The ASSEMBLY Show featured not only the machinery needed to assemble parts, but also the supplies, such as adhesives.

For example, 3M Industrial Adhesives and Tapes displayed its new Scotch-Weld acrylic adhesive DP8425NS and Scotch-Weld low-odor acrylic adhesive DP8825NS. Once mixed, these two-part structural adhesives have a work life of 25 minutes, but they reach handling strength in 45 minutes and structural strength (1,000 psi) in 50 minutes. That means less clamp time and greater efficiency. In addition, engineers can use the adhesives to bond large assemblies that were once thought impossible, because they won’t have to worry about switching out mixing nozzles or dealing with the difficult cleanup of a cured adhesive.

In addition to the extended work time and fast cure time, the new adhesives have an 18-month shelf life and a higher impact of resistance compared to conventional acrylic adhesives. These low-sag adhesives do not require refrigeration and are mixed at a ratio of 10-to-1.

When mixed, Scotch-Weld DP8425NS has a viscosity of 70,000 centipoise at 75 F. When fully cured, it has an overlap shear strength of 3,700 psi at 75 F and 800 psi at 180 F.

Scotch-Weld DP8825NS is a nonflammable, low-order formula. When mixed, it has a viscosity of 80,000 centipoise at 75 F. When fully cured, it has an overlap shear strength of 3,000 psi at 75 F and 800 psi at 180 F.

The adhesives are available in 45- and 490-milliliter side-by-side cartridges, as well as 1-, 5- and 50-gallon containers.

UV-Cure Adhesive for Bonding Needles

Dymax Corp. manufactures light-curable adhesives, gaskets, coatings and oligomers, as well as light-curing equipment and fluid dispensing systems.

Among the new products on display at the Dymax booth was a UV-curing medical device adhesive, 1405-M-UR-SC. Curing at both 385 and 405 nanometer wavelengths, the adhesive has a low viscosity of 150 centipoise, making it ideal for tight-tolerance needle-bonding applications.

The adhesive is formulated with Encompass technology, which incorporates Dymax’s UV-curing, See-Cure color change and Ultra-Red fluorescing technologies. As a result, manufacturers gain efficiencies from rapid on-demand curing with easy cure confirmation and post-cure bond-line inspection.

While in an uncured state, the adhesive is blue in color for easy verification of placement. As the product cures with sufficient exposure to UV light, its blue color transitions to colorless and provides obvious visual confirmation that the adhesive is fully cured and the bond site is secure.

After cure, the adhesive fluoresces bright red under low-intensity black light (365 nanometers), contrasting well on plastics that naturally fluoresce blue in color (like PVC). This allows manufacturers to incorporate automated or manual quality inspection to verify complete and accurate placement of the adhesive after cure.

The product is also available in a high-viscosity (7,000 centipoise) version, 1405M-T-UR-SC, offering excellent dispense control for larger bond gaps.

Both products are suitable for bonding stainless steel, polycarbonate, acrylic and ABS.

Structural Methacrylate Adhesive

Hernon Manufacturing Inc. makes high-performance adhesives and sealants; precision dispensing equipment; and LED UV-curing equipment.

The company’s catalog of adhesives includes Fusionbond 370, a two-component methacrylate adhesive for structural bonding of thermoplastics, metal, wood and composite assemblies. It is an excellent choice for composite bonding applications in the marine, automotive and construction industries, because it requires virtually no surface preparation. The adhesive provides superior toughness at temperatures from -100 to 250 F.

The 100-percent solids adhesive is mixed in a 1-to-1 ratio by volume. It resists fatigue, impacts and salt spray. It has good gap-filling ability (0.38 inch) and can bond dissimilar substrates.

Working time ranges from 10 to 15 minutes, and fixture time with steel parts ranges from 10 to 15 minutes. When fully cured, it has a shear strength of 3,000 psi on steel, 2,000 psi on aluminum, 2,520 psi on PVC, and 620 psi on ABS.

Fluorescent Cyanoacrylate

Palm Labs Adhesives manufactures cyanoacrylate, anaerobic, and structural adhesive products, including primers, accelerators, debonders, threadlockers and anti-seize products.

Among the new products on display was Turbo Fuse 130FY, an advanced-formula cyanoacrylate (CA) that bonds quickly at room temperature by absorbing surface moisture. Equally important, it glows yellow when exposed to ultraviolet light—enabling manufacturers to perform accurate high-speed visual inspection of bonded parts.

