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What’s the best way to choose a plastic injection molding manufacturer? What criteria do you need to consider, and how can you tell if a molder is the right partner for you? According to Plastics News, there are nearly 600 injection molders in North America alone. Researching all of them would be incredibly time-consuming, but the good news is there’s a better way to find what you need.  

Here are our top five guidelines for selecting a plastic injection molding partner.     

  1. Volume and capacity
  2. Product applications
  3. Value-added services
  4. Manufacturing capabilities
  5. Quality and on-time deliveries
plastic injection molding manufacturing

#1 Volume and Capacity

Some plastic injection molders specialize in high volume production. Others take jobs with lower production volumes, but still have minimum order quantities (MOQs). Typically, low-to-moderate volumes are defined as 10,000 molded parts or less. With high-volume plastic injection molding, production runs can exceed 750,000 parts. If you select a manufacturer that specializes in only high or only low volumes, however, you may need to find another partner if demand for your product changes dramatically.

Fictiv’s Digital Manufacturing Ecosystem includes plastic injection molding suppliers who produce all types of volumes, including quantities of complex parts. You can even get injection molded prototypes that use cost-effective tooling made from either aluminum or steel. When considerations such as time-to-market count, we can provide you with T1 samples in as fast as ten days. 

#2 Product Applications

In addition to high or low volumes, plastic injection molders may specialize in product applications. That’s important to consider because different industries may use different plastic resins. These injection molding materials don’t just differ in terms of their physical properties — they also support different part tolerances and have different flow rates, which affects mold designs and costs. A plastic injection molding manufacturer who works in a specific product area also develops application expertise.

Plastic injection molding manufacturer

For example, a medical injection molding company may specialize in working with engineered plastics such as PEEK or Ultem®. Because these materials are harder to heat, the injection mold may require a hot oil system. Medical injection molds can also require precision tolerances, which adds costs because the tool must be CNC machined more precisely. The size of the injection molded part is a factor as well. Many molders work with a range of part sizes, but micro molding is an area of specialization. 

#3 Value-Added Services

The right plastic injection molding partner doesn’t only produce parts. An ideal partner also offers design for manufacturability (DFM) feedback, rapid prototyping, and material selection guidance to ensure your project’s success. Uploading your CAD file is an important step, but it’s not the final one if you can get DFM feedback. It’s good to find out if potential suppliers provide advice about draft angles, undercuts, and how to simplify part geometry while still meeting specifications. 

Mold design is also a critical consideration because non-planar parting lines and the addition of shutoffs and side actions increase tooling costs. Mold flow analysis is valuable, too, because it can uncover design issues and help improve quality and performance. From new product development to new product introduction (NPI), look for a plastic injection molding company that can explain the advantages and disadvantages of your different options, such as pros and cons of various injection molding gates

plastic injection molding partner

#4 Manufacturing Capabilities

Manufacturing capabilities encompass both tooling and machines. An injection molding manufacturer with in-house tooling capabilities doesn’t have to wait for your mold to arrive from a distant toolmaker. Instead, the molder can machine the tool in-house and with the tolerances and finishes that you need. SPI surface finishes can range from a rough textured finish (D3) to super high glossy (A-1), but finer finishes cost more and may be more than your application requires. The right partner will explain those differences.

The injection molding machine that a manufacturer uses is also important to know because of its tonnage, aka the amount of force that’s required to keep the tool closed during the injection molding process. If the clamping force is too low, defects such as flashing, short shots, wall thickness variations, and irregular surface finishes can result. Machines with high clamping forces are more expensive, and a less experienced or commodity molder may not have the necessary equipment or technology to deliver what you need.

Plastic molding parts manufacturer

#5 Quality and On-Time Deliveries

Finally, it’s critical to select an injection molding manufacturer based on quality and on-time deliveries. How does the manufacturer address manufacturing variability? How do they perform inspections? When can you expect samples? And what happens if there are defects? Quality control (QA) isn’t just about certifications. Instead, high quality is about achieving a consistent level of product quality that meets the requirements, or specifications, of a job.  

Sourcing Simplified – Start Your Next  Project With Fictiv

If there are production issues, on-time deliveries can suffer. That’s why the guidelines for selecting a plastic injection molder span more than just design and development. Fictiv provides designers with a faster and easier way to get quotes with free DFM feedback that uses 3D visualization technology to accelerated design cycles and get to production faster. We have no MOQs, and you can manufacture domestically or internationally.

Fictiv is the perfect injection molding supplier because our global network connects you to the world’s best manufacturers, and saves you from finding, vetting and onboarding them yourself. Our quote-to-order platform makes it easy to communicate design requirements and compare pricing, and we match every order with our best available manufacturing partner for the job. Plus, you’ll get injection molded plastic parts fast.

In other words, Fictiv lets engineers, like you, engineer. Create an account and upload your part to see what our instant quote process, design for manufacturability feedback, and intelligent platform can do for you.