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Reflow Oven Chain Lubrication

Mike

#21919

Reflow Oven Chain Lubrication | 13 October, 2002

Hi Everyone

What lubricants do your maintenance people use for the chains in your Reflow ovens?

The manuals for our ovens have one recommendation - but I am always open to other people�s experiences and recommendations. Another option may be easier to obtain locally.

I have identified one particular locally available option -but in comes in a minimum of 20l containers - enough for years given our requirements.

Has any one had any concerns regarding outgassing / contamination from chain lubricants exposed to reflow temperatures?

Any experience with problems caused by oil contaminants? (Obviously excluding extreme excess lubrication getting on PCA's, killing flux activity and causing solderability problems.)

What I am referring to is contaminants such as carbon or sulphur vapours from the degradation of the lubricant.

What components should be avoided when choosing a lubricant to be used near SMT assemblies?

E.G. If you look at the silicone situation of using neutral cure instead of Acetic acid cure based options.

Thanks in advance for any help you can provide.

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MarcS

#21922

Reflow Oven Chain Lubrication | 14 October, 2002

Mike,

I have been using a fully synthetic motor oil on the links of my chains of my Hella for 7 years now, and have had no problems. As long as you do not place the oil on the fingers, where it makes contact with the PCB, then you will have no problems. Regards

Marc

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#21924

Reflow Oven Chain Lubrication | 14 October, 2002

Mike, we use a product called Dow Corning 321 dryfilm lubricant. BTU reccomends it. You can find it in Mcmaster Carr for about 21.00 a can. Mcmaster PN is 1255K14. I reccomend pulling the chain off when you are lubricating it to avoid over-spray.

This lubricant works very well because it is a dry film which means you don't have to worry about it getting all nasty. It is Moly/Graphite based.

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Mike

#22120

Reflow Oven Chain Lubrication | 23 October, 2002

Hi Marc

I too have been using a fully synthetic Motor oil on Heller reflow ovens for a number of years. In our case Mobil 1 5W-50.

We have a field failure problem with some 1% resistors under conformal coating where sulphates are dissolving the silver plating. Why it does not appear to be affecting 5% resistors I have yet to hear.

With the Mobil 1 the flash point is @215 degrees. A representative from Mobil suggested that below this temp some outgassing will occur. One of the decomposition products for this oil are sulphur oxides - so we were concerned this maybe causing our problem.

Subsequently we have found that our problem has been caused by the resistor supplier changing their manufacturing facility. With this a change of the protective system over the resistive material happened. Original manufacturing process used glass encapsulation, the new manufacturer used epoxy. The sulphur compounds causing our failures appear to be outgassed from the epoxy coating during reflow.

The lubricant recommended by Heller for the Heller ovens is Almasol 2799. According to a reference I have this can be applied to chains up to 246�C (450�F). With higher oven temps required for lead free other lubrication options need to be considered.

Thanks to those that have replied. More contributions would be appreciated.

Mike

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Thermal Interface Material Dispensing

Reflow Oven