The one-part ethyl CA cures within 24 hours and has a viscosity of 100 centipoise and sheer strength of 3,000 psi. It withstands temperatures from -65 to 180 F and can be used on standard plastics, metals, elastomers and wood. The adhesive comes in standard 1-ounce bottles and other size containers.

Adhesives for Needle Bonding

Bonding dissimilar substrates is the primary challenge of needle assembly. Needles are almost always stainless steel, whereas the plastic housing could be any of a variety of substrates, including polycarbonate, nylon, ABS, or more exotic molded plastics. Cyberbond LLC has developed a variety of adhesives for bonding multiple substrates in needle assembly.

Among them is Cyberlite U306, a thixotropic, medical-grade, UV-curable acrylate adhesive that bonds well to glass, metal and various plastics. It combines high viscosity (20,000 centipoise) and hardness to make it an ideal potting compound, and it bonds well to both similar and dissimilar substrates. The adhesive is certified to the ISO 10993-5 standard for cytotoxicity.

This clear adhesive sets in less than 4 seconds when exposed to UV radiation of 50 milliwatts per square centimeter. It adheres to polycarbonate with a strength of 500 to 700 psi. It withstands a temperature of -55 to 120 C.

Another option for needle bonding is biocompatible cyanoacrylates: Apollo 2008, 2028, and 2240-05.

Apollo 2008 is a single-component, low-viscosity cyanoacrylate specifically formulated for all types of rubber bonding applications. This extremely fast-setting adhesive has a viscosity of 15 centipoise and withstands temperatures from -65 to 200 F. When bonding steel to steel, it has a tensile shear strength of 3,200 psi. It meets ISO 10993-10 and 10993-11 standards.

Apollo 2028 is a single-component, medium-viscosity cyanoacrylate for rubber and plastic bonding applications. It has a viscosity of 180 centipoise and withstands temperatures from -65 to 200 F. It meets ISO 10993-5, 10993-10 and 10993-11 standards. It bonds to metal in 12 seconds, rubber in 5 seconds and plastic in 8 seconds.

Apollo 2240-05 is medium-viscosity, rubber-toughened ethyl cyanoacrylate that provides superior shock and thermal resistance when bonding rubbers, metals and plastics in harsh environments. With a viscosity of 500 centipoise, the adhesive is highly resistant to heat and shock. When bonding steel to steel, it has a tensile shear strength of 3,400 psi. It bonds to metal in 35 seconds, rubber in 15 seconds and plastic in 10 seconds.

Flexible Epoxies

Permabond Engineering Adhesives is a leading supplier of cyanoacrylates, UV-cure adhesives, anaerobics, epoxies, modified epoxies, modified silane polymers, polyurethanes and structural acrylics.

The company has recently introduced a line of modified epoxies. These 2-to-1 mix ratio formulas form durable, strong and flexible bonds to many substrates. They absorb and distribute stress caused by thermal expansion, broadening the range of material choices for engineers.

Permabond MT382 is self-leveling and MT3821 is non-flowing; both cure to form durable, strong, flexible bonds that are weather resistant. Typical applications include bonding and sealing a variety of substrates, including nylon, ABS, polycarbonate and various metals. Both products are very flexible with low shrinkage, so that thin panels can be bonded with no read through. They make excellent potting compounds for sensitive electronic components, since their low shrinkage provides less stress on sensitive components.

When fully cured, MT382 produces bonds with a shear strength of 600 to 1,000 psi on mild steel, 900 to 1,200 psi on aluminum, 600 to 900 psi on ABS, and 700 to 1,000 psi on fiber-reinforced plastic.

Permabond’s flexible adhesive line also includes another modified epoxy, MT3809, which is mixed in a 10-to-1 ratio and is ideal for bonding plastic. One-component modified silane polymers and two-component polyurethanes are also available.

UV-Cure Silicone

Novagard Solutions Inc. is introducing the 800 series of UV-cure silicone sealants. The materials maintain all of the performance characteristics of conventional silicone-based sealants with processing speeds unmatched by other technologies. Their unique chemistry allows even deep sections to cure almost instantly. If desired, a moisture-curing component can be included with the adhesive to ensure curing in those areas unexposed to the UV light source.

The sealant adheres to most common substrates, including plastics and metals. It is extremely flexible and high elastic, with a soft touch and no tackiness. It provides excellent thermal stability, electrical insulation, and weather resistance. Service temperature ranges from -65 to 500 F.

The solvent-free sealant is available in transparent, translucent and highly pigmented formulations.

Applications include automotive headlight assemblies, electrical enclosures, HVAC equipment, appliance housings and speaker assembly.