What Are the Essential Guidelines for Injection Molding Wall Thickness?

Defects like sink marks or warpage in your plastic pieces are the result of one determining design choice: wall thickness. Failure can lead to material waste, lost production time, and high expense — all translating into harm coming from your bottom line. Complying with proper wall thickness rules is the key to the future of producing rugged, high-grade pieces in high volume with first-shot success in your project.

The ideal thickness for mold injection also depends heavily on the material, but the average range is from 0.040-0.140 inches (1mm-3.5mm), and most importance should be given to the uniformity. Walls should be retained as uniformly thick as possible in order to prevent defects like sink marks, warping, and voids. Special thicknesses for material are also listed in some material datasheets. ABS varies from 0.045-0.140 inches, and Nylon can be utilized with thicknesses from 0.030 inches. Always use a material datasheet for the best information.

It is an excellent beginning to be familiar with the general rules. However, it is the practical use of these rules to your chosen design and choice of material that makes the difference. I have gained experience over four years running my own business molding and CNC that this one feature of design can either make or break a project. Now, we shall explore more on why these guidelines are so essential and how you can use them to your projects. We will deconstruct the details, including keeping uniformity in it, and selecting the appropriate thickness of common plastics. Let’s get started.

What Is the General Recommended Wall Thickness for Injection Molding?

You’re designing a new plastic part but are at a loss for where to start with the thickness of walls? Selecting a number blindly can lead to severe molding problems later down the line, which can mean expensive redesigns and modifications to tools. This indecision can immobilize a project even prior to ever getting started. By coming from a proven, general-purpose range, you’re setting yourself up with a healthy foundation from which you can then more easily refine things and have a more efficient path to production.

Rules of thumb: Most injection molded parts perform best with a thickness in the range from 0.040 through 0.140 inches (1mm through 3.5mm), but that’s only an estimate. The single largest determining factor here is the plastic resin you’re actually working with. Thinly flowing resins like Polypropylene can tolerate thinner sections, but highly viscous resins like Polycarbonate typically require heavier walls. You should always aim for the thinnest possible thickness which still realizes the structural and functional requirements of your part.

When I first started, I helped a client who wanted to use a “one-size-fits-all” 0.125-inch wall for every part they made, regardless of the material. It worked for their ABS parts, but when they switched to a glass-filled nylon for a stronger component, they faced a nightmare of short shots and weak spots. The more viscous, glass-filled material simply couldn’t flow into the corners of the part at that thickness. We had to adjust the design to a thicker, more uniform wall of 0.140 inches and add generous radii to help the material flow. It was a valuable lesson: the material is the boss.

Why Material Choice is Key

The flow characteristics of a plastic resin, often measured by its Melt Flow Index (MFI), directly impact the wall thickness you can achieve.

• High-Flow Materials (High MFI): Plastics like Polypropylene and Nylon flow like water. They can easily fill long, thin sections of a mold before they cool and solidify. This gives you the freedom to design thinner, lighter parts.
• Low-Flow Materials (Low MFI): Plastics like Polycarbonate or glass-filled resins are more like honey. They are stiffer and more resistant to flow. For these materials, you need thicker walls to ensure the plastic can reach every part of the mold cavity before the pressure drops or it freezes off.

Balancing Strength and Cost

Your goal is always to find the sweet spot between structural integrity and manufacturing efficiency. Thicker walls are generally stronger, but they come with significant downsides. They use more material, which increases cost. More importantly, they take much longer to cool, which dramatically increases the cycle time for each part. In high-volume production, a few extra seconds of cooling time per part can add up to thousands of dollars in lost machine time. Aim for the thinnest wall that can do the job.

Common Plastic	Typical Wall Thickness (inches)	Typical Wall Thickness (mm)
ABS	0.045 – 0.140	1.1 – 3.5
Polycarbonate	0.040 – 0.150	1.0 – 3.8
Polypropylene	0.025 – 0.150	0.6 – 3.8
Nylon (PA)	0.030 – 0.115	0.75 – 2.9
Acrylic (PMMA)	0.025 – 0.500	0.65 – 12.7

How Do You Maintain a Uniform Wall Thickness in Your Design?

Have you ever approved a design that looked perfect on screen, only to see the physical parts come out warped or with ugly sink marks? The culprit is often non-uniform wall thickness. Abrupt changes from thick to thin sections create uneven cooling and pressure, ruining the part’s integrity and appearance. Mastering the art of uniform walls is the secret to flawless parts. It ensures plastic flows evenly, cools uniformly, and produces consistent, high-quality results every time.

