The Truth About 3D Printed Injection Molding Tools | Jaycon Systems

Have you been looking for solutions for creating plastic parts for your business on a small scale? Maybe you’re curious whether a small business or hobbyist can use 3D printers as their sole manufacturing outlet.

This article discusses all of the specifics regarding 3D-printed injection molding tools. We’ll cover the basics, the pros, the cons, and how the printing process works.

First, we’ll talk about why someone would choose a 3D-printed injection mold tool instead of the more traditional methods like die casting. Then, after covering the specifics, we’ll show you how someone can do it themselves at home.

Why 3D Printing?

Manufacturers have been making custom molds for decades, but new technologies bring new complexity. For example, die casting is an expensive process requiring highly skilled labor, while CNC machining has high setup costs and requires specialized equipment.

With 3D scanning technology, manufacturers can create complex geometries within minutes at a much lower cost than other options. There are several compelling reasons to start using 3D-printed injection mold tools over more conventional means. Consider the following examples.

Lower Cost

The most significant advantage of 3D printing lies in its low initial investment compared to both die-casting and machining processes. While each method may require unique hardware setups like laser cutting machines and plasma cutters, the result is nearly identical regardless of which approach is used.

However, die castings are significantly cheaper per part made than 3D printing alone when considering materials and consumables. For example, consider that most high-quality resin filaments can run around $20/lb, whereas nylon-6 material runs upwards of $80/lb for top-grade stock.

Furthermore, the price difference goes up exponentially depending upon size. A 1" x 2" piece of metal might cost roughly $15, while a 4' x 8' sheet could easily exceed $500. It should be no surprise that these savings add up quickly once volume increases.

Traditional steel and aluminum molds for plastic injection molding require substantial initial investments but often last much longer.

Faster Product Development Cycle

Another significant benefit of 3D printing is speed. Quick turnaround times are critical to maximizing productivity when working with prototypes or short runs.

Traditional prototyping techniques may take months or years between design models' completion and physical product delivery. Thanks to rapid prototyping software solutions like Fusion 360, designing products digitally allows designers to iterate designs faster without sacrificing quality.

Once finalized, users can even output STL files directly from CAD programs to begin work immediately. Since many FDM printer owners already have existing machinery, the time to get started is drastically reduced.

No Tooling Setup Required

Unlike die casting, 3D printing does not involve any particular setup. All the manufacturer needs is access to a computer running a slicer program. Many modern FDM printers support various file inputs (STEP, IGES, DWG), meaning most people won’t encounter problems here.

Increased Flexibility

Finally, one of the best things about 3D printing is that it offers greater flexibility in terms of customization. Because individual pieces aren’t mass-produced, customers can request specific changes or modifications to an otherwise readymade product design.

Perhaps a customer wants a different color scheme, or perhaps they’d prefer a non-functional area removed entirely. Companies can accommodate almost every conceivable request by going digital rather than relying solely on pre-production samples.

Of course, this also applies to post-sale services too. For instance, what happens if a component breaks after shipment? Can it be fixed remotely or replaced locally? These questions often plague larger businesses that rely heavily on standardized components. 3D printing gives them a way out.

These benefits are especially valuable for smaller operations or startups looking to enter the market. But don’t forget that not everyone owns a 3D printer yet!

What Are Injection Molds And Mold Making Equipment Used For?

Before discussing specifically how to manufacture injection mold tools yourself, let’s briefly discuss what those tools are used for. An injection mold is essentially a cavity where molten polymer flows through precise channels and fills corresponding cavities.

After cooling, these polymers become semi-rigid plastics known as thermosets. Injection molding is widely used across industries to produce finished goods from electronics to furniture.

As mentioned earlier, injection molds can vary significantly based on application. They serve three primary purposes: packaging, structural applications, and decorative covers.

For packaging, injection-molded containers ensure safe transport by protecting against damage during handling and storage. Similarly, automotive bodies receive similar treatment before assembly. Lastly, decorative items like bathtubs, kitchen sinks, and toilets feature molded shells that protect underlying plumbing systems.

Mold makers specialize in creating these molds either manually or via machine. Manual creation involves handcrafting intricate patterns onto surfaces called pattern plates. Patterned plate construction typically occurs in stages, starting with simple geometric shapes and moving toward increasingly complex ones.

