The 4 plastic variables

[Sergio Diaz]

Hi, I like to start by saying that this forum is grate.

Two months ago I started to write a systematic troubleshooting plan for injection molding to implement in the manufacturing floor and I decided to us the 4 primary variable as base for this systematic troubleshooting plan. For me the 4 primary variable are temperature, flow rate, pressure and cooling rate this is what I learn at one of the master molder class that I when to
but now some of the guys that I work with are asking me, why do I use cooling rate as one of the 4 primary variable? They are saying that the 4rd variable is time, I been working in injection molding for 15 years and I just got in to scientific molding 5 years ago this guys have been in the injection molding industry for a long time and I do not know if what they are telling me is correct or not

can someone please explain to me why time should be the 4 variable and not cooling rate ?
For me time is a machine variable and not a plastic variable

[Suhas]

Hi Sergio,

Cooling Rate = Rate at which you are cooling the plastic = heat removal per second which is proportional to the time you need to cool the part.

So it is one and the same thing.

Hope this helps.
Regards,
Suhas

[Sergio Diaz]

Thanks this is very helpful!!!

[iautry1973]

Suhas is correct it is the same. It is more a train of thought. However if you look at cooling rate just as a function of time you miss the element of being able to change the cooling rate with speed or temperature.

[JayDub]

Hi, I like to start by saying that this forum is grate.

I been working in injection molding for 15 years and I just got in to scientific molding 5 years ago this guys have been in the injection molding industry for a long time and I do not know if what they are telling me is correct or not



About fifteen years ago I worked with a technician who gave me a priceless insight when he said: "There are a lot of people in this company who have been here for thirty years. Some of them have thirty years experience, and some have one years experience thirty times." Trust your training, stay curious, and keep learning.

[chrisprocess]

This sorta might help them understand:

Literally speaking four plastic variables are Temperature, Flow Rate, Pressure, and Cooling Rate and Time (aka cooling rate and cooling time).

Technically speaking four variables (variables in an equation) are Temperature, Volume, Pressure, and Time.

Flow Rate = Volume per Time
Cooling Cate = Temperature per Time

Just how you interpret it I suppose lol