9 Mistakes to Avoid When Designing Injection Molded Parts

1. Avoid Non-Uniform Wall Thickness for Molded Parts

When designing a part for injection molding, having the wall thickness come as close to uniform as possible will make for a stronger part. Otherwise, for example, thinner areas will tend to sink and warp. If you need to design thinner walls in places, they should be no less than 40-60% the width of adjacent walls. And watch out—some materials have quite specific thickness requirements to keep parts strong. Knowing material specifications can save you a lot of pain later.

If you are looking for more details, kindly visit WIT MOLD.

2. Transition Gradually From Thick to Thin Areas in Molding

No one likes weak, saggy parts, so here’s something to think about that will help you avoid them. After ejection from a mold, parts have to cool. Thin areas will inevitably cool faster than thick ones. That temperature differential can create weak areas, which lead to sink and warp. The solution is to avoid sharp differences in wall thickness, something we just touched on. Instead, create gradual transitions between these areas. You and your parts will be happy you did.

3. Be Cautious with C-Shaped Molded Parts

No matter how you turn it, C-shaped parts are inherently weak, unless supported. Poorly designed molded parts have a tendency to warp, especially when using glass-filled materials. Fiber-reinforced materials are used for their added strength properties, also for heat resistance. Fibers in the plastic counteract shrinkage effects due to molecular orientation whether in amorphous or semi-crystalline materials. But fibers don’t expand or contract as temperature changes, so fiber-filled materials typically experience reduced shrinkage in the direction of their orientation.

Because the fibers cause non-uniform shrink within the molded part, supported C-shaped parts can warp even more than an unfilled material.

4. Consider Carefully Your CAD File Format

Sometimes we get CAD files that were translated from .STL files. While .STL files are acceptable for 3D printing, they create problems with molded parts. That’s because they reveal the part’s surface as a series of triangles, rather than the true curves you would find on real parts.

The bottom line is that we will be unable to quote these designs and send them back requesting changes, which costs you time.

Instead, output your designs as STEP files using CAD software such as SOLIDWORKS, Inventor, Pro-E, Catia, or any number of others and define thicknesses clearly, then you’ll be good to go.

5. Use Radii Wisely for Injection Molding

Building radii into a part can be a hit and miss proposition. Only use them in necessary areas, for example, to eliminate sharp edges that an end user may touch, or in critical functional areas such as a lead-in to an assembly.

Some radii are used on inside corners of critical features to make more robust geometry. Inside radii can also help on material flow patterns. In general, proper placement of corner radii can create stronger molded parts.

6. Be Careful with Parting Lines and Radii for Molding

Parting lines always make for interesting design and manufacturing challenges. Typically, we want them to be as unnoticeable as possible, and deciding where to locate them is an exercise filled with aesthetic and mechanical considerations. But watch out. If you try putting a fillet or radius around a parting line, you might end up with undesirable minor undercuts in your mold and maybe even flash.

7. Eliminate Undercuts in Molded Parts if Possible

Undercuts are features that make it difficult to eject a part from its mold. Sometimes these are created using techniques such as side-action cams or pick-out inserts, but these add manufacturing time due to molding costs and complexity. If it’s possible to eliminate undercuts, it will definitely speed up manufacturing time.

8. Determine if Cosmetic Finishes are Necessary

Cosmetic finishes are possibly the most overlooked piece of the design puzzle. If you don’t need them, don’t order them. You can always go back and add cosmetic finishes to future parts, if necessary. It’s yet another way to save yourself some time and expense. That said, if you do have any questions, don’t hesitate to call our applications engineers to discuss specific finish grades. Also, don’t forget that all-over finishes take longer to, ahem, finish, than targeting specific areas.

9. Treat Each Part as Separate Quote

Assemblies represent a collection of parts, and sometimes you only want one of those parts quoted and manufactured. Even if you want pricing on every element contained in an assembly, treat each part as a separate quote. It makes it easier for us to figure out what you want quoted, and doing that will help speed up the quoting process.

General Injection Molding Rules that Totally Rule

Beyond those issues to avoid or carefully consider, here are some best practices items to keep in mind. We couldn’t go through all this information without listing a few things you should do.

Shutoff angles
Maintaining a 3-degree shutoff between mold components is critical for long-lasting, robust molds.

Text/Engraving
To get raised (embossed) text in your part, use engraving in your mold design. The text you mill into the mold will become raised text on your part. Milling the text into your mold is a fast process, leading to faster turnaround times. Also maintain at least a 0.020 in. (0.508mm) stroke width to achieve clean text.

Did you know that plastic injection molding is one of the quickest production technologies available today? No matter how simple or complicated the final result is, this method can quickly make the product you need.

If you want to learn more, please visit our website custom plastic injection molding.

Partnering with a company that meets and exceeds your standards is important if you want to use high-quality plastic injection molding services. This is especially so if you’re in the automotive industry.

With modern technology and a focus on sustainability, finding the proper injection molding firm is vital. Here are five questions to ask when looking for injection molding services. These will help you find a successful partnership with an injection molding company.

1. What Is Your Custom Injection Molding Experience?

When it comes to injection molding services, experience matters. Find out if the company has worked with clients in your sector before. Ask them about their experience with custom injection molding.

Look for a company with a proven track record in delivering high-quality products. Their knowledge of industry standards and specific criteria can make or break your project.

2. Do You Have Samples of Injection Moldings?

To assess the quality and capabilities of an injection molding company, ask for samples of their previous work. These samples will give you a visual idea of the following:

• Their expertise
• The precision of the manufacturing
• Their attention to detail

When inspecting the samples, pay attention to the following:

• Quality of the finishes
• The precision of the parts
• The overall durability

Requesting injection molding samples is a good way to determine if the company can meet your particular needs. These samples show that they are skilled, precise, and pay close attention to detail.

3. What Technologies and Equipment Do You Use?

Technology plays a vital role in modern injection molding. Inquire about the company’s technologies and equipment in their injection molding processes.

Look for companies that embrace advanced technologies such as the following:

• Computer-aided design (CAD)
• Computer-aided manufacturing (CAM)
• Simulation software

These tools enable the following:

• Accurate designs
• Efficient production processes
• Reduced time to market

Furthermore, companies investing in state-of-the-art equipment are committed to quality and precision.

4. How Do You Check Quality and Consistency?

Product quality and consistency are crucial factors in injection molding. Ask the company about its quality control processes and certifications.

Look for companies that follow rigorous quality management systems, such as ISO . Additionally, inquire about their inspection and testing procedures during the manufacturing process.

A reliable injection molding company will have strong quality control measures. This is to ensure that every part meets its specifications consistently.

5. Can You Provide a Detailed Quote and Timeline?

Know your injection molding project’s cost and timing before committing. Request a detailed quote that includes all the necessary factors, such as the following:

• Tooling costs
• Material costs
• Production costs
• Any additional fees

Also, inquire about the projected timeline from the initial design to the delivery of the final products. A reputable injection molding company will provide you with a transparent quote and timeline. This will allow you to plan accordingly.

Injection Molding Services: Make the Right Choice!

Asking the correct questions helps you find injection molding services for your industry. Remember to choose a sustainable, high-tech enterprise.

For more information, please visit automotive injection molding.