David Titone
Director of Sales, The Americas
EFD, Inc.
dtitone@efd-inc.com
www.efd-inc.com

Operator fatigue, inconsistent shot size, and slow production speeds are common problems when trying to make small deposits of high viscosity assembly fluids like silicones, greases and epoxies.

The medical style hand syringes often used for these applications typically produce poor results. The process is also slow and fatiguing for operators, due to the tremendous force needed to push thick materials through the small orifice of a dispensing needle, with no way to guarantee that the same amount of material is applied to every part. It becomes even more difficult when the production process requires the use a long needle, which further restricts fluid flow.

With many fluids and applications, these issues can be resolved by replacing hand syringes with an air-powered dispenser that uses a timed air pulse instead of operator guesswork to determine deposit size. These compact benchtop devices are capable of producing up to 100psi of dispensing force, which is usually more than sufficient to dispense most thick fluids. Dispensing speed can be increased even more by replacing standard straight steel dispensing needles with tapered, precision molded polyethylene tips designed to provide faster, less restrictive flow of material.

In some instances, however, even 100psi of dispensing pressure and tapered tips will not be enough to move an extremely thick fluid, especially if the application demands the use of a smaller gauge tip, or a long dispensing needle is required to fit into a recess.

To meet this challenge, EFD developed a high-pressure dispensing tool that increases the output of a standard 100psi dispenser into the equivalent of 700psi of dispensing pressure for fast, effortless application of very thick fluids through dispense tips as small as 0.004” in diameter.

Designed for use with 100psi dispensers and disposable syringe barrels and dispense tips, the tool consists of a lightweight aluminum retainer with an oversized internal piston assembly. The piston shaft extends into a disposable syringe barrel containing the fluid to be dispensed, and a dispense tip attached to the syringe outlet protrudes through the cap at the bottom of the tool.
The top of the retainer is connected to the dispensing unit by a flexible, lightweight air line. Depending on the application, the tool can either be held like a pen, gripped like a screwdriver, or mounted on a dispensing robot. When the dispenser is actuated, air pressure is applied through the air line and over the top of the oversized piston. Because of the piston’s large surface area, the dispenser’s 100psi output is effectively multiplied into 700psi of dispensing pressure.

The dispenser can either be set to timed mode when a series of identical shots is needed, or to steady mode if an application requires visual confirmation that sufficient material has been applied. With the dispenser and high-pressure tool doing all the work, the process becomes faster, the risk of repetitive stress injuries is eliminated, and it becomes easy for operators produce more consistent parts in much less time.

For more information, contact EFD at 401-431-7000 or info@efd-inc.com or www.efd-inc.com/pr/asm-0309.