Podcast – Which Process is More Cost-Effective for Simple Parts: Extrusion or Injection Molding?

All right, so we're diving into manufacturing today.
Okay.
And specifically, we're going to try to answer the question extrusion or injection molding for simple parts. And all of our sources seem to be kind of pointing at extrusion as being the more cost effective option.
Yeah. We're here to find out if that's always the case. Right. Yeah.
It's a bit like, you know, you have a recipe and you assume that the one with fewer ingredients is always going to be cheaper.
Yeah.
Sometimes it's those fancy ingredients that really make the dish special.
Right.
So we need to understand what's happening under the hood.
Yeah, exactly. Okay. So first things first. We got to define these things. Right. What even is extrusion? What even is injection molding?
Right.
So I think we've all seen, you know, those long PVC pipes that are used in plumbing.
Yeah.
That's excretion in action. Right, Right. It's like squeezing toothpaste out of a tube. You're creating this continuous shape.
Injection molding is a little bit more like, I guess, making jello.
Okay.
You pour this liquid material into a mold, let it set.
Yeah.
And then you kind of pop out the finished part.
Yeah. That's a great visual.
Okay, cool.
And I think you can already start to see why extrusion might be the more cost effective choice for those pipes.
Right.
You've got this continuous flow of material. There's less waste, and you can potentially have faster production.
Right. And our sources dig even deeper. They point to the machines themselves as being kind of a key factor in the cost difference.
Absolutely.
A simple single screw extruder, which is like, I guess the workhorse for a lot of extrusion tasks. Right. Is surprisingly affordable.
It is. I mean, you can get one for really a fraction of the cost of an injection molding machine.
Wow.
And that's because those injection molds, molding machines are much more complex.
Oh, okay.
So think of it like, you know, comparing a basic hand mixer to a high end stand mixer with all the attachments. An injection molding machine has to very precisely control pressure, temperature, injection speed.
Oh, wow.
Especially if you're making something that has a lot of intricate details.
Okay. So, yeah. One of our sources actually told this really interesting story, a about how they were using a budget friendly extruder for some simple parts. And they were just like, this is like finding a hidden treasure.
Right.
But wait, there's more to this cost puzzle, Right. There is material waste, right?
Absolutely. Material utilization is all about how much of your raw material actually Ends up in your finished product.
Right.
And extrusion does very well here. Think about that pvc pipe example again. Almost all of the material that you feed into that extruder Becomes part of the final product.
So it's like when you're baking cookies. You want to use all the dough. You don't want to waste anything.
Precisely. But with injection molding, you have these things called gates and runners.
Gates and runners. Okay, so imagine little channels that are carved into the mold that guide the plastic into all the different little nooks and crannies. But those channels themselves end up solidifying along with the part.
Oh, so there's extra plastic.
Extra plastic that you have to trim off and often discard.
Oh, so like those little bits of plastic on a new toy that you gotta cut off.
Exactly. And while a good mold designer can minimize that extra plastic, it's still an unavoidable part of the injection molding process.
Oh, wow.
So if you are all about efficiency and you want to minimize waste.
Right.
Extrusion definitely has an edge.
Okay.
But we also have to consider the time it takes to make those parts.
Oh, right. Because time is money.
Exactly.
The faster you can make these parts, the lower your labor costs.
Exactly.
And I'm assuming extrusion maybe wins here too.
It does.
Okay.
Once an extruder is set up and running.
Yeah.
It can pump out parts continuously with very little human intervention.
So imagine like a conveyor belt that's just constantly delivering perfectly formed plastic shapes.
Wow, that's amazing.
Yeah. One of our sources even shared an anecdote about how this continuous operation was a game changer for a project that had a very tight budget.
Oh, wow.
They were able to quickly scale up production without needing to hire a bunch of extra workers.
Wow, that's incredible. But injection molding, with its mold filling, cooling, ejecting cycle, that seems like it would take a lot more hands on attention.
