How To Build A Sustainable Supply Chain Post-COVID-19

How To Build A Sustainable Supply Chain Post-COVID-19

Supply Chain: More Sustainable and Agile After COVID-19

COVID-19 put a kink in the global supply chain. And it exposed weaknesses with the power to halt the flow of business. Now, as the world takes steps to define a new business-as-usual post-pandemic, manufacturers are rethinking their supply chain.

As a result, instead of relying on overseas suppliers, companies are exploring opportunities to create a more robust and sustainable supply chain closer to home. One with the flexibility to meet changing production needs, and the accessibility to do so with greater reliability.

Now, manufacturers must begin the process for establishing a more resilient supply chain that can endure the unexpected and continue to thrive during times of uncertainty.

To build such a supply chain, a manufacturer’s plan should include three essential components:

  1. Improve supply chain visibility
  2. Partner with suppliers that can quickly scale production
  3. Prepare an action plan for transforming to a more digital ecosystem

Gain Real-time Supply Chain Visibility 

Real-time visibility is one of the most sought-after ideals for optimizing the flow of goods and services. For one, it enables supply chain managers to track products from the source of raw materials to the final destination. Also, it empowers companies to seamlessly adapt to disruptions and serve customers with greater confidence.

For example, Forbes published a recent Oxford Economics survey of 1,000 supply chain executives. It found that 49% of Supply Chain Leaders can capture real-time data insights and act on them immediately. 51% use AI and predictive analytics to capture insights. This enables Supply Chain Leaders to react in real time to changing conditions. From widescale disruptions to individual customer complaints.[1]

Of course, achieving this degree of end-to-end visibility has always been a challenge—long before COVID-19. Now, faced with the reality of critical vulnerabilities brought to light by the pandemic, learning how to restructure relationships with suppliers will help companies to better understand the impact of disruptions and react accordingly.

Build A Transparent Supply Network: Top 3 Tactics 

Whether you opt to reshore or rely on overseas suppliers, approaching venders as part of a supply network rather than a chain can help to increase visibility. Networking will help to build collaborative, transparent relationships to facilitate proactive decision-making.

Therefore, to help increase visibility with your suppliers, consider these three tactics:

  1. Understand the pain points of your customers, internal teams, and suppliers.
    Prepare a process for gathering pain points that impact your customers, internal teams, and suppliers. For example, set a cadence for distributing a quarterly survey to establish an open line of communications. By understanding specific pain points, you can react quicker and more effectively to mitigate risk to your supply chain.
  2. Invest in technology and systems to optimize communications and provide easy access to critical assets.
    COVID-19 served as a catalyst for many businesses to rethink their supply chain and relationships with suppliers. For example, optimize methods for communicating critical assets and intel between suppliers, internal teams, and critical stakeholders. Invest in technology and systems to create greater transparency and make it easier to communicate essential information.
  3. Set Key Performance Indicators (KPIs) for success.
    Define terms and conditions of a successful vendor relationship. First, identify key suppliers. Then, set clear KPIs to enable real-time tracking of inventory, services, and production capabilities. Measure them on a regular basis. This will provide a more transparent view of suppliers’ flexibility to scale production as needed.

For more information about supply chain KPIs, visit Logistic Bureau’s blog, KPI Key Performance Indicators in Supply Chain & Logistics. You’ll learn best practices for setting KPIs, tips for implementing a hierarchy structure, and additional resources.

Partner With Suppliers That Can Quickly Scale Production

Headlines announcing crisis-level disruption to the heart of electronics manufacturing in China due to the Coronavirus surfaced on CNBC as early as February. Leaders in the industry explained that many consumer goods manufacturers in the U.S. could miss holiday deadlines. Because with factories closed in China, they could not manufacture prototypes, complete testing, or ramp up to full production. As a result, the pandemic created a great deal of market uncertainty that individuals and industries are still struggling to navigate.

