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While most of us are unfamiliar with vacuum forming, the process is responsible for the packaging surrounding millions of everyday products. Vacuum forming is actually a simplified version of thermoforming, in which a thin sheet of plastic is heated to a high temperature so the plastic can be stretched onto a mold by use of a vacuum.

The process offers a wide range of benefits to manufacturers with its high-volume capability and simplicity of storing large quantities of plastic sheets. High quality, high volume, and low cost are all attractive to customers as well.

Vacuum Forming At Work

Left to its own devices, vacuum forming is only capable of producing shallow products such as plastic signs, covers, and product packaging for small items. Ubiquitous blister packs and clamshell packaging use this process.

To obtain three dimensions, manufacturers combine vacuum forming with line bending equipment, making it possible to create everyday products like TVs, speakers, point of sale displays and plastic containers. In fact, vacuum forming has proven to be highly adaptable and is used today for a variety of display marketing and promotional items. It’s fast, low cost and easy, making for reliable turnaround.

Vacuum Forming Mold Material

The first step of the vacuum-forming process is to create your mold, also known as “tooling.” This is usually the most in-depth step of the process. The most commonly used plastic in vacuum forming is acrylonitrile butadiene styrene (ABS). Other plastic will work, but keep in mind that the thicker the plastic is, the more heat and vacuum pull you need.

There are several ways to create vacuum forming mold; the one you use ultimately depends on your end goal, available resources, and how long you need the tool to last. Molds used in vacuum forming are made of an array of materials including: cast, plaster, clay, resin, wood, aluminum, and polyurethane.

Here is a look at the most common mold material options:

• Wood or MDF. Best for smaller production runs or teaching the basics of the technology as opposed to producing usable parts.
• Cast Resins. Ideal for larger production runs because resin tools can be sanded to a very smooth finish.
• Cast Aluminum. Cast aluminum tools may require extra finishing but the end product is very strong and this option is ideal for large production runs.

Other mold materials can also work well, depending on your project needs. To determine which mold is best suited to an application, you’ll want to analyze the inherent details and select a mold material that results in the highest quality with most efficient resource use.

Odds are good that you will purchase some kind of consumer product today. It might be anything from a package of new AA batteries to a toy for your child. Whatever the item is, it will likely be ensconced in vacuum sealed plastic. Indeed, a large majority of today’s products all over the world are sealed and made sale-ready in some form of plastic packaging.

Have you ever wondered how companies wrap products in such form-fitting dress? The process is called thermoforming, which is a plastic molding manufacturing technique that heats thin plastic sheets to a pliable temperature, at which the plastic is easy to manipulate and form over a mold. Vacuum forming is a simplified sub-process of thermoforming, where heated plastic is stretched onto a mold and forced against the mold via a vacuum force.

Vacuum Forming’s Inspiration

Innovative people have used natural rubbers and cellulose to accommodate many different life needs for thousands of years. The development of synthetic plastics, however, didn’t really get its start until the 19th century. Celluloid was the world’s first highly-usable plastic, developed by inventor John Wesley Hyatt. His cellulose creation was an improved version of parkesine, a plastic created by Alexander Parkes, one of Hyatt’s English inventor colleagues. In addition to improving celluloid, Hyatt also patented the first injection molding machine.

When it comes to vacuum forming, we salute a trio of innovative minds. The first thermoforming machine patents were filed by H.L. Helwig of the Rohm & Hass Company, and R.E. Leary, an engineer at DuPont. These crafty inventors employed a variety of methods to heat plastic, such as convection and radiant heat, or using hot oil or steam. In 1947, along came G.W. Borkland from Indiana, who filed a patent for a “vacuum forming” machine. Borkland would go on to make many other improvements in the world of vacuum thermoforming, and his influence introduced the world to a new form of product sealing.

Vacuum Forming In Action

The vacuum forming concept is relatively simple: A vacuum is used to produce an even distribution of pressure on a material’s surface to allow the material to conform to the shape of a mold. Thin sheets of plastic are fed into a vacuum thermoforming machine and heated until they are malleable, and then forced onto the mold in a very precise process.

In addition to sealing everyday items, vacuum sealing is also used to create intricate and incredibly strong products such as road signs, boat hulls, and an array of protective covers.