To have even thickness in the walls, in part design, keep all the walls as close in thickness as possible. In unavoidable thickness variations, keep the change gradual, with ramps or fillets, and not abrupt corners. A good practice is keeping the thickness variation in an adjacent wall below 25-30% of the nominal thickness. Coring out the thick spots and ribs for support are very good techniques used in making the thickness even while keeping the strength and minimizing the material usage.

I always tell my clients that uniform walls are the most important, non-negotiable rule of injection molding design. It’s more important than the exact thickness itself. Plastic is like water in a river; it wants to flow smoothly. Any sharp corner or sudden change in thickness is like a dam or a sudden waterfall, causing turbulence and chaos. This “chaos” in plastic flow is what leads to nearly all common molding defects. By designing smooth, uniform pathways for the plastic to flow and cool, you are setting your project up for success before the mold is even built.

The Golden Rule: Uniformity

When molten plastic is injected into a mold, it flows to the path of least resistance, which is typically the thicker sections. These thick sections also take much longer to cool than thin sections. This difference in cooling rates causes immense internal stress. The thin sections cool and shrink first, while the thick sections are still molten. As the thick sections finally cool and shrink, they pull on the already-solidified thin sections, causing the part to warp and twist out of shape.

Techniques for Achieving Uniformity

Instead of creating thick, solid sections for strength, use smarter design features to achieve the same goal while keeping walls uniform.

• Coring: This is the process of removing material from the inside of a thick section, leaving a hollowed-out area. This creates a uniform wall around the feature without sacrificing its overall shape or position. It dramatically reduces material use and cooling time.
• Ribs: Instead of making an entire wall thick for strength, keep the wall thin and add a series of supporting ribs. This provides excellent rigidity and strength while using a fraction of the material and keeping the wall thickness uniform. As a rule, a rib’s thickness should be about 50-60% of the wall it’s attached to, preventing sink marks where it joins the wall.
• Gradual Transitions (Fillets & Rounds): When you absolutely must change from one thickness to another, never use a sharp, abrupt step. Use a gentle, chamfered ramp or a smooth radius to transition between the two thicknesses. This helps the plastic flow smoothly and reduces stress concentrations that can make a part weak.

What is the Significance of Wall Thickness in Product Design?

The importance of the wall thickness in the product design is based on the fact that it is a key factor that directly affects the material consumption, the quality of the product, its structural integrity, cost, and efficiency. The thickness of the walls will directly influence the quantity of raw material required-by the thicker the wall, the more costly and more weight the product will have and it is also possible that the walls might be too thin and therefore cause structural failure or defects.
Standardized and optimized wall thickness is useful to minimize manufacturing flaws including warping, sinkholes and short shots which may increase rejection and overall production expenses. Also, wall thickness determines cooling time in such processes as injection molding, which impacts on speed of production and cycle time. Balancing the wall thickness would make the product strong enough to be used, cost effective to make, and manufacturable with no quality problems.

Design and Factory Engineering.

One of the design parameters in the manufacturing process of injection molding, extrusion, CNC machining, etc. is the wall thickness. Designers aim at uniformity in wall thickness or a gradual change in thickness such that concentrations of stresses and part deformation do not occur.

Design-for-manufacturing (DFM) principles and CAD software help to obtain and analyze the right wall thickness. Functional performance may include proper thickness and, as a consequence, a thermal stability, flexibility, minimization of weight as per the product requirements. In the case of plastics the common minimums, are depending on the material, but need to be thick enough to maintain integrity without unnecessarily raising the cost or the cycle time.

Implication on Cost and Quality.

Stronger walls raise prices of materials, weight of products affecting shipping and handling. Thin walls can contribute to minimizing the material consumption, however, they can lead to the rise of the defect rates and the early failures of the products. The cost reduction is offset by the increase in the waste quantities and the need for repairs. The consistency in wall thickness minimizes the warping of the wall and aesthetic flaws, enhancing the level of yield and satisfaction among the customers. Thickness means a longer cooling time in the process of molding operations and thus slows production and increases costs, and thickness optimization is therefore necessary in order to achieve quick and cost-effective production.

