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.
When a California-based medical company was assembling its new infusion pump, they knew it was critical for every part to work perfectly and be free of defects. One of the most important parts was a custom rear housing that encases all of the internal components of the device. Having worked extensively with GMN in the past, they knew they could trust our team with the production of this vital component.
The housing was complex, featuring an injection-molded plastic casing, 15 separate brass inserts, electromagnetic shielding, and a latch closure. While each component was inspected at various stages of the production process, given the complexity and the assortment of components involved, it was still possible for an issue to be overlooked. While it was rare, this occasionally resulted in a defective part making it through to the next phase of production, where it would be flagged and removed from the production line. Upon further analysis, it was discovered that these occasional defects stemmed from the improper positioning of the brass inserts. Even a single missing or misaligned insert could cause issues during assembly.
To resolve this issue, the experts at GMN decided to implement a custom vision inspection system. This vision system would automate part of the inspection process, lowering the total possibility for error as well as making the production process more efficient. After some experimentation, the team ultimately decided to integrate the inspection system directly into the heat stake where the brass inserts were positioned and inserted.
The vision system consisted of two cameras located directly above the platform where heat staking took place. This allowed the system to verify the presence and proper alignment of all the brass inserts before being injected into the assembly. As a secondary measure, the vision system checked the alignment of the inserts after they were heat staked into the housing.
After adopting the vision system, the defect rate dropped to nearly zero. It significantly reduced the production time, allowing more defect-free parts to be fabricated in the same time frame. The vision system has earned a permanent place at GMN’s Beaverton, OR plant to uphold the quality of the infusion pump housing.
This is just another example of GMN leveraging custom technologies to enhance the quality of its products and improve manufacturing processes. To find out how GMN can help with your next product, request a consultation with our experts.
FLIR, a global leader in thermal imaging camera systems, had developed a line of fixed-mount thermal marine cameras with a protective metal housing. However, their existing housing was not only heavy but also expensive and time-consuming to manufacture. Looking to re-design the metallic housing, FLIR approached GM Nameplate (GMN) for an alternative solution.
As the housing remains an integral part of the thermal camera system, it would be repeatedly exposed to challenging surroundings including ultraviolet rays, seawater, and high winds. Keeping the severe outdoor conditions in mind, GMN proposed to replace the metal housing with a robust, industrial-grade plastic that can endure prolonged marine use and environmental damage. Additionally, plastic is not only cost-effective but also seven times lighter than metal and faster to fabricate. The housing was fabricated via injection molding at GMN’s Beaverton, OR division.
FLIR’s original design also comprised of a chrome-plated logo attached to the metal housing with hooks. The hooks were attached to the metal via heat staking, a process of melting metal to create a bond. However, the seal formed via heat staking was not airtight, causing unwanted water to seep through the crevices and gradually oxidizing the metal hooks and housing. To resolve this sealing issue, GMN switched the original chrome-plated logo with a 3D electroform logo. This unique metal decoration technique deposited nickel and chrome directly on the desired form to create a high-quality, corrosion-resistant, three-dimensional logo. The distinct logo was brought to life at GMN’s Monroe, NC division and adhered to the plastic housing with a pressure-sensitive adhesive. Offering extremely high durability and visual appeal, the finished product flawlessly married plastic with metal.
GMN brought together two of its core capabilities and manufacturing locations (metal decoration at Monroe, NC and plastic injection molding at Beaverton, OR) to effectively meet the needs of the program. Following the successful completion of this project, FLIR returned to GMN to develop both a smaller and larger housing for a similar camera line.
To learn more about plastic decorating capabilities and value-added assemblies, visit our website here.
While plastic injection molding remains the cornerstone of GMN Plastics, plastic machining is one of the many complementary capabilities offered to our customers. With a dedicated area and automated equipment for machining, GMN Plastics can machine parts up to 20”x40” in size. But how does plastic machining benefit our customers? Plastic machining is ideal for secondary machining of injection molded parts. For parts that need to be modified to create a unique part number or multiple from a host molded part, machining is a cost-effective solution to minimize the cost of the tool.
Some of the core advantages of plastic machining include –
- Lowered cost – Depending on the order quantity, utilizing machining over a tool can result in significant cost savings. For instance, machining can eliminate the need for tooling in lower volume projects, thereby reducing non-recurring engineering (NRE) costs.
