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SC-450 PreciseCoat C onformal C oating J et Troubleshooting © 2024 Nordson Corporation 41 6.3 Troubleshooting Procedures Table 6-1 SC-450 Troubleshooting - Symptom B ase d Symptom Possible Cause Recovery No Fluid Jetted …

6 Troubleshooting

6.1 Overview

To quickly identify problems, look for obvious signs such as burnt, missing, damaged, or loose parts, as

well as obstructions and spills. Recurring problems indicate there may be other root causes. Table 6-1

through Table 6-3 identify troubleshooting symptoms, recovery procedures, hierarchy, and setup

variables. These procedures cover only the most common problems that you may encounter. If you

cannot solve the problem with the information given here, contact Technical Support.

NOTE

Refer to the EasyCoat User Guide or EasyCoat Help for recovery procedures pertaining

to EasyCoat.

6.2 Safety First

Operation of your SC-450 PreciseCoat Jet involves air pressure, electrical power, mechanical devices,

and the use of hazardous materials, and sometimes may involve heat. It is essential that every person

servicing the dispensing system or components fully understands all hazards, risks, and safety

precautions. See Section 2 - Safety for additional information.

WARNING!

Allow only qualified personnel to perform the following tasks. Follow the safety

instructions in this document and all other related documentation.

WARNING!

Ensure the fluid system is completely depressurized prior to loosening any fittings

in the fluid path. Failure to do so may cause serious injury to personnel.

WARNING!

DO NOT hot swap connections when working with electrical and pneumatic power

supplies. Turn the main circuit breaker off before disconnecting the external power

plug from the facility.

SC-450 PreciseCoat Conformal Coating Jet Troubleshooting

6.3 Troubleshooting Procedures

Table 6-1 SC-450 Troubleshooting - Symptom Based

Symptom Possible Cause Recovery

No Fluid Jetted

Empty or Old (expired) fluid Replace fluid.

Clogged Nozzle Clean or replace fluid needle.

Fluid temperature too low/off

Verify heater is turned on and set at the

correct temperature. Verify electrical power

at the Jet connector. Verify proper heater

element/RTD resistance.

Fluid pressure too low/off

Verify the proper air pressure is delivered

to the fluid syringe.

Solenoid not actuating

Verify electrical signal to valve. Valve air

pressure low or off - set to proper value.

Electrical cable or pneumatic line

damaged. Repair/replace.

Blocked pneumatic path

Check jet body. Remove the stroke

adjustment assembly, spring, button and

needle assembly.

Needle assembly not actuating

Stroke set to zero - set stroke to proper

value. Remove stroke adjustment

assembly, remove fluid chamber, manually

verify needle assembly slides in the

bearings. Verify spring is installed. Valve

air pressure low or off - set to proper value.

Valve On/Off time set too low -

set to

proper value (Minimums of 3 ms ON and

3 ms OFF).

Stroke adjust was not properly

adjusted when first dispensed on

machine (Needle Hat Seal

inverted)

Remove the stroke adjustment assembly

and needle. Reinstall using the proper tool.

Poor Quality Jetting

Any of the causes above As above.

Changed software settings Check timing values.

Dirty, worn, or damaged wetted

parts (fluid chamber, fluid seal,

chamber O-ring, seat, nozzle,

needle assembly)

Thoroughly clean. Inspect all sealing and

mating surfaces for scratches and traces of

fluid. Check seat, nozzle, needle, and

seals for wear. Replace as necessary.

Air Leak

Broken pneumatic line Replace line.

Improper assembly

Verify all O-rings are installed. Verify

gaskets are installed under solenoid end

caps.

Stroke adjust was not properly

adjusted when first dispensed on

machine (Needle hat seal

inverted)

Remove the stroke adjustment assembly

and needle. Reinstall using the proper tool.

SC-450 PreciseCoat Conformal Coating Jet Troubleshooting

Symptom Possible Cause Recovery

Leakage of Fluid

through Weep Hole

Needle assembly or fluid seal

worn or damaged

Disassemble all components from the jet

body. Thoroughly clean fluid from the jet

body bearings and weep hole. Inspect all

sealing and mating surfaces for scratches

and cured fluid. Check the needle

assembly and the fluid seal for

wear - replace if worn. Insure that the

stroke adjust assembly is opened 7-8 turns

prior to tightening fluid body.

Fluid body seal gland scratched

or dirty

Fluid body screws not torqued

properly

Table 6-2 SC-450 Troubleshooting - Set-up Based

Set-up Variable Effect Notes

Fluid

Properties

Dispense

Volume and

Quality

If this is a new process, contact Technical Support for

assistance in process development. If this is a qualified process,

fluid properties may have changed. The fluid may have

exceeded its pot life, or been mishandled or set-up incorrectly.

In addition, air bubbles are a common problem in mixed, high

viscosity fluids. Improper thawing can introduce air to the fluid

supply, which results in intermittent shots. De-gas the fluid if

possible in a vacuum chamber.

Fluid Pressure

Dispense

Volume

Verify that the fluid supply has been set up correctly and that

fluid is free to flow to the jet chamber. Verify the pressure setting

is correct. Insufficient fluid pressure results in small shot

volumes or no shots. Too much fluid pressure leads to larger

shot volumes.

Valve Pressure

Dispense

Volume

Needle assembly travel is affected by valve pressure. Lower

valve pressure increases jet reaction time. In high duty-cycle

applications, sufficient valve pressure is required to meet

performance specifications.

Jet On/Off

Time

Dispense

Volume

The time the solenoid control signal is held on is termed “On

Time”. The time between “On” signals is termed “Off Time”.

On/off times that are too small will not allow the needle

assembly to fully open or fully close. On times set too large may

cause excess fluid to flow through the jet.

Dispense Gap Dispense Quality

A jet with the dispense gap set too low will “plow” through the

dispensed fluid and accumulate fluid on the nozzle tip. Dispense

gaps set too high will result in poor shot shape with a higher

frequency of dispense “satellites.”