As a thermoforming mold maker, we build the vacuum forming tools that turn plastic sheet into trays, blisters, clamshells and lined crates. Buyers usually meet thermoforming for the first time on the packaging side, but the same tooling logic covers automotive liner trays, medical blister packs and point-of-sale displays. This page explains what a thermoforming mould actually contains, how aluminium and steel tool bodies differ, and the specification sheet you should request before ordering vacuum forming tools. If you are comparing tool sources, our plastic mould tools catalogue covers related mould categories, and this guide on how to verify a Chinese plastic factory sets out the checks worth running before a tool deposit is paid.
What Goes Into a Thermoforming Mould
A vacuum forming tool is not one block of metal. It is an assembly, and each element is a separate cost and quality line on the quotation:
- Mould body - the female cavity that gives the part its shape, usually CNC-machined from billet rather than cast, so surface finish and draft angles stay under control.
- Vacuum network - drilled holes and slots that pull heated sheet against the cavity. Hole density and diameter decide how corners and deep draws reproduce.
- Cooling circuits - channels that set the part before it is released. Under-cooled tools stretch the cycle and thin the sheet at the draw points.
- Trim fixture - the cutting jig that removes the formed part from the web. A matched trim fixture is what keeps edges square across thousands of cycles.
Aluminium or Steel: Choosing the Tool Body
6061 aluminium is the default for short and medium runs. It machines roughly three times faster than steel, so tooling cost and lead time stay low, and it conducts heat well enough for packaging cycles. The trade-off is wear: aluminium tools show erosion at deep-draw corners after a few hundred thousand hits. P20 or 718H steel bodies cost more up front but hold edges and vacuum slots far longer, which matters when the tool runs every day on a high-speed form-fill-seal line.
Specifications to Request from a Toolmaker
- Cavity count and pitch, plus whether family tools are quoted as one frame or separate tools.
- Sheet thickness range the tool is designed for, and the maximum draw depth per cavity.
- Cooling circuit layout and the target cycle time at a stated sheet temperature.
- Trim method: in-place punch, offline router, or CNC-trimmed with a fixture supplied.
- Tool material, surface finish target, and the polishing grade on cosmetic faces.
Lead Time and Tooling Cost Drivers
Vacuum forming tools sit in a wide cost band because the drivers are transparent: cavity count, machining hours, material choice and trim complexity. Ask for the quotation split by body, cooling and fixture - a single-cavity aluminium packaging tool is a fast job, while a twelve-cavity steel tool with matched trim fixtures is a project in its own right. When you shortlist suppliers, the verified company directory lists toolmakers alongside adjacent mould categories, which makes side-by-side requests easier.
