If you’re a plastics manufacturer, you’ve got to understand molds and tooling. This includes learning about the various parts, materials, life cycles and other considerations. By knowing what you’re dealing with, you’ll be better able to make informed decisions.
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Side-Action Cores
Side-actions are devices that slide into a part cavity perpendicular to the axis of the mold. They are used to form undercuts and add features to a molded part. Some typical applications include overhangs, undercuts, holes, slots, vents, cables, and fan vents.
Side actions are most frequently used for undercuts. Undercuts give the molded part a gripping force and keep the seal in place. Test tubes and small closures often have these undercuts.
In addition to undercuts, side-actions can also create threaded features and decals. When used correctly, side-actions can dramatically improve the geometries and function of a part.
To achieve this, a quality side-action system provides 100% preload to the rated load. The system maintains the preload at zero psi hydraulic pressure. This can help minimize draft requirements and improve cycle speeds.
Material Selection
One of the most critical steps in plastic mold manufacturing is choosing a suitable material for the job. If you select the right one, your brand can benefit. This can lead to expensive recalls and negative reviews. In addition, the wrong selection can result in cracks, discoloration and even breakage.
The first step in choosing a material is defining the physical and mechanical properties of the part. For example, if your product is subject to a harsh environment, it will need a durable material that can withstand the elements.
Another factor to consider is flexibility. Some materials are very flexible, making them suitable for moving parts. But others can be difficult to bend.
Choosing the suitable material for the job is a complex process. Your manufacturer or supplier can help you select the appropriate material, but you must also consider the environmental conditions your part will be exposed to.
Two-Shot Molding
Two-shot molding is a plastics manufacturing process that enables designers to create products with multiple materials. It offers high levels of accuracy, a more reliable product, and superior aesthetics. The process can also lower costs and labor.
Typical applications for two-shot injection molding include power tool grips and toothbrush handles. Other products created by this process include caps, switches, and airtight seals. Also known as dual-shot or multi-shot molding, this process requires specific technical expertise and attention to detail.
This process can be completed in one machine cycle, which saves time and energy. It reduces waste and provides a superior mechanical bond.
Two-shot molding can be performed using the same material, with additives or chemically compatible materials. For best results, the wall thickness of the first shot part and the second shot should be equal.
Lifecycle Costs
The lifecycle costs of plastic molds and tooling are a complex issue. The cost of producing an expected market demand is driven by various factors, including machine use, raw materials, energy and labor. However, it isn’t easy to quantify which components are the most important.
The newest development is the development of process-based cost models. These models integrate output and input and allow a comprehensive estimate of mold production costs. They are an excellent way to determine the best mold design for a specific product and market.
This is done by looking at several factors, such as the part’s complexity, cycle time, specifications, and production volumes. It’s also important to consider the material and geometry. Having more cavities will increase the mold’s production life, and tight tolerances will boost manufacturing efficiency.
Draft Angle
If you plan to design an injection molded part, you must consider draft angles. The draft angle is a slant applied to each side of most features of the injection molded part. This helps to reduce the force required to demold apart and release it from a mold. It also helps to reduce the friction that is associated with the ejection.
Choosing a suitable draft angle depends on the material you are using. Some materials can be molded without a draft, but others require a considerable amount. Generally speaking, a higher draft angle is considered to be better.
For every inch, the cavity is more profound; it’s a good rule of thumb to increase the draft by one degree. Adding a draft will allow you to create more substantial parts for shorter molding cycles.