- Quality control – Machining provides with greater control over part quality and production process. By eliminating the need to sub-contract machining and performing it in in-house, machining has allowed GMN Plastics to reduce paperwork and handling charges.
- Fine trimming and de-gating – Most plastic parts, especially from highly regulated industries such as medical and aerospace, require a smooth finish. Machining can be used to remove the gate from an injection molded part, making the surface smooth and gate-free.
- Taping holes – Machining offers the ability for holes to be taped rather than using an unscrewing tool. While it’s not only cost-effective for lower volumes, it also allows for better control of threads and holes.
There are several factors to consider while deciding between tool and machining. While machining may eliminate the tooling cost, it increases the price per part. So, depending on the volume, tooling may be more affordable. But if you need to change an existing part, secondary machining may be the process of choice.
Currently, GMN Plastics serves customers in nearly every industry with its machining capabilities. To determine if this is a good fit for your next project, request a consultation with our plastic experts.
This blog is the third in our series on statistical process control (SPC). In the previous blogs, we discussed the basics of statistical techniques and process capability indexes. In this blog, we will be focusing on control charts and their core benefits in the manufacturing landscape.
The control chart is a very helpful tool in identifying unwanted variation in a production process. The goal of statistical control is to identify process variation and to determine which variation is beyond our control. While some variations are inherent to the process, others are special or assignable. These deviations are outside of the “normal” variation that we typically see in a process. It can be identified using statistical tools to be reduced or eliminated from the normal process.
To understand control charts, let’s first discuss variation. In a perfect world, there would be no variation. Whenever we turn on a machine, it would produce the exact same part every time. However, we don’t live in a perfect world - machines fail, internal parts abrade, molding tools wear out, temperatures change, and materials subtly change from one production badge to the other. There are several inputs to a given production process that must work together to produce parts that meet customer requirements. By measuring key characteristics of the finished part, we can evaluate the manufacturing process. Using control charts, we can identify inherent variations from special variations (e.g. an injection mold wearing off or an improper machine setting). By eliminating these unique discrepancies, we can return the process to “normal”.
The two types of control charts that are regularly used at GMN Plastics are individual charts and x-bar R charts. As seen in the below example, both these charts feature two elements – 1) a center line which is the mean (average) for the particular data set being studied, and 2) upper and lower control limits which are statistically calculated from the same data set. Measurement data for key characteristics are collected and entered at regular intervals over time.
The control limits, calculated statistically, represent plus/minus three standard deviations from the average (mean). These lines represent the threshold at which the process output is considered to be statistically “unlikely”. In other words, the control limits represent the division of the natural variation of a process from the “unlikely” variation, occurring due to special or assignable causes, that can be eliminated from the process. Data points that appear outside of these control limits or unusual data runs (data increasing or decreasing over six or more successive measurements) should be investigated to determine and eliminate the source of the assignable variation.
One of the biggest advantages of identifying and addressing variations early in the production cycle is to prevent problems before any out-of-specification parts are produced. It maximizes machine and material efficiency, which in turn lowers production cost and time. The various statistical tools employed by the process engineers at GMN Plastics continue to play a pivotal role in meeting customer demands and consistently building high-quality parts.
This blog is the second in our series on statistical process control (SPC). In the previous blog (read here), we learned about the fundamentals of statistical tools and techniques. In this blog, we will be focusing on one of the most commonly employed statistical tools in the manufacturing industry – process capability indexes (Cpk).
Process capability index is an indicator of how the production process is performing with regards to key process control parameters and customer specifications. Besides the obvious reason of satisfying customer requirements, there is another reason to develop and use capability indexes. They can be critical predictors of future performance and a robust method of measuring the ability of production processes to produce high-quality parts consistently.
