Metal insert molded component with bonded plastic and metal

Metal Insert Molding

Metal components - bushings, threaded inserts, terminals, structural brackets - are placed into the mold before injection. Plastic is molded around them, creating a single integrated metal-plastic component in one cycle without secondary assembly.

DA and DK Series vertical machines can be reviewed for metal insert molding. Rotary or slide table configuration depends on insert size, weight, mold design, and production volume.

Application Overview

What is metal insert molding and why use a vertical machine?

The process

A metal insert - bushing, threaded nut, terminal, or structural bracket - is placed into the lower mold. The vertical clamp closes from above, plastic flows around the insert, and after cooling the bonded metal-plastic part is ejected.

This eliminates post-molding assembly: no press-fitting, no staking, no adhesive bonding of metal to plastic. The result is a single component where the metal provides strength, conductivity, or thread engagement, and the plastic provides form, insulation, and corrosion resistance.

Why vertical clamping matters for metal inserts

Metal inserts are heavier than the plastic resin - gravity is a significant force. In a horizontal machine, the insert can drop or tip during mold closing, causing scrap or mold damage. Vertical clamping holds the insert naturally in place:

Threaded brass or steel inserts remain perpendicular to the mold surface
Large structural brackets stay seated in the lower mold cavity
Multi-insert layouts - all inserts remain in their cavities during clamping
Heavy metal cores (several hundred grams) that would need complex retention in horizontal molds

Common Challenges

Production challenges in metal insert molding

The interaction between metal insert placement, clamp force, and injection parameters determines part quality and tooling life.

Insert positioning and retention

Metal inserts must stay precisely positioned during mold closing and injection. Vertical clamping uses gravity for natural retention. Slide and rotary tables let the operator place and verify inserts at a dedicated loading station outside the clamp area.

Clamp force selection for metal-plastic bonding

Insufficient clamp force causes flash around the insert; excessive force can deform or crush it. Proper tonnage depends on projected area and insert geometry. Deboge helps evaluate the right clamp force for your mold and insert combination.

Loading efficiency for heavy inserts

Large metal inserts (brackets, structural cores) are heavy and awkward to load. Slide tables move the lower mold out for ergonomic loading. Rotary tables let the operator load while another station molds, improving throughput without rushing insert placement.

Configuration Review

Recommended machine configuration for metal insert molding

Starting points - final selection depends on insert size and weight, mold design, material, and production volume.

Machine series

DA Series

Standard vertical clamping + vertical injection. Broad coverage - from small threaded inserts to mid-size metal brackets. Fixed, slide, or rotary table. 15T-800T.

View DA Series →

Machine series

DK Series

Vertical clamping + horizontal injection. Commonly considered for larger-tonnage metal insert applications. 100T-800T.

View DK Series →

Table configuration

Rotary table

Multi-station rotating table for efficient insert loading. Operator loads at one station while another molds - labour time overlaps cycle time.

View Rotary Table Machines →

Table configuration

Slide table

Lower mold slides out for accessible loading. Single or double slide. Suits large or heavy metal inserts needing careful placement.

View Slide Table Machines →

Machine size must be confirmed from project data - Review projected mold area, insert size and geometry, cavity count, material, and mold structure before selecting tonnage.

Materials

Typical materials for metal insert molding

The plastic must bond well to the metal surface. Metal surface preparation (cleaning, texture, pre-heating) and insert design affect bond quality and cycle consistency.

PA66 (Nylon)

Common for mechanical components with metal threaded or bushing inserts. Good mechanical strength and heat resistance. Glass-fiber-reinforced grades for higher stiffness.

PBT

Common for electrical and electronic parts with metal terminal inserts. Good dimensional stability and electrical insulation. Low moisture absorption.

PPS (Polyphenylene Sulfide)

Engineering thermoplastic often reviewed for under-hood automotive and industrial electrical parts. Chemical and heat resistance should be selected from the supplier material grade data.

PP (Polypropylene)

General-purpose material for consumer and industrial components with metal inserts. Good chemical resistance. Cost-effective for high-volume production.

POM (Acetal)

Precision mechanical components - gears, bearings, sliding parts with metal shaft or bushing inserts. Low friction, high dimensional stability.

PC+ABS

Consumer and industrial housings with threaded brass or steel insert molding. Good impact resistance and surface finish.

Products

Typical metal insert molded products

From automotive to industrial equipment - metal insert molding produces structural, conductive, and threaded plastic components.

Metal insert molded industrial component

Structural brackets & housings

Plastic housings with molded-in metal structural inserts for load-bearing assembly points.

Threaded insert components

Brass or steel threaded inserts molded into plastic for durable assembly fastening points.

Electrical terminals & connectors

Metal terminals and contact pins molded into insulating plastic housings for electrical applications.

Fastener & hardware integration

Screws, nuts, and hardware molded directly into plastic parts for one-step assembly-ready components.

DA Series - Standard Vertical Injection Vertical clamping + vertical injection. Commonly reviewed for metal insert molding applications. DK Series - Vertical Clamping Horizontal Injection Vertical clamping + horizontal injection for larger-tonnage metal insert molding. Rotary Table Machines Multi-station rotating table for efficient insert loading and molding. Slide Table Machines Single and double slide table for accessible heavy insert placement.

FAQ

Metal insert molding - frequently asked questions

Why use a vertical machine for metal insert molding?

Vertical clamping holds metal inserts in place by gravity during mold closing - critical for heavy metal inserts that would shift or fall out in a horizontal machine. The operator loads inserts into the lower mold half, and the clamp closes from above without disturbing placement.

Which table configuration fits metal insert molding?

Rotary tables suit higher-volume production - load at one station while another molds. Slide tables move the lower mold out for accessible loading, preferred for large or heavy metal inserts. Fixed platen works for simpler insert configurations with direct loading.

How should machine size be reviewed for metal insert molding?

Tonnage should be reviewed from projected mold area, cavity count, insert size, insert geometry, material, and mold structure. Metal insert projects vary widely, so the machine size should be confirmed from the actual part and mold data.

Which machine series is commonly reviewed?

DA Series is commonly reviewed for metal insert molding. DK Series may be reviewed for larger metal insert applications where vertical clamping with horizontal injection fits the mold and shot requirements. Selection depends on part size, insert weight, material, and mold design.

What materials are commonly used for metal insert molding?

PA66 for mechanical components and connectors. PBT for electrical parts. PPS for high-temperature applications. PP for general-purpose components. POM for precision parts. The plastic must bond well to the metal surface - surface preparation and insert design affect bond strength.

Can a machine be customized for large or complex metal inserts?

Yes. For large structural metal inserts, unusual geometries, or automation integration, the engineering team can discuss a custom platform after reviewing your product details, insert layout, mold design, and production targets.

How do I discuss machine configuration for metal insert molding?

Send your product details, metal insert specifications, material, mold dimensions, and production volume through the contact form. An applications engineer can review the project and discuss a suitable machine series, table configuration, and machine-size direction.

Tell us about your metal insert molding application

Discuss machine configuration for your metal insert molding project

Send your product details, metal insert specifications, material, mold dimensions, and production target. The engineering team can review the project data and discuss machine series, table configuration, and machine-size direction.

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