics offer a step up in durability from surface applied raised text and in many applications, a product that will stand up in a high vandalism environment.
As with the other manufacturing methods this process offers great design options for both first and second surface graphics. The UV flatbed printer can lay down very detailed artwork at the same time the raised text and braille are printed. In addition, many decorative wood and metal laminates work well when UV printed tactile graphics are added to the surface of these attractive and unique materials.
A UV flatbed tactile printer provides layers of print ink resulting in ADA compliant raised text and braille. The material surface is prepared with an adhesive promotor that assures a high bond of the print ink to the sign surface. Signs of multiple colors and messages can be printed in the same run adding to the flexibility and efficiency of this production method
Examples of UV printed signs. This process allows for many artistic options and a very durable sign finish.
UV tactile printing has quickly gained popularity with both designers and manufacturers, but it takes a competent manufacturer to understand the preparation and ink selections needed to produce a durable product.
Signing Off
For someone just entering the ADA sign market the various construction methods, design options and available materials might seem a little overwhelming. As your wholesale interior sign partner, Park Place Sign Systems can help you determine what type of ADA sign construction is appropriate for your particular project and make the process as easy as….ABC.
This article was created as a collaborative effort between Park Place Sign Systems and JD Hamilton.
JAMES DEAN HAMILTON has been writing for Sign Business and GraphicsPro magazines since 1995. With over 30 years of experience, he has a vast knowledge of everything signage, marketing, and workflow management. His website is www. jamesdean130.com and he can be reached at jamesdeanjdh@gmail.co
