Aluminum Molds Vs. Steel Molds | Plastic Injection Molding

Aluminum Molds Vs. Steel Molds | Plastic Injection Molding

Aluminum Molds vs. Steel Molds: Five Critical Points of Comparison for Product Designers and Engineers 

Choosing between steel and aluminum tooling is a critical decision for product designers. This is because the tool impacts part quality, cycle time, cost, and even time-to-market.

Therefore, understanding how each material will perform during the injection molding process will help you to make more informed decisions—for today and future needs.

In this blog we provide a critical comparison between P20 Steel and QC-10 Aluminum for five key areas:

  • USA vs China: Where you quote tooling impacts the cost/time to create and change molds
  • Tool life comparison: how many parts can be produced with steel vs. aluminum molds?
  • Thermal conductivity and the ability to control the temperature of each mold type can influence fill, form, and cycle time
  • Part size and complexity by mold type
  • Material and surface finish options for aluminum and steel

Where you quote tooling matters: USA vs. China

Deciding between an overseas and domestic supplier for tooling can influence your entire injection molding project—from supply chain management and production cost to the time it takes to build and change your mold.

For one, vast discrepancies in material cost between the USA and other countries, notably for this discussion, between aluminum and steel as raw material.*

 

In the USA, for example, aluminum is the default material used to create molds because it is cheaper than steel. Conversely, in China raw steel is used as the default material because it is cheaper than aluminum. One country uses a soft material while the other uses a hard material.

Therefore, if you quote tooling in different locations, chances are you will not be looking at an apples-to-apples comparison. This is because soft and hard materials perform differently during the injection molding process. Which can impact cycle time, cost, and time-to-market.

Cost and time to create or change steel molds vs. aluminum molds

When quoting tooling there are two critical costs to consider. First, the initial cost to create the mold. And second, the cost to make changes to the mold. Below is a comparison of cost and time for steel vs. aluminum tooling.

 

Cost  to create or change steel molds vs. aluminum molds

The cost to create an aluminum mold is about ¼ to ½ the cost of creating a steel mold. In general, aluminum tooling will prove to be the most cost-effective option even when comparing a quote from a China-based vendor for steel tooling to a USA aluminum quote.

The type of mold you choose can also impact the cost of making changes. For example, aluminum tooling is roughly 1/10 of changing a steel tool—regardless of where it is manufactured. This is because it takes much longer and is harder to machine steel versus aluminum.

Time to create or change steel molds vs. aluminum molds 

The time required to create an aluminum tool, on average, is about 15-25 business days. In contrast, the average time required to create a steel tool is about 35-60 business days.

On average, the time required to change an aluminum tool is about 5 business days. Compared to an average of 20 business days required to change a steel tool. 

What is the tool life of P20 Steel Tooling vs. QC-10 Aluminum Tooling?

(And how much volume can I produce with each tool before investing more money to keep it running?)

The time required to create an aluminum tool, on average, is about 15-25 business days. In contrast, the average time required to create a steel tool is about 35-60 business days.

On average, the time required to change an aluminum tool is about 5 business days. Compared to an average of 20 business days required to change a steel tool. 

Please note, the estimated volume for steel and aluminum molds will depend on material selection for use during the injection molding process:

  • P20 Steel tooling, average life of 50,000-100,000 parts
  • QC-10 Aluminum tooling, average life of 10,000-25,000 parts

According to Taylor Foster, Account Executive at Xcentric, quantity often determines whether to choose steel or aluminum tooling.

“Simply put, steel tooling will always offer a longer tool life than aluminum tooling,” Taylor said. “This means, it can produce a higher volume of parts before the mold requires maintenance due to wear and tear, or total replacement.”

Therefore, if you are going to need hundreds of thousands—or millions of parts in a year, steel tooling is likely going to be the best option.

Alternatively, Taylor said “if you do not anticipate this level of production volume, and instead plan to stay in the 10s of thousands over the next year or so, then aluminum will be the best option.”

Aluminum Molds vs. Steel Molds: A Comparison

Video Presentation - Featuring Taylor Foster, Account Executive at Xcentric

When moving parts to production, product designers are faced with a choice: steel or aluminum tooling? Watch the webinar to learn common misconceptions between the two along with a side-by-side comparison that will help you to make more informed decisions. 

