Investment Casting vs. Metal Injection Molding: A process comparison

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Do you know the differences between Investment Casting and Metal Injection Molding? How about the unique benefits each process brings to the manufacturing world? 

While it’s true both processes result in strong, precision metal components, there are certain differences that could make one process more suitable for your application and what you are trying to achieve. 

MIM achieves an extremely dense, net-shape part that is scalable with less investment over time than you would spend in a traditional route like machining. Investment Casting, on the other hand, offers virtually limitless alloy selection and unmatched complex part geometry at varying production volumes.

In this webinar, John O'Donnell, of OptiMIM, and Konrad Roell, of Signicast, will review:

• Material options
• Tolerances
• Medical/Dental case studies
• Aerospace/Defense applications
• Volumes
• Surface finishes and more!

 

Fill out the form to sign up for our free webinar!

 

Interested in any other topics on investment casting and MIM? You can view Signicast and OptiMIM resources on Prototyping for Mass Production, Medical Grade Investment Castings, or Part Consolidation with MIM. 

 

Katie Yarborough:

Hello, everyone, and welcome to today’s webinar on investment casting and metal injection molding. My name is Katie Yarborough, and I’m a content strategist here at Form Technologies, and I’ll be your hostess for today’s webinar. For those of you, though, who are not familiar with Form Technologies, I’m going to share some info here. Form is a leading global group of precision metal manufacturers, including three major brands.

 

We have Dynacast for die casting, Signicast for investment casting, and OptiMIM for metal injection molding, but for the purposes of today’s discussion, we will be breaking down the similarities and the differences between those latter two. But before we get started with the presentation, I do want to go over just a few housekeeping items, so everyone knows how to participate in today’s event.

 

For the best viewing experience, we do recommend attending this webinar using one of our supported browsers, which are Google Chrome, Firefox, or Safari. Also, you may notice, there’s no dial-in for this webcast, so all of the audio is going to come through your computer speakers or headphones. And then, as far as the ON24 platform goes, what you’re viewing right now is what we refer to as a series of widgets. There’s lots of little boxes on your screen, and all of these are customizable.

 

So, you can move them around, resize them, to set up the console in a way that works best for you, but I want to put out just a couple of widgets before we get started, as you might find them useful during the presentation today. First, on the right-hand side, you’ll notice our resources widget. You can access free downloads of our blogs and white papers related to today’s topic in that section, and then at the bottom, you should notice the Q&A widget.

 

We’ll actually be holding a live Q&A after the end of the webinar, so please get your questions in there, and we’re going to try to get to as many of those as we can. And then, if you have any technical issues throughout, you can also use that Q&A widget to alert us, and we’ll try our best to troubleshoot, if you aren’t, you know, hearing sound, or slides aren’t progressing, anything like that. But today’s format, we’re actually going to try something a little bit different than our traditional webinars.

 

We’re going to be asking for the audience’s participation through a series of poll questions. So, that’ll really help John and Konrad lead the discussion. So, I’m going to go ahead and send one out, more or less as a test, just a simple, why have you joined today’s webinar? So, you should get a pop-up with the responses there, and while you’re working on that, I’m going to introduce our speakers.

 

So, first, we have John O’Donnell. John has been with OptiMIM for 16 years, and he’s currently responsible for OptiMIM’s global business development. Prior to this role, John worked as a senior applications engineer specializing in product design and development of customer products, optimizing OptiMIM technologies, and utilizing DFM practices. John is a veteran presenter of our webinars. You’ve probably seen his face before, but we’re thankful to have his time today, and of course his thought-leadership.

 

And then, next we have Konrad Roell. Konrad has been with Signicast for over ten years, and first he was a project engineer, and then as a sales engineer. He specializes in new product development and manufacturing process conversions, putting his years of experience as a project engineer to work for his customers. So, with that, I think we can get started. John and Konrad, I will let you both take it away.

 

Konrad Roell:

Awesome. Well, thank you very much, Katie, for the great introduction today. As Katie mentioned, we’re going to have quite a lot of questions and polls today, so your participation is greatly appreciated. So, I’d like to kick that off with, have you experienced any of these manufacturing issues, or are you experiencing any of these manufacturing issues today?

 

So, here’s a quick list, and while we get your guys’s answers, why don’t we do a brief overview of the investment casting process and then a brief overview of the MIM process, so we have a good starting point when we start comparing the two processes. So, to kick this off, let’s just start with a quick video that the team has put together.

 

Video Audio:

Investment casting solves many of the most critical challenges faced in manufacturing today, but how does it actually work? It all begins with the creation of a wax injection die that allows us to produce precise wax patterns. Pinpoint accuracy is critical, as the wax pattern is an exact replica of the finished part. Specially-formulated wax is then injected into the die. For this, Signicast employs a unique proprietary system that precisely controls the wax temperature.

 

This allows us to achieve outstanding dimensional conformity at far greater speed and a higher-quality finished component. The wax patterns are assembled onto a sprue to form a complete mold. We then use advanced robotics to coat the assembly with layers of slurry, and then rapidly dry the mold using our proprietary drying technology, a process that radically cuts shell-build time from a week or longer with other investment casters to just one day.

 

The mold is put into an autoclave. We use steam and pressure to remove the wax from the mold, which is then preheated and ready for molten metal. To ensure it meets specifications, the metal is spectrographically analyzed before being poured into the mold. After the metal is solidified, the shell is then removed with automated high-pressure water jets. The final parts are then separated from the runner. If required, secondary operations such as gate-grinding, machining, painting, blasting, and heat-treating are performed.

 

Ultimately, because we’ve automated virtually every part of the investment casting process, Signicast can achieve far higher quality for less total cost, in a fraction of the time of other manufacturers. It means that with investment castings from Signicast, you can meet your most critical challenges head-on. Signicast.

