Daily Maintenance inspection for Station-type soldering irons

Daily Maintenance inspection for
Station-type soldering irons

(Using SOLDERING TESTER 192 & THERMOMETER 191)


Tools Needed:
1. Hanstar-Hansun 191 thermometer
2. Hoslen-SLD 192 thermometer tester with built-in surface resistance tester
3. 191- 212 or 191- 211 sensor
4. Hansun 199 (FG-100)
5. Thermocouple wire type K with plug

Objective:
Prevent device damage and soldering failure

The Hoslen-SLD 192 measures tip temperature, leak voltage and tip-to-ground resistance & surface resistance. Hanstar 191 measures tip temperature. Every soldering operator should have one on their workbench to ensure their soldering equipment is operating properly at all times.

Procedure:

Inspection 1. Checking the leak voltage
(using Hoslen-SLD 192)

Inspection 2. Checking the tip-to-ground resistance
(using Hoslen-SLD 192)

Inspection 3. Checking the tip temperature
(using Hanstar-Hansun 191 or 199 (fg-100))

Inspection 1. Checking the leak voltage (using Hoslen 192)

The following factors cause electric current to be leaked from the tip to the P.W.B. and the device, resulting in adverse effects on objects being soldered. For this reason, check the leak voltage periodically.
• Even though an insulative ceramic material is used, long-term use has caused the heating element to deteriorate and the leak voltage to increase.
Accumulation of oxides on the parts such as tip/element cover caused contact failure to be generated and leak voltage to increase.

How much leak voltage is normal?
The lower the leak voltage, the better. The MIL standard which has been abolished at present specifies that the leak voltage is designated to be lower than 2mV; therefore, all Hanstar station-type soldering irons have been delivered with the leak voltage set to 2mV or less in conformance to the MIL standard. The MIL standard is a US military-based standard and the standard MIL-STD 2000A regarding soldering irons has been abolished.
Point for measuring the leak voltage

Measure the leak voltage after adjusting the temperature setting to the maximum. When the leak voltage is measured at the highest temperature, the highest leak voltage will be recorded. If normal results are obtained even in unfavorable conditions such as at the highest temperature, it is judged that normal results will be obtained at other temperature settings. (This method is based on the MIL standard.)

If the leak voltage is higher, what actions should be taken?
1. If the heating element has deteriorated
- Replace the heating element with a new one. The heating element will be oxidized and blackened in this case.

2. If oxides have accumulated on other parts
- Remove oxides with steel wool (Tinsel Tip Cleaner Top S-603). An oxidized tip causes the wetting characteristics to deteriorate. The chemical is convenient to use for recovering the tip wetting characteristics.

Inspection 2. Checking the tip-to-ground resistance

When Oxide and flux stuck on the tip, the element cover and nut will cause the tip-to-ground resistance to become higher. As a result, the leak voltage will become higher; therefore, periodically check the tip-to-ground resistance.

* For the tip-to-ground resistance, let the current temperature increase to the set temperature to make the temperature stable before measurement.

How much tip-to-ground resistance is normal?
As with leak voltage, the lower the tip-to-ground resistance, the better.
The MIL standard which has been abolished at present specifies that the resistance is designated to be lower than 5Ω; therefore, all HANSTAR station-type soldering irons have been delivered with the resistance set to 2Ω or less which is stricter than that of the MIL standard.

If the tip-to-ground resistance is higher, what actions should be taken?
Polish the contact sections such as the tip and element cover with sandpaper, steel wool, etc. to remove any oxide films. An oxidized tip causes the wetting characteristics to deteriorate. A soldering chemical paste is convenient to use for recovering the tip wetting characteristics.


Inspection 3. Checking the tip temperature

If the tip, element cover, etc. are oxidized, heat conduction will be deteriorated, causing the tip temperature to become lower, resulting in soldering failure. To prevent soldering failure, measure the tip temperature daily.

*Tip temperature can be measured by Hoslen- SLD 192 ,& HANSTAR-HANSUN191 &199 (FG- 100)

The indicated tip temperature may be lower than the actual temperature due to other factors.

Other Accessories:
PROBE A1310 - THERMOCOUPLE PROBE USED FOR SOLDER POT
A1310 Temperature probe

note: HET acknowledge www.hakko.com for many of the information listed here