WATCH NOW

Thermal Conductivity of Aluminum is 5 times greater than Steel

Thermal conductivity is a material’s intrinsic ability to transfer heat. The thermal conductivity of aluminum is about five times greater than steel. This is important because it directly impacts the fill, flow, and cycle time of aluminum molds.

Fill, flow, and cycle time: benefits of aluminum molds

  • Material fills the mold faster and more evenly than steel molds
  • Plastic can flow longer distances with less injection pressure in aluminum
  • Cycle time is less due to quicker heating and cooling, meaning faster creation of your parts using aluminum molds
  • Parts have minimal warp and much better dimensional stability – giving a higher acceptance rate on parts

Aluminum molds’ superior thermal control can reduce cycle time up to 40%

In an article published in Moldmaking Technology1, Douglas Bryce provides details about an IBM tooling study of aluminum molds for high-volume production. The five-year study used identical steel and aluminum molds to produce identical plastic parts.

According to the study, the aluminum molds cost up to 50% less to build than steel molds and produced higher-quality parts. Further, the aluminum molds’ superior thermal control made it easier to manipulate areas of the tooling which resulted in cycle times up to 25-40% less than the steel molds.

Achieve better temperature control with aluminum molds, reduce cost and cycle time

Controlling the temperature of a mold is often a challenge because it depends on variables such as the material, design, ejection process, and other issues within the tool.

Still, achieving better temperature control can help to optimize cost and reduce cycle time. This has been tested and proven in studies like the one featured in Flow Front by Claudia Zironi2. (Table 1)

QC-10 Aluminum vs. P20 Steel; Polystyrene vs. Nylon

In this study, Claudia Zironi conducted a side-by-side comparison of two materials, polystyrene and nylon, being injected into a QC-10 aluminum mold and a P20 steel mold.

Both materials were run in the same process to showcase a completed part within the same spiral tool design. When completed, the overall cycle time for QC-10 Aluminum was much faster than that of the P20 Steel.

Per the study, the P20 steel molds retain more temperature during the molding process than the QC-10 aluminum molds.

Also, recovery after each shot does not come down as fast as the temperature in aluminum tooling. This is because thermal temperature releases out of aluminum faster than steel. Because of this, there was a 20-second freeze time in the P20 steel to ensure the part was cooled for ejection.

Table 1 Claudia Zironi, Flowfront Magazine, “Competitive Advantages of Aluminum Molds for Injection Molding Applications: Process Simulation Used to Evaluate Cycle Times,” April 2005.

Part size and complexity by mold type

Based on the data discussed so far, aluminum has more to offer than prototyping and low-volume production. Though it is softer than steel, aluminum molds can be a cost- and time-efficient option for high-volume production and larger parts.

Of course, there are applications where a steel mold would be a more optimal choice.

Will the type of tooling limit material selection, surface finish, or secondary operations? 

Choosing aluminum tooling instead of steel tooling will not drastically—if at all, compromise your options for material, finish, or secondary operations. Here is a brief overview when comparing P20 steel and QC-10 Aluminum tooling.

Plastic Material Selection

In general, you can expect the same material options for both steel and aluminum tooling. Please note two exceptions where steel tooling is likely to be the best option due to wear and tear:

  •  Exotic materials like Ultem which requires very high heat
  • Abrasive material such as glass fill or other ad

For more detailed information about materials, visit Xcentric’s plastic material selection guide.

Surface finish options

Whether using steel or aluminum, your options for surface finish will be the same. Please note, to achieve an SPI A-1 finish, you need special facilities and/or equipment.

Also, Finish and clarity are reliant on the material you choose; some materials are not capable of achieving an optically clear finish no matter the level of polish used.

FREE 8-Piece Sample Kit

Choosing the optimal surface finish for your material is critical when designing plastic parts for injection molding. Our 8-piece surface finish plaques can help you to make more informed decisions early in the process.

Yes! Send My Free Samples!

Aluminum molds advantage: flow and fill rates

Aluminum molds demonstrate better thermal conductivity, flow rate, and fill advantages over steel molds. Which makes aluminum a better option when you are producing long, large parts.

Also, considering the superior temperature control, aluminum is a better option for part designs with complex geometries that could cause fill issues.

Steel molds advantage: thin walls and complex features

In contrast to aluminum, steel tooling proves to be a more effective for injection-molded parts and tooling that require extremely thin walls. This is because of the increased hardness of the mold material. The thin features and areas in the tool will hold up much better to the pressure during the molding process when using steel.