For example, many consumers are already experiencing decreased disposable income. Which makes it difficult for consumer goods and electronics manufacturers to predict with confidence production volumes needed to meet the upcoming holiday season.

Design Challenges?

Need help optimizing your design for injection molding? Contact Xcentric’s consultants. We’re here to help!

Therefore, manufacturers must consider suppliers that can quickly scale production as market demands change.

Minimize costs with a flexible production model

Choose suppliers who can help minimize initial costs with an economical, flexible production model. This can help get back on schedule for the holiday season while minimizing the risk of uncertain demand. Look for suppliers who have the ability to quickly ramp up if demand surges and support lower volumes at price points that don’t damage profits if demand does not return to normal.

For example, consider Xcentric, a leading rapid manufacturer in the U.S. We provide first parts within a few short weeks and can quickly scale up to supply hundreds of thousands of parts per year. We can also bridge the gap to millions of parts per year to help mitigate risk.

Digitize Your Supply Network

Digitizing your supply chain and transitioning from a traditional, enterprise-focused operating model to a digital ecosystem is a major initiative. It will require substantial investment and restrucutring of your organization. We are including it, because the potential benefits to your supply chain merit sharing the information.

Managing a multi-tiered supply chain will always present a challenge. Still, in a world that runs on technology, preparing an action plan for creating a digital ecosystem and digitizing your supply network can help to build a more robust supply chain.

A traditional business operating system (BOS) functions at the enterprise level. It is a hardwired business model of processes and methods of communication. Alternatively, a network BOS is fully digital. Agile and flexible, it provides an optimized, fully accessible digital ecosystem.

Webinar Replay: Plastic Injection Molding Parts Clinic

Join Xcentric injection molding experts John Sidorowicz and Glen Miller to see common design mistakes and learn how to avoid them in your own part design.

What is a digital ecosystem?

A digital ecosystem uses technology to connect your supply chain. Suppliers, customers, stakeholders, internal teams, applications, third-party data providers, and digital assets. All connected via a network-based system to ensure your supply chain function in any global climate.

Digitizing your supply network helps to create a more resilient supply chain by:

  • Optimizing all members of the ecosystem with real-time visibility and flexibility to connect with all suppliers on the network
  • Providing a single point-of-contact and version of the truth; everyone connected has access to the same information

If you would like to learn more about digitizing your network, please visit Supply & Demand Chain Executive’s post, Intelligent Digital Ecosystems: How to Digitize Your Supply Network. The post does a great job explaining each component of a networked business operating system.

Conclusion and Key Points 

COVID-19 revealed a shockingly fragile global economy. And, it served as a catalyst for many businesses to rethink their supply chain. The unexpected disruption impacted businesses of all sizes in nearly every industry and country. In fact, Fortune reported that 94% of Fortune 1000 companies felt the disruption caused by the Coronavirus. [2] Conversely, the pandemic also showed us how quickly we can adapt to a virtual environment.

Go beyond COVID-19 with a more resilient supply chain. One that can sustain unexpected disruption and thrive in uncertainty. Consider implementing these tactics:

  • Increase real-time visibility into your supply chain. Take time to understand pain points of your customers, internal team, and suppliers
  • Set KPIs you can measure on a regular basis
  • Invest in technology to optimize communications and provide easy access to critical assets
  • Partner with suppliers that can quickly scale production. A flexible, agile supply chain will respond quickly to fluctuations in market demand
  • Digitize your supplier network. Create a digital ecosystem that connects customers, suppliers, and critical stakeholders


Working on a project?

Let us help you get that first prototype underway and have that part in your hands in as few as five days. Our engineers help you through the design process. Get your project started now!

Mold Flow Analysis For Injection Molding

Mold Flow Analysis For Injection Molding

Designing Plastic Parts For Injection Molding? Run Mold Flow Analysis Before Cutting The Mold

Mold flow analysis is not required for the injection molding process. But maybe it should be, especially considering it can help to predict manufacturing issues before production starts.

