Hello to all members, have anyone a rule to define a standard pressure, temperature, and water flow for PP injection molding…I know that should depend of the mold, weight of the plastic…etc

If you are asking these questions, you should contact a processing expert. Reasonable answers cannot be provided with the information given. Molding is non-trivial and specific to each situation. If you want general information on processing Polypropylene look online at the material suppliers website and\or the numerous plastics reference websites.
HOwever, since the nature of your question is this basic I do feel the correct course of action is for you to buy some consultant time and get your questions answered. Good luck -edo

Edo: Typical Temperature is 60 F . You also need turbulent water flow (Reynolds #) Look on line to calculate. There are also many factors that will contribute to cooling rate. Shape of part, Thickness of part, Distance of water circuit to mold surface...etc.
I hope this is of assistance to you.
Regards,
Dan

Typical water temperature controllers run about 60 psi off your chiller supply system. Gallons per minute will depend upon hose, fittings and mold channel size, bigger more flow smaller less flow. And for setting the water temp use a material data sheet for the grade from the material suppler or ides websites. Follow the data sheets recommendation or you can destroy the molecular structure of the plastic and change th properties. Usually 60 to 120 depending on part and mold design.

The information provided is not sufficient, part design and size are very important but you can do this: the Melt Temperature recommended is aprox. 400 F you can measure this using the 20/20 rule approach, mold temperature for PP is aprox. 100F but also you need to ensure that cooling system is generating turbulent flow with a Reynold # over 4000, if the mold's cooling lines have 1/4" ID your system need 0.55 GPM, if cooling lines are 1/2" ID you need aprox. 0.9 GMP on each. use flow meters for it. Injection plastic pressure should be 10,000-15,000 psi and 3,000 psi at the end of fill.

Thanks to everyone, I know that depend of the mould, shape of the product, cooling channels etc.. if I`m designing the size of the cooling system for the plant...with 20 machines of diferent sizes, 15 diferent materials and 150 moulds...how can I try to choose the pumps to ensure a reazonable flow?.