Pad printing is an offset printing process where ink is transferred from a cliché to the required component via a pad. Bringing together a blend of consistency, repeatability, and durability, pad printing can help you achieve intricate patterns and designs. While most decorative techniques such as screen and lithographic printing require a flat surface, pad printing is one of the very few processes that is well suited for decorating gently curved, irregular, textured, and/or cylindrical surfaces. Predominantly seen in the automotive, electronics, appliance, personal care, and medical industries, pad printing is often chosen for applications that will endure significant handling and need to withstand the test of time.
Custom pad printing process
Our latest video was created to not only equip you with the essentials of pad printing, but also to walk you through the step-by-step pad printing process.
- The artwork is etched onto the cliché (flat plate), and ink is deposited into the etched recess.
- A silicone pad picks up the inked image and descends onto the part to transfer a clean, crisp, and lasting image.
- The pad is pressed on a polyester film to remove any excess ink. Comprising of a low-tack pressure-sensitive adhesive, the polyester film removes any residual ink from the pad prior to the next printing cycle.
From standard to programmable multi-axis printers, the video below offers a glimpse into the different pad printing presses utilized at GM Nameplate (GMN). Armed with a rotating fixture, the programmable multi-axis printer is capable of numerous hits in multiple color combinations on different axes, all in a single set-up. This capability eliminates the need to transfer the part manually from one station to the other, resulting in significant time and cost savings.
Pad printing on different substrates
Pad printing is compatible with a broad range of substrates including stainless steel, polycarbonate, polyethylene terephthalate (PET), glass, polyvinyl chloride (PVC), acrylic, and acrylonitrile butadiene styrene (ABS). Very few plastic materials such as low (LDPE) and high-density polyethylene (HDPE), and polypropylene aren’t cohesive with pad printing inks and require a pre-treatment to ensure good adhesion.
Pad printing considerations
For every project, custom fixtures are designed and built to register the component to the pad printing head. The alignment of the ink pad with respect to the size and geometry of the part is specifically engineered to ensure exact registration. As seen with the Nissan badge in the video, the pliability of the silicone pad allows for printing with extreme precision, preventing the ink from coming in contact on the inside walls of the recessed letters. Maintaining the viscosity of the ink is extremely crucial to ensure the ink deposition accuracy and consistency. While the ink needs to be fluid enough to deposit on the substrate, it should not bleed out of the impression area. Thinners and adhesion promoters can be added to inks to achieve the desired viscosity level. Most of the inks used for pad printing at GMN are air-dried and are usually cured in conveyor ovens. Several other factors including the shape, material and durometer of the pad, location and color of the etched artwork, and tilt of the ink pad, are critical to the success of any project.
To see the pad printing process in action, watch our video here.
In our previous blogs in the bonding technology series, we discussed air gap and liquid optically clear adhesive bonding. Today, we will be presenting the final article in the three-part series focused on GMN’s bonding capabilities: optically clear adhesive (OCA) bonding. The most recent of all of our bonding processes, OCA bonding is quickly gaining popularity in several industries.
What is optically clear adhesive (OCA) bonding?
Rigid-to-rigid vacuum OCA bonding is a cutting-edge technology that allows GMN to provide thinner bond lines and as a result, thinner overall stack-ups. OCA bonding employs the use of a dry film pressure-sensitive adhesive to adhere layers together. For adhering two rigid components, a vacuum chamber removes all air from the part and applies the components together with optimum optical clarity, without forming any bubbles. OCA can also be used to adhere a non-rigid component (such as an overlay) to a rigid component, in which case a roller carefully pushes out all of the air between the two layers.
Why choose optically clear adhesive (OCA) bonding?
The main advantage of this bonding technology is the thinner bond line. Whereas liquid optically clear adhesive (LOCA) bonding can achieve a bond line between .015” to .030”, OCA bonding can get even smaller, achieving a .005” to a .008” bond line. This bonding capability is well suited for thin components including cover glass, touchscreens, and frameless LCDs.