Conclusion: Steel Molds vs. Aluminum Molds

In conclusion, aluminum molds provide value beyond prototyping. Instead of choosing steel molds for high-volume production, consider aluminum molds instead. They prove to be a cost- and time-effective solution for plastic injection molding.

Xcentric is located entirely in the USA with two production facilities in Michigan. Though we specialize in aluminum tooling, we also offer steel tooling. Our on-site material experts are eager to help you make the most informed decision for your next injection molding project. Please contact an Xcentric Application Engineer with questions or concerns. We are here to help bring your concept to market on time and on budget.

Taylor Foster is an Account Executive at Xcentric. He has a background in Mechanical Engineering and Business, attended the University of Kentucky, and has been working in the manufacturing industry, specializing in injection molding consultation and education as well as customer experience for the past 2 years. Get connected on LinkedIn with Taylor Foster

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!

References

  1. Douglas Bryce, Moldmaking Technology, “Why Offer Aluminum Molds for Production”, April 2002
  2. Claudia Zironi, Flowfront Magazine, “Competitive Advantages of Aluminum Molds for Injection Molding Applications: Process Simulation Used to Evaluate Cycle Times”, April 2005

* While steel as a raw material is cheaper than aluminum in both geographies, several other factors including market share, labor, and production costs must be factored into the material of choice in each country.

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.

Mold 

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.

How to Eliminate Knit Lines In Injection Molding

How to Eliminate Knit Lines In Injection Molding

Knit lines are formed when two or more plastic flow fronts collide and solidify or “knit” together during the molding process.

Overall, injection molding is a relatively simple process. A thermoplastic resin is heated to its melting point and injected into the cavity of an injection mold to produce a specific part geometry. The part is cooled in the mold until it reaches a temperature where it is solid enough to be ejected.

Knit lines most commonly occur around holes or other obstructions to the melt flow such as bosses. A boss is a feature with a hole that designed for a threaded fastener. A gate is an area where the resin is injected into the cavity.

Some thermoplastic resins with lower flow rates such as ABS and filled resins are more prone to having knit line issues. There are approximately 85,000+ thermoplastics available in the marketplace. Within the vast material options available, there are approximately 40 polymer blends or families.

While the presence of knit lines does not always compromise the structural integrity of the plastic part, they are almost always a cosmetic issue.

Changing the injection profile parameters – modifying the fill time for instance – may cause the knit line to move to a more favorable location.

Material selection, part design, tool design, and process parameters all also affect knit lines.

How to eliminate Knit Lines

  • Select resins that are less susceptible to knit line formation.
  • Change the boss or gate locations.
  • Thicken part walls to slow down the resin cooling process however be careful not to make them too thick that it causes sink marks.
  • Place knit line causing features farther from the edge of parts when the design allows for it to do so.

Do you have a question regarding knit lines? Send your design to one of our Technical Specialists for review at 586-598-4636 or sales@xcentricmold.com.

Rapid Molding vs. Traditional | Digital Manufacturing

Rapid Molding vs. Traditional | Digital Manufacturing

The Difference Between Traditional and Rapid Molding

By Leslie Langnau, Design World 

Rapid molding is a key player as the “digitization” of nearly every process to make products continues. The latest industry to experience this shift is molding. Here’s a look at how digitization may affect traditional molding service providers.

Pierre Viaud-Murat | Senior Vice President of Sales

Digital manufacturing offers many benefits across multiple touch points: it can reduce time to market, labor overhead and asset use, plus it helps customers control quality and inventory. These advantages allow users to explore new revenue streams, develop and enhance innovative designs and respond to market demands. The digital age can enhance designers freedom to create and develop through one streamlined methodology.

The traditional manufacturing process
The traditional manufacturing process usually consists of a several-step sequence within the manufacturing flow. Team members monitor and ensure that safeguards are in place throughout the entire part lifecycle. Throughout the process, various testing for form, fit and function are required to discover any part flaws. Each team member should be aware of these critical-path processes, as the traditional method of manufacturing requires more manual than automated production.

traditional manufacturing

The traditional injection molding manufacturing process usually consists of several steps. Throughout the process, various testing for form, fit and function are required to discover any part flaws. Usually, the traditional method of manufacturing requires more manual than automated production.

