Steps for Adhesive Application 220

air spray

The process of dispensing an adhesive onto a surface by injecting the adhesive into a stream of pressurized air.

airless spray

The process of dispensing an adhesive onto a surface by forcing the adhesive through a small opening at high pressure.

air-pressure method

Also called the time-pressure method, the process of dispensing an adhesive by applying air-pressure to the top of a syringe. The air-pressure forces the adhesive through a tip or needle.

auger

A device consisting of a shaft with a threaded flange that rotates to force material from one end to the other. A variation of the positive-displacement method, an electric motor rotates the auger, which forces adhesive along the threads of the auger and toward the tip of the syringe.

axes

Imaginary lines that pass through the center of an object. In automated dispensing methods, a robot moves along specified axes to dispense an adhesive.

baffle

A device that mixes materials together by diffusing the flow of material. Baffles are used to mix adhesive components together as they pass through a dispensing nozzle.

centrifuge

A tool with a compartment that spins rapidly around a central point to separate materials into their individual parts. A centrifuge is used to remove air bubbles from an adhesive.

clamp

A device that holds objects together by applying inward pressure. The inward pressure holds parts together while the adhesive cures.

clamping range

The minimum and maximum thickness a clamp can hold.

curing

The process during which an adhesive undergoes a chemical reaction and becomes a solid. Curing may require pressure, heat, or a specific amount of time.

curing agent

Also called a hardener or catalyst, the substance that hardens the adhesive when mixed with resin. A curing agent must be metered carefully to ensure sufficient curing, flexibility, and strength of a joint.

cyanoacrylate

A type of structural adhesive made form acrylic, a manufactured polymer. Cyanoacrylates should be stored in a low-humidity environment.

density

The amount of mass within a specific volume. Adhesive components must be mixed thoroughly to ensure uniform density.

dispense

The process of removing an adhesive from a container or syringe and distributing the adhesive onto a surface to join parts.

epoxy adhesive

A type of structural adhesive made from epoxy, a manufactured polymer. The auger method more accurately dispenses two-component epoxies.

fixturing

The process of ensuring that two parts bonded together remain in the same place during curing. A nest or clamps can be used to hold the parts together.

hot spray

The process of dispensing an adhesive onto a surface by heating an adhesive to decrease its viscosity, and then spraying the adhesive. Hot spray systems can involve either air or airless means of spraying the adhesive.

metering

The process of measuring the resin and curing agent to ensure that the correct amount of each is used to produce the adhesive. Metering can be done manually or with automatic machinery.

meter-mix-dispense equipment

MMD equipment. Typically used to dispense two-component adhesives when production volume is high, MMD equipment automates the metering, mixing, and dispensing processes.

MMD equipment

Meter-mix-dispense equipment. Typically used to dispense two-component adhesives when production volume is high, MMD equipment automates the metering, mixing, and dispensing processes.

mold release agent

Any chemical that is used to help release the molded part from the mold cavity. Mold release agents can contaminate adhesive dispensing equipment.

needle

A long, narrow cylinder with a small orifice placed at the end of a syringe. Needles used to dispense adhesives come in a variety of shapes and sizes, depending on the amount of adhesive to be applied.

nest

A device that houses parts, holding them firmly in place while the adhesive cures. Parts used in assembly are usually held in either metal or plastic nests.

one-component adhesive

An adhesive in which the the resin and curing agent are packaged together, already mixed.

physical property

Any aspect of a substance that can be measured or can change without altering the chemistry of the substance. While in storage, an adhesive's physical properties are vulnerable to change.

piston

A piece of metal that moves up and down inside a hollow cylinder in response to a pressure change. A variation of the positive-displacement method, a leadscrew is driven by an electric motor to push the piston, which in turn pushes the adhesive out of the syringe.

pitch

The distance between a point on an individual thread to the corresponding point on the next thread. When using the auger system to dispense an adhesive, the pitch of the thread on an auger determines the amount of adhesive pushed out of the syringe.

plunger

A cylindrical device in a syringe. The time-pressure system involves applying air pressure to a plunger, which actuates the dispensing of the adhesive from a syringe.

positive-displacement method

The process of dispensing an adhesive by either moving a piston or rotating an auger incrementally. With each incremental movement of the piston or rotation of the auger, there is an identical movement of adhesive out of the syringe.

pot life

Also called working life, the period of time after mixing during which an adhesive remains suitable for use. The more adhesive that is mixed, the more an adhesive's pot life decreases.

production volume

The amount of product being produced in a given time. Manual adhesive dispensing methods are typically used when production volume is low, while automated methods are typically used when production volume is high.

resin

A solid or semi-solid organic material that tends to flow when subjected to stress. Resin must be metered carefully to ensure sufficient curing, flexibility, and strength of a joint.

shelf life

Also called storage life, the length of time an adhesive can be stored in specified environmental conditions and still remain suitable for its intended application. Adhesive viscosity typically increases after an adhesive's shelf life expires.

silk screen

A screen or cloth with holes or pores through which material can be forced. A silk screen is sometimes used to dispense adhesives that must be applied only to specific areas of a surface.

six-axis robot

A robot designed to move along six axes according to the Cartesian coordinate system. Valves are often mounted to a six-axis robot for fully automated dispensing of adhesives.

static mixer

A specialized tip placed at the end of a valve used for adhesive dispensing. After the valve dispenses the adhesive components, the components are mixed in a static mixer.

storage life

Also called shelf life, the length of time an adhesive can be stored in specified environmental conditions and still remain suitable for its intended application. Adhesive viscosity typically increases after an adhesive's storage life expires.

syringes

A type of equipment used to dispense a specified amount of adhesive onto a surface. A syringe exerts pressurized force for a specific period of time to dispense a specific amount of material through needle or tip and onto a surface.

tare weight

The weight of the containers used to meter adhesive components without the weight of the adhesive components. Each weighing container should be labeled with its tare weight.

time-pressure method

Also called the air-pressure method, the process of dispensing an adhesive by applying air-pressure to the top of a syringe. The air-pressure forces the adhesive through a tip or needle.

tip

A conical bar with an orifice placed at the end of a syringe. The orifice can be wide or narrow, depending on the application.

two-component adhesive

An adhesive in which the resin and curing agent are packaged separately and mixed prior to or during application.

ultraviolet light

UV light. Light that is invisible to the naked eye because it consists of wavelengths shorter than those of visible light.Some adhesives are treated with a dye that fluoresces when exposed to UV light.

UV light

Ultraviolet light. Light that is invisible to the naked eye because it consists of wavelengths shorter than those of visible light.Some adhesives are treated with a dye that glows when exposed to UV light.

vacuum chamber

An enclosure from which air is removed by a vacuum pump. A vacuum chamber is used to remove air bubbles from an adhesive.

valve

A mechanical device that regulates the flow of liquid. Valves are often used to dispense adhesives when production volume is high.

viscosity

A measure of a material's resistance to flow. An adhesive is typically too viscous to use once its shelf life has expired.

working life

Also called pot life, the period of time after mixing during which an adhesive remains suitable for use. The more adhesive that is mixed, the more an adhesive's working life decreases.

zero shaft syringe

Typically used in dispensing adhesives, a syringe that is not tapered at the end. The straight syringe helps to prevent adhesive from getting caught during dispensing.