Another advantage of optically clear adhesive bonding is that no curing is needed. Whereas LOCA bonding requires curing the liquid adhesive, this isn’t necessary for OCA bonding because a sheet adhesive is used instead. Using a sheet adhesive also allows the OCA bonding to provide a tighter tolerance and as a result, a consistent and flat bond line.
While there are several benefits to using OCA bonding, it may not be suitable for all applications. Unlike with LOCA bonding, optically clear adhesive bonding results in a bonded adhesive that cannot be reworked, which can result in lower total manufacturing yields and less room for error.
GMN is very excited to offer a wide variety of bonding options to meet every project need. Learn more about the process behind OCA bonding by watching our video below.
Read our other blogs in the bonding series:
In our previous blog, we discussed the benefits and drawbacks of air gap bonding. In the second blog of our three-part bonding technologies series, we will focus on the most widely used bonding capability at GMN: liquid optically clear adhesive (LOCA) bonding.
What is liquid optically clear adhesive (LOCA) bonding?
As the name suggests, this process involves bonding parts of the stack-up together with a liquid adhesive. Instead of leaving a gap between components as with air gap bonding, the clear adhesive fills in the entirety of the space between the two layers. Primarily used when bonding two rigid materials, LOCA bonding is typically chosen for its increased impact resistance, sunlight readability, and optical clarity.
For each display, GMN’s engineers develop custom fixturing to fit the precise dimensions of the components. A program is then designed to find the proper amount of adhesive and optimal dispensing pattern which is unique to each assembly. Highly precise metering equipment then dispenses a consistent amount of the liquid adhesive specific to the fixturing and program.
LOCA bonding takes place in a class 10,000 clean room and the adhesive is UV-cured. Lastly, GMN employs a series of sophisticated test and inspection methods to ensure quality control.
Why choose liquid optically clear adhesive (LOCA) bonding?
LOCA bonding technology is highly regarded due to its strong overall performance and high level of impact resistance. To see the strength of a liquid optically bonded display in action, watch our ball drop test comparing LOCA bonding to air gap bonding.
Another major benefit of LOCA bonding is the optical clarity, which is achieved due to the liquid adhesive not allowing any air gaps to form in the stack-up. LOCA bonding is also a popular solution because it is a re-workable process. If needed, components can be salvaged and re-used, increasing overall manufacturing yields.
LOCA bonding is a robust technology that GMN has been providing for more than a decade. GMN leverages proprietary processes and adhesives to provide the best bonding solutions to our customers. To learn more about this unique bonding process, watch our video below.
Read our other blogs in the bonding series:
As displays become omnipresent in today’s world, display and touchscreen performance are becoming critical considerations when designing devices. A typical display is composed of many layers such as cover glass, a touch panel, and/or an LCD, that are combined to help the display function properly under its intended condition. GMN combines these separate pieces together using high-grade adhesives and unique bonding technologies.
As a front panel integrator, GMN offers three bonding technologies to help customers develop the ideal construction and stack-up of display components - air gap/framed adhesive, rigid-to-rigid liquid optically clear adhesive (LOCA), and rigid-to-rigid optically clear adhesive (OCA) bonding. These bonding solutions serve a wide range of industries, including medical, military, automotive, instrumentation, and industrial controllers.
We will discuss the benefits and challenges of each of these bonding technologies in this three-part blog series. To begin, we will be reviewing our original bonding capability – air gap bonding.
What is air gap bonding?
Air gap bonding uses a framed adhesive gasket that goes around the perimeter of the layers, leaving behind a small air gap within the stack-up. As there are no liquid adhesives to dispense or curing times, air gap bonding is significantly lower in cost than other bonding options.
Why choose air gap bonding?
Cost-effective and lightweight, an air gap construction is a popular solution for applications with no readability or impact-resistance requirements.
While the lower cost is a benefit, this construction can present a few challenges. When the layers are integrated with a gasket and an air gap is formed, it can affect the clarity of the screen in bright light due to additional light refraction. The inclusion of the air gap also causes the product to be more susceptible to moisture damage and breakage, so it isn’t ideal for outdoor applications or harsh environments.
