Soldering Iron Temperature Control

[gbcqc]

Definition of calibration: Comparing against a known standard.

Andy, if you check your soldering iron with a thermocouple, then you've calibrated it.

Putting the thermocouple to the soldering iron, did you calibrate it or verify the status of it's calibration. If the temp. does not meet what the temp. control switch is set at (ex. - set at 650 F reading 450 F. Requirements is for the iron to hold temp at set temp. +/- 9 F) It is out of calibration. Then to calibrate it, you will have to adjust or fix the soldering iron to match the setting to the actual temp. within the set requirements.

 

[George Weiss]

The lowly SOLDERING IRON,
This item is a very strait forward electronics device, maybe this causes the confusion.
It appears as if there is agreement of there being several courses of action, and degree of same.
Out of concerns and ignorance we sometimes overkill to avoid undershooting the target. A good plan.

1. Simplest is let someone else do it, likely once a year.
2. Select requirements (yours = ?), (other’s = comply with you SOP’s for ISO9000 etc.)
3. Implement as desired, being more time & money = better, but maybe overkill
4. You indicate that ESD is not and issue, but could it be one someday? Marking items as not ESD tested maybe would be a best practice.
5. Write an SOP and/or procedure to test tip temperature, and then implement it on your desired time table. Track the items maybe with some records and device tags or markings.
6. Consider what you are making, and if +/-5deg.F. or +/-20deg.F or >700 full scale is enough. Put it in the procedure, and go with it. Write what you do, and do what you say/write.
7. Using a temperature meter or DVM with a valid calibration would also be advised if ever audited.
8. The is no concrete rule, but many people who say, to cover all possible what-ifs you should do this/that.

In the beginning it was, "is +/-5deg.F. every three months ok?" Yes it is……………

 

[AirdrieQPA]

When we were challenged during our audit, we found we had nothing to prove the accuracy of our equipment. Since we are an Airforce repair facility to the component level, the quality of our work was imparative for safety reasons. Therefore we purchased the tip monitoring unit and we do a survey once a month. (Our units are metcal) To our surprise we found two leads that were marginal, one bad iron and to date 7 tips that were delivering heat below the rated accuracy range. Need less to say, surprise, surprise to us.

We also wrote a special process to handle soldering, that seemed to satisfy the auditor.

Just my two cents worth.

 

[George Weiss]

Give that guy, (calvin), a star ===>
I wish everyone would just do it like you have.
I am suprised you have not run into bad grounding problems. They crop up after some usage time. I found the need to keep a collection of replacements on hand. cleaning the heating assemblies was not very effective. The very simple soldering iron. So under/over done....

 

[Manix]

I have a question that relates to this.

We currently use Wellar soldering irons, that have no temperature control, you simply buy the tips that regulate the temperature you require.

Since we have used this system, we have not done ANY temperature checks using a Thermocouple (our Thermocouple packed up a few years back). Now we have always managed without the checks and basically relied on the tips being reliable!

I think we maybe at risk in relying on this OR am I being too pessimistic? I have thought about it and I think:

a) Tips could be faulty and/or incorrectly packaged.
b) Tips with use over time may degrade in terms of their ability to regulate themselves.
c) The iron itself may go 'faulty' and not be able to heat the tip to the required temperature.

I don't know whether we stopped doing the checks because we went to this style of tip/iron OR because the Thermocouple packed up. This was before I took this role on!!

So far we have had multiple audits and a solder expert in and explained the situation and to date no one has commented that it's 'risky' or a non-conformance, but I still think perhaps we should check this, maybe monthly moving to quarterly depending on findings as suggested earlier in the thread.

What does anyone think? Should we check temperatures?

Note: we do manual soldering on a weekly basis (not daily) and small batch quantities (not mass production - just one operator)

 

[BradM]

I have a question that relates to this.

We currently use Wellar soldering irons, that have no temperature control, you simply buy the tips that regulate the temperature you require.

Since we have used this system, we have not done ANY temperature checks using a Thermocouple (our Thermocouple packed up a few years back). Now we have always managed without the checks and basically relied on the tips being reliable!

I think we maybe at risk in relying on this OR am I being too pessimistic? I have thought about it and I think:

a) Tips could be faulty and/or incorrectly packaged.
b) Tips with use over time may degrade in terms of their ability to regulate themselves.
c) The iron itself may go 'faulty' and not be able to heat the tip to the required temperature.