Mold flow analysis software* simulates an injection molding cycle using a specific plastic and part design. It evaluates the design for manufacturability before cutting the mold. This allows designers to identify design flaws that would otherwise result in expensive redesign and time delays.

This post will explore the basics of mold flow software, identify how it helps to optimize the injection molding process, and look at sample data generated by the analysis.

First, let’s briefly review three key components that are critical to the injection molding process: design, mold, and material.

Injection Molding Manufacturing

Injection molding is the most widely used method for mass-producing plastic parts. It’s economical, efficient, and can produce simple to complex parts with low waste. For details about the 6 stages included in the process, visit Xcentric’s injection molding process page.


The injection molding process requires a mold, or tool, to produce plastic parts. Mold design engineers design a custom injection mold and then expert mold makers build the mold for production.

Even if the mold is designed and built to exact specifications of the part, issues could still arise during the injection molding process if the part itself isn’t optimized for injection molding or if gate locations aren’t placed in optimal positions for material flow. For example, the plastic may not completely fill the mold cavities resulting in voids, or part defects. Mold flow analysis helps to determine how a given plastic will perform in the mold.

The “plastic” in plastic injection molding

Not all plastics flow, heat, or cool the same. In fact, there are more than 85K polymers to choose from when designing for plastic injection molding. The vast polymer options can make material selection a challenge.

Mold flow analysis enables designers to evaluate the material for variables such as material shrink rate, cooling properties, ability to fill cavities, and potential for aesthetic flaws.

Mold flow analysis: optimize the injection molding process 

Mitigate risk before production begins

Mold flow analysis helps to mitigate risk and create a successful mold from the start. It helps designers to:

  • correct potential cosmetic and structural problems
  • determine the appropriate wall thickness
  • troubleshoot potential problem areas of the mold
  • identify optimal gate locations
  • adjust for ample corner radius
  • create even and clean edges
  • identify the best material for the desired outcome
  • create a successful mold from the start

Design Challenges?

Need help optimizing your design for injection molding? Contact Xcentric’s consultants. We’re here to help!

Mold flow analysis diagnostic reports

The analysis generates color-coded reports to illustrate how the plastic would perform in the mold. Reports include Fiber Orientation, Average Temperature, Knit Lines, Air Traps, Confidence of Fill, Sink and Warp, and Fill Time Result.

We’ll examine elements of two reports: Fill Time Result and Confidence of Fill.

Fill Time Result

The Fill Time Result report presents the position of the flow front at regular intervals as the mold cavity fills. A balanced flow of plastic pattern indicates the plastic part has a good fill time.

The report provides the result in a color-coded diagram. For example, note the contrast between diagram 1, a good fill time, and diagram 2, poor fill time.

Diagram 1

Diagram 2

How to read the results

The designer evaluates the image for flow paths that finish and reach the edges at the same time. Evenly spaced contours indicate the speed at which the plastic is flowing. Widely spaced contours indicate rapid flow; narrow contours indicate the part is filling slowly. 

Things to look for

The Fill Time Result report provides insight into the following:

  • Short shot: A part is short shot when the flow of plastic does not completely fill the mold cavity, thereby resulting in an incomplete part
  • Hesitation: Hesitation occurs when the flow of plastic stops or slows down resulting in asymmetrical and unpredictable flow patterns
  • Overpacking: The result of one flow path finishing before others. Overpacking can result in high part weight, warp, and non-uniform density distribution
  • Weld lines: Also known as knit lines, these are molding defects that occur when two flow fronts meet without the ability to “weld”
  • Air traps: A bubble of air trapped when plastic flow fronts coincide. Air traps can cause structural and visual defects
  • Racetrack effect: Occurs when the flow races through the thick areas of a mold cavity before the thin sections have filled

Mold Flow Analysis Guide

Download our guide to help interpret results generated by mold flow analysis.

Confidence of Fill Result

Confidence of Fill Result report addresses the probability of the plastic filling the mold cavity. 