To learn more about air gap bonding, watch our latest video.
Read our other blogs in the bonding series:
Diamond carving, also known as diamond drag engraving, is a common metal decoration technique that enhances metal components by adding a unique texture. Performed at the back-end of the manufacturing process, this technique creates extremely fine, sharp, and crisp lines on an embossed aluminum surface, which cannot be achieved through any other decoration process. These deeply carved lines on the metal surface also provide a tactile feel, further augmenting the appearance of the component.
Decorative enhancements if any, such as screen printing or brush finishing, are always applied to the metal before the carving process. Once the aluminum sheet is decorated, the area to be diamond carved is embossed or raised to a height ranging between 0.015” to 0.018”. The embossed sheet is then cut into strips and held in-position on a flatbed table by vacuum. The strips are lubricated with oil to enable smooth and uniform engraving of the metal without galling. The strips are fed into a machine that consists of a large 12” rotating wheel, also referred to as the platinum. A small industrial-grade diamond chip, approximately 0.125” in diameter, is mounted to the platinum. As the wheel spins, the diamond chip abrades the aluminum surface with every rotation, thereby creating parallel lines at a depth of 0.003”. Diamond, being the hardest mineral, works flawlessly to create the desired pattern. In addition, the height of the wheel from the flatbed table can be adjusted vertically to compensate for metals with varying thicknesses and/or embossing heights.
The spacing between the lines is determined by the speed of the wheel. The slower the speed, the broader the gap between each line, and the faster the speed, the lesser the gap. The number of lines per inch and the angularity of the lines is often customized according to the design intent. The texture or pattern can vary from extremely fine textures that create a subtle shimmer to coarse lines that add a more jagged look.
While diamond carving has been a popular technique for several decades, GM Nameplate (GMN) brings a creative twist to the process. GMN’s expertise and capabilities allow you to apply a layer of transparent ink of any color to the diamond-carved surface. It not only adds a unique look but also retains the beauty and texture of diamond carving. The ink is always transparent to enable one to see the scribed lines below. Once the ink is screen printed, the ink is cured by baking the component in strip form.
Seen largely on electronics and handheld appliances, GMN has developed diamond-carved nameplates for numerous companies including Mitsubishi, Philips, Bose, and Lincoln. To see the diamond carving process in detail along with the various textures, patterns, and looks you can achieve with his metal decoration technique, watch our video below.
When it comes to custom manufacturing, prototyping remains an integral part of the design process. Whether you are testing the fit, form, and functionality of a new product, evaluating the feasibility of a unique material, or merely experimenting with novel ideas and concepts, prototyping services enable us to venture into new territories. The prototyping services at GM Nameplate (GMN) not only provide quick-turn solutions but also offer design support to help customers navigate a path towards production.
The prototyping solutions offered by GMN can be briefly divided into the following three types -
1) Quick-turn prototypes
Quick-turn prototypes, also known as rapid concept prototypes, put the focus on speed. This program aims to deliver a product into the customer’s hands as quickly as possible, which in turn takes them a step closer to production. Customers can assess multiple design considerations with accelerated lead times and reduced costs compared to full production parts. While rapid concept prototypes are not intended for qualification testing, they facilitate customers to experiment, refine, evaluate, and validate designs while making swift iterations. So, if you are looking to assess different material options for a gasket or compare a satin finish versus a gloss finish, then rapid concept prototyping is the way to go!
GMN has a dedicated product development team and manufacturing equipment that operates outside of regular production schedules, which helps us stay agile and accommodate varied needs. While developing prototypes, GMN utilizes digital printing for parts that will often use alternate printing processes in final production to remain cost and time-efficient. Similarly, for die-cut prototypes, GMN often uses materials specified for the final product but utilizes laser cutting and other “soft tooling” methods before transitioning to hard tooling for production. This allows customers to compare multiple design options without investing in the appropriate production tooling.
