Free oil under machine - influence of evaporation on injected parts

[Jendalf]

Hi All,

I have a question about influence of the free oil under machine on the moulded parts.

Oil evaporates, thats clear but generally less than for example water (i´ll not bother you with physics of tensions of the vapour, etc.) but roughly its about 25x less than water.

I have a lot of free oil under machines because of the age and conditions of the machines and tools. The area from that can the oil evaporate is around 50m².
Is it possible that this oil (evaporation) could influence injected parts and how? (injected material is PP and/or ABS).

I´m looking for any direct experience and examples. I´ll appreciate any theory about this issue.

Thanks
J.

[Suhas]

Hi J,

In theory - Yes, In practice - No.

Oil evaporation is very slow compared to say water. In fact even water is slow. Having said that, the parts that fall from the mold are probably not at the machine for long. Depending on the size they are there for a few minutes to may be the whole day (for smaller parts). During this time, they are are exposed to the oil vapors but depending on the type of plastic, the absorption will be zero to negligible. All plastics are not compatible with all oils.

What have you seen? Let us know.

Regards,
Suhas

[Pilot]

Hi to all.

I have a looooooooot of oil under machinery :-) but without of any influence on the part due to evaporization. I am doing a lot of tests like surface tension, adhesion etc, but I do not see any influence. Other case is sprayed oil (or oil fog) or oil drops on the part. Yes, in this case you will have a problem.....

regards Pilot

[Jendalf]

thx a lot for answers Suhas and Pilot,

I thaught so. Experiment I´v made was short term (5 hours of exposing the part above the oil) tested by standartized inks (subjective test). No influence was observed on the part sufrace tension during these test.
Sprayed fog damn EPDM sealings

J.

[Airwinghma]

Greetings;

Why did you ask this question? Was there an issue that was attributed to possible oil contamination?

Scott

[brentb]

Depending on resin,if parts fall INTO the oil, they can be adversely affected!

KOM

brent

[Jendalf]

Hi,
My question was in a theoretical way. Because of the low evaporation ability of oil at standard conditions. I didn´t expect direct influence on part surface quality during 80s cycle but...I know that nothing here is 100% sure.
Original issue was small streaks on the surface. The source hadn´t been found yet. So I´m trying to check all possibilities.

J.

[Airwinghma]

Greetings;

Ya Brent I agree that most any part is adversely affected if they ejected into oil. I was asking for more specifics on the evaporation theory and if they had any data that leads to the oil being an issue that way. It looks like Jendalf was covering all the defect possibilities, maybe from a 5 why.

Scott

[rickbatey]

What's the streaks look like? Have you identified the type of material that the streak is comprised of? At 80s, the residence time could be the issue. What's resin, color, and pre-color or color at press? Where are the streaks?
Rick.

[Jendalf]

Maybe i´ll do differend thread for this streaks.
now its not issue anymore as the tool was outsourced (not only bc. of this streaks)

J.