Tag Archives: dispensing

Dispensing Principles

Most 1-Component and 2-Component materials of virtually any viscosity can be extruded. An extrusion nozzle is selected with a round or shaped orifice dimensionally near the bead profile desired and large enough to pass any filler components to prevent clogging the nozzle. The factors that determine valve and nozzle selection are material dispense pressure, material viscosity, pressure drops and the required flow rate based on the available tip speed of the nozzle, dispense time and part configuration.

When the tip speed is faster than the material velocity at the orifice outlet then the bead is stretched and the bead diameter is reduced. When the tip speed is slower than the material tip velocity then the material piles up and the bead diameter is increased. The tip also has to have the correct stand-off distance off the part. Too close to the part can damage or wear the extrusion nozzle. Too far from the part can cause the bead to stretch, curl or miss the bead path target.

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A stitched bead pattern is a series of short extruded bead segments created by turning the dispense valve on and off accurately at high speed. Bead stitching is used when a few short beads can be used instead of an entire bead length, similar to welding, saving material.

The dispensing principle is the same as an Extruded Bead except the dispense valve and valve actuator selection becomes more critical.

In some cases, stitching is faster than dispensing shots and may shorten the dispense time in the production cycle. For bead stitching applications, the important criteria is selecting the proper size dispense valve for material viscosity and flow rate, and selecting the proper dispense valve style (No-Drip, Snuf-Bak or Tip-Seal) and orifice for the desired bead profile.

Request a quote or e-mail us to select the proper dispense valve and extrusion nozzle for your application.

Many 1-Component and 2-Component materials can be streamed. A round orifice zero-angle tip is typically selected with an orifice that provides the bead profile, flow rate and tip speed and is large enough to pass any filler components to prevent clogging the nozzle.

The factors that determine valve and stream tip selection are the desired bead profile, material dispense pressure, material viscosity and the required flow rate based on the available tip speed of the nozzle and dispense time.

Depending on the material rheology and fluid pressure, the bead profile can be a smooth flat ribbon, oval shaped or erratic in shape. Advantages of streaming over extruding are faster dispensing time and increased tip stand off distance above the part. Disadvantages are higher pressure dispensing systems, faster tip wear and bead profile dimension stability.

Request a quote or e-mail us to select the proper dispense valve and extrusion nozzle for your application.

A filling operation requires a specific volume of material to be dispensed into an open or closed cavity. Filling a cavity is sometimes called a moulding application and can be performed with a 1-component dispensing system or 2-component meter, mix dispensing system.

In this application, the critical portion of the system is the module that controls the volume dispensed. Fill Dispense volume can be controlled by a Time and Pressure Meter, a volumetric controlled Meter or volumetric controlled Dispense Valve.

Request a quote or e-mail us to select the proper dispense valve and extrusion nozzle for your application.

A Shot Metering operation that dispenses a small amount of heavy bodied mastic material is called a Hershey drop or daub or potting. When dispensing a small metered shot of low viscosity material on a flat surface its called Doming.

Shot Metering is a specific volume of material dispensed onto a surface or into a part. Shot Metering can be performed with a 1-component Dispensing System or 2-Component Meter, Mix Dispensing system.

In Shot Metering, the critical portion of the system is the module that controls the volume dispensed. The Shot Metering volume can be controlled by a Time and Pressure Meter, a Positive Displacement Meter, a measured volume meter or volumetric controlled Dispense Valve.

Request a quote or e-mail us to select the proper dispense system, Dispense Valve and extrusion nozzle for your application.

A Multiple Orifice nozzle has many stream-type orifices in a specific pattern. The pattern can be linear orifices or circular. The shower pattern nozzle delivers multiple streams of 1-component material onto the part. Typically, the material profile is many times thicker than the Stream Bead and the dispensing system requires more material flow and pressure.

A Multiple Orifice nozzle is selected with orifices sized for the bead profile, flow rate and tip speed and large enough to pass any filler components to prevent clogging the nozzle. The factors that determine valve and nozzle selection are the desired bead profile, material dispense pressure, material viscosity and the required flow rate based on the available tip speed of the nozzle and dispense time.

Request a quote or e-mail us to select the proper dispense valve and shower nozzle for your application.

Many 1-Component materials can be sprayed to provide a coating or protection to a part or surface. Spray tips are available in many shapes, orifices and fan angles. With most sealants, adhesives and lubricants an airless spray gun is used to deliver the material to the spray tip. The orifice and cut of the tip along with the material rheology define the material pattern. A spray tip is selected with an orifice sized for the coating thickness and width, flow rate and tip speed and large enough to pass any filler components to prevent clogging the nozzle. The factors that determine valve and stream tip selection are the desired bead profile, material dispense pressure, material viscosity and the required flow rate based on the available tip speed of the nozzle and dispense time.

Advantages of spraying are thinner material thicknesses, increased pattern coverage and increased tip stand off distance above the part. Disadvantages are higher pressure dispensing systems, faster tip wear, pattern width dimension stability and over-spray.

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Many 1-Component and 2-Component materials can be swirled. A round orifice zero-angle tip is typically selected with an orifice that provides the Swirl bead profile, flow rate and tip speed and is large enough to pass any filler components to prevent clogging the tip. Typically, swirl tip orifices are larger than stream tips and deliver a higher material flow rate. The factors that determine valve and stream tip selection are the desired bead profile, material dispense pressure, material viscosity and the required flow rate based on the available tip speed of the swirl tip and dispense time.

Depending on the orifice size, tip rotation and fluid pressure, the bead profile can be a narrow to wide open loop, single filament bead pattern or a narrow to wide flat ribbon shaped pattern. Advantages of swirling are variable patterns, variable widths, faster dispensing time, increased tip stand off distance above the part and long tip life. Disadvantages are higher pressure dispensing systems and higher valve cost. In many cases, swirling can significantly lower production costs.

A ribbon nozzle is typically a slotted nozzle tip that is available in various sizes for a specific pattern width. The ribbon slot nozzle delivers a ribbon-like stream of 1-component material onto the part. Typically, the material profile is thin and wide.

A ribbon nozzle is selected with orifices sized for the bead profile, flow rate and tip speed and large enough to pass any filler components to prevent clogging the nozzle. The factors that determine valve and ribbon nozzle selection are the desired bead profile, material dispense pressure, material viscosity and the required flow rate based on the available tip speed of the nozzle and dispense time.

The advantages are the ability to bridge wide gaps and create a thin and wide pattern similar to streaming and swirling. The disadvantages are nozzle wear, bead width control, tip clogging, curtaining or folding appearance and tip angle positioning.

Request a quote or e-mail us to select the proper dispense valve and ribbon nozzle for your application.

Select from our wide range of Precision Dispense Valves for your 1-Component and 2-Component fluid dispensing application. We offer basic air operated systems up through robotic applied dispensing systems with touch screen operator interface control. Let us assist you with your fluid dispensing process by reviewing your requirements and sending you a quote for a high-quality and reliable dispensing valve or system engineered, manufactured and installed by our highly trained personnel. Our team can also integrate and program your dispensing system with automation or robotic process equipment. Your new dispensing system will be assembled to satisfy your exact application requirements.