2) Conceptual development prototypes
Conceptual development prototypes focus on translating concepts into concrete solutions. This development process optimizes ideas to achieve a viable product by evolving designs towards production-friendly solutions. By letting us perform quick risk mitigation testing on new materials or designs on the front-end, it reduces unexpected challenges later in the design process. While this prototyping solution often comes into play while working with unique materials, it can also be helpful if a design is ahead of the technology curve. When a customer approaches GMN with unique material, we can address the unknowns associated with processing the material. This includes testing ink adhesion, verifying substrate compatibility with the manufacturing processes, optimizing processing parameters, and testing new design applications before engaging in larger production runs.
GMN’s customers bring a variety of cutting-edge products to market and the complex nature of these projects requires a focused and methodical approach to development. Conceptual development prototypes are often accompanied by a formal development proposal including a statement of work with discrete milestones that allow GMN to periodically regroup with its customers to determine the design or processing solution that best meets their needs.
3) Pre-production development prototypes
Pre-production development prototypes bring a design concept to a repeatable and robust production solution. Pre-production prototyping ensures that regulatory requirements, including Design Failure Mode and Effect Analysis (DFMEA), Process Failure Mode Effects Analysis (PFMEA), or Production Part Approval Process (PPAP), are met. Pre-production development prototypes emphasize on establishing process capabilities, improving yields, and optimizing designs for high-volume manufacturing. Since this approach utilizes all of the standard full-scale production equipment and process controls, it is best suited for products that are ready to transition into volume production and can be used for purposes such as final qualification and testing.
INIT, a leader in the public transit industry, was redesigning their ticket vending machine and wanted to revamp their current labeling system. Installed in transit stations throughout the country, the ticket machine contained eight separate recessed sections that provided important information on user inputs in both printed text and braille format.
The labeling system that they were previously using consisted of separate stainless-steel overlays affixed to the front of the ticket vending machine. While these were durable, they were expensive to manufacture and difficult to mount. Ideally, the customer wanted to maintain the same durability while cutting down on production costs.
As the machines were located across different bus and train stations, the overlays needed to be durable enough to withstand frequent interactions from hurried passengers, varied weather conditions, and other outdoor elements. The size and thickness of each part was also highly specified, as each overlay needed to fit precisely into a recess on the machine.
After experimenting with a few different materials, GMN’s experts concluded that constructing the eight separate overlays in polyester would be the best approach. Autotex polyester was not only available in the required thickness to fit the recessed sections on the machine, but also was a very durable material that could handle the outdoor environment. Each overlay was die-cut to the exact size required to fit the corresponding recess. A custom Lexan die-cut spacer was added to the rear side, along with two layers of 3M’s 467 and 468 adhesives for additional thickness and durability.
Once the material and adhesives were determined, the next challenge was figuring out the best way to print the text and braille characters. Due to the inclusion of braille, the printed characters had to comply with the strict standards of the Americans with Disabilities Act (ADA) in terms of reaching a certain height and maintaining adequate spacing and proportions.
GMN employed a unique digital printing process to create the raised characters to specification. As opposed to raising the characters via embossing, which can stretch the substrate and make it less durable, this specialized printing technique prints the letters with the deposition of solid ink. The use of this printing method not only raised and shaped the characters to precise proportions but also made them robust enough to endure outdoor conditions. After successfully passing several environmental tests, the new overlays made their way onto the ticket machines in transit stations across the United States.
Ultimately, GMN leveraged its labeling, die-cutting, and digital printing capabilities to deliver a custom solution that met all the project requirements. The durable and cost-effective overlays are currently in production in a few different colors and styles, with more variations in development. To learn more about GMN’s vertically integrated capabilities, visit our website here or schedule a free consultation with our technical experts here.
