When should I choose vacuum forming over injection molding?

Vacuum forming is ideal for large parts (like automotive dashboards or radomes), low-to-medium production volumes (500 to 10,000 units), and projects requiring rapid prototyping. The tooling costs are a fraction of injection molding because the molds only need to withstand atmospheric pressure, not high-tonnage injection pressure.

What materials can be vacuum formed?

Common thermoforming materials include ABS, High-Impact Polystyrene (HIPS), Polycarbonate (PC), HDPE, and PETG. We frequently use UV-stabilized and flame-retardant grades for outdoor and transportation applications.

How are vacuum formed parts finished?

Because vacuum forming creates a part from a continuous sheet, the edges must be trimmed. We utilize 5-axis CNC routers and robotic trimming stations to cut the final perimeter, drill mounting holes, and route out internal windows with high precision.

Industrial Vacuum Forming & Thermoforming

When your component is too large for an injection press, or your production volume doesn't justify a $50,000 steel mold, Custom Molding Company provides heavy-gauge industrial vacuum forming. Operating from our quality-assured facility in South Africa, we deliver large-format plastic enclosures and trays at highly competitive landed costs.

Vacuum forming (a simplified form of thermoforming) involves heating a flat sheet of thermoplastic until it becomes pliable, stretching it over a single-surface mold, and applying a vacuum to pull the sheet tight against the mold geometry. Once cooled, the part retains its shape and is transferred to our CNC finishing department for precision trimming.

Vacuum Forming Specs

Heavy-Gauge Sheet (up to 12mm)
Large Format Enclosures
Low Tooling Cost (Aluminum/Epoxy)
5-Axis CNC Trimming
In-Mold Texturing

Compare Tooling Costs ↓

Heavy-gauge industrial vacuum forming machine shaping a large ABS automotive dashboard panel

Tooling Economics: Why Vacuum Forming Wins

The primary advantage of vacuum forming is the tooling cost. Injection molding requires massive, two-part hardened steel tools capable of withstanding thousands of tons of clamp pressure. Vacuum forming only requires a single-sided tool (either a male "plug" or a female "cavity") that only needs to withstand 14.7 psi of atmospheric pressure.

Tooling Material	Production Volume	Cost Profile	Lead Time
MDF / Wood	1 - 50 units (Prototyping)	Extremely Low	1-2 Weeks
Cast Epoxy Resin	50 - 500 units	Low	2-3 Weeks
Cast/Machined Aluminum	500 - 50,000+ units	Medium (fraction of steel)	4-6 Weeks

5-Axis CNC Trimming & Finishing

Vacuum forming is a near-net-shape process. The formed part remains attached to the surrounding plastic sheet and must be separated. At Custom Molding Company, we utilize advanced 5-axis CNC routing stations to perform post-mold finishing.

Our robotic routers follow precise CAD toolpaths to cut the final perimeter, machine out internal windows (e.g., for display screens or ventilation), and drill mounting holes. This ensures that every vacuum-formed enclosure meets the exact dimensional tolerances required for final assembly.

Common Materials & Applications

ABS (Acrylonitrile Butadiene Styrene): The most common thermoforming material. Excellent impact resistance. Used for automotive interior panels, luggage boxes, and medical equipment housings.
HIPS (High-Impact Polystyrene): Cost-effective, easy to form, and readily printable. Widely used for point-of-purchase (POP) displays and custom packaging trays.
HDPE & Polycarbonate: Used for heavy-duty industrial applications, radomes, and protective covers requiring high impact and chemical resistance.

Have a Large-Format Project?

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