Nordson 2304 - Page 82

6-24
Troubleshooting
13. Hot melt material
application problems
(continues
Problem
Adhesive
Stringing at
cut-off
Possible Reason
Nozzle positioned too far from
substrate
Adhesive too viscous
Corrective Action
Refer to
Reposition nozzle closer to substrate
Section 4
(recommended distance is 0.50 in./13
mm from substrate)
Increase temperature slightly, or
Section 4
change to compatible adhesive with
lower viscosity
Cold adhesive
Gun speed too slow
Raise channel setpoints as required
Section 4
Use a faster-acting gun, use an
Section 4
air-piloted relay valve between
solenoid and gun, or reduce distance
between solenoid and gun
Adhesive too old
Flush system and refill with fresh
adhesive
Section 5
Adhesive
Drooling from
Gun
Unequal
Deposits
Between
Nozzles in
Multi-Module
Installation
Gun temperature too low
Increase oun temperature as required Section 4
Spring tension of gun too low
Readjust gun spring tension as
Gun
required.
manual
(all
Ball or needle and/or seat of gun
Clean or replace gun module
versions)
module worn or partially clogged by
char
Different nozzle sizes
Use same size nozzles
Gun
manual (all
Unequal spring tension or improper Adjust modules
versions)
needle lift adjustment in zero-cavity
guns
Nozzle clogged or damaged Clean or replace nozzle
Foreign material in gun module Rebuild or replace module
.
Insufficient and/or unequal air
Adjust as required
pressure to guns
.
Hydraulic pressure not equal at guns
Compensate for difference by using
different nozzle sizes or adjusting gun
travel
Debris or slight imperfections in
nozzles
Clean or replace nozzles
Adhesive in air motor section of
module
Rebuild or replace module
PIN 106 701A
41-2300SP - l/94
FD Nordson Corporation 1994
All Rights Reserved