To ensure the success of any glass-printing application, there are numerous factors that go under consideration such as the glass type, inherent tint of the glass, ink type, ink color, curing process, and environmental conditions. However, one crucial factor that needs to be determined is the print method. Glass can be printed on using one of the three techniques - screen printing, digital printing, or frit printing. While all these methods support different shapes, sizes, thicknesses, types of glasses, and allow the use of multiple colors, there are unique pros and cons that distinguish them.
Screen printing on glass
Well-suited for a wide range of applications, screen printing is the most cost-effective and most dominantly used glass printing technique. It primarily utilizes two types of inks: enamel inks and UV-cured inks, both offering good opacity. UV-cured inks offer a larger color selection than enamel inks. Since every color requires a separate screen, the process can be time-consuming if the design has several colors involved. In most cases, the graphic features are printed on the rear side of the glass, which eventually gets sealed or bonded with a touchscreen or display. Except for the edges of the glass, the ink is almost never directly exposed to ambient conditions and corrosion. However, if the ink is not specially formulated for printing on glass, it can lose adhesion and begin to chip off very quickly.
Digital printing on glass
Digital printing on glass works like a regular inkjet printer, where all you need is a digital art file to print. It offers greater flexibility in terms of changing designs at the last minute. Unlike screen printing, where even the smallest design variation requires the construction of a new screen, modifying an art file for digital printing is extremely quick and easy. This makes it a great choice for prototyping and achieving faster time-to-market products. But it is important to note that the inks utilized for glass digital printing are thinner as compared to the inks employed in screen printing. Hence, while working with light or pastel shades, multiple layers may be required to achieve a sufficient level of opacity. This can lead to an increased thickness, posing challenges in the optical bonding process. In contrast to screen printing, where one color is printed at a time, digital printing also allows the printing of all the different colors at once. Digital printing on glass is currently undergoing continuous developments to accommodate more types of inks.
Frit printing on glass
Frit printing is very similar to screen printing with the exception of the ink utilized and the curing process. A unique powdered-glass ink is screen printed on the glass and then cured during the heat tempering process. It causes the ink to fuse to the glass, thus offering strong adhesion and making it extremely difficult to remove or scratch the ink off. Since frit printing offers the highest durability out of all the techniques, it is chosen for demanding applications where the glass is regularly exposed to challenging environmental conditions such as in the defense, heavy industrial, and automotive sectors. However, it is also the most expensive printing method and therefore, not as frequently employed. One of the limitations of this method is that while frit printing can be done on heat-tempered glass, it cannot be utilized for chemically-strengthened glass and the glass thickness is limited to greater than 2mm. Frit colors are also limited to black, white, and some grays.
Bringing together the right mix of functionality and durability for your custom application, the experts at GM Nameplate (GMN) can not only help you select the most suitable printing technique for your glass application, but also support your glass printing and bonding needs from prototyping through production. To learn more about GMN’s bonding solutions, visit our capabilities page here.
Minimizing electrical interference is critical to a product’s performance, especially in highly regulated industries where excess interference from components can be disastrous or life-threatening. Excess electrostatic, radiofrequency, or electromagnetic signals can affect sensitive components, causing a multitude of issues or possible failure. Fortunately, there are several ways to mitigate the input and output of undesired electronic signals.
What is shielding?
Shielding is the process of preventing both the input and output of radiofrequency interference (RFI), electrostatic interference (ESD), or electromagnetic interference (EMI) from impacting the proper functioning of electronics. It is typically done by the addition of a sprayed, adhered, or molded metal to help absorb the interference. The metal is connected to the ground plane, where any excess inbound or outbound electronic signals are pulled to ground to avoid damaging sensitive internal components.
Below, we’ll be going over common types of shielding for electronic components.
Common EMI/RFI shielding methods:
- Metal cans: One of the most frequently used shielding methods, formed aluminum cans or covers are added over computer chips on the circuit board. Each can contains small extensions at the bottom which go through the board and connect to the ground plane. Given aluminum’s excellent conductivity and the ease of adding metal cans after production, this is an effective option for covering any hotspots that may have been missed and emanate interference.