The letter “C” in SPC stands for control. But, what are we controlling? Statistical analysis of a production process is all about controlling and reducing variation in the process. It aims at identifying and separating the natural causes of variation, that are inherent to the process, from the special or assignable causes that can be controlled, adjusted, and/or eliminated. Process capability is the ability of a process to produce a product that is both accurate and precise. The accuracy and precision of a set of measurements can be illustrated as follows:
Cpk takes into account both the accuracy and the precision of the measurement around the average. Statistical software takes measurement data and shows the process capability as a single number that represents the process’ ability to provide both – an accurate and precise product. At GMN Plastics, we aim for a Cpk of 1.33 or greater for most of our customers. The core benefits of creating a process that delivers high-level capability include optimizing manufacturing time and materials, reducing scraps and re-work, and equipping the production system to create more products in the least amount of time possible.
Ultimately, process capability is all about creating products that meet customer specifications with a minimum variation over time. Stay tuned to learn more about control charts in our next blog. Until then, check out our other blog on Qualification process: Four parts to ensure part consistency.
As customer needs become more nuanced, it is incumbent on us, as injection molders, to continually innovate and improve our processes to meet their evolving demands. The tools of statistical process control (SPC) are critical in understanding process capabilities, identifying unwanted variations, and refining manufacturing processes. Overall, it enables us to efficiently and consistently meet our customer’s sophisticated needs for quality, lead time, tolerances, delivery, and cost.
Primarily developed by Walter Shewhart at the Bell Labs in 1920s, statistical techniques have been around for decades. Competitive companies worldwide have implemented a wide array of statistical tools to help reduce costs by mitigating scraps, re-work costs, and variances in production processes. These tools range from simple graphing to more complex analysis including Pareto analysis, histograms, capability analysis, fishbone charts, and control charts.
In recent times, advanced statistical software has made “data crunching” easy and efficient. At GMN Plastics, it provides us with a quick overview of how our injection molding processes are performing by analyzing data from internal product characteristics and/or customer-driven product features. This data can be viewed in several forms - as a line graph (Individuals data charting), or by stratifying data into a histogram (including process capability indexes), or a control chart (typically x-bar/R). These tools allow us to understand process conditions and provide actionable data to our engineers in the event of an unforeseen production issue or bottleneck.
We, at GMN Plastics, work with a broad spectrum of part sizes, shapes, forms, and complexities every day. When manufacturing a wide array of components for diverse customers and industries, it is critical to identify machine capabilities and production processes. Being able to make prompt decisions based on statistical data, developed during both initial qualification and in-process production, gives us flexibility in production and allows us to develop sound process controls.
In our upcoming blogs, we will discuss two of the most commonly used statistical tools at GMN Plastics – capability indexes (Cpk) and control charts. Until then, stay tuned and visit our website to learn about our plastic manufacturing capabilities.
There are several factors that dictate the type of mold or tool that is best suited for producing complex injection molded plastic parts. Understanding the requirements for part design, material type, and product life cycles are essential to evaluating and selecting the optimal mold type. In order to define standards for injection mold construction and corresponding life expectancy, the Society of the Plastics Industry (SPI), now known as the Plastics Industry Association, has established the following mold classifications -
1) Class 101 - This class of tooling offers the highest quality molds compared to its counterparts. When production exceeds one million cycles, Class 101 is chosen for its ability to support high volumes. Designed for extreme durability, the mold base is made with heat-treated stainless steel that is hardened to a minimum of 280 BHN. Other molding surfaces, including the cavities and cores, also offer very high wear resistance and can withstand resistance from abrasive additives in the plastics.
2) Class 102 - Supporting medium to high production volumes (ranging from 500,000 to 1 million parts), Class 102 molds work best for abrasive materials and/or parts requiring tight tolerances. Similar to Class 101, the mold base and surfaces under this classification are also made with heat-treated tool steel to effectively combat premature wear and tear.
3) Class 103 - Class 103 tooling is typically made with P20 steel and is commonly used for low to medium volume programs, ranging between 250,000 and 500,000 cycles. While only some tools are heat-treated for wear resistance, the mold base is made with a minimum hardness of 165 BHN. Since the base is softer as compared to Class 101 or 102, these tools aren’t recommended for fabricating parts with stringent tolerances. Striking a balance between quality, performance, and cost, Class 103 molds usually fall within the average price range.
4) Class 104 - Moving a degree lower, Class 104 tools are good for manufacturing parts with non-abrasive materials. With the mold base and cavities constructed of either mild steel, aluminum, or alloys, this classification supports low-cost projects and low-volume production, not exceeding 100,000 cycles.