I don't know whether we stopped doing the checks because we went to this style of tip/iron OR because the Thermocouple packed up. This was before I took this role on!!

So far we have had multiple audits and a solder expert in and explained the situation and to date no one has commented that it's 'risky' or a non-conformance, but I still think perhaps we should check this, maybe monthly moving to quarterly depending on findings as suggested earlier in the thread.

What does anyone think? Should we check temperatures?

Note: we do manual soldering on a weekly basis (not daily) and small batch quantities (not mass production - just one operator)

Hi Manix!

I have seen some processes where it would not matter, and some where it would.

Do you know if excessive high or low temperature would affect the quality of the joint, the flow of solder, damage the surface, etc.?

If all I was doing is weekend solder work on speakers or something, I would not care. If there were sensitive parameters involved, I might be more concerned with verifying the temperature of the tips.

 

[WannaDoQA]

I apologize for dragging this thread out of the grave but I think it fits best for my question(s). Hopefully someone can give some insight!

We do quarterly checks on our soldering irons: Temperature & Tip-to-Ground resistance. My questions will really only be about the temperature testing.

We are using Hakko irons and the tip series that can be used in the irons have an accuracy of +/- 15C according to the tip's package (for any size tip). To test the tip temperature we use the Hakko FG-100 tip tester (which is calibrated annually) which uses a sensor. The FG-100 has an accuracy of +/-3C according to its manual.

A little more info: Each assembler has their own soldering iron and a variety of tip sizes to use. New tips are kept in stock so people can get new ones when tips die. We manufacture PCBs - we solder all the SMD and through hole parts onto bare boards either by using automated machines or by hand. Basically we are soldering by hand all day every day. We are also ISO 9001 certified.

To test the temperature and deem it "calibrated", we set the soldering unit to 399C (which is ~750F) then test with the tip tester. We have been using the tip's +/- 15C accuracy as our "window" when we test the tips which gives us a range of 384C-414C. Normally, without using the offset of the unit, we would get anywhere within that range for most any tip size tested. Recently I came across some tips that were measuring outside the range which lead to some questions about the accuracy window we are using and the use of the offset of the unit. I could get into great detail about this if necessary.

Hopefully someone stuck through all that and still wants to offer some advice on my questions. My questions are:

-Have we been using the wrong range this whole time by only using the tip's accuracy of +/-15C?
-Should we be using the offset of the unit to bring the tip temperature close to or at 399C and using only the +/-3C accuracy of the tip tester for our range?
-What about the J-STD? I will have to find out whether or not we tell customers we meet the J-STDF for testing our irons but do we then just use the +/-10C as described in Appendix A?
-Regardless, do we need to factor in the accuracy of the tip tester to the range we specify? What about the accuracy of the soldering unit itself?

I realize this may be confusing as I am confused myself (I'm sure any reader could tell), but ultimately I just want to make sure the tips are putting out the right temperature and that we are using the correct range to test our tips. We work on some medical products and so it is important.

If there are any questions about our process or anything I will be happy to answer, and any/all help or advice will be greatly appreciated. Thank you for reading.

 

[Marc]

Any takers on this one?

 

[Big Jim]

This may come as a shock, but not all ISO 9001 registered companies that solder find a need to calibrate the soldering irons.

In the cases where the irons are not calibrated, the solderers (operators) are trained to proper technique and how to recognize a good solder joint.

You might be making too much work for yourself.

Similarly, most welding machines are not calibrated. Welders are trained on how to obtain and recognize a good welding bead and know how to determine the correct settings for conditions.

 

[somashekar]

-Have we been using the wrong range this whole time by only using the tip's accuracy of +/-15C?
-Should we be using the offset of the unit to bring the tip temperature close to or at 399C and using only the +/-3C accuracy of the tip tester for our range?
-What about the J-STD? I will have to find out whether or not we tell customers we meet the J-STDF for testing our irons but do we then just use the +/-10C as described in Appendix A?
-Regardless, do we need to factor in the accuracy of the tip tester to the range we specify? What about the accuracy of the soldering unit itself?

399 is way too high ...
+/- 10 is easily achieved at the right working temp.
Use the offset of the unit to the optimum temp required for the job, which is based on the solder used and size of tip. Seal the offset from unintended drifts
Do not use the accuracy of the tip tester for your requirement. Maintain to your working range.
Ensure that the tip fits tight and full over the stem of the iron.
Operator qualification is more important than worrying about the accuracy of the soldering unit.