How are rubberized grips made?

Skills materials and processes
1

I’m designing a hand tool, and I am trying to find out how rubberized/gel grips are made, specifically this style: http://www.oxo.com/p-668-bypass-pruners-with-quick-cut-setting.aspx#

I’d like to know what material they are made from, how the pads are made, how they are attached to the handle, and who can manufacture them. I have no experience with this, so any information would be helpful.

Thanks.

2

TPR
Injection Mold

3

There are many ways to attach the injected thermoplastic rubber to the metal part. Best to get a sample and take it apart and see how they have done it.

4

google ‘gls overmolding’

5

Depending on the shape and material, some are compression molded.

6

Over molded or twin shot depending on your supplier, with a locking feature designed into the main part to ensure the material does not roll or pull away. Take a look at tooth brushes it is the same thing.

http://www.glstpes.com/pdf/om.pdf (read this)

7

This is a rubber part on top of a metal part according to my read of the link. Looking at the closeup I see a radius and a space under the rubber part, not a smooth flush transition that would indicate overmold. It looks like an assembled joint, glued or mechanical locking.

The trickiest similar assembly is a Gillette 3 blade razor, which definitely seems overmolded, I still cannot figure out that molding.

8

Theres a lot of places out there that do really high quality overmolding and avoid a lot of the steps/reveals/shutoffs typically associated with overmolding.

To nxakt’s point, that is just a rubber handle on a metal part - which may just be a rubber part that is staked down. I’ve seen examples of this where the rubber is overmolded onto a hard plastic part, and the plastic part gets heat staked in place, or where the rubber just has a series of barbs that can be pushed through in manufacturing but are harder to remove. Each application has advantages/disadvantages in tooling costs, but different levels of durability associated with each. Large areas of rubber by itself tends to not be very strong without a hard substrate.

9

The clue is in the way the grip (which is injection moulded) is held in the handle. For obvious reasons the aluminium handles are not solid. The recesses in each handle house the location areas of the grip. It is basically pushed into place as an assembly operation.

A lot of grips on these sorts of products are PVC, not TPR/ Rubber. PVC is much lower cost and if moulded in a textured tool, provides adequate grip. PVC is also used in dip moulding (the type of grip found on a lot of inexpensive tools such as pliars).