Processing

Once materials are purchased and received, they need to be processed. The processing of materials can be divided into two types of processes. These two types of processes are Primary Processes and Secondary Processes.

What are Primary Processes? Primary processes are processes that change raw materials into industrial materials.

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Primary Processes Activity

There are three kinds of primary processes: mechanical, thermal, and chemical. The following are examples.

Metal ore is mined and crushed. These are mechanical processes.
The ore is heated in a furnace. This is a thermal process.
Materials are added to the ore to give it different properties. This is a chemical process.

Upper left: Satellites provide engineers with important data used to locate mining areas on earth.
Upper right: A huge track-hoe loads a transport truck with ore.
Below: An engineer uses the latest technology to monitor the mining process.

What are Secondary Processes? Secondary processes are processes that turn industrial materials into finished products. These processes include forming, separating, combining, and conditioning.

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Secondary Processes Activity

Here pure metal and scrap metal is melted in a huge furnace and poured
into molds to create large slabs that will later be formed into metal sheets.

Forming. Forming changes the shape of a material. Nothing is added to or taken away from the material during this process. Forming is done in several ways:

Rolling squeezes the material between rollers. Sheet metal is made this way.
Casting involves pouring or forcing softened material into a hollow mold.
Forging hammers or squeezes material into shape. Blacksmiths used to shape horse shoes this way. Most hand wrenches are shaped by forging.

Stamping squeezes sheet metal between dies to give it shape. Stamping is used to shape some automobile body parts like fenders and doors.

Presses such as this hydraulic press use dies to force
sheets of metal into various shapes.

Extrusion pushes the material into a shape similar to the way icing is pushed through a cake decorator. The shape of the opening in the dies determines the shape of the material.

Separating. Separating is the cutting of materials to size and shape. Some material is usually lost during a separating process. Sawing, sanding, and filing are traditional forms of separating. However, heat, light, chemicals, and even water can also be used to separate certain materials.

This is a close-up of a vertical milling machine cutting into a metal block.
Milling is an example of the secondary process of separating.

Shearing is separating a part of a solid material from the rest of the material. Shearing is one separating process where no material is destroyed. Thin materials like paper and sheet metal can be separated by shearing.

Material can also be separated by cutting. Usually, cutting a material involves chip removal.

Combining. Combining is the process of joining materials. Combining is done in a variety of ways:

Mixing. Materials may be mixed together to form new materials. Food products such as cake mixes and soup mixes are made this way.
Mechanical fasteners. These include nails, screws, staples, and nuts and bolts. Automobiles and many other products are assembled using removable mechanical fasteners. Doing this makes it possible to replace parts.

There are many types of mechanical fasteners
used in the manufacture of products.
Soldering, brazing, and welding. These are processes that involve heat. In soldering and brazing, a filler material is melted along a joint between pieces of metal. The metal pieces themselves do not melt but soak up the molten material which hardens when cooled, thus joining the parts together. In welding, the heat melts the two pieces together.

Robots performing a welding
process on a modern assembly line.

Coating. This process uses one material to cover another. It may be done to decorate or protect the covered material. Some coatings do both. Painting is the most common coating process.

We saw earlier how computers play an important role in the design of products by using CAD, or computer-aided design to produce drawings and plans. Computers also play an important role in the processing of materials.

What is CAM? CAM stands for computer aided manufacturing. We have already learned about CAD. Click here if you want to review CAD. After CAD is used to design a product and make the drawings, there are two ways to make the finished product. One method is to give the drawings to a skilled machinist who could make the product using a machine tool such as a lathe or milling machine.

However, a good thing about CAD drawings is that they can also be downloaded into a computer on a CAM machine. The CAM machine can then talk to the computer and follow the computer's directions to make the part.

This machine tool is one CAM machine used to cut metal into shapes. Notice the computer on the right. Design plans and cutting instructions are downloaded into the machine directly from the CAD system. Once the machine begins its process, it does not require an operator. It even changes cutting tools by itself. The CAD/CAM system is a very valuable tool in modern manufacturing facilities.

Once the machine's computer is programmed, it does not require an operator. CAM speeds up production, reduces machining errors, and produces high quality uniform parts.