Very nice post there
Ronen I agree there that aside from paying attention to the RH, the proper handling/storage/dispensing of the mold material is very critical also. And please also consider the kind of mold material you have. I am not that familiar with injection molding plastic resins but in semiconductor molding our EMC (Epoxy Molding Compound) follows strict stock management based on (as
Renon stated earlier) it's characteristics and manufacturer's instructions. They may differ per manufacturer such as in Henkel they advice us to:
1. Store at 5deg or below (cold storage)
2. Remove from cold storage thaw from 16-24hrs prior usage.
3. Handle with lint free gloves.
4. Keep away from heat.
5. Keep desiccant bags with the pail/box until used up.
6. Replace lid on pail after each use.
7. Consume within 24 hours of opening.
8. Unused --unopened material which has been already thawed and exposed to room temp min 48hrs (with within spec RH)can be restored/refreezed to cold storage only once(at 5deg or below). Thawing and other conditions apply.
Floorlife (72hrs): Thawing time(24hrs) + Exposure Time (48hrs)
RH: 40-65% (SPC recorded)
Temp: 20-27deg C (SPC recorded)
Samsung EMC's differ from Henkel as they allow
1. Store at 5deg or below (cold storage)
2. Remove from cold storage thaw from 16-24hrs prior usage.
3. Handle with lint free gloves.
4. Keep away from heat.
5. Keep desiccant bags with the pail/box until used up.
6. Replace lid on pail after each use.
7. Consume within 24 hours of opening.
8. Unused --unopened material which has been already thawed and exposed to room temp min 72hrs (with within spec RH)can be restored/refreezed. Refreeze can only be done once.
Floorlife (72hrs): Thawing time(24hrs) + Exposure Time (48hrs)
RH: 40-65% (SPC recoreded)
Temp: 20-27deg C (SPC recorded)
Refreezed materials can be used for production within 24hrs. If unopened it will be scrapped. If opened and used it must be consumed with the 24hr period otherwise it will be scrapped.
Also I'd like to add that we have observed that the time of preheating EMC shortens as the summer months come (despite the proper control of humidity with the proper storage and handling). That short pellet preheat time is within pellet temp requirement. I do not have a copy of that particular study that our engineers have done as I am not privy to it but I was involved with it. Mold EMC exposure over time (in the production floor) during the summer months and the cold months. Humidity, stock management/handling, machine settings/parameters(which include preheat time) etc affecting quality.
Good-luck
Some links if it may help in a small way,
http://www.pharmtech.com/pharmtech/data/articlestandard/pharmtech/022005/141826/article.pdf
http://www.asse.org/professionalsafety/docs/Alan McCartney Article.pdf
http://www.toray.jp/plastics/en/products/amilan/technical/tec_007.html