How to improve the designs of your injection moulded parts.
In this 2nd volume of Designing for Mouldability, packed with useful tips on designing parts for injection moulding, designers can address the challenges of parts that have indentations, through-holes, and other features that don't point straight up or down. Download this FREE paper to learn about side-action cams, sliding shutoffs, pickouts, and bumpoffs.
Here is an extract from Designing for Mouldability Volume 2: Undercuts and Through-Holes
A Sideways Look at Rapid Injection Moulding
Houses in Monopoly™ land have no doors or windows. Maybe the tiny people who live there spend a lot of time indoors, or perhaps they've perfected teleportation. More likely, it's because doorless windowless plastic houses are easy to make in simple two-part moulds.
In the real world - including the world of plastic parts - life is more complicated. Houses have doors, and parts have indentations, through-holes, and other features that don't point straight up or down and could act as undercuts in a two-part mould. Designers using rapid injection moulding can address these challenges in a variety of ways, including side-action cams, sliding shutoffs, pickouts,
and bumpoffs as discussed in this volume.
Side-Action Cams
The most obvious approach to undercuts is side actions - mould pieces that act from the outside of the part, moving perpendicular to the direction of mould opening. These produce side-facing features in a closed mould and then automatically withdraw, allowing the A-side mould half to withdraw, as the mould opens, and the part to be ejected from the B-side. In Figure 1, a side-action cam produces the door, sealing against the B-side core as the mould fills and then withdrawing to allow ejection. A similar technique could produce non-through indentations that would otherwise act as undercuts.
To continue reading download our Designing for Mouldability Volume 2: Undercuts and Through-Holes white paper here.