A guide to on-demand manufacturing for low-volume injection molding

For a long time, the rapid and flexible production of injection-molded parts with high life expectancy and use requirements has become an urgent problem for the mold manufacturing industry. With the diversification and individualization of social needs and the application of many new materials and processes, the structural form and cavity requirements of modern molds are becoming more and more complex, and if the traditional injection molding parts manufacturing methods are used to produce low-volume injection molded parts, not only are the costs high and productivity low, but more importantly, it isn’t easy to meet the quality requirements. Therefore, the traditional mold design and manufacturing technology can not meet the market’s requirements for mold. This article mainly introduces the issues related to low-volume injection molding, which is popular in the market now.

What is on-demand manufacturing?

On-demand manufacturing refers to producing goods only when there is a demand. This differs from traditional manufacturing processes, where goods are mass-produced and stored in warehouses until sold. On-demand manufacturing allows for greater flexibility and responsiveness to changing market demands and reduced waste and inventory costs.

What is low-volume injection molding?

Low-volume injection molding is a manufacturing process used to produce small quantities of parts. It involves injecting molten plastic into a mold, which is then cooled and ejected as a substantial part. This process, also called rapid injection molding, prototype injection molding, or bridge tooling offers a better option for customers who need to mold parts in small batches. Not only can it produce hundreds of production-grade plastic parts close to the final product for validation testing, but it can also produce end-use parts on demand.

Benefits of Low-Volume Injection Molding

Low-volume injection molding has several benefits, including.

Cost-effective. Low-volume injection molding is cost-effective in producing small quantities of parts compared to traditional injection molding methods, which require a significant upfront investment in tooling and equipment.

Flexibility. Low-volume injection molding offers greater flexibility in design changes and modifications, allowing manufacturers to respond quickly to customer needs and market trends.

Faster turnaround times. Low-volume injection molding offers shorter turnaround times than traditional injection molding methods, which require longer production cycles to achieve cost efficiency.

Quality control. Low-volume injection molding allows for tighter manufacturing process control, resulting in consistent quality and fewer defects.

Types of Low-Volume Injection Molding

There are two types of low-volume injection molding.

Prototype injection molding. This process is used to produce low-volume parts for product testing and validation. It involves the creation of a prototype mold, which costs less than a production mold and can be used to produce a limited number of parts.

Bridge Production Injection Molding. This process is used to produce small parts as a bridge between prototyping and full-scale production. It involves the use of a production mold to produce a limited number of parts that can be used for field testing, market research, or to fill a small order.

Designing low-volume injection molded parts

There are several factors to consider when designing low-volume injection molded parts.

The geometry of the part. The part’s geometry will influence the mold design, material selection and manufacturing process.

Material selection. The material used for the part should be selected based on its mechanical properties, chemical resistance and other performance requirements.

Wall thickness. The wall thickness of the part should be consistent to ensure uniform cooling and to prevent defects such as sink marks.

Draft angle. The design should include a mold pull angle to facilitate mold release.

Gate location. Gate locations should be carefully selected to avoid part defects and to ensure proper filling.

How does low-volume injection molding work?

Low-volume injection molding involves several steps.

Mold design. The mold is designed based on the geometry of the part and material selection.

Mold manufacturing. The mold is manufactured using CNC machining or 3D printing.

Material selection. Select the material for the part based on the performance requirements of the part.

Injection Molding. Melted plastic is injected into the mold cavity under high pressure.

Cooling. The mold is cooled to allow the plastic to solidify.

Eject. The part is ejected from the mold.

Finishing: The part is trimmed, cleaned and inspected.

What plastics are used in low-volume injection molding?

The plastics used in low-volume injection molding are usually thermoplastics such as ABS (Acrylonitrile Butadiene Styrene)，nylon, polycarbonate, polypropylene, polyethylene, and acetal. The choice of plastic depends on the specific requirements of the part, such as mechanical properties, chemical resistance and environmental conditions. It is important to select a material that will meet the functional and aesthetic requirements of the part while also being compatible with the injection molding process.

Choose the right injection molding partner to benefit from small production runs

Thermoplastic injection molding is a standard process. It requires additional knowledge, skills, expertise, and the appropriate equipment and tools. Many important elements must be monitored in real-time, including temperature, pressure, material flow rate, clamping force, cooling time and rate, material moisture content and fill time, and the correlation of part characteristics with key molding variables. From the initial tooling part to the production of the final product, a range of knowledge is included in the design and manufacture of a process resulting from years of experience by highly trained and skilled engineers and machinists.

xtmade is a low-volume manufacturer, and we all apply unparalleled expertise to ensure the quality and repeatability of each part. To learn more about the plastic molding process, please contact us.