 

Konrad Roell:

Now, that does a great job of going over a brief overview of what the process can really do, but let’s go through it one more time in a little bit more detail. So, we’re going to start with a die that’s very, very similar to any injection-molded die. It’s going to be made out of 7075 aluminum, and what we’re going to do is we’re basically going to build a cavity that’s an exact replica of the final steel part that we want to produce. It’s going to have all the fine detail, whether it’s lettering, critical features, maybe even some texturing. It will all be formed within that die.

 

We’re then going to take those patterns, and we’re going to assemble them onto a feed system that we call a sprue. Once all those patterns are attached to that sprue, we call that a mold or a tree, it’s traditionally used for the investment casting process. We’re going to take somewhere between four to five of those molds, and assemble them onto a cluster assembly or cluster in there, and that’s going to go through our shell-building process, where we’re going to apply somewhere between seven, six to seven, sometimes eight layers of ceramic shell, and we’re doing that through a combination of sand and slurry.

 

So, the first few layers are very, very fine sand. That allows it to get in all the nooks and crannies and get that very, very good surface finish, as well as fine detail. The remaining layers are basically going to add strength to that shell, so that can support the metal that’s going to be put into the shell. Once that shell’s been fully built around the wax patterns, we’re going to put it into autoclave. We’re going to use steam pressure to basically support the outside of that shell and melt out the wax.

 

Once the majority of the wax is melted out of that mold, we’re then going to send it into a burnout oven and fire that shell. So, not only does it get rid of any residual wax, to improve quality, but it also fires that shell, so when you put 3,000-degree metal into it, it can get into all the little nooks and crannies and thin-walled features. It’s also going to allows that shell to become porous. So, where, like, sand castings, for example, you have problems with trapped air or gas porosity, a lot of those gases are just going to escape through the shell in the investment casting process.

 

Those molds are then going to continue on to our melt decks, where we’re going to alloy up any material that our customers specify, make sure it’s meeting those requirements with a spectrometer before we pour. Then, we’re going to pour roughly about 120 pounds of metal into a mold at a single time, and let those molds cool for another three to four hours. We’re then going to have the molds with all the feeder system and all the parts in steel already formed.

 

We’re going to use water blast cabinets to basically spray 10,000 PSI water, clean up a lot of that shell, the ceramic shell off the mold, and then we’re going to remove each individual part from that feeder system. We can do that cryogenically with carbon steels and 400 series, but when we’re talking about 300 series and nickel alloys, each individual part has to cut off. Those parts will then go to sand blast, get cleaned up, and go on to any other operation, such as gate-grind.

 

If a gate witness needs to be, say, flushed to negative-10,000s, plus or minus 10,000s, or maybe it can just even be left, we’ll finish the gate to the print specifications. Once it gets through gate-grind and hundred-percent visual inspection, there may even be some gauging at visual inspection for any critical cast features, it will go off to finishing. Typically, this involves machining of IDs, tap holes, cleaning up critical surfaces or very, very tight flatness callouts, and then any other finishing, such as plating or painting after that machining.

 

So, once we’re all the way through that process, here are a few examples. You can kind of see how we start with an exact replica, a wax pattern. It’s just scaled a little bit larger to account for the metal shrinking during solidification, but you can see that we can do very, very fine features, and basically, anything that we can tool in an injection-molded type die, we can then use to produce that steel or even aluminum casting.

 

John O’Donnell:

Thanks, Konrad, for the overview, and thank you, everyone, for joining us today. So, in comparison, to provide another overview of the metal injection molding process, especially for those of you that are not familiar with it, we’ll provide you a brief overview of that process, and give you some comparisons, kind of compare and contrast these technologies and really how they complement each other. So, let’s start off with a process video, then I’ll take you through some highlights of the MIM process.

 

Video Audio:

Metal injection molding, or MIM, has a well-deserved reputation for delivering the highest-performing small precision parts in the metal-forming industry. Its secret, MIM’s unique production process. This achieves significantly higher density than anything possible with standard powdered metallurgy. It starts when super-fine metal powders are combined with a primary paraffin wax material and a secondary thermoplastic polymer.

 

The resulting mixture is extruded and chopped into tiny pellets. These are heated before being injected into a mold cavity under high pressure. It is a technique that delivers tighter net shape tolerances over high production runs, making it possible to produce extremely complex components with enhanced surface finishes. Once molded, the component, what we call a green part, has an identical geometry to the finished part, but is about 20 percent larger.

 

This allows for shrinkage later in the process. The part is then put into a furnace to remove most of the binders during the debinding process. At this point, it is referred to as a brown part. In the final stage, sintering heats the component to temperatures near the melting point of its metal. This eliminates the remaining binder and gives the part its final geometry and strength. The result, high-precision parts delivering world-leading strength, corrosion resistance, and density. OptiMIM, when only the best will do.

 

John O’Donnell:

So, that overview of that video just provides a, you know, provides a highlight of what the MIM process is, but to take another side step to understanding MIM a little bit better, especially, again, for those of you not familiar with it, what is metal injection molding? First of all, it is not a molten metal process. It’s a hybrid technology between powder metallurgy and plastic injection molding. So, MIM starts out with a feed stock, and that is combining a couple different materials.

 

We’re combining raw metal powders that we at OptiMIM source ourself, and then we combine that with a paraffin wax and a polymer plastic. Those materials get all mixed together, and compounded, and pelletized in a material that we call feed stock, that can then be presented to the metal injection molding machines. So, the MIM process itself, even though the video outlined kind of an overview of it, I want to break it down in a little bit more detail here.

 

So, it starts out with atomized powder. This is something that OptiMIM sources. One of the differences is that OptiMIM produces our own feed stock, versus what you can buy on the market. That gives us process over