What is dip moulding?

Think of a pair of pliers. Specifically, the cushioned handles. They were made with dip moulding to make the grip comfortable, while protecting the metal underneath.

Dip moulding is a process that coats metal parts with polymers. You’ll find applications of dip moulding everywhere, from petrol pump handles and chair armrests to medical devices.

It’s both a cost-effective and time-efficient process. A mould, sometimes called a ‘mandrel’ or ‘tool’, is made of either steel or aluminium, and is single-sided. This typically only takes a few hours to make, as the mould required is usually straightforward. Think of those simple plier handles, compared to a mould for complex, intricate components utilising injection moulding, and you get the idea. Keep in mind that both processes have their own advantages, so the one you use depends on the application.

How dip moulding works

Step 1: Once the mould is made for the dip moulding process, it’s dipped in the desired material, such as neoprene, urethane or the most commonly used material, plastisol. Again, it depends on the application. For example, latex works well for medical devices, such as stethoscopes, as it’s robust and can withstand chemical abrasions.

Step 2: The material attaches to the mould. The thickness of the material depends on the ‘dwell time’, meaning the length of time the mould remains in the material. Depending on the desired results, this can vary anywhere from a few seconds to a few minutes.

Step 3: The moulds are placed in an oven to cure the material into a solid state.

Step 4: The moulds are then dipped into water to cool enough so that the products can be removed.

Step 5: The products are then removed, either manually or using compressed air.

The advantages of dip moulding

Dip moulding can cost less than other processes. Again, that’s because the moulds are single-sided and geometrically less complex than say, moulds made for injection moulding, so they’re faster to make.

Prototyping is also cost effective for this reason. Any changes to the mould are relatively easy and fast to make. All of this contributes to short delivery times for the manufacturer.

Dip moulding is especially cost effective for small-to-medium batches, though it can certainly be utilised for much larger volumes. The cost savings in making the mould are still the same. It’s also ideal when the material needed does not require a high rigidity level, as parts using injection moulding usually need.

Essentra are experts at both dip moulding and injection moulding. It’s worth talking to them to get help with considering your options and determining which process perfectly fits your objectives.