For example, generating a quote using a DFM analysis and confirming an order manually can take approximately a week, if all of the process steps are accurate and on track the first time through. In the event that any modification is required, the same process steps would be repeated before finalizing the order.

Once an order has been placed, the mold design is reviewed for viability. When that design is finalized, it will go onto the next phase of the traditional manufacturing process. This can be a lengthier portion of the process, ranging from three to eight weeks. Additional delays may also occur if project issues are not identified early in the quoting process, which will result in re-quoting, redesigning or redefining the project. Any of the three can result in significant delays.

With all of the production factors in place, the part will then be molded. After the first shots, a visual and dimensional inspection will be done. If the part passes inspection, it is shipped out to the customer for review and feedback.

Once the customer inspects the part, they have the opportunity to approve or reject the run. In the event of a non-approval, the process would be modified and revisited again with continual iterations until the optimal part is achieved. Any combination of these factors can impact the cost, quality and timing in a traditional manufacturing process.

The digital manufacturing process
Another approach to injection molding involves the digitization of as many injection-molding steps as possible. This approach is referred to as rapid or digital manufacturing, and is a natural progression of traditional manufacturing. The streamlining possible by digitizing many traditional molding steps can reduce total costs.

digital manufacturing

An evolution of traditional injection molding manufacturing is referred to as digitization. It involves digitizing as many injection-molding steps as possible to streamline many traditional molding steps to reduce total costs.

Digital manufacturing begins with the upload of a 3D CAD file to a service provider’s servers. The geometry and part requirements are analyzed, usually with proprietary software. Then the customer receives an interactive quote. Once the customer approves the quote, an order is generated and the mold design finalized and a tool-path created, often within hours.

The initial mold can often be created with modular components, which is another cost savings. Then, the mold is usually machined, a process that takes a couple of days. After benching and finishing, the mold tool is assembled for first production shots and inspection.

This process of rapid mold development can shorten development lead-time to weeks instead of months.

Digital manufacturing can accelerate every step of a part creation process. In traditional manufacturing, the retooling investment could push the break-even manufacturing numbers into the thousands – a cost-prohibitive change for many smaller businesses. Digital manufacturing, however, can implement that small design change for approximately a quarter of the investment in a quarter of the time.

Digital manufacturing is scalable and flexible. Should demand rapidly increase, the digital manufacturing process can move between low-volume to mass production. Thus, designers can react to market behaviors quickly and easily. If demand drops, rapid manufacturing enables adjustments while still achieving the lowest total cost. Thus, regardless of a market’s volatility, digital manufacturing lets users respond accordingly.

The digital manufacturing process allows customers to quickly go through multiple iterations easily. Low-cost tooling makes low-production runs economical enough to test on select markets and use the feedback as a learning curve. Customers can maintain their existing quality controls, while developing good parts that can get to market faster.  Some service providers offer optional services, such as inspection and project management consulting. Digital inspection allows for rapid feedback and tool modifications, if necessary. Service providers usually have experienced tooling experts who can consult during the mold development process to solve any problems that arise.

Mold considerations
Mold service providers strive to ensure a mold tool is available over the lifecycle of a project. Often, the tool is made from a high-grade aluminum base material, like QC-10, which offers an excellent strength-to-weight ratio.

Compared to steel, aluminum is softer and less dense, dissipates heat quickly and efficiently and costs up to 75% less. It’s also a recyclable material, an attractive feature when material waste can be higher than 50% per part. Recyclability and material reuse can help recoup initial material costs.

Although aluminum may not be the right material for every type of mold, it works well for prototyping, bridge tooling and low volume production. Depending on the size and structure of the parts, the heat dissipation within an aluminum mold can be up to 50% higher than steel or other metals, creating faster production turnaround times. Aluminum molds will usually last through production runs of several thousands of parts. DW.

The article above is featured in Design World’s Make Parts Fast.

If you would like additional information on the rapid molding process, contact one of our Technical Specialists today at 586-598-4636 or sales@xcentricmold.com.

Plastic Molding Processes: Know The Basics

Plastic Molding Processes: Know The Basics

4 Plastic Molding Processes

We are frequently asked about different plastic molding processes and how each effect the process of part design and production. In this post we explain the basics of 4 plastic molding processes: plastic injection molding, blow molding, rotational molding, and vaccuum molding.