The colors displayed in the Confidence of Fill indicate:

  1. All green: Plastic fills the part easily and the part quality will likely be acceptable.
  2. Some yellow: The part can be difficult to mold, or quality is probably not acceptable. As the percentage of yellow increases, the difficulty in molding the part increases, and the part quality decreases.
  3. Some yellow and red: The part is difficult to fill, or quality is probably unacceptable. As the percentages of yellow and red increase, the difficulty in molding the part increase, and the part quality decreases.
  4. Any translucent: The part cannot be molded because a short shot will occur.

Results help to determine the probability of molding a quality part

One way to use the results to determine whether you can mold a quality part is to consider how much of each color is displayed. The results could indicate a need to:

  • change the design to better balance flow paths
  • choose a different injection location to ensure the part is completely filled
  • re-evaluate the material selection
  • change the processing conditions

Mold flow analysis: optimize the design before cutting the mold

An accurate mold is critical to producing high-quality, repeatable plastic parts. Mold flow analysis software can help to optimize the process before cutting the mold.

Xcentric is a trusted partner for injection molding solutions. Contact our team to discuss design challenges and upcoming projects.

*Moldflow, owned by Autodesk, produces simulation software for high-end plastic injection molding. All information and diagrams for Fill Time Results and Confidence of Fill in this blog courtesy of Autodesk.

High-Performance Plastics

High-Performance Plastics

Design Optimization: Increasing Performance Through Substituting High-Performance Plastics For Metal

Key Points:

  • High-performance plastics may allow reduction in
    weight and cost while maintaining mechanical performance
  • Part count reduction may further reduce weight
    and simplify designs
  • Elimination of secondary operations saves time
    and expense
  • Production cost and production rate improvements
    with injection molding
  • The cost of prototyping and tooling for
    injection molding is not prohibitive

Progress often dictates reevaluating fundamental decisions

Design and manufacturing professionals are constantly challenged to improve the performance of their products, whether it be reduction in fuel or energy consumption in transportation applications, comfort in wearable devices, or the efficacy of medical equipment and medical devices.

In the ongoing reevaluation of what can be done to improve product performance, one of the most fundamental questions to ask is, “are we using the optimal material for this application”? 

This is no simple matter since in many instances, entire factories and their related supply chains are literally tied to the material selection of a core component.  Think of cast aluminum induction components for internal combustion engines for example.  However, to improve functional and financial performance in a meaningful way, material choice must frequently be reevaluated objectively.

Material substitutions require careful reflection

Considering the implications of substituting a new material for a product or sub-component noted above, the threshold for an acceptable benefit to cost ratio must be high.  In some applications, the reward is obvious: saving a few kilos in a race car means winning or losing, reducing the time to assemble a product might make it commercially viable or a no-go, improving the ability to sterilize a medical device could accelerate adoption.  In marginal cases, the math becomes more difficult, putting pressure on designers to seek fractional performance gains wherever they can be found.  In many important cases these gains are found in substituting older metal designs for high-performance plastics.

High-performance plastics have many advantages

Although high-performance plastics are no substitution for metal alloys for many applications, there are countless applications where metals cannot perform the role of a polymer.  It is between these two spaces where either a polymer or metal could perform the desired functions at an acceptable manufacturing cost in commercially meaningful volumes.  So, when one looks to achieve a high benefit, cost outcome by transitioning from metal to plastic components, where does one start?

  1. Evaluate a simple material substitution of the component design – Can a meaningful improvement be achieved with an engineering-grade polymer with essentially the same physical / geometrical design?  This is not often the case due to the much different mechanical properties between metals and high-performance plastics, but it may happen where the initial metal design was far from optimal, making a substitution of a lighter and less expensive-to-manufacture plastic component possible.
  2. Evaluate a redesign that takes the advantages of molded plastics into accountPlastic injection-molded components can be very complex at high production rates and low per part costs once the injection molding process has been proven out. This allows the designer to consider reducing part count in assemblies by combining functions into a single component.  This saves weight, production time, additional project logistics, and ultimately cost.  Additionally, molded polymers can incorporate aesthetics via more complex organic shapes and molded-in colors that again reduce secondary operations.  Finally, the wide spectrum of mechanical, physical, and chemical properties of polymers opens many new avenues for clever design not possible with metals.
  3. Evaluate combining the best of both worlds – Polymer components with overmolded inserts can combine the benefits noted above from the use of injection molding and those of metal features in certain critical areas such as threads, embedded wiring, metal tubing for fluid or gas lines, heat dissipation features, or aesthetic elements.     