Once completed, pattern plate assemblies must undergo secondary processing steps like sanding, drilling, and reaming. Depending on whether the resulting mold is intended for large-scale batch production or consumer markets, additional finishing touches like polishing or painting may occur.

For industrial applications involving higher volumes, automated equipment is commonly employed. Instead of having operators perform tedious manual tasks, machines automatically remove entire pattern plates from the built environment and insert replacement plates.

Some machines also utilize robotic arms to complete certain subtasks, such as mounting pattern plates to baseplates. Regardless of type, mold makers generally operate in controlled environments to avoid accidents and maximize efficiency.

What Are 3D Injection Mold Tools?

Now that we understand what injection molds are, let’s explore how 3D printing fits in this picture. To summarize, 3D injection mold tools allow consumers to produce customized plastic objects using commercially available 3D scanners.

The user uses software like Fusion360 to create a virtual version of their desired object (called a.STL file). Then, the 3D CAD data is converted into G-code compatible format (.GCX), which instructs the printer in building the actual item.

CAD software is used to view, share, and edit 3D files.

A typical workflow begins with capturing images of real-world objects. Next, the user imports the photo (s) into 3D modeling software to isolate critical points.

The software determines the exact dimensions needed to create accurate representations of the original sample. Once finalized, the user exports the geometry as a series of triangles (the STL file mentioned above).

From there, users send the STL to their chosen 3D scanner provider. Typically, a professional lab will scan hundreds of copies of the same object simultaneously to minimize waiting times. After receiving the scans, the company places orders with multiple providers to order the necessary raw materials.

Once received, the raw materials go through their respective processes. Resins must pass rigorous standards set forth by ISO certification agencies like UL and cUL.

Plastics must meet industry specifications regarding strength, durability, and chemical resistance. Most importantly, every step of the production process needs to follow strict safety guidelines to prevent injury or property damage.

Resins and additives react together under extreme heat and pressure during the mixing phase to form the final product. Other essential factors include rheology (a measure of fluidity), melt viscosity, molecular weight, curing agents, reaction rates, and ambient conditions.

Next, the hot liquid mixture passes through a heated chamber known as the cure station. There, it reaches temperatures above 300 degrees Fahrenheit, causing molecules to link together until eventually forming crosslinked networks.

Eventually, the mix cools and hardens into a durable thermoplastic composite. At last, the finished product arrives for the customer, awaiting further action.

How to Print 3D Injection Mold Tools

First, let’s begin with the specific materials you can use.

Materials

As a general rule, you’ll probably want to select an extremely rigid and strong product so it can stand up to the force during the injection process. You’ll also want something that can take high-heat situations.

These are some of the most common products used for 3D printed injection molds:

• TPE (thermoplastic elastomers)
• PP (polypropylene)
• ABS (acrylonitrile butadiene styrene)
• Nylon (a.k.a. polyamide)
• PETG (polyethylene terephthalate)
• POM (polyoxymethylene)

FDM, SLS, SLA, and material jetting can also create these molds. Typically, SLA is the most preferred method because of the dimensional accuracy and smooth surfaces it produces.

SLA 3D Printing Explained In Simple Terms

You should be aware of one critical piece of information regarding metal frames and their role in injection molding. These frames are present to provide additional strength against the force and heat of plastic injection.

Metal frames may be used across the board — only the molds need to be printed using a 3D printer. Changing the design of them is simple and leaves you with options.

However, when the entire mold is created using a 3D printer, you’ll need additional materials and more time for printing.

To recap:

1. After designing your mold, you’ll use your computer and desired software to print the mold.
2. You’ll use your metal frame to clamp the mold.
3. Move forward with the injection process using your desired materials (SLA usually is the best).
4. Proceed with the cooling process.

Now, let’s examine the pros and cons of 3D-printed injection molds.

3D Printed Injection Mold Pros and Cons

Like anything else, 3D-printed injection molds have their pros and cons. This can be an efficient option for producing molds, but it doesn’t come without pitfalls.

Pros

• Using this method has minimal costs. Using traditional methods to create injection molds is extremely hard on the budget and takes more time. You’ll also need industrial precision machinery, plus the brains of engineers. Choosing this method can save you nearly 80% compared to the alternative.
• 3D printing substantially lowers your design stage time. Pretty much anyone who has used a 3D printer can design a mold. If you’re unsatisfied, you can change the design and give it another shot. Rapid prototyping provides many benefits in the design stage.
• Typically, conventional methods like CNC machining have a high cost, which is more suitable for large-scale production jobs. 3D-printed molds have a much lower upfront cost, making small-scale production much more appropriate.