Plastic Injection Molding

Xcentric Mold specializes in plastic injection molding for low-volume and protyping. Injection molding is one of the most versatile manufacturing processes. It is used for producing simple and complex plastic parts for nearly every industry.

The injection molding process involves injectiong molten material into a mold. The, material is fed into a heated barrel, mixed (using a helical shaped screw), and injected into a  mold cavity. Finally, the material cools and forms the plastic part.

Not all materials heat (or cool) the same.

When designing for plastic injection molding, material selection is a critical for success. After all, materials do not all perform the same – during or after the injection molding process. To achieve the intended fit, form, and function of your part design, work with your supplier to choose the optimal material.

The injection molding process can be performed with a host of materials including: plastic, metal (for which the process is called die-casting), glass, elastomers, confections, and most commonly, thermoplastic and thermosetting polymers.

Common examples of plastic injection-molded parts include medical equipment and medical devices, automotive, marine, industrial, agriculture, aerospace and tight tolerance parts.

Other Molding Types

Below are some molding types which are not specialties of Xcentric Mol. However we may be able to provide you with recommendations of other suppliers who can assist you.

Blow Molding

Blow molding is a specific manufacturing process by which hollow plastic parts are formed and can be joined together. In general, there are three main types of blow molding:

  • Extrusion blow molding
  • Injection blow molding
  • Injection stretch blow molding

The blow molding process begins with melting down the plastic and forming it into a parison or in the case of injection and injection stretch blow molding (ISB) a preform. The parison is a tube-like piece of plastic with a hole in one end through which compressed air can pass.

The parison is then clamped into a mold and air is blown into it. The air pressure then pushes the plastic out to match the mold. Once the plastic has cooled and hardened the mold opens up and the part is ejected.

Common examples of blow molding products include bottles, containers and other hollow shapes.

Rotational Molding

Rotational molding is comprised of a heated hollow mold which is filled with a charge or shot weight of material. It is then slowly rotated (usually around two perpendicular axes), causing the softened material to disperse and stick to the walls of the mold. In order to maintain even thickness throughout the part, the mold continues to rotate at all times during the heating phase and to avoid sagging or deformation also during the cooling phase.

Common examples of rotational molding include parts larger than 2’ such as containers, utility carts, storage bins, car parts, tanks (oil, septic, water) and leisure products such as kayaks.

Vacuum Molding

Vacuum molding is a process by which a sheet of plastic is heated until it becomes pliable, stretched onto a single-surface mold and forced against the mold by a vacuum to create a shape.

This process can also include thick-gauge thermoforming, a type of vacuum molding, that is known for producing a variety of products including disposable cups, containers, lids, trays, blisters, clam shells, and other products for the food, medical, and general retail industries.

Common products produced with the vacuum molding application include industrial containers and crates, pallets, exterior door panels, plastic totes, plastic trailers, passenger cabin window canopies for winged aircraft, and lawn mower hoods.

Would you like additional information about the plastic injection molding process and its capabilities?  Contact our Application Engineers today at 586-598-4636 or sales@xcentricmold.com.

Wall Thickness Guide For Plastic Part Design

Wall Thickness Guide For Plastic Part Design

Wall Thickness Guide For Plastic Part Desgns

Our wall thickness guide will come in handy when you’re designing plastic parts for the injection molding process. Regardless of industry or application, designing plastic parts can be a challenge. Investing time early in process to optimize your design for manufacturability can help to save time and money.

Top 5 design tips for optimal wall thickness

Maintaining uniform wall thickness throughout your plastic injection molding part design is critical.  Without uniform wall thickness, many issues can occur such as sink, warping, short shot (meaning the material in tool does not fill correctly), and cosmetic imperfections.

  • A 10% increase in wall thickness provides approximately a 33% increase in stiffness with most materials
  • Walls should be no less than 40%-60% that of adjacent walls
  • Core out all unneeded thickness and wall stock
  • Sharp internal corners and long unsupported part spans should be avoided
  • Use ribs as stiffening features and supports to provide equivalent stiffness with less wall thickness

plastic injection molding

Material Selection

Selecting the proper material for your part design has a significant impact on wall thickness.  How the part is expected to perform and under what conditions will play a considerable role in material selection.

There are thousands of materials available to choose from.  Material properties not only effect wall thickness but also effect strength and durability.  Below are some recommended wall thickness guidelines with some common materials.

wall thickness

For further information, please visit our material selection guide.