Once the rudimentary analysis
suggested above is done, the detailed work starts.  From the design perspective, the full
analysis of the static and dynamic performance of the component under the
foreseen environmental conditions must be simulated, tested, and validated.  In parallel, the manufacturing team must plan
the component substitution, estimate tooling, training, and production
validation timelines and capital and operating costs.  Ultimately, the commercial team will merge
the data from the design and manufacturing teams to generate an expected return
on investment (ROI) for the substitution, essentially the mathematical
calculation of the benefit: cost ratio. 

Companies frequently substitute high-performance plastics for metal

Just think about the many products that were once metal that have been replaced by a superior injection-molded plastic component: consumer products, medical devices, sporting goods, and automotive components, all have excellent examples of significant improvement through substituting high-performance plastics for metal. However, there are far more untapped applications that may seem mundane, where the real potential still lies, and the cost of conversion is far lower. 

For example, we have helped clients in the electrical industry convert sheet metal assemblies with multiple fasteners and manual assembly, to sculpted single components that do not require assembly, painting, or electrical insulation. 

The direct per component cost is lower, assembly time is shorter, and the entire manufacturing logistics chain is simplified, all while delivering a superior end product.  This is the power of high-performance plastics.

Actually, incredibly often.  Just think about the many products that were once metal that have been replaced by a superior injection-molded plastic component: consumer products, medical devices, sporting goods, and automotive components, all have excellent examples of significant improvement through substituting high-performance plastics for metal. However, there are far more untapped applications that may seem mundane, where the real potential still lies, and the cost of conversion is far lower. 

For example, we have helped clients in the electrical industry convert sheet metal assemblies with multiple fasteners and manual assembly, to sculpted single components that do not require assembly, painting, or electrical insulation.  The direct per component cost is lower, assembly time is shorter, and the entire manufacturing logistics chain is simplified, all while delivering a superior end product.  This is the power of high-performance plastics.

Injection molding tools, especially for prototypes and short run production, can be very cost effective

Returning to the benefit: cost calculation, the amortization of tooling costs is a big factor in the denominator of the equation.  Even if these costs are capitalized, it is still a cash outlay that must be factored in to project planning when comparing machined, cast, metal injection molded (MIM), or stamped metal parts (to name a few of the most common processes).  For high volume production, the impact of a polymer solution can be dramatic, but even for low volumes due to advanced mold making and molding processes, like those employed at Xcentric, the costs to switch to a plastic component can start to pay off quickly. 

Firstly, Xcentric tooling costs a fraction of that of hardened steel tools and are producing end product literally in a matter of days for simpler projects, and two to three weeks for very complex products.  This accelerates cash generation for the customer and gives early feedback about the viability of the substitute component.  If additional iterations are needed for testing or validation, the lower difficulty of making modifications to the prototype tooling and process parameter changes keep costs under control and the project on track (for more information on project timelines in injection molding click here).  When these factors are combined with the direct and indirect manufacturing gains and end use enhancements, injection molding tools are well worth the investment.

Summary: Substituting high-performance plastics for metals can really pay off

Whether it be increasing the performance of the latest sporting equipment, or making the new kitchen appliance more attractive, or reducing the cost and weight of an aircraft interior component, plastic injection molding has proven endless times that it is a viable substitute for metal in very demanding applications.  So, the next time you and your team is considering methods of improving the performance of your products, consider every area where a plastic component might bring a performance or economic advantage.  You may be surprised that the benefit to cost works out very well indeed.