Proper specification and control of the wall thickness are essential in the manufacture of cost-effective, high quality and reliable products within manufacturing industries like plastics, metals, and composite.

What Problems Arise from Incorrect Wall Thickness?

Do you have frustrating defects in your molded parts and can’t seem to find the root cause? You almost want to blame the machine or the material, but in most cases the root cause is designed right into the part with the wrong wall thickness. Apparently invisible defects are the cause of high scrap rates and production nightmares. To immediately determine the specific defects caused by walls that are too thick or too thin and correct them in your next part’s design.

Inconsistent wall thickness produces a variety of molding defects. Too thin walls can produce “short shots,” in which the mold does not fully fill. Walls which are too thin can also be brittle. Walls which are too thick are immensely more serious offenders, causing sink marks, voids (internal air bubbles), warpage due to non-uniform cooling, and prohibitively long cycle times. It raises part cost while decreasing quality. Consistency always takes first priority in order to prevent such defects.

I remember a project for a client making a handheld electronics enclosure. The designer had put a large, solid block inside to hold a screw boss. The wall thickness in that area was over three times the rest of the part. The result was a disaster. Every single part had a huge, ugly sink mark on the outside surface right opposite the block. The cycle time was also incredibly long because we had to wait for that thick section to cool. We had to halt production, help them redesign the part to core out the block and use ribs for the screw boss instead. The new part was perfect, lighter, and produced twice as fast.

The Dangers of Thick Walls

Thick sections are the number one cause of cosmetic and structural defects.

• Sink Marks: These are small depressions or divots on the surface of the part. They occur when a thick section of plastic cools and shrinks, pulling the outer surface material inward.
• Voids: These are air bubbles trapped inside a thick section. The outer surface of the part cools and solidifies first, and as the inner molten core continues to shrink, it can pull apart, creating a vacuum bubble. This severely weakens the part.
• Warpage: As explained earlier, the differential cooling between thick and thin sections creates internal stress that physically bends and warps the part as it cools.

The Risks of Thin Walls

While generally better than thick walls, going too thin has its own set of problems.

• Short Shots: If a wall is too thin for the plastic’s flow properties, the material may cool and solidify before it has completely filled the mold cavity. This results in an incomplete part.
• Breakage: Walls that are too thin may simply not have the mechanical strength required for the part’s function, leading to cracking or breaking under stress.
• Gas Traps: Air inside the mold needs to escape as plastic flows in. If the flow path is too thin, air can get trapped at the end of the fill, causing burn marks or structural weaknesses.

Problem	Caused By Walls That Are…	Solution
Sink Marks	Too Thick / Non-Uniform	Core out the thick section, reduce thickness, use ribs for support.
Voids	Too Thick	Reduce wall thickness, add a packing pressure profile.
Warpage	Non-Uniform	Design for uniform wall thickness throughout the entire part.
Short Shot	Too Thin	Increase wall thickness, use a higher-flow material, improve gating.
Part Breakage	Too Thin	Increase wall thickness, add ribs or gussets, switch to a stronger material.

Why Is Uniform Wall Thickness Important In Injection Molding?

Wall thickness design in injection molding plays a critical role in the performance, cost, production efficiency, and generally the quality of the plastic products.

• Excessive wall thickness may result in wastage and high expenses in material, and may also cause extra weight and time in production.

• On the other hand, too thin walls can lead to deformation, cracking, and other problems that can jeopardize the durability and performance of the product.

• As an example, in the injection molding process, the regions with dissimilar wall thicknesses cool at dissimilar rates, resulting in imbalanced shrinkages.

• This may introduce defects to the surface such as sink marks or internal defects such as voids.

• Also, the inconsistency of the wall thickness may also lead to warping, deformation, and internal stresses that adversely affect the mechanical properties and aesthetic quality of the product.

• Consistency of the wall thickness is vital in maintaining structural integrity, performance, and appeal of injection-molded products as well as maximizing production factors and output.

How To Design For Uniform Wall Thicknesses?

Uniform wall thickness design entails creating products so that the thickness of the walls is the same all over or that the thickness changes gradually to different thicknesses in order to maximize material flow, cooling and strength.

The following are the guidelines to be followed in designing uniform wall thickness.

1. Wall thickness should be 40 percent to 60 percent of the adjacent walls to avoid sink marks, warpage and uneven cooling.