Cons

• Plastic has a lower heat conductivity when compared to metal, so 3D molds will take longer to produce the finished products during the injection process. This will make the production time longer and reduce your manufacturing rates.
• You’ll also have issues with shrinkage, which is familiar with 3D-printed objects. During the cooling process, it’s not uncommon for many of the items using this method to experience issues when exact dimensions are required.
• Additionally, 3D-printed molds are crafted from plastic, which isn’t suitable to stand up against high pressure and heat for extended periods. This means they have challenges with degrading the weld line.

3D Printed molds can show degrading after only a few uses, and resulting pieces may warp or shrink.

How Can I Improve 3D Printing Quality?

Now that we’ve covered all the pros and cons, let’s examine some recent events and developments in this field.

Surface Coating

3D-printed injection molds have a tendency to fail under high temperatures and increased pressure. You can improve the surface structure’s efficiency by using a protective coating. This helps you avoid the challenges associated with heat degradation.

Depositing layers of metal, ceramic, metal nitrates and oxides on the injection molds' outer layers leads to additional heat protection levels.

Thermal Conductive Composites

Thermal conductivity is an object’s ability to take high levels of heat. Naturally, metals are much better at standing up to heat than plastics. They can also be cooled much quicker.

Because 3D printed injection molds have extended heating and cooling periods than molds made using CNC, there’s a longer cycle time involved. The cost of production increases compared to standard metallic molds because fewer products can be manufactured.

Thermal conductive additives are found in mold materials to enhance the injection process. Boron nitride can be added to ABS and iron particles for epoxy resin. This solves the heating and cooling issues associated with plastic molding.

Metallic Injection Molds

Why wouldn’t you use 3D-printed metallic injection molds? There have been numerous technological advancements in 3D printing, so this is currently a realistic scenario.

However, 3D printing metal is more expensive than plastic, so expect much higher upfront costs.

Consider these final tips before starting the printing process and creating 3D-printed injection molds on your own.

Final Tips

Keep all of these essential points in mind to assist in a more efficient process.

Do 3D Printed Molds Last?

You should know the number of units you’re looking to create. 3D-printed injection molds are only efficient for small-scale jobs. This means no more than 100 runs, depending on the specific mold.

You may need a more standard mold if you’re thinking of something higher, like 1,000 units.

Add a Draft Angle

When you add right angles, this makes the molded parts difficult to remove from the mold. You might want to attempt to add a 2-degree draft angle, making the parts much easier to remove.

Use a Printing Service

Don’t forget you can always use a printing company. This will help you create and print molds exactly how you want them without having to do any complicated work. Jaycon Systems provides solutions for all of your printing needs, with attention to quality and speed.

So, what’s the final verdict on 3D-printed injection molds? There’s much to be said about creating these molds without moving from your desk.

They’re not the be-all-end-all solutions to manufacturing parts on a large scale, and the process certainly doesn’t come without flaws. However, the same can be said for large-scale processes as well.

Any manufacturing method has its own set of pros and cons, and in the case of 3D-printed injection molds, we feel the pros outweigh the cons. If you’re a small business or simply an enthusiast that does a lot of work from home, being able to create your molds is a game-changer.

Sure, it might make the injection process a little slower. But the chances are, if you’re a small business, you’re not going to have a line of thousands of clients waiting for their parts. You can probably afford to sacrifice some additional time in exchange for the convenience and affordability of this process.

Additionally, since technology moves at such a fast pace anyway, all of the potential bugs and cons associated with this process will be worked out soon. Honestly, it won’t be long until the next big breakthrough is unrolled in the manufacturing world.

Overall, if you’re a small business looking for a way to level up, 3D-printed injection mold tools are great. You’re not going to crank out thousands of parts with this process in 2022, but who’s to say that this won’t be a possibility in a few years?

Are you interested in injection molding or 3D printing for your product? Request a 24-hour quote today — submit your STEP files through our contact form (jayconsystems.com/contact), and an engineer will be in touch with you. Don’t worry; your files are safe with us — we also offer you the ability to sign a mutual NDA before your submission.

Originally published at https://jayconsystems.com on May 10, 2022.