5) Class 105 - Known as prototype tooling, Class 105 is suited only for quick-turn prototypes or volumes under 500 cycles. The molds are made with extremely fragile materials including soft aluminum, epoxy, cast materials, or any other alloys suitable to produce minimum quantities. These tools exhibit accelerated wear and tear, low strength, and minimal durability.
While GMN Plastics utilizes class 101 through 103 for the majority of its production, it usually steers clear of Class 104 and 105 tooling. Utilizing the above SPI mold classification to determine the correct mold type for your project is crucial to ensure process repeatability, minimize production downtime, and reduce defects and scrap rate. With extensive experience and technical know-how, the engineering team at GMN Plastics can help guide you through the unique parameters for each classification to select the best mold type to meet your quality, production, and cost objectives. To learn more about our tooling and tool room services, visit our website here.
A US-based customer of GMN was designing an electrical connection between two plastic housings for an outdoor application. In order to establish the connection, it was vital to achieve a permanent, air-tight seal between the two housings. Given the nature of the design, even the slightest ingress of moisture or foreign particles would hinder the optimal performance and durability of the product. Hence, shielding the seal from dust and water was critical. Additionally, the seal also needed protection from extreme temperatures and flames.
Originally, the customer utilized a bead of silicone (silicone rubber paste) on the edges of the two housings that hardened over time to form a seal. However, this approach presented several manufacturing challenges and shortcomings. Dispensing a uniform layer of silicone rubber was not only cumbersome, but also inconsistent, leading to an uneven bond line. As the paste became rigid upon drying, it formed a seal that was susceptible to breaking under stress, thereby producing cracks and weakening the bond strength. The drying and curing of the silicone rubber paste also spiked up the processing time, creating a bottleneck on the assembly line.
The customer approached GMN to achieve a better form-fitting solution to prevent moisture ingress. After learning about the environmental conditions that the seal was required to withstand, GMN proposed a custom-fit Roger’s BISCO® silicone foam gasket. From the extensive range of BISCO® silicones available in the market, GMN narrowed it down to HT-800 family to strike the right balance between seal-ability and compressibility. As a Preferred Converter of Rogers Corporation, GMN delivered a high-performance solution with accelerated lead time and competitive pricing.
Roger’s BISCO® silicone, with its high flame resistance, seamlessly fit the needs of the project. In addition to excellent viscoelasticity, it provided high dimensional stability and sealing capability. Contrary to the previous solution, BISCO® silicone foam does not break under stress or pressure. It allowed for quick and easy application, eliminating the extra processing time associated with bead of silicone.
Although, selecting the right material wasn’t enough. Creating a custom shaped gasket to fit the exact configurations of the housings was equally important. Since the customer had initially planned to utilize silicone paste, they did not have the dimensions of the housings readily available. Based on the customer’s sketch and 3D file of the housings, GMN developed a CAD file for the laser tool to fabricate the gasket. By flowing into every nook and cranny of the surface area, the gasket flawlessly married the two housings together to achieve an enhanced seal.
With the help of GMN’s dedicated rapid prototyping team and equipment, we then created two distinct prototypes of custom BISCO® silicone foam HT-800 gaskets in two different thicknesses and durometers. It enabled the customer to test compression and seal strength of the two different gaskets and choose the most optimal solution.
GMN’s ability to determine and source the right material and create a tailored-fit gasket allowed the customer to meet the functional requirements of the project without compromising on the aesthetics. Given our extensive experience and technical expertise with die-cut components, customers can truly rely on GMN to efficiently provide quick design fixes and improvements.
GMN is welcoming the new year with exciting changes! Effective today, we are rebranding Elite Plastics to GMN Plastics. In addition to unifying the company’s different brands (GMN Aerospace and GMN Automotive), the new name and logo will continue to put the focus on our plastic services, while also reflecting the full extent of the vertically-integrated capabilities and solutions that GMN can provide.
This rebranding initiative has allowed us to reflect on all the successes we have celebrated as “Elite Plastics”, and everything we aspire to achieve as “GMN Plastics”. We hope to embark upon a new journey in the growth of our plastics capabilities and services under the new brand name, GMN Plastics.
To learn more about the rebranding, read our press release here.