2. Sharp internal corners should be avoided, radii applied to inside corners with a range of between 25 and 50 percent of the wall thickness (50 percent any of these values is recommended), in order to minimize stress concentrations.

3. Put in ribs or gussets to make the sides stronger where they need to be, these must be a third to half of the main wall thickness to even it out.

4. Apply draft of not less than 1 degree/ inch of cavity depth to facilitate release of the mould and eliminate accumulation of stress.

5. Long unsupported spans and weight change transitions should be avoided to eliminate structural vulnerabilities and production flaws.

6. Use design software such as mold flow analysis to simulate material flow, cooling and shrinkage and hence optimize the wall thickness and identify issues before they arise.

Sponsoring Design Practices

1. Select materials that have good flow characteristics to enable thin and uniform walls to be made without affecting strength or manufacturability.

2. In cases where the change in thickness is needed, then make it gradual transitions instead of sharp ones, which will assist in even cooling and reduce warping.

3. Equal wall thickness results in the shortening of the cooling time, better quality of parts, lessening wastage, and increased output.

4. Adherence to these principles will result in high quality injection-molded or manufactured parts that are durable, economical and can be produced at low levels of defects.

What is the Ideal Wall Thickness for Polypropylene (PP)?

Planning an application for Polypropylene because it’s such a great chemical-resistant material and competitive in cost, but you’re wondering how thin you can really go? PP’s a great material, but its properties demand specific design considerations. Guessing at the thickness can get you parts too weak, or longer-than-desired cycle times, which rob its economy. Knowing PP’s favorable thickness range allows you to design light, strong, and inexpensive parts that take full advantage of this useful plastic.

For Polypropylene (PP), the usual minimum thickness we recommend is from 0.025 to 0.150 inches (0.6mm to 3.8mm). PP’s excellent flow behavior enables it to fill very thin gauges well and so suits applications such as living hinges. Due to its semi-crystalline nature and high shrinkage characteristics, however, keeping the walls even and uniform is very important in order not to cause warpage. For structural parts, aim for the mid to the high part of this range.

Polypropylene is one of my favorite materials to work with because it’s so versatile. I’ve seen it used for everything from simple food containers to complex automotive parts. Its ability to form a living hinge is almost magical. A living hinge is a thin, flexible web of plastic that connects two rigid sections of a part, allowing it to open and close thousands of times without breaking. The key to a successful living hinge is getting the thickness just right—typically around 0.010 to 0.015 inches—while ensuring the main walls of the part are thick and uniform enough to be rigid.

Why PP is a Special Case

Polypropylene is a semi-crystalline thermoplastic. In other words, its molecules, when cooled, pack together in neat, crystalline structures. To produce this, there is a greater shrinkage than in amorphous plastics such as ABS. If the thickness of the walls isn’t consistent, then respective parts of the plastic will contract at different rates and cause severe warpage. To its credit, however, PP does boast a very high Melt Flow Index (MFI), which simply means it melts very freely. It is this which enables it to flow into extremely thin sections and which makes it ideal for light parts and features such as living hinges.

Design Considerations for PP Parts

When designing with PP, you have to balance its high flow with its high shrinkage.

• Living Hinges: To design a successful living hinge, the hinge section should be thin (0.010-0.015″), while the adjacent walls should be thick enough to be rigid (e.g., 0.060-0.100″). The transition should be smooth to avoid stress points.
• Warpage Control: Uniformity is everything. Even a small variation in thickness can cause a large, flat PP part to warp like a potato chip. Use ribs and gussets to add stiffness instead of increasing wall thickness.
• Material Grade: Different grades of PP (Homopolymer, Copolymer) have slightly different properties. Homopolymer is stiffer, while Copolymer is tougher and has better impact resistance. Your choice might slightly affect the optimal wall thickness for your application.

PP Feature	Design Recommendation
General Wall Thickness	0.025″ – 0.150″ (0.6mm – 3.8mm)
Living Hinge Thickness	0.010″ – 0.015″ (0.25mm – 0.40mm)
Preventing Warpage	Maintain strict wall uniformity; add ribs for stiffness.
Material Flow	Excellent; well-suited for long, thin parts.

What is the Minimum Wall Thickness for PBT Plastic?

Are you looking for a material with excellent electrical characteristics and dimensional stability such as PBT for your next part? Though PBT is a robust engineering resin, forcing the thickness of the wall too low without knowing its threshold can lead to defective parts if you reinforce them with glass fibers. Knowing the minimum and the ideal thickness for the PBT allows your parts to be moldable, robust, and with the exact tolerances necessary for high-function applications such as sensors and connectors.

