As automotive manufacturers happen to be driven to lessen vehicle weight, Tool Engineering has upped it game of helping develop more and more complex plastic injection molds. While soft tool overmold tolling process is also considered to be a substitute for dual injection molding process, making and building plastic injection molds for overmolding applications, gating, insert, substrate placement and retention throughout the molding cycle are critical. Engineering the overmold to interface with automation to ensure that parts might be loaded just before molding (after which removed) is essential to allowing’ our customers run these molds at top efficiency, producing high-quality parts.

Our engineers love the task.

The intricacies involved with manufacturing a car door handle, for example, are difficult to assume. The geometrical complexity of designing a plastic injection mold that creates plastic with the effectiveness of steel is demanding.

Overmolding has shown to be a highly effective way of accomplishing this finish.

What’s Overmolding?

Over-molded Tooth Brushes In overmolding, just one part is produced using a mix of several various materials. The very first material (the substrate) is partly or fully taught in subsequent (overmold) materials throughout the manufacturing process.

Hard plastic substrate provides structural support. The 2nd material usually supplies a soft texture. (For example, screwdriver handles and toothbrushes are typical hard-soft overmolded products.) Overmolding enables using two various materials without needing additional glues or fasteners.

The substrate might be just about anything: a machined metal part, a molded plastic part, or perhaps an existing product (for example threaded inserts, screws or electrical connectors). The substrate may be the grounds for what’s going to eventually be just one continuous part, produced from chemically glued (and frequently robotically interlocked) materials of various types.

The overmold materials are frequently plastic-based and therefore are typically by means of pellets. These pellets will be combined with colorants, foaming agents and other kinds of fillers. The pellets are melted lower and also the resulting liquid is injected in to the mold tooling.

How Do You Use It?

The overmold process is rather straightforward:

1. The substrate material or part is positioned into a shot molding tool
2. The overmold materials are injected into, onto or round the substrate
3. The overmold materials are permitted for stopping or solidify
4. The end result: two materials became a member of together like a single part.

Typical over-mold combinations include:

Plastic Over Plastic – A rigid plastic substrate is molded first, adopted by another rigid plastic overmold around or on the substrate. The 2 plastics frequently differ colored and/or resin.

Rubber Over Plastic – A rigid plastic substrate is molded first, adopted by Soft Tool Overmold Tooling with a soft rubber or TPE overmold. (TPE, or thermoplastic elastomer, is a mixture of polymers, typically plastic and rubber.) This method is frequently used to produce a rigid plastic spend a gentle grip area.

Plastic Over Metal – Metallic substrate is first machined, cast or created. This will make it placed into a shot-molding tool, in which the plastic is molded onto or round the substrate. This method is frequently accustomed to capture metal components inside a plastic part.

Rubber Over Metal – Metallic substrate is first machined, cast or created. This will make it placed into a shot molding oral appliance rubber or TPE is molded onto or round the metal. This method can be used to produce a rigid metal spend a gentle grip surface.

Why Overmold?

Over-molded Hands Held Electric DrillThe most typical causes of while using overmold process are:

To interrupt up color (for appearance)

To supply a soft grip surface around a rigid part (e.g., hands tools)

To include flexible areas to some rigid part

To capture one part within another part without using fasteners or glues

To lessen production time. Overmolding eliminates the necessity to assemble two individually manufactured components (like a metal oral appliance a rubber hands grip). Overmolding the metal tool having a rubber handgrip eliminates the set up process.

Replacing Metals with Plastics

AdobeStock 108665382For the automotive industry, replacing metal rich in-performance plastic injection or compression-molded components is really a proven technique for vehicle fat loss. Typically, vehicle fuel mileage improves 2% for each 100 lbs. of fat loss.

For instance, overmolding with a few of the new all-plastic composites has become replacing overmolds which use heavier plastic-metal “hybrid” composites. To date, these new overmolded plastics are used mainly on automotive interiors. But additional applications are anticipated.

When mass production is coupled with vehicle fat loss, the outcomes are astonishing. Lowering the vehicle weight from the 70 million lightweight vehicles created yearly wouldn’t only decrease CO2 emissions it might save 90 million gallons of fuel – enough fuel to power 180,000 vehicles for any year.