Vacuum Form / Thermoform

The processes are similar, in both cases a sheet of thermoplastic is heated to a "drape form" temperature so that the sheet is pliable. The sheet is then placed over a male mold configuration, when the I.D. (inside dimensions) are critical or a female configuration, when the O.D. (outside configurations) are critical.

Pressure is then applied to the sheet. The pressure can be manual, matched male-female molds, or gravity. The part is allowed to cool and removed from the mold and is a thermoformed part. The process becomes vacuum forming when vacuum is introduced to the interior of the mold and the inside pressure is reduced below atmospheric pressure. The sheet is sealed against the mold surface through vacuum vents, and atmospheric pressure forms the part. Detail can be enhanced with the use of a pressure box or a vacuum assist.

Every project is different and has its' own challenges. These processes are nore of an art than a science. With over 3 decades of experience, Hagans Plastic Company (HPC) is capable of dealing with each challenge. "FIT", "FORM" and "FUNCTION" are words that are used to describe the customer's basic requirements.

Thermoforming or vacuum forming provide the "form" requirement. Fit and Function, normally the most expensive portion of the part cost are provided by secondary operations.

Secondary Operations

"Fit" is achieved by trimming the part to a specified dimension. The most basic method is to hand lay out each part with scribe lines. A skilled employee uses various hand tools to trim the part. This is a very labor-intensive operation usually reserved for prototyping or 2-5 parts. Until the latter part of the last century, the most common method was to "fixture" a project.

A trim fixture is built to the desired dimension. The part is indexed to the fixture and is clamped to the fixture. A hand router is then used to trim the part. Function depends on the requirements of the part. The requirement may be drill holes, slots or cut outs to be routed, etc. The process is currently used when a small quantity of parts are required.

The most cost effective, accurate, and repeatable process of obtaining "fit" and "function" today is the use of a Computer Numerically Controlled (CNC) router.

Injection Molding

Injection molding is a process where small beads of plastic are fed into a processing barrel, melted and injected into a mold with high pressure. This process is ideal for medium-high quantity products, also where complicated features are required in the part design. The first injection part was a billiard ball in 1868.