For unfilled Polybutylene Terephthalate (PBT), the minimum thickness can be about 0.025 inches (0.6mm), but a broader range of 0.040 to 0.120 inches (1.0mm to 3.0mm) is a safer recommendation. When PBT is filled with glass fibers, the minimum thickness should be at least about 0.050 inches (1.2mm). The glass fibers hinder flow, so the sections must be heavier in order for the mold to fully pack and the fibers are in the correct orientation in order for the material to be strong.

I work with many clients in the consumer electronics and automotive industries, like Michael, where PBT is a go-to material. They use it for things like sensor housings, bobbins, and electrical connectors. The challenge with these parts is that they are often small and intricate, with very thin walls required to fit into tight spaces. The biggest mistake I see is when a designer takes a part that worked well with unfilled PBT and simply switches to a 30% glass-filled version for more strength, without changing the design. The part immediately fails to fill because the viscous, glass-filled plastic can’t navigate the thin walls.

Unfilled PBT vs. Glass-Filled PBT

Understanding the role of fillers is critical when designing with engineering plastics.

• Unfilled PBT: This is the base resin. It flows relatively well and can be used to create parts with fine details and thinner walls. Its strength and stiffness are good, but not exceptional.
• Glass-Filled PBT: In these grades, small glass fibers are mixed into the plastic. These fibers act like rebar in concrete, dramatically increasing the strength, stiffness, and heat resistance of the material. However, they also make the molten plastic much more viscous (thicker) and abrasive. This thick-flowing material requires more pressure to inject and struggles to fill thin sections. You must design with thicker walls to accommodate it.

Key Applications and Thickness

The application often dictates the necessary thickness. For an electrical connector, the walls need to be thick enough to provide good dielectric strength (insulation) and to withstand the forces of being plugged and unplugged repeatedly. This often puts the ideal thickness in the 0.050″ to 0.100″ range, especially for glass-filled grades. For a simple bobbin that just holds wire, you might be able to get away with thinner walls if the material is unfilled. Always consider both the molding process and the end-use requirements.

What is the Recommended Wall Thickness for Delrin (POM)?

Selecting Delrin (Acetal/POM) for its low friction and high rigidity, ideal for gears or bearings? Due to its distinctive behavior in the mold, the material’s specific characteristics result in the material acting differently in the mold. Faulty wall thickness can cause trouble with shrinkage and stress, which can compromise the high precision your part needs. By adhering specifically to the required wall thickness for Delrin, you can create parts with the outstanding dimensional stability and mechanical properties that this high-end engineering plastic is famous for.

The minimum thickness for walls in Delrin (POM) stock ranges from 0.030 to 0.120 inches (0.75mm to 3.0mm). Due to high shrinkage, Delrin is a semi-crystalline plastic and thus regularity in the thickness of walls is very critical in order to prevent warpage and sink marks. Though it can produce thin sections, below 0.030 inch thickness becomes risky and the result can be incomplete filling. In load-bearing applications such as gears, heavier, consistent walls in the range of 0.080 – 0.120 inches are commonly specified.

Delrin, or its generic name Acetal (POM), is a fantastic material for parts that need to be slippery and tough. I’ve made thousands of small gears, clips, and conveyor belt links from it. The key challenge with POM is its desire to shrink and warp if you give it a chance. I once had a client design a long, flat plate out of POM with a thick rib running down the center. When the parts came out of the mold, they were all bowed like a banana. The thick rib cooled much slower than the thin plate, and the resulting stress was too much. We had to modify the tool to replace the single thick rib with several smaller, thinner ribs to achieve the same stiffness while keeping the thickness uniform. The problem vanished.

The Challenge of Crystallinity and Shrinkage

Like Polypropylene, POM is semi-crystalline. As it solidifies, its molecules form tightly packed crystal structures. This process leads to high, and often unpredictable, shrinkage. If one part of the component cools faster than another (because it’s thinner), it will shrink differently, creating internal stresses that lead to warpage. For a material prized for its dimensional stability, controlling this shrinkage through uniform wall thickness is absolutely paramount. Sharp internal corners are also a major issue, as they create stress concentration points where a POM part is likely to fail under load.