Custom Injection Molding

Custom Injection Molding

Custom Injection Molding Project? Speaking With A Sales Engineer Will Yield Better Results Than An Automated Quote

custom injection molding

Product design teams are required to consider the manufacturing lead time and cost implications of their designs, necessitating the submission of multiple requests for quote (RFQ) to suppliers for prototype and pre-production components.  This can be a time consuming and difficult process, hence the recent race by suppliers to shorten the time to provide quotes, with some even offering “instant” quotations.  But is this really a good thing for complex, custom injection molding projects? Instead, invest the time to work with our team for a custom quote.

The constant pressure to deliver information faster is very real

In almost everything we do as consumers today, we demand instant feedback, one click ordering, immediate information, and around the clock personal support.  Accelerating this responsiveness arms race further, the pressure to actually predict our desires before we have them, and present solutions proactively is real and increasing.  These demands are fueled by the successes of Amazon, Google, and myriad others who have trained us that we can inform ourselves, make purchasing decisions, and have them fulfilled immediately regardless of where we are, 24/7, with incredible accuracy and delightful convenience. 

Fast does not necessarily equate to good

These B2C expectations are naturally being translated to B2B customer interactions as well, but is instant gratification universally good in business? 

Certainly, the argument can be made for standard, off-the-shelf products that are simple and well understood, the immediate fulfillment of specifications and pricing information via self-service downloads or web configurators: e.g. “How much does the new iPhone 11 with a silver case cost?” But what about truly customized products (as distinct from configurable products)? 

But what about truly customized products (as distinct from configurable products)?

Is instant gratification universally good in business?

For many industries, including custominjection molding, the need to convey and confirm understanding of complex information regarding primary and secondary specifications between the customer and supplier is critical to the successful outcome of the project.  It is currently not possible to have this level of understanding between remote parties via any automated quoting tool, primarily due to their inability to capture the nuances of what is important.  So while they may return a result very quickly based on a few parameters, the result should be considered as directional at best, and misleading at worst.

The value of investing in a custom quote is high

We know that our customers’ custom injection molding projects are very often part of large multimillion-dollar product development efforts, so the benefits of investing a few more minutes are much more valuable than offering an instant, yet unrefined quote.  While we understand the need to get information back “up the chain” quickly for decision purposes, we feel it is better for our clients to take the few extra minutes to discuss and eliminate an extra iteration or two from the process.

Quoting accurately as fast as possible for custom injection molding projects

Expertise on demand

At Xcentric, everything we do is custom and done on an extremely short timeline.  And it is precisely due to these factors that we take as much time as needed to properly understand our customers’ requirements for every single project during the quotation phase.  The more we invest with our customers at this phase the higher likelihood that we will meet the overall project timeline and budget.

Xcentric quote

Factors outside of the information conveyed with a 3D model and 2D prints can often be make or break for product development timelines, particularly when subjective aesthetic considerations are in play, or where the customer is not familiar with the nuances of injection molding.  In CAD everything looks perfect, but to achieve close to perfection in the real world one must apply considerable human expertise still well beyond the best automated quoting engines today.

Experts backed by leading technology    

The complexity of considering the many factors that go into quoting the production of injection molding tools and the production of parts from those tools is very high.  Xcentric has built its business on streamlining the entire production process from quotation through to final delivery of injection molded parts. 

Our experts are supported by Xcentric’s proprietary quoting engine which is linked to each step in our internal mold-making and molding departments, bringing years of past experience and technical detail to bear on each project to augment the judgement of the quoting engineer, not to replace it.  Truly the best of both worlds.

Getting it right quickly is better than getting something instantly

While we strive to do everything as quickly as possible for our customers, we are focused on the ultimate goal: completing each project as quickly as possible in the required quality.  This means that we may take time at certain critical phases in the project to be sure we have everything we need to then execute extremely efficiently.  The most important of these steps is right at the beginning when we collaborate with our customers on creating a custom quote for every valuable project.  

