So, you’ve designed the perfect plastic part. That’s awesome. Now you need to make… well, thousands of them. You’ve heard that plastic injection molding is the gold standard for mass production. And it is! But then you get that first injection molding quote.
That upfront cost can be a real shock. The injection molds themselves can cost thousands, or even tens of thousands, of dollars.
It makes you ask, “Is there any way to make this cheaper?” Yes, there is. A lot of the cost of Plastic Injection Molding is locked in before you even talk to a mold manufacturer. It’s all in your design.
In this post, we’re going to talk about just that. We’ll cover the main injection molding costs and then dive into 10 real-world tips to reduce them.
How much does plastic injection molding cost?
This is the big question, right? But honestly, it’s like asking “How much does a car cost?” It just depends. The total injection mold cost is a huge variable. Are you making a tiny, simple part? Or something vast and complex?
The main driver is the injection mold cost itself. A simple, single cavity mold made from an aluminum block might be just a few thousand dollars. But if you need complex molds? You know, with moving parts, or made from hardened pre-hardened steel for a million shots? That tooling cost can skyrocket.
We’re talking about the mold design, the mold size, and the mold material. Things like electrical discharge machining (EDM) to create intricate details add to the mold costs. So, the Plastic Injection Molding cost isn’t one number. It’s a range based on your part’s complexity.
What are the benefits of injection molding?
So if injection molding is expensive, why does everyone use it? It’s simple: mass production. Once you pay that considerable upfront cost for the injection mold tooling, the price per part becomes tiny. Pennies, even.
The injection molding process is incredibly fast. You can stamp out thousands of identical plastic parts every single day. This makes the cost-effectiveness amazing for high volumes. You also get incredible precision and the ability to use tons of different plastic resins. For making 100,000 of the same part, nothing beats the low cost per piece of the injection molded process.
5 Factors That Affect Cost of Injection Molds
Multiple factors influence the cost of injection molds. I will discuss five of them that play a huge role in determining the cost of injection molds.
#1 Mold Size
The size of the part to be produced considerably impacts the price of the plastic injection molding costs. Larger and more robust molds are needed for larger parts. More materials are needed to make the large molds, which typically results in higher material prices and longer machining times.
Additionally, larger molds need more powerful and expensive injection molding equipment, raising operating expenses.
#2 Parts Materials
The type of material used for the injection-molded component greatly influences the injection mold cost. Certain materials may require particular mold features, cooling channels, or surface treatments because of their unique qualities and requirements.
Some plastic materials, particularly those that are high-temperature or abrasive, wear down injection molds and reduce tool life. To overcome this challenge, harder molds built from particular grades of steel are used, which increases the plastic injection molds cost more.
#3 Part Complexity
Simple, single-cavity molds and 3D prints made at home in low volumes are examples of relatively uncomplicated parts that are typically less expensive to make. These components often just need simple tooling and mold design, have simple designs, and have few functionalities. As a result, the fabrication of the mold is simpler, and the cost of making it is lower.
The cost of injection molds rises when parts are more complicated, have more features, or have more mold cavities. If parts have many cavities, more parts may be created during each injection cycle. This enables greater production rates. However, making molds with several cavities requires more engineering, machining, and accuracy to guarantee that each cavity is accurately reproduced. The costs of making such molds are greater as a result of their complexity.
#4 Part Finishing
In my many years of experience manufacturing specialized injection-molded components for luxury consumer gadgets, I have found that the amount of finishing needed for these pieces always has a big influence on the cost of the plastic injection molding itself.
The process of injection molding gets increasingly difficult as part finishing complexity rises. For the process to be optimized, finishing needs must be properly taken into consideration in mold design and production planning. To consistently achieve the desired finish, appropriate tooling materials and the insertion of cutting-edge mold features are required. These call for additional costs in mold-making.
#5 Part Quantities
We can never overemphasize the importance of part quantities when determining injection mold costs. The volume of objects to be produced through injection molding influences the manufacturing process and material selections for the mold.
3D-printed or lower-grade machined aluminum molds may be appropriate for small-scale applications because they are more affordable. High production quantities, on the other hand, call for using several molds or high-grade steel molds to control the process without compromising the quality of the products produced. However, high-volume molds yield a reduced cost per component because the extra expense is split among more pieces.
10 Tips to Reduce Injection Molding Costs
Okay, so we know the mold is the big expense. The good news is, you have a ton of control over that. Here are 10 practical tips to reduce plastic injection molding cost right from the design stage.
1. Eliminate undercuts
This might be the biggest tip of all to reduce plastic injection molding costs. What’s an undercut? Think of a clip, a snap-fit, or even a handle. It’s any feature that prevents the part from being pulled straight out of the injection mold. To create these features, the mold requires moving parts called slides or lifters. This makes the injection molds much more complex and expensive. It also increases repair costs down the line. If you can design your part without them, you will dramatically reduce injection molding costs.
2. Get rid of unnecessary features
I see this all the time. Designers add cool-looking, but unnecessary features. Maybe it’s a logo that’s engraved, or tiny textures, or ribs that aren’t really needed. Every single one of these features has to be machined into the injection mold. This takes time on CNC machines or even electrical discharge machining. Ask yourself: Does this feature need to be there? If not, get rid of it. Simpler plastic components mean simpler, cheaper molds in-house. This is a core part of lowering the cost of injection molding.