Designing for Precision with POM

When you’re making a part like a gear, dimensional accuracy is everything.

• Uniformity is King: This cannot be overstated for POM. Any thick section will cause sink or warp, ruining the precision of the part. Core out any and all thick sections.
• Generous Radii: Avoid sharp internal corners at all costs. A good rule is to make the internal radius at least 50% of the wall thickness. This distributes stress and helps the part withstand mechanical loads.
• Gate Location: The location where plastic enters the part (the gate) is also critical. A poorly placed gate can affect how the plastic molecules align, which in turn affects shrinkage and the final dimensions of the part. This is something you should discuss in detail with your molder.

What Are the Wall Thickness Rules for Acrylic and Nylon?

Do you need a clear, optical part with Acrylic, or a tough, flexible part with Nylon? These two popular materials have completely different behaviors during molding. Applying the same wall thickness rules to both will surely lead to failure, from brittle Acrylic parts to warped Nylon components. Understanding the distinct wall thickness requirements for each material allows you to unlock their unique benefits and produce successful parts for any application.

For Acrylic, used in optical applications, a thickness of 0.025 to 0.500 inches (0.6mm to 12mm) is common, but thick sections require very long cycle times to prevent defects. For Nylon, a versatile engineering plastic, the range is typically 0.030 to 0.115 inches (0.75mm to 2.9mm). Nylon’s good flow allows for thin walls, but it is hygroscopic (absorbs moisture), which can affect its dimensional stability, making uniform thickness even more critical.

I’ve made parts from both these materials, and they couldn’t be more different. Acrylic is like working with glass—it needs to cool slowly and evenly to be perfect. Nylon is tough and forgiving, but it has a secret: it loves to absorb water from the air. This can change the size of the part after it’s been molded. The key to both is, once again, uniform wall thickness. For Acrylic, it prevents optical distortion and stress. For Nylon, it ensures that any swelling from moisture absorption is even and predictable, so the part doesn’t warp out of shape over time.

Designing with Acrylic (PMMA)

Acrylic (PMMA) is an amorphous plastic prized for its exceptional clarity and is often used as a lightweight, shatter-resistant replacement for glass.

• Optical Parts: When making lenses or light pipes, wall thickness uniformity is critical to prevent optical distortion.
• Thick Sections: Acrylic can be molded in very thick sections (up to 0.500″ or more), but this is a major challenge. A thick acrylic part needs an extremely long cooling time to prevent internal voids and stress, which makes the part cost very high. It’s often better to find a design that doesn’t require such a thick section.
• Brittleness: Acrylic is notch-sensitive and can be brittle. Avoid sharp corners and design with smooth, flowing curves.

Designing with Nylon (PA)

Nylon (Polyamide or PA) is a semi-crystalline workhorse known for its toughness, temperature resistance, and good lubricity.

• Hygroscopic Nature: Nylon’s biggest design consideration is that it absorbs moisture from the atmosphere. This absorption causes the material to swell and can change its dimensions and mechanical properties. Designing with a consistent, uniform wall thickness ensures that this swelling is predictable and even.
• Excellent Flow: Like PP, Nylon flows very well, making it suitable for thin-walled applications where toughness is still required.
• Reinforced Grades: Like PBT, Nylon is often filled with glass fibers (e.g., PA66 GF30) for high-strength applications. Remember that these grades require thicker walls than their unfilled counterparts to ensure the mold fills properly.

Material	Recommended Wall Thickness (inches)	Key Design Consideration
Acrylic (PMMA)	0.025″ – 0.500″	Very long cycle times for thick sections; prevent optical distortion.
Nylon (PA)	0.030″ – 0.115″	Uniformity is critical to manage swelling from moisture absorption.
Liquid Crystal Polymer (LCP)	0.030″ – 0.120″	Extremely high flow, ideal for very thin, complex parts.
Long-Fiber Reinforced (LFRT)	0.075″ – 1.000″	Requires very thick walls to allow long fibers to flow without breaking.

Conclusion

Getting thickness correct for the walls is more than a detail of engineering; it’s the key to a successful part. Keep in mind, my friend, uniformity is your first rule. Always size your wall thickness for the stock material you’re using, and employ intelligent design features such as ribs and cores to get added strength with minimal bulk. Obey these rules, and you’ll experience a marked enhancement in the quality of your part, a decrease in cost, and a far easier route from design layout to production.