How to estimate the thickness of a thermoforming products?

When the thickness of the unformed material is known, we can roughly estimate the thickness of the thermoformed part. Due to the irregular distribution of the designed wall thickness and the final formed wall thickness of the part, the final calculation result must take into account the wall thickness distribution of ±30%. For this calculation, it must be assumed that the volume of the material remains unchanged throughout the forming process.

Therefore, the following formula holds: V₁=V₂

So:                F₁·S₁=F₂·S₂

Thus:                S₂=F₁/F₂·S₁,

Where        V₁: Material volume excluding clamping edge;

V₂: Volume of hot-formed part;

F₁: Material area excluding clamping edge;

F₂: Part surface area;

S₁: Raw material thickness;

S₂: Part wall thickness.

Example of wall thickness calculation:

① Determination of wall thickness of rectangular hot-formed part.

Let F₁/F₂=0.33. For a thermoformed part with a raw material thickness of S₁=4mm and uniform thickness distribution, its wall thickness is: S₂=0.33×4mm =1.32mm. Due to the uneven fluctuation of the wall thickness of the thermoformed part, the actual thickness of the part is distributed between 0.9 and 1.7mm.

S₂±30%=1.3mm±0.4mm≈0.9～1.7mm

② If the wall thickness of the part is specified, the thickness of the required material is determined.

If the average thickness of the part is S₂=2mm, what is the thickness of the required raw material?

The following is the calculation result of the material thickness: S₁=S₂·F₂/F₁=2/0.33mm≈6mm Due to the irregular distribution of the wall thickness of the part, the thickness of the selected material should be increased by 30% compared with the calculated value, which can be 8mm (6+30%≈8mm).