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680SD BRUSHL ESS SERVO PUM P Dispe nsing Needles 14 680SD B rushless Servo Dri v en Pump Dispensing Needles Descrip t ion Attention Needles that are used on the 680SD pump are not interchangeable with needles used on oth…

680SD BRUSHLESS SERVO PUMP

Dispensing

Operation and Maintenance Guide 13

Dispensing

Introduction This section provides information about needles used on the 680SD pump, describes

factors that affect dispensing, and provides recommendations for dispensing.

In this Section Refer to the following:

Topic See Page

Dispensing Needles 14

Factors that Affect Dispensing 15

Dispensing Recommendations 15

680SD BRUSHLESS SERVO PUMP

Dispensing Needles

14 680SD Brushless Servo Driven Pump

Dispensing Needles

Description

Attention

Needles that are used on the 680SD pump are not interchangeable with needles

used on other pumps. The leadscrew ball seats in the needle to shut off material flow

and establishes the lift height (ZERO). Damage to the leadscrew will result if the

proper needles are not used.

The pump is designed to be used with unique stainless-steel needles. A variety of

needle sizes are supplied with the pump.

680SD BRUSHLESS SERVO PUMP

Factors that Affect Dispensing

Operation and Maintenance Guide 15

Factors that Affect Dispensing

Description Several factors determine how accurately and reliably materials will be dispensed

including:

• Temperature of the media. If the temperature is outside the recommended work-

ing range, viscosity changes will cause more or less material than is called for to

be dispensed.

• Needle gauge and length in relation to flow characteristics of the media. Media

with very high viscosity will not flow through a very small tip. Increased needle

length requires more pressure for dispensing.

• Gap between the needle tip and the work surface. The gap includes initial height

settings and surface flatness.

• Media condition

• Air pressure on barrel

• Clearance between dispensing screw and needle seat when dispensing

Dispensing Recommendations

Description Refer to the following:

• Apply only sufficient air pressure to keep the pump full. Most materials require 1

to 10 PSI (0.07 to 0.7 bar) to keep the pump full. Excessive air pressure will

increase dispense volume, will affect weight accuracy, and can create separation

of two-part materials. Insufficient air pressure can create voids along the lead-

screw and subsequently at the needle tip.

• Ensure material is within the expiration date and is stored at the correct tempera-

ture.

• Use the correct needle gauge for the application.