Plastic Injection Molding

Plastic Injection Molding Service In China


Injection molding is a popular manufacturing process for producing large quantities of plastic parts from materials called thermoplastics. It’s the process of melting plastic, injecting it into a mold then repeating the process to make thousands or even millions of the same part.

Whether making 1 part or 1,000,000 parts, GEMS Manufacturing have set up Scientific Production Molding Program, a proven system of checks and balances to make sure your parts are produced correctly and on time. GEMS Manufacturing uses thermoplastic materials; both engineering and commodity grades.  There are numerous grades and options for plastic material choices, plus new, innovative products are readily available. An example of the products processed and manufactured here are ABS, PC/ABS, Nylon, Acrylic, Acetal, polyester, polystyrene, polyethylene, polypropylene, PPO, PPS plus thermoplastic rubbers.  

In addition to these grades, purpose-driven materials are offered including food grade, medical grade with UL yellow card listings and automotive grades. These products are available with additives for strength and other disciplines.  Some additives we process include glass (both short & long fiber), carbon, conductive, non-conductive, anti-static, anti-microbial, fire retardant, lubricative, wear resistant, talc, calcium, UV stabilizers and more. Colors available are any color in the rainbow.

Common Defects in Plastic Injection Molded Parts


While each molded part is unique and there is no universal remedy for all molding defects, there are common quality-related issues which can be resolved with simple adjustments to either the machine conditions or the mold design. Consulting is included and recommended. Many unknowns will happen when not cultured in the plastic injection industry.  

The table below highlights 5 common defects and their probable causes, which can assist you in determining and correcting the issue to ensure a quality molded part.  Other problems that can occur include;  parts not to print, warp, non-uniform part shrinking, deformations, trapped gas, flow lines, weakness, jetting, discoloration, brittleness, delamination, gate blush, weld lines, voids and more. 

While above defects are the most common causes for components being scrapped in the injection molding process, they aren’t the only problems that can happen. Working with an experienced injection molding supplier who has the capability to spot potential defects and the knowing-how to prevent them is one of the greatest supply chain management strategies to avoid injection molding troubles. With strong backup by in-house mold making and regular mold maintenance services, GEMS takes pride in its experience and expertise in injection molding manufacturing, which allows us to offer high-quality products free from defects.

Handbook: Plastic Injection Molding Problems, Causes and Solutions

Contact GEMS-Manufacturing


+86 1392 653 1254



Integrated Factory Resources

We are your one-stop manufacturing solution provider for customized products with the joint effort & support from our 120 partnership subcontractors mainly for the production of metals & plastics. We can expand much faster but the top management decide to keep GEMS a compact, dedicated and professional company, which allows our team to really focus and deliver on your projects without any excuse or compromise. We strive to be a long-term, reliable and trustworthy partner of our customers rather than just being a contractor, and look forward to growing the company with customers’ success.

Manufacturing Veteran Team

With the passing years, we are proud to build up a manufacturing veteran team with rich experience and full expertise to fulfill your specific demand. From mold making, injection molding, die casting, stamping and sheet metal, to 2nd processes like CNC machining, oil spraying, powder coating and chrome plating, and then assembling and packaging and related, we always have someone in house to be an expert to resolve the issues in different stages of product development. We also specialize in providing charger, cable and hub, plus other electronic accessories that support a complete set of product.

Strong Project Management

“Think global, execute local” is the principle of our work. Time, quality and cost are the three key elements to be considered throughout the product development from concept design to mass production. A detailed plan with weekly conference call update is a critical gateway to ensure these three key elements are successfully implemented, also assuring that all parties are on the same page. Communication is the Secret to Success . Everyone works independently to take care his own job, but together we are a team to get things done and are your daily eyes and ears onsite in China.

Flexible Operation & Customization

We offer a wide variety of products, such as mold, component and assembly product, and certain value-added services. For logo or branding product, we have in house resources to complete a color mix that can perfectly match a brand’s unique colors in fast and cost-effective way. Understood the client needs production parts but having a hard time to find a vendor since the order quantity is as low as 1000 or lower. GEMS is well set up for low volume injection molding or die casting projects. Surely our team is also capable of building SPI Class 101 mold that is designed & made for 1 million cycles or more of producing the same high quality parts consistently.