10 Considerations in Blow Mold Design

1. Mold construction

Choose a mold construction that supports machining, maintenance and removal of the finished part.

Color-coded jerry can mold design illustration

2. Parting surface

Review the parting surface against the product shape, tooling complexity and release from the mold.

3. Cavity dimensions

Account for the chosen resin and the actual product design. Shrinkage assumptions should be confirmed for the material and process.

Color-coded container mold section illustration

4. Cooling

Arrange cooling around the product’s wall distribution and geometry so that the trial can establish a consistent cycle.

5. Mold envelope and guidance

Confirm the external mold dimensions, guide arrangement and mounting against the machine specification.

Jerry can mold with highlighted side regions

6. Venting

Consider trapped air in the cavity and select the venting approach for the geometry, material and surface requirements.

7. Mold material

Balance thermal behavior, strength, wear, corrosion, finish, manufacturing and maintenance requirements.

8. Machine compatibility

Check head spacing, platen opening, mold movement and the other dimensional limits of the selected configuration.

9. Pinch-off and cutting edges

Design the pinch-off and cutting features for the material and required joint or flash condition.

10. Flash accommodation

Provide the necessary flash space and assess the pinch-off region on trial parts. Confirm product integrity as well as trimming performance.

Review with the finished part

Bring the drawing, resin, required product checks and proposed machine together in the mold review. See the machine selection guide for a project checklist.