Material Selection: Plastic Injection Molding

Material Selection: Plastic Injection Molding

Plastic Injection Molding Material Selection

Material selection for plastic injection molding part production is critical. There are approximately 85,000 thermoplastics available in the marketplace. Within the vast options available, there are approximately 40 polymer blends or families.

We carry 40 resins in stock.  In addition, we will assist you with sourcing non-stock materials, custom colors, specialty resins and accept customer provided materials.

Detailed information on the attributes of each material and their families can be obtained from suppliers in the form of data sheets, design manuals, online searches and other resources. It is important to do your homework in advance. Your final selection is vitally important to the rapid manufacturing process and part performance.

A variety of attributes should be considered when making a final material selection such as:

Durability-What is the material’s ability to withstand pressure, damage or wear?
• Flexibility-Can it bend without breaking?
Chemical Resistance-Will it need to protect against  chemical or solvent reaction?
• Tensile Strength-What is the resistance of the polymer to breaking under tension?
• Temperature Resistance-Will the product be exposed to high or low temperatures? How will it react to other factors or polymers in the manufacturing process?
•  Aging-Is there a shelf life required?
• Impact Resistance-What is the ability of the material to withstand a high  force or shock applied to it over a short period of time?
• Environment-Will outside factors impact the product such as weather, chemicals, or other conditions?
• Material Cost-Will you select a premium or equivalent grade polymer?
Product Availability-What is the lead time (availability)?
Overmolding-Working with two independent materials, how and
will the two materials interact with each other in the manufacturing

Working on a project?

Let us help you get that first prototype underway and have that part in your hands in as few as five days. Our engineers help you through the design process. Get your project started now!

Top 3 Injection Molding Pitfalls To Avoid

Top 3 Injection Molding Pitfalls To Avoid

Top 3 Injection Molding Pitfalls

Before we jump into the injection molding pitfalls you should avoid, here’s a quick review of the Injection Molding Process, Injection Molding Basics, and Rapid Injection Molding.

What is Injection Molding

Plastic resin pellets are loaded into the hopper, where it travels into the barrel of the injection molding machine. Through both heat and pressure, the plastic pellets are melted into a molten material that is ready to be injected. As the screw turns it creates pressure which will help push the molten plastic through the nozzle and into the mold.

what is injection molding


Our proprietary process engine creates ideal pressure, temperature and time cycle which is critical to creating high quality custom parts. Once the right environment inside the barrel is met, the ram moves forward driving the screw and channeling the molten plastic into the mold cavity through the nozzle. Once allowed to cool, the mold will open and the ejection plate engages, releasing the final part from the mold.

Injection Molding Basics

Injection Molds consist of two main components: the mold cavity and the mold core:

CORE (Mold Half B) – forms the main internal surfaces of your custom part
CAVITY (Mold Half A) – forms the major external features

The cavity and core separate (Draw) along the parting line and, with the aid of ejector pins, releases the finished plastic part where the process can be repeated. Depending on your part design, the parting line can either fall on the top, bottom, stepped or angled to accommodate all irregular part features.

injection molding basics


High quality, efficient tooling relies heavily on good part design as well as advanced skills in mold design and the manufacturing of the tool. An injection mold is a highly precision tool that must be rugged enough to withstand hundreds of thousands of high-pressure molding cycles. By optimizing your part design and focusing on consolidating many key features, you can reduce your overall investment costs significantly.

Rapid Injection Molding

Rapid injection molding is possible when a manufacturer has developed sophisticated digital manufacturing practices to significantly increase the speed of the mold building process. We can reduce a typical mold build time of 6-18 weeks to just a few days. With this advancement, you can get real injection molded parts to use either as production or prototype.

Producing prototype parts quickly will help you to get your products to market faster than your competition. The cost is often less than what most injection molding companies charge for a prototype mold without the life expectancy limitations. Done correctly, you can often skip rapid prototyping because the process is so fast and affordable allowing you to produce low-volume production quality parts.