It does. Each cycle requires careful monitoring, Skilled labor to make sure everything's running smoothly. So that could mean higher labor costs compared to extrusion. Yeah, especially if you're making a large quantity of parts.
Okay, so are we starting to see why extrusion is the more budget friendly choice for these simple parts.
Yeah, I think so.
Okay, so it really does sound like extrusion has a lot going for it, Especially when you're trying to keep costs down. Yeah, But I'm guessing injection molding has some advantages too.
Oh, it does. It's not like it's sitting on the sidelines.
Right.
It's actually the go to choice for a whole range of applications. Right. Remember when we were talking about those intricate little details on like your phone case? Extrusion wouldn't be able to handle that.
Oh, that's right.
That kind of complexity.
Yeah. It's like you're trying to make a really detailed sculpture.
Yeah.
But you're only using Play Doh. Snakes.
Right.
You wouldn't be able to get that same level of precision.
Exactly. You can't make those sharp corners and the intricate textures and even those tiny little lettering details that you see on, like, electronics.
Yeah.
And then when it comes to materials, injection molding opens up a whole new world of possibilities.
Oh, that's right. We were so focused on the cost thing.
Right.
We didn't even talk about the materials.
It's easy to get caught up in the numbers.
Yeah.
But the material itself.
Yeah.
Is a huge factor in deciding which process is right for you.
That's.
Injection molding can handle a huge variety of plastics.
Right.
Each with their own unique properties.
Right.
Like think about a car bumper.
Yeah.
That needs to be tough, impact resistant, Able to withstand some pretty extreme temperatures.
Yeah. And I bet those sleek, high gloss finishes that you see on some cars.
Yeah.
That's injection molding.
Got it too. It's much easier to achieve those smooth, polished surfaces with injection molding. Okay. And then you have things like medical devices.
Oh, right.
Which often require specific material properties to ensure biocompatibility and sterility.
Wow. So many things to consider. Yeah. It's fascinating how the choice of material can just completely change the game.
It does. And then there's a question of quantity.
Right.
How many parts do you need to make?
Okay. Yeah. Let's talk numbers.
Okay.
So we know that extrusion has those lower upfront costs.
Yeah.
But what if you need to make like a million parts?
Right. That's where the concept of per unit cost comes in.
Per unit cost.
So while injection molding may have higher initial costs.
Okay.
Think about designing and building that complex mold.
Yeah.
The cost per part actually decreases.
Okay.
As you produce more and more.
So it's like buying in bulk.
Right. It's like those giant tubs of pretzels at the warehouse store.
Exactly.
It seems expensive at first, but the more pretzels you eat, the cheaper each one becomes.
Exactly. And that's why injection production molding can actually become the more economical choice.
Right.
If you're making a ton of parts.
Especially for mass production.
Right.
If you're churning out thousands or even millions of identical parts.
Yeah.
Those initial mold costs get spread out over a much larger volume.
It makes sense.
Yeah.
So it's not just about the upfront cost. It's also about how that cost kind of amortizes over the whole production run.
Exactly. And of course, we can't forget about the budget.
That's true.
Sometimes even with all of this knowledge, the decision comes down to simple economics.
Right.
What can you afford?
Right. You can get really excited about all these possibilities, but if you don't have the budget for it.
Right.
You gotta be practical.
Yeah. That's where extrusion often shines. Those lower equipment costs and the efficient use of materials makes it a great choice for those simple parts when you need to keep a close eye on your expenses.
So it's not just a simple one is better kind of situation.
Right.
It really depends on what you're trying to do.
It does. And sometimes the decision making process isn't just about the technical aspect and the numbers.
I thought we covered it all.
We've laid a great foundation.
Right.
But there are some less obvious factors that can play a role. Like for example, what about the environmental impact?
Well, that's a really good point.
Of each process.
We didn't even talk about sustainability.
Exactly. Different plastics have different recycling properties and the amount of waste generated during production can vary. Vary?
Yeah.
Between extrusion and injection molding.
That's true.
