Solder ingots

Metal strip is the basic material used in Semiconductor Packaging Materials precision stampings. Semiconductor Packaging Materials has the ability to alloy, cast, roll, and slit most of the metals used in its stampings. Semiconductor Packaging Materials also rolls and slits vendor supplied material as needed.

At Semiconductor Packaging Materials, metal strip is created in a four step process. First, an alloy is calculated and melted. Once melted, the alloy is cast, typically in strips. The strips are then rolled to the proper thickness, and then slit to the proper width.

Alloying is a process where two or more metals are melted together to form a different material. Alloys often have different physical properties compared to the constituent metals. Alloys are often prefered over base metals for a variety of reasons; because they have a higher or lower melting points, for their special conductivity attributes, or improved thermal expansion values. Depending on the alloy, Semiconductor Packaging Materials will use either an induction furnace or a casting operation to create the alloyed material. If the induction furnace is used, the alloy is poured into bars or ingots for a future use. While the combining of metals into an alloy may seem obvious, it requires special care to reduce contaminates and oxidation.

After an alloy is "melted", it is poured into ingot form - the ingots are then placed into a caster, which remelts the material. Casting is a process of converting the melted (liquidus) state of the alloy into a cast strip or rod. The casting process requires a starting bar for the liquidus material to cling to; once the starting bar is in place - it slowly draws the liquidus metal through a form die where it cools and solidifies. The result is a consistent - well balanced alloyed bar of material that is ready for subsequent rolling.

Semiconductor Packaging Materials has been working hard to refine the casting process. New vacuum casting equipment is being employed to reduce impurities and increase productivity, the casting process is constantly being improved to provide the most uniform material available in the market.

Once the material has been cast - it needs to be rolled to the final thickness using a rolling mill. Often times, many passes through the rolling mill are required to get the material to the desired thickness. The metal is feed through the rolling mill at a predetermined temperature and pressure.

	Precision guage measurment

After successive rollings, a precision gauge measurement device helps to determine the proper thickness. Sometimes the repeated rolling of the material causes the material to become overly hard - in these instances the annealing process is needed to soften the material.

Annealing is a heat treatment process that promotes "grain growth" in the material thereby softening the product. For a variety of reasons, Semiconductor Packaging Materials' customers have a specified temper requirement on this material - annealing is a standard method of reducing the hardness of metals.

Once the rolled material is at the proper gauge and hardness - the material is slit and cut to the desired length and rolled onto the finished roll. Slitters are used to trim material to the desired width using a set of knives to remove excess material.

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