By using engineering grade resins, your injection molded prototype parts can be tested under the same conditions as your final parts and can be made of similar, if not the exact, finish materials. This allows you to test in real mechanical, chemical and environmental circumstances and help you create the best possible part design for your product.

With high speed mold making, you can also obtain Bridge Tooling when you need prototypes using real materials or when your project is not quite ready for full production. Essentially bridging the gap between Prototype and high-volume production. Knowing that your Bridge Tool can be used for production parts, backed by a Lifetime Mold Guarantee can help save you time and money and will give you the advantage over your competition.

Click here for more About Injection Molding, and read on to learn about the key pitfalls you should avoid within the injection molding process.

Now, let’s discuss three common injection molding pitfalls: knit lines, sink and warp, and material shrinkage.

Pitfall #1 – Knit Lines

The injection molding process is fairly simple, plastic resin is heated to its melting point and forced through the machine and into your mold to produce your plastic parts. The leading edge of the molten material is often the coolest point and the closest to solidifying. When the molten plastic meets an obstruction, it must travel around and meet at the other side. If the plastic has cooled too much during the injection process it can lead to knit lines in plastic parts when they meet past an obstruction.

knit lines


ABS is the most common resin to be prone to knit lines. If you are concerned about potential knit lines, turn to the mold flow analysis of your part and address any design issues that can be easily modified. Review similar materials that may be less prone to show knit lines. With good part design and a well-designed mold, knit lines can often be significantly reduced or removed completely. Click here to learn more About Mold Flow Analysis

Pitfall #2 – Sink and Warp

Variations of shrinkage in materials can lead to warp, distortion and dimensional issues with injection molded parts. As the plastic material cools, the molecules that make it up move closer together. If the cooling rate is different, such as thinner or thicker walls the stress caused by cooling can lead to the material wanting to warp. As the plastic in the mold cools from the outside in, it can cause pulling on the outer walls resulting in sink marks. Thinner wall thickness will help to prevent this. Where possible, always try to design a part with thinner and consistent wall sections to minimize warp and sink marks.

Sink and warp

Careful consideration to part and mold design must be addressed to create high quality, consistent plastic parts and at Xcentric, we provide you with the tools and experience to reduce or eliminate potential cosmetic or structural defects of your plastic custom parts.

Download: Material Shrinkage Guide

Pitfall #3 – Shrink

With most injection-molded resins, a certain degree of shrink can be expected due to the materials chosen. Some materials tend to shrink more than others so careful consideration on material choice should be made. Rapid changes to wall thickness are the most common cause of shrinkage due to the pressures exerted for the plastic material to fill your mold. When designing your parts try to eliminate thin wall sections leading into thicker wall sections and create parts with uniform wall thickness throughout.

If thick and thin sections are necessary try to transition the change gradually, utilizing angles to help aid the flow of materials throughout your plastic parts. Controlling part shrinkage is critically important especially in tight tolerance plastic parts.


Adhering to best practices can help to avoid injection molding pitfalls. Consider the following “checklist” as a baseline to meeting your part expectations.

Wall Thickness

• Maintain uniform Wall Thickness throughout
• Utilize Ribs to reinforce walls without adding to thickness
• A 10% increase in thickness = 33% increase in stiffness
• Core out unneeded thickness and wall stock


• Maintain a minimum of 0.5° draft angle on all features perpendicular to the parting line. 1° – 2° is ideal.

Tight Tolerances

• Utilize low-shrinkage materials for parts with tight tolerances

Ribs & Bosses

• Design ribs and bosses to approximately 60% of the joining wall thickness for minimum risk for sink marks.


• Undercuts will add cost to the mold. Minimize them when you can. Otherwise, there are no limits.

Corners and Transitions

• Use gradual transitions if wall thickness must change.
• Corners: R1 + T = R2

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Interested in obtaining more advice? Reach a Technical Engineer at, or call (586) 589-4636