3. Use a core cavity approach
This sounds technical, but it’s a simple idea. Instead of machining your entire mold from one giant, solid metal workpiece (like a pre-hardened steel block), you use a “core and cavity.” These are inserts that fit into a standard, reusable mold base. This is great for cost variations. The inserts are much smaller, so they are faster to machine. This is a widespread way mold manufacturers’ shops create high-quality molds at a lower cost. It’s much cheaper than making the entire injection mold tooling from scratch.
4. Reduce cosmetic finishes and appearances
Does your part really need to be shiny like a mirror? A high mold polish looks fantastic, but it takes a ton of manual labor. Someone has to sit there and polish that metal workpiece by hand for hours. This adds a lot to the molding cost. If the part is internal, or if a standard “as-machined” finish is okay, just say so. Avoiding fancy cosmetic finishes is one of the easiest tips to reduce the cost of plastic injection molding that people overlook.
5. Design self-mating parts
This is a brilliant trick. Let’s say you’re making a small box with a lid. That’s two plastic parts, right? That means two injection molds. That doubles your tooling cost. Did you design the part so that two identical pieces snap together? You’d design self-mating parts. Now you only need one single half mold. You make two of the same part, and they fit together perfectly. This one tip can literally cut your injection mold cost in half.
6. Modify and reuse molds
Do you have an existing part that’s… almost right? Don’t start over! It’s often much cheaper to modify existing injection molds. You can make small changes (called mold mods) by welding material into the mold or machining more out. This is way faster and cheaper than building a whole new mold base. Always ask your mold manufacturer if reusing or modifying an old mold is an option. It can save you a fortune in manufacturing costs.
7. Pay attention to DFM analysis
DFM means “Design for Manufacturability.” Before anyone cuts metal, get a DFM report from your mold manufacturer. This analysis will spot problems. It will find thin walls that won’t fill, or thick spots that will sink. Catching these problems in the design stage costs $0. Are you catching them after the mold production is complete? That’s a disaster. Good DFM is a key part of the whole manufacturing process and one of the best tips to reduce plastic injection molding cost.
8. Use a multi-cavity or family mould
Okay, so you have your part. A single cavity mold makes one part per molding cycle. That’s fine for low volumes. But if you need mass production, you want a multi-cavity mold. This mold has two, four, or even 16 mold cavities of the same part. This increases the cost of the mold, but it slashes your part price.
What about a family mold? This is cool. A family mold has multiple cavities for different parts. Say, the left and right sides of a casing. You get all the parts for one assembly in the same mold. This is a great, cost-effective solution to lower injection molding costs.
9. Consider part size
This seems obvious, but it’s crucial. The bigger the part, the bigger the injection mold. A bigger mold requires a larger mold base, more steel, and additional CNC machining time. All of this drives up the cost of Plastic Injection Molding. It also means you need a bigger injection molding machine to run it. Bigger molding equipment costs more per hour. So, if you can make your part even 10% smaller, you’ll see real savings in plastic injection molding costs.
10. Cycle time and labor
The final cost of your part includes more than just the mold. It’s also the molding costs. This is driven by the molding cycle (how long it takes to make one shot) and labor costs. A long molding cycle ties up the injection molding machine and costs more. How do you shorten it? Use thin walls (they cool faster). Pick an easy-to-flow raw material. These things speed up production efficiency. Lowering the cycle time by just one second can save you thousands over a long production volume. This is a huge factor in the injection molding price.
11. Use Overmolding
Over molding may be a cost-effective alternative for sections that need new materials or other functionalities. The use of over-molding eliminates the need for separate assembly procedures by allowing you to integrate numerous materials or components in a single mold.
Frequently Asked Questions
Q: What is a cheaper alternative to injection molding?
A: For low volumes, 3D printing is much cheaper. There’s no tooling cost at all. However, the cost per part is very high. For a small production scale, CNC machining an aluminum mold can be a good low-cost injection molding option, but it won’t last as long as a steel mold.
Q: Is plastic injection molding expensive?
A: Yes, the upfront cost is high. Making molds is a complex manufacturing process. This is why injection molding is expensive to start. But for mass production, the cost effectiveness is outstanding. The cost per part is extremely low, which is why it’s so popular.
Q: What is the most important consideration when estimating the cost of injection molding tooling?
A: Part complexity is the #1 factor. This includes the part’s size, any undercuts, and the cosmetic finishes required. A complex mold design is the most significant driver of the cost of Plastic Injection Molding.
Q: How to increase productivity in injection molding?
A: To boost production efficiency, use multi-cavity molds or family molds to make more parts per cycle. Also, focus on reducing the molding cycle time by optimizing the mold design and injection molding material.
Conclusion
So, there you have it. As you can see, the Plastic Injection Molding cost is not fixed. It’s something you have a ton of control over, right from your computer.
The injection mold is the most significant chunk of the costs of injection molding, and almost every tip we discussed comes back to a straightforward idea: keep your design simple.
By working with your mold manufacturer and using these tips to reduce plastic injection molding cost, you can make your project a success.
It’s all about innovative design before you cut any metal. These tips to reduce plastic injection molding costs will help you get a better quote and manage expenses to make your project affordable.