So if you're a company that is committed to sustainability, these are important things to consider.
So it's not just about the cheapest or the fastest.
Right.
It's also about making responsible choices.
Exactly.
Yeah.
And what about the availability of skilled labor in your region?
Yeah.
Injection molding often requires more specialized expertise.
Operate those machines. Right.
To operate those complex machines and to troubleshoot any issues that are rise.
So even if injection molding looks great on paper, you need to make sure you have the right people to actually run the show.
Absolutely. And let's not forget about technology.
Oh gosh. Yeah.
It's constantly evolving.
Yeah.
There are always new innovations popping up in the manufacturing industry.
Right. 3D printing and all this advanced automation.
Constantly changing the game.
It's like this whole hidden world of manufacturing that's just constantly evolving and adapting.
It is. And that's what makes it so fascinating.
Yeah.
It's not just about following a set of rules.
It's about staying curious.
Yeah.
And informed about the latest trends and advancements.
I like that.
Yeah.
Okay, so time for a little self reflection. After learning all of this, what stands out to you the most?
Yeah. What has you thinking differently?
Yeah.
About the Manufacturing process.
Yeah. What questions are bubbling up in your mind?
Yeah. Take a moment to ponder this and we'll be back in a flash to tackle those lingering thoughts and leave you with a final thought provoking challenge.
Welcome back. I feel like we've been on this incredible journey exploring the world of manufacturing.
Yeah. It really is amazing how much goes into making even the simplest things.
Right, Right. And I think what really struck me is that it's not as straightforward as we might have thought. It's not just about, like you said, cost of equipment or how fast you can make something. It's all these other things too. It is like materials and how complex the design is, how many you need.
And even things like you were talking about the environmental impact.
Yeah.
Having enough skilled workers.
Absolutely.
And then, of course, technology.
Right.
Always changing, which just throws everything up.
In the air again, constantly evolving.
So where do we even go from here? What have we learned?
I think one of the biggest takeaways for me is that there's no right answer.
Okay.
What works for one project.
Yeah.
Might not be the best choice for another. It really depends on your specific needs.
It's like having a toolbox full of tools. Right.
Yeah.
You wouldn't use a hammer to try to screw in a light bulb.
Exactly. You got to pick the right tool for the job.
And that's why it's so important, I guess, to understand, like you were saying, the strengths and weaknesses of extrusion.
Right.
And injection molding. Like, when does extrusion really shine? I guess when you need simple shapes.
Yeah, simple shapes.
High volume.
High volume. And when you're on a budget.
Right. And injection molding is more for when you need.
Yeah. When you have those really intricate details. Okay.
You need a lot of different material options.
Yeah.
And you're making a lot of complex parts.
But it's not just about the technical stuff.
Right.
We were talking about, you know, having skilled labor and all of that.
Exactly. You need the right people.
Yeah.
To make it all happen.
And ethical suppliers.
Yeah. All those things factor in.
But realizing all those little plastic parts are connected to this giant web web of things.
They are. It's a whole system.
Yeah. And I think that's what's so fascinating about this whole thing.
It is. It's not just about making stuff. It's about understanding the impact.
Yeah.
And, you know, trying to do things better.
So we've really gone beyond just like the how of manufacturing.
Yeah.
We've gone deeper and really explored the why.
Absolutely.
And I think that's really what we've tried to do today.
Yeah. To give our listeners the knowledge to make better decisions.
So as we wrap up this deep dive.
Yeah.
I have one final question for you, the listener.
When you're making your next manufacturing decision, what's going to be most important to you?
Yeah.
Is it just going to be about the money.
Yeah.
Or are you going to think about those bigger issues like the environment or social impact?
It's a lot to consider.
It is.
But hopefully this episode has given you the tools to navigate those questions.
Yeah.
And to approach manufacturing with a sense of curiosity, responsibility and keep learning. Yeah. Never stop learning.
So on that note, we'll sign off for today.
Okay.
Keep those gears turning and we'll see you next time.
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