WHAT IS VACUUM FORMING?

Vacuum forming is a type of thermoforming that involves taking a plastic sheet and draping it over a mold to form a part of a shape. The sheet is heated to form over the mold, and then completely vacuum-sucked to the mold so there is no air between them. Then, the sheet is removed from the mold and cooled off. Finishing services can be performed, including trimming if the sheet is too long for the actual part.

Vacuum forming utilizes either male or female molds; the former requires the sheet to be placed over the mold, and the latter has the sheet placed inside the mold.

HOW DOES VACUUM FORMING WORK?

There are several steps involved in the vacuum forming process, which begins with the clamping of the thermoplastic sheet into a frame. Heat is then applied until the sheet starts to sag.

Once the sheet has been heated enough to be formed, vacuum pressure is applied to pull the sheet across the mold and form the final shape. The next step is the cooling process, followed by the removal of the plastic part from the frame and the trimming of excess material.

WHAT KINDS OF PLASTICS DO YOU USE FOR VACUUM FORMING?

Many types of thermoplastic can be used in the vacuum forming process. Some of the most common materials include:

CAN POLYPROPYLENE BE VACUUM FORMED?

Yes. Below are some of the pros of using this type of polymer in the process:

  • Polypropylene is less expensive than some other plastics.
  •  It is good at high temperatures, of 100°C and up.
  •  It is good in harsh environments.

Tips to keep in mind when vacuum forming with polypropylene:

  • Putting cavities or moats in the mold can prevent the polypropylene sheet from sliding.
  •  Pressing the sheet between two surfaces also helps keep it in place.
  •  Female molds are better when using polypropylene sheets.

BENEFITS OF VACUUM FORMING

Vacuum forming isn’t expensive, due to the low pressure required that allows molds to be made from less expensive plastics. The process is quick and efficient, so anything from prototypes to large production runs can be created easily.

Less tooling is involved than in traditional thermoforming, which can be very complicated. It is also a good alternative to other thermoforming processes, 3D printing, and injection molding.

APPLICATIONS OF VACUUM FORMING SERVICES

An expanding application is growing trays for greenhouse and indoor growing applications including flood benches, sub-irrigation, and re-circulation systems.

Some of the common applications include:

  • Medical devices and components
  • Enclosures
  • Machinery guards
  • Signage
  • Trays

VACUUM FORMING BY WS HAMPSHIRE

WS Hampshire is a class-leading specialist in vacuum forming operations. We can form acrylonitrile butadiene styrene, high-density polyethylene, high-impact polystyrene, polyvinyl chloride, polycarbonate, polyethylene terephthalate, and most other polymers.

We can also form your choice of materials, with a tolerance of .250”. Our molding processes include deep drawing, pressure forming, and both single-sheet and twin-sheet vacuum forming.

Our processes conform to many different industry standards, with the most common being:

  • American National Standards Institute (ANSI)
  • American Society for Testing and Materials (ASTM)
  • Military specifications (Mil-spec)
  • Restriction of Hazardous Substances (RoHS) compliant

To learn more about our vacuum forming processes or to get started on a project, contact us to request more information.

MOLDED BENCH TRAYS  Request Information

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    Thermoforming & Vacuum Forming Capabilities

    Operations

    Thermoforming
    Vacuum Forming

    Material Thickness

    0.062 to 0.375 in

    Maximum Sheet Length

    72 in

    Maximum Sheet Width

    54 in

    Tolerance (+/-)

    +/- 0.250″ in

    Molding Process

    Deep Draw capable
    Pressure Forming

    Vacuum Forming

    • Single Sheet
    • Twin Sheet
    Equipment Capabilities

    Manual

    Materials

    ABS
    Acrylic
    H.I.P.S.
    Lexan
    PET

    Polyethylene
    Polypropylene
    PVC
    Styrene

    Additional Services

    Mold Design
    Mold Fixture Making
    Assembly
    Deburring
    Drilling
    Riveting

    Silk Screening
    Edge Polishing
    Stress Relieving
    Hardware Insertion
    Painting

    Typical Products

    Barrels
    Belt/Chain Guards
    Power distribution line insulators
    Safety equipment

    Heavy Equipment Components

    • Guards
    • Covers
    • Panels
    Production Volume

    Specialty Production Shop
    Prototype

    Low Volume
    Small Run

    Lead Times Available

    3 – 4 weeks on repeat production parts
    6 – 8 weeks on new parts

    Quoted on job by job basis
    Expedite services available

    Industry Focus

    Agricultural
    Safety Products
    Marine

    Industry Standards

    ANSI
    American National Standards Institute
    ASTM
    American Society for Testing and Materials
    CE
    The CE mark (officially CE marking) is a mandatory conformity mark on many products placed on the single market in the European Economic Area (EEA).
    CSA
    Canadian Standards Association
    Mil-Spec
    Military Specifications
    RoHS
    Restriction Of Hazardous Substances (Compliant)
    REACH Compliant

    Efficiency

    Lean Manufacturing

    File Formats

    #4 Preferred – AutoCAD (DWG,DWZ)
    # 3 Preferred – DXF
    Drawing Interchange Format, or Drawing Exchange Format
    GIF
    Graphics Interchange Format
    #2 Preferred – IGES
    Initial Graphics Exchange Specification, ANSI file format.
    JPG or JEPG
    Joint Photographic Experts Group
    PDF
    Portable Document Format
    #1 preferred – SolidWorks (SLDPRT, PRT)
    TIFF
    Tagged Image File Format

    Machine Manufacturers

    Monarch
    Comet