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Cope and drag

Cope and drag

(OP)
Hi everyone

I need to decrease the amount of sand which we used in cope and drag as much as possible. Any idea how can I calculate minimun height of needed cope and drag for a cast? ( specially for drag; in which motlten metal doesnt penetrate out of buttom of the drag)

RE: Cope and drag

How many failures due to breakout can you accept?
You will be making the molds weaker if you reduce the thickness.
Are these supported in frames?
What metal are you pouring, what is the mold size, what is the casting size.
Give us a clue.
We used to pour some long narrow parts, we oriented them diagonally in the mold (couldn't fit 2) and put large hollow plugs in teh opposite corners.

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P.E. Metallurgy, Plymouth Tube

RE: Cope and drag

You have not told, what size of pattern, parting line of pattern, molding box size, sand system, simple or intricate with several cores, alloy, machine molding or floor molding etc. As Edstainless has stated, it is a call you got to take between safety and economics.

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

RE: Cope and drag

(OP)
@to all

My apology.
We are talking about a jaw crusher with about 8 cm thichness and several lenght like 110*90 or 60*80 or etc. And with part line in midle
It is usualy cast with magnesium steel or carbon steel .
We are using silica sand with resin and co2. And use chromite sand in sensetive parts.
We have a lot of cop and drags made of steels with several size and we need to make sure what is the minimum size we need to reduce consume of sand( along with safty of course!)

RE: Cope and drag

2
Jaw plates are usually flat and long . You can have 50mm to 100mm bottom sand thickness depending on rigidity of your mold ox, strength of sand mold and finally weight of casting.

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

RE: Cope and drag

In general, especially when pouring high temps like you are I prefer to keep the mold bottoms thicker, but often the mold tops can be thinned.

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P.E. Metallurgy, Plymouth Tube

RE: Cope and drag

(OP)
@arunmrao : thank you

@EdStainless: what is your suggested thickness from last part of the model to the ground in drag?

RE: Cope and drag

Take some existing molds after pouring and look to see how much solid sand you have now.
I like a couple of inches of good solid sand on the bottoms and sides of a mold.
The top can be a bit thinner than that.

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P.E. Metallurgy, Plymouth Tube

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