What are Some Mold Design Considerations?

Design and engineering, Tolerances, Expected lifecycle of the mold, Gates, sprue bushings, and runners, Cooling channels and vents, Ejector pins, Compatibility with the press, Materials, Equipment

Mold Building Capabilities - Dramco Tool Co. Inc.

Injection molding is an efficient and cost-effective way to mass-produce virtually identical components and parts. This process is compatible with many types of polymers and can be used to create high-precision, complex, and intricate parts in a range of sizes. But an injection molded component is only as good as the metal mold used to form it.

At Dramco, we support high-quality injection molding by designing and building precision small and high cavitation molds. We also offer design and build of EOAT (End of Arm Tooling) and robotic cells for full automation for all your molding needs. Learn more about mold design considerations and our full-service capabilities.

Dramco has an extensive background in designing and building of composite tooling including layup, compression and RTM Molds with multi piece mandrels. With these services we also offer bond fixtures, drill and trim fixtures, vacuum machining fixtures and autoclave tooling carts. Dramco has experience with high nickel content materials such as Vascomax or Maraging Steel Alloys materials.

Mold Design Considerations

While choosing a suitable plastic for the injection molding process is important, the design and manufacturing of the mold itself are critical to creating the part features, holding tolerances and obtaining efficient cycle times. There are several important considerations that go into developing a high-quality mold for injection and composite molding.

Design and engineering. CAD software is used to create a computer model of the mold. It includes specifications like the draft angles, rib placement, number of cavities, and wall thickness for optimal results. This stage of design also includes planning the cavity shape and core for ejection.
Tolerances. Molded parts are produced to be within tolerances for dimensions, flatness, and other measurements. These are sometimes called resin tolerances, since they refer to the actual produced part. However, it is also important that the metal molds be manufactured within designated tolerances, especially in multi-cavity molds. This is the machined tolerance. Both types of tolerances are critical to part fit and function, and must be defined for each application.
Expected lifecycle of the mold. The production characteristics for the part have an impact on mold making design and materials. It’s important to know if the mold will be used for long-term production, if high-volume molding or fast cycle times are anticipated, and if the mold will be regularly swapped out of the press for other molds.
Gates, sprue bushings, and runners. Gates are areas where fluid plastic material enters the mold cavity. The type of gate, such as direct, hot runner, or runner, and the location allow the material to completely fill the mold. The sprue bushing presses against the injection nozzle and directs the plastic through machined runners into the mold cavity or cavities. These must be designed carefully so they evenly distribute the melted plastic.
Cooling channels and vents. Properly placed cooling channels and vents help control the release of heat so the part cools, solidifies without gas trapping.
Ejector pins. These components push completed pieces out of the mold cavity, and must be placed correctly and exert sufficient force to reliably eject the part without causing damage.
Compatibility with the press. Presses use a variety of tonnage to clamp the two halves of the mold together and apply pressure as the material cools and solidifies. Molds must be constructed to withstand the forces they will be subjected to repeatedly during production.
Materials. Things like production volume, production run length, and even plastic choice help determine the appropriate metal for injection molds. Hardened tool steel is common, although aluminum or even beryllium copper can be used for certain applications.
Equipment. Our facility houses a full suite of CNC machines for vertical and horizontal milling, EDM, and turning to remove material and create precise mold cavities, along with equipment for grinding, cutting, punching, and sheet metal fabrication.

Our Mold Manufacturing Capabilities

Dramco is a full-service mold manufacturer with a focus on designing and building custom molds for complex parts and components. We serve the automotive, consumer products, aerospace and defense industries, along with other applications that require high-quality, precision injection molds. Our capabilities include:

Single or multi-cavity mold for making one or multiple parts at once.
Molds to fit in presses up to 1,300 ton capacity.
Parting lines that maintain alignment for the life of high-volume production runs.
Two-shot or multi-shot injection molds for overmolding and other applications.
Complex shapes and intricate part features, including undercuts, bosses, and tight corners or angles.
Surface finishes can be built into molds, including glossy, smooth, or textured.

Molds for A Variety of Plastics and Composites

At Dramco, we manufacture molds that are compatible with a large variety of plastics and composites. These include ABS, nylon, and polypropylene for automotive applications, and ABS, polycarbonate, TPE, and polypropylene for the consumer goods market, including household and fashion items. In addition to these materials, our molds can be used with acrylic, nylon, HDPE, LDPE, polystyrene, PVC, SMC, BMC, and more.

We have vast experience designing and building molds used with many types of plastics, part sizes, and features. Our team can build molds that hold tight tolerances, accounting for material shrinkage and other factors.

Why Choose Dramco?

As a full-service mold manufacturer, Dramco provides expert engineering, design, and manufacturing of high-quality, precision injection molds, compression molds and composite tooling. We work with customers in multiple industries to support a range of molding techniques and materials.