Frequently Asked Questions
Are aluminum tools just for prototypes and low volume production?
Answer...
QC-10 has outstanding hardness and strength for increased mold life. The myth that aluminum molds
are only for prototypes and limited production is false. Tool life is the subject of debates and it is clear that the
factors that affect tool life include:
- part geometry
- plastic resin type
- molding conditions / environment / training required when running AI molds
- tool design
What about the types of resin used to mold my part?
Answer...
We recommend "General Purpose" unfilled molding resins only. Glass filled resins or resins requiring mold temperatures in excess of 200°F are not recommended. Customers running unfilled polypropylene, have reported
aluminum molds still going strong after more than several hundred thousand molding cycles.
Toolmakers tell me about different types of steel such as P-20 and others. Are there different types
of aluminum?
Answer...
Yes, there are several types of aluminum but the 6000 and 7000 series alloys are the most common. AIM designs and builds injection mold tooling utilizing Alcoa's QC-10® aluminum. QC-10® is a high hard type of aluminum mold plate and is an optimum material for a wide
range of injection and blowmold applications. With a thermal conductivity near five times that of
steel, QC-10® can improve production cycle times by up to 25%.
Do aluminum tools have to be handled differently in production?
Answer...
Aluminum tools must be treated with a bit more care than steel tools. They can be damaged with
excessive clamp pressure, excessive injection pressure or by removing stuck parts without
proper care. Things like a screwdriver should never be used. Training in the set-up, running and maintaining of aluminum molds is highly recommended.
Can aluminum molds be polished or textured?
Answer...
Yes, they can be polished to a near SPI #1 finish. With few exceptions, any texture added to a steel mold can be added to any aluminum mold. Any plating and coating can be added but the application temperature must be below 250°F.
Does the mold material affect flatness of the part?
Answer...
When molding molten plastic into any mold the hope is that the plastic will cool evenly at the end of the molding cycle. If it does not, the hotter areas of the plastic, often caused by hot spots in steel molds will continue to shrink as they cool causing internal stress and that usually leads to parts that warp or are not flat or straight. Aluminum's ability to manage temperature evenly across the surface of a mold completely eliminates hot spots.
Can your molds be used for the gas assist process?
Answer...
We have customers who use aluminum molds for gas assist and also
the Mucell process. The nature of the process is one where less injection pressure is required to complete the fill and uniform mold surface temperature is a must.
I get the same price and leadtime quoted for an aluminum mold as I get for steel. So why not just go
with steel?
Answer...
It is common for mold makers to not offer both steel and aluminum. If they do, the price
and leadtime is often about the same. This is often because they build both types of molds with the same process no matter the metal. You will most likely get your best quote on steel from a steel mold-maker as you will get your best price on aluminum from an aluminum mold-maker.
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