Decoupled Process

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Decoupled Process

Postby not related to on Mon Jul 05, 2010 10:40 am

My boss thinks that decoupling the mold is the cure all on all molding defects. Decoupling the mold is a great starting point but it doesnt guaranty a good part.What you say?
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Re: Decoupled Process

Postby rickbatey on Tue Jul 06, 2010 12:33 pm

I think it will help with many of the issues any molder struggles with (the fires you have to keep putting out), but this is still a tool and you need the correct tool for the job. I learned many of the decoupled steps from more experienced peolpe, and have used them because they work....BUT, even the proponents tell you it won't work with EVERY mold and process. If you mold lids with this process, they will come out warped liked potatoe chips. Sometimes you can throw the shear rate studies out the window due to the increased fill rate makes horrible looking parts. So, it works, but not for every mold and process. But it can help you prove that you need machine maintenance as well!
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Re: Decoupled Process

Postby M&M on Thu Jul 08, 2010 10:34 am

Decoupled processing as I have seen it for years is a method to discover what you can and can not do with a mold. As Rick correctly points out your going to be in trouble molding lids with it BUT you will know WHY you can't mold them like that.

When you design a DC2 process and find your fill time is kind of high, you plot the RV curve and ya your fill time has you in a bad place of the curve you know you need to change something right? Say the customer gated on a surface they don't want blush on and that means you need to be creative with the fill profile, well thats what you have to do. knowing that your process is not bullet proof due to the gate location is a big step in creating an inspection program that is aware of possible issues due to viscocity changes, so you mark up end of fill and tell the operator to watch for shorts, you weigh parts as part of inspection etc.

Decoupled processes are easier to touble shoot and fix also, think about it. You have a first stage that does one thing right, form x amount of the part by weight in x amount of time. If you make a part that weighs that much in the correct amount of time that stage of the process is fine.

Second part of the process takes the part you made in the first stage and finshes filling it, packs it out and holds it to a known weight for a defined time. If you can make a part that weighs that much in the time given your second stage of the process is ok.

So if you can look at the parts at transfer and inspect them say to yourself 'yes these parts are the same as test parts at transfer" and you can look at your packed parts aqnd say they weigh the same and where cooled at the same rate as the sample test parts THEN you say to yourself, machine and process is ok in must be something else.
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Re: Decoupled Process

Postby M&M on Thu Jul 08, 2010 1:35 pm

Take heart guys, at least your still processing plastic. These days I heat up a Toshiba EC180 to 955 degrees, load a zinc/aluminum alloy into the hopper and mold parts out of that.

I don't process any more I just pray none gets on me :mrgreen:
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Re: Decoupled Process

Postby 110Ton on Thu Jul 15, 2010 6:08 pm

Decoupled processing... wonder if this would work with thermoset rubber.
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