Aluminum tooling is becoming more and more attractive when compared to steel because of the
cost of aluminum as well as the
ease of manufacturing. Aluminum tools can be cut much quicker than steel saving a lot of time and money.
However, having something quicker and cheaper can sometimes come at a price.
The above table compares the properties of aluminum and steel. Based on this table, we can determine the following.
Density: Aluminum is 2.79 times less dense than Steel
Thermal Conductivity: Aluminum is 6.55 times more conductive than Steel
Elasticity: Aluminum is 2.89 times more elastic than Steel
Poissons Ratio: Aluminum deforms more than steel
Advantages of Using Aluminum for Injection Molds
Now that we've compared aluminum to steel, we can take a look at the advantages of using aluminum for injection molds.
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Lighter weight so the shipping costs are lower
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Softer which makes it easier to cut, sparing cutting equipment
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Higher thermal conductivity for rapid heating and cooling for quicker cycle times
Disadvantages of Using Aluminum for Injection Molds
Since aluminum is more elastic than steel, it will deform much more. Because of it's willingness to deform, we have to be concerned about a couple of things.
1) Core Deflection
2) Fatigue limit
If the tool has any individual core components which can deform, we have to consider how much they will deform and how many cycles the tool will experience before the cores will deform and ultimately fail. An aluminum tool that has any deformation will have a finite life span.
Even if there are no individual core components to deflect within the tool, the tool itself can deflect as seen above.
If there is high cavity pressure, then the aluminum tool will want to deflect much more than a steel tool. If this kind of deflection occurs, then the machine platens will have to take on the burden of the tool flexing which can put excessive wear and tear on a machine. It might even be necessary to ensure the platen thickness on the machine is greater than normal when running an aluminum tool.
In essence, when considering using aluminum for injection molds it may be necessary to weigh some serious factors. If core deflection is a concern, Bozilla Corporation can run an analysis and identify any core deflection and the magnitude of that deflection.
Contact Bozilla Corporation for your FEA and injection molding troubleshooting needs and please visit our website at www.BozillaCorporation.com.