- Aluminized mylar: Typically one of the least expensive options, aluminized mylar consists of a thin sheet of mylar coated with aluminum. The sheet is die-cut and adhered to the inside of an enclosure using an adhesive. The mylar is connected to the chassis ground to effectively absorb and dissipate electronic interference.
- Screen-printed conductive ink: For a wide variety of substrates, a popular option is to use screen-printed conductive ink. The ink is printed around the perimeter of an enclosure to absorb excess interference. The ink is then connected to the chassis ground where any absorbed EMI, RFI, or ESD signals are pulled to ground. For substrates where screen printing may be difficult, the ink can also be applied via spraying or pad printing.
- Vacuum deposition: As an alternative to pre-formed aluminized mylar or screen-printed inks, vacuum deposition can be used to coat the inside of an enclosure, creating a thin layer of metal on the substrate. This layer of highly conductive metal blocks EMI, ESD, and RFI signals, pulling them to ground. This shielding method is typically used for plastic enclosures or irregularly shaped enclosures where it may not be ideal to print conductive ink.
- ITO films and mesh: Indium tin oxide (ITO) films and meshes are frequently used to provide shielding on displays. Applied directly to the glass or plastic, ITO films are almost see-through. The high level of transparency and conductivity allows displays and touchscreens to maintain functionality while mitigating outbound and inbound electrical interference.
How to determine the right type of EMI/RFI shielding?
When it comes to finding the right type of shielding, there are several important questions to ask. Is the product for use in a highly regulated industry such as military or medical, where EMI or RFI could be detrimental? Does the product need to adhere to specific industry standards to meet an acceptable threshold of incoming or outgoing signals? Is there a specific substrate where certain shielding methods may be ineffective?
Ultimately, substrate selection, part size, and even cosmetic requirements can be important factors in selecting a suitable shielding method. Different types of shielding are often mixed and matched to find the perfect solution.
To find out which shielding option is right for your next project, schedule a consultation with our experts.
Have you ever walked up to an ATM or gas pump and noticed the cracking, fading numbers on the keypad? It is a prime example of why the material selection is vital for graphic overlays. At GMN, the two most common materials used for graphic overlays are polyester and polycarbonate. Depending on the application, there are advantages and disadvantages to both materials.
When evaluating overlay materials, one of the most important factors to consider is durability. Polyester and polycarbonate are both extremely durable materials, but polyester is generally known as the more durable option. Polyester has a longer actuation life (over 1 million actuations vs. 200,000 actuations), meaning that it can endure more switch actuations before the overlay starts to crack or deform. As a result, polyester is a better choice for membrane switches and overlay designs that include embossed buttons. Polycarbonate has a broader thickness range and increasing the thickness of an overlay can help make it more durable. However, polycarbonate is best suited for applications with minimal flex requirements because continual flexing can cause stress fractures over time.
Polyester is also resistant to abrasion and significantly more resistant to acids and chemicals, making it an ideal substrate for the medical, industrial, and appliance industries. While polyester is flammable, polycarbonate is flame retardant, making polycarbonate perfect for industries in which safety is of high importance, such as the aerospace industry. Alternatively, a hard coating can be added to significantly improve the durability of both materials.
While polyester has an edge in terms of durability, polycarbonate has some cosmetic advantages over polyester. Polycarbonate offers a broader range of textures and finishes, which can be attractive when the design is the most crucial factor. It also has very high clarity and color brilliance. If an overlay is being used purely for appearances and won’t be exposed to frequent use, polycarbonate may be the most appropriate substrate choice.
In terms of production, polycarbonate tends to process easier than polyester. It’s easy to print effectively on polycarbonate of all thicknesses. Polycarbonate is also easier to die-cut and emboss, which can help to reduce manufacturing costs. While polyester is slightly more expensive than polycarbonate, the cost difference between the two materials is minimal.
Ultimately, the choice between the two materials will depend on the overlay’s design requirements and environmental conditions. To see how polyester and polycarbonate compare, visit our graphic overlays page or watch the video below.