Any tricks how to process PP with fast cycle times. Using low mould temperature is causing a lot of condensation due to very hot air temp. Any suggestions

Condensation on tools is due to humid air. Either control humidity or run mold above dew point, which varies day to day, even hour to hour.
Watch coolant flow rather than concentrating only on mold temp.

Keep on molding!

brent

First of all I would agree with Brent regarding condensation. If you want to run a colder mold the biggest problem is to keep the condensation off of the parting line i.e. water running on the mold faces. With that, you can cut a .12" deep groove approximately .08" from the parting line on the mold plates on 3 sides. Basically, a "U" shaped channel. This will allow the condensation to run down the channel and off of the mold. Certainly, not a 100% fix but it helps a great deal.

Hi Antoine, In order to address this issue, the Clamping section need to be covered except there area where the part drops or being picked up by the robot. We need to supply dehumidified air into this section using a dehumidifier. This will eliminate any potential of condensation occurring on the tool and avoid all moisture related issues

Hello Antoine, if possible use the lower limit of cylinder temperature than decreasing mold temp too much. I also agree on previous ideas to make cooling system more efficient by using smart design of cooling channels.

Antoine, If you don't have the option to have your press in a climate controlled room, the condensation can be a tough problem to solve. I would ask that in your normal molding cycle, is most of the condensation located on the exterior of your mold base, or do you collect condensation on the mold faces and Core/Cavity surfaces ? For condensation on the exterior tool surfaces you might consider a simple fan or 2 to blow across the tool which will help the evaporation rate and likely keep the surfaces dry. This may have an affect on your tool temperature which might require adjustments to your processing temps. If you are seeing condensation on the interior surfaces you can look at adding air nozzles that will be aimed at the key areas and are triggered during the "Mold Open" time. Both of these approaches may sound like "Old School" approaches but it appears that your options are limited.

There are several companies offering mould area dehumidifcation systems. They will all prevent mould sweating. Eisbaer from Austria and Piovan from Italy come to mind readily. Wittmann may also have solutions. Eisbaer offers a rather unique solution using part of the cooling water used for mould cooling to keep the surrounding air at same temperature through heat exchangers. This will ensure the mould and the air around it will have temperature balance thus preventing mould sweat, no matter at what temperature the mould is run.

How about raising the temperature above the dew point and adding a Nucleation agent to the PP to make it crystallize faster and lower the cycle time. If clarity is needed put in a classifier. All classifiers are nucleators but not the other way around.

Lots of great information to look into regarding cooling, dehumidification of the molding area, and material. Stepping away from actual machine processing for a moment and looking at the overall process, and your question of faster cycle times for PP, there may also be an opportunity incorporate some of the suggestions mentioned earlier and also integrate the placement of parts on a cooling belt or drop parts into a post molding water bath. This does not always work due to other part or facility constraints, but if done properly, and under control, this can be very beneficial.

One of the questions that need to be answered is where or not there is turbulent flow present during the mold cooling. If not there needs to be. Mold cooling temperature alone can not do the job, especially if quick mold cycles are trying to be achieved.