Manufacturing Methods Every Engineer Student Needs to Know

The manufacturing industry is one of the world’s leading business sectors, and for good reason. Almost every product we have, every tool we use, even the stuff that we wear is manufactured in some way. With the wide array of designs and materials that can be used to create products, it’s no surprise that there is a plethora of manufacturing methods and techniques that countless companies from all across the globe are using.

Some methods are used because they are cheap and make manufacturing more profitable, while others are being utilized because they’re lean, create less waste and, therefore, are good for the environment. Every single manufacturing method out there has some merit, otherwise, it would not be as widespread as it is. There are far too many variations and different techniques to make a list of a sensible length. So, this article explores some of the most common and well-utilized methods for manufacturing plastic, wood and metal. This should provide a great overview of manufacturing and includes all the methods an engineering student should know.

Plastic

Plastic is one of the most-used materials for manufacturing because it’s super durable, fairly lightweight, cheap to use, and, when warmed to the right temperature, is super easy to mold and shape. On the flip side, plastic is not a great material for the environment, due to how it takes a long time to decompose and how when burned or consumed it can produce harmful toxins that can damage wildlife and habitats. There is a huge challenge for manufacturers on the horizon: How to use plastic in a sustainable way? Some options are to use recycled source materials and to utilize lean manufacturing to reduce waste products. Find out more about lean principles here. Regardless, plastic is set to continue to be one of the main materials for end-use parts and products for a long time. Here are some of the top manufacturing methods.

3D Printing

3D printing has emerged as a super-effective way to manufacture plastic items over the past few years and is a super ingenious development that’s expected to rise in popularity and change how consumers buy and create goods. 3D printers create three-dimensional parts directly from CAD models by precisely building layers upon layers of plastic until the desired shape is created. There are three main methods of 3D printing, and each one alters the process slightly. They are:

  1. Fused Deposition Modeling (FDM), which melts a plastic filament to create the designs.
  2. Stereolithography (SLA), which cures liquid resin to create the desired shape.
  3. Selective Laser Sintering (SLS), which fuses plastic to create items.

3D printing technology can create a whole host of goods, such as parts for machinery, cutlery and so much more. The printers require no tooling and the minimal setup makes the accessible to use, plus it’s a really cost-effective way of making custom one-off parts, making it a perfect device for businesses that make individual products per order. Depending on the product, the time it takes to produce something is short as well, which is why 3D printing is really favored when making prototypes, as it drastically decreases the development time for new ideas.

CNC Machining

CNC machinery includes gadgets such as mills, lathes and other computer-controlled processes that work by subtracting from a source material that can either be plastic or metal. In the same way a sculptor can chip away at a piece of marble to create art, a CNC machine does the same thing and removes all excess material from the block material until the desired shape is created. This is known as a subtractive process and goes against the norm for most plastic manufacturing techniques.

To operate, these machines need a wellcreated toolpath, which is computer guidelines to let the machine know where to move it’s cutting tools, at what speed it should operate at and when a tool changeover is required. Getting this toolpath correct is vital as any miscalculations could botch the whole project.

CNC machines are perfect for creating intricate shapes and geometric designs that are tough to mold, however, the cost of manufacturing does increase depending on the complexity of the item. In addition, as the machine is chipping away at a material, it does result in a fair amount of waste product. These machines work great on all forms of hard plastic, including Acrylic, Polycarbonate and Polystyrene.

Polymer Casting

Polymer casting is a great manufacturing method used to create multiple iterations of a product quickly. It works by filling either a reactive liquid resin or rubber into a mold that when it reacts chemically solidifies and turns into a hard, durable plastic. Once hardened any excess casting artifacts like flash, sprues and seams are cut away or sanded down to create a fine, polished finish.

The molds used to shape the plastic can either be made out of an inexpensive latex rubber or vulcanized silicone rubber, however, these materials can quickly degrade after use due to how the chemical reactions of the resin can affect the material, meaning that each cast usually lasts around 25-100 times. Despite that, these materials are highly favored because of the precise detail they can reproduce, allowing manufacturers to create high-quality cast parts.

What makes polymer casting a pretty expensive method is the physical labor that is required for post-processing, increasing the cost per part. This means that this method is almost exclusively used for prototyping, short-run batch productions of limited items, as well as bespoke dental and jewelry applications.

Wood

Working with wooden materials is a far more tactile production process and usually requires a lot more manual labor to create high-quality products. Wood isn’t a very common production material, but still has a high presence in the furniture industry as well as in musical instruments and other tools. High-quality wooden goods can be pretty valuable, due to the craftsmanship involved, and come in two forms: hardwoods and softwood. Here are a couple of manufacturing methods for wood production.

Turning

Similarly to how CNC machines work, the process of turning wood involves attaching a piece to a lathe and carving away at the material as it spins at speed. A turning tool is then used – most commonly operated by a carpenter – and is pressed into the wood to alter its shape. This method is great for creating cylindrical and spherical shapes, such as bowls, bed posts and even baseball bats, but does require specialist skills from the work person operating on it. The turning tools are also really sharp so are quite hazardous for those working on the wood, and splinters can commonly fly off the material, so safety precautions need to be followed when using this method.

Steam Bending

Steam bending is a far more traditional method of shaping wood and uses the process of bending to create desired shapes and configurations. It works by placing strips of wood into a watertight chamber and pumping steam into it. This softens the fibers of the wood and enables it to be bent easily with reduced chances of it snapping. The bent wood is then clamped into a mold so that it dries in this new configuration so that it holds its new shape. This method is often used on timber and is great because the wood keeps its natural strength, making it a great structural product.

Metal

Metal is a really popular material used for heavy-duty items due to how strong it is and how it can withstand high pressure. Metal products keep their shape as well as the other properties of metal. Shaping metal can be a little tricky, however, due to the metal’s properties, but there are interesting ways to design metal and create useful and interesting shapes. Here are a couple of them.

Punching

To add holes into a sheet of metal, punching is required as this is an effective and precise way to manipulate the material. Punching machines work by placing the metal under a die and submitting it to a really high and concentrated amount of force to create a hole. For the hole to be the correct size the circumference of the drill must slot correctly through the die.

Punching is used for two reasons: the main one is to use the holes created to fasten latches or other foreign parts, while the other is to use the material punched out to create a smaller part of the project.

Casting

Casting metal has some similarities to polymer casting plastic products, however, for metal it’s a far more intense and hotter process. The process of casting metal starts out by melting metal into liquid form inside a furnace. Due to the high melting points of some metals, these furnaces get super hot and dangerous. Once the metal is in liquid form it’s poured into a mold and left to solidify where it takes up a new shape. This process is good for creating complex shapes and is often used to shape metals including steel, iron, copper, magnesium, silver and even gold.