Process Toolkit - General Assembly

Crimping	Crimping is a process where a small tab of material is deformed to create a retention feature. The tab may already be present in the component to be crimped, or it may be formed during the crimping process with a punch-type crimper. Crimping works best with ductile materials, and can be used for plastic materials with the addition of a pre-heating step to soften the substrate.
Dispensing	Many dispensing technologies are available for automated assembly, but all of them can be divided into two main categories - time/pressue and volumetric. Time/pressure systems use pressure to control the flow rate, and time to control the volume of dispense material. A valve may be used to shut off the flow more decidely, or the system may just use the cessation of pressure to cut off flow. With volumetric dispensing technologies, the actual fluid volume is controlled. The fluid may be fed through a positive displacement valve, where a chamber and piston are used to dispense a measured amount, or an servo-auger might be used to drive a precise amount of fluid out the nozzle. All dispensing technologies suffer from issues with clogging and cleaning. Volumetric systems provide better precision and control, but require deeper cleaning. Time/pressure systems are simpler, but show variance at the start and stop of the dispensing cycle, and can exhibit consistency problems as the volume of material in the supply reservoir varies.
Encapsulation	Encapsulation or potting is surprisingly effective means to secure sub-components within a larger assembly. If the product requires drop resistance or water sealing, encapsulation is a good way to provide both. Encapsulation is typically performed using a two-part meter mix system, a dispensing station and a curing station. Depending on the encapsulant, curing can be through thermal acceleration or UV acceleration.
Laser Part Marking	Laser part marking involves the use of low power lasers to permanently mark parts with serial, lot or product information. Laser part marking is fast and easy to maintain. The main automation issues being the construction of a suitable enclosure to comply with laser safety standards, and the removal of gases that might be generated by the process. In selecting a laser, one needs to consider the material to be marked, and requirements of the mark itself. Some materials mark better than others. Plastics, in particular, can be problematic. Marking may not provide enought contrast to be readible, or it may produce discoloration (burning) that is unsightly and not very consistent. Different lasers types will definitely provide different results. However, one would hope to achieve acceptable results with a low-power CO2 laser, as it provides the best economy and is easiest to enclose.
Orbitforming or Orbital Riveting	With orbitforming, a metal pin or boss is deformed to create a retention head, similar to a rivet head. The orbitform process is essentially a rotary forming process, where the material is slowly worked over to form a head. Orbitforming can work with a variety of materials, but works best with ductile materials that are easily formed. Less ductile materials require much higher forces, which make automating the process more difficult. Some plastics can also be orbit formed.
O-Ring Installation	O-ring installation requires a custom feeding system and the use of an installation mandrel. The o-ring is frequently lubricated during the feeding process to help it slip onto the mandrel, and then onto the target feature. Pre-lubricated o-rings cannot be used, as the lubrication rubs onto the bowl feeder, leading to grunge and the accumulation of contaminants.
Potting	See encapsulation.
Priming	Priming is often necessary as a part of a component bonding application. Primers are typically sprayed using a atomizing nozzle. As they are often volatile, isolation and fume extraction is often combined with the priming process to provide a hygenic industrial environment.
Screwdriving	Automatic screwdriving is a common automation process whereby one or more screws is automatically fed and driven with a preset torque to join to components. An automatic screwdriver typically consists of a means to feed the screws to the head, the screwdriving head itself, and a means to bring the head in contact with the work piece. This later mechansim may be a simple pneumatic slide, or it may involve a robotic manipulator, depending on the application. Automatic screwdriving works best if the screw is designed for automatic applications, and is matched well to the screwdriver.
Swaging	Swaging, like crimping, is used on metal components to create a retentive feature. Swaging generally refers to a squeezing process whereby a sleeve is reduced in diameter to hold a rod or wire. The terms are somewhat interchangeable. However, we generally consider crimping to be a spot process, and swaging to be a process around the entire perimeter of a component.
Thermal Curing	Thermal curing is used to accerlate the curing process for an encapsulant or adhesive. Temperature and time in the curing chamber are typically controlled to ensure thorough curing. Curing tunnels are quite common, but with high-volume applications may require too much floor space. Vertical curing elevators can be used in these situations to reduce the size of the deployment.
UV Curing	In UV curing, a uv-curable adhesive or encapsulant is cured through the exposure to UV light. UV curing can be performed with a spot source or in a curing tunnel. Most deployments focus on processing speed and the need to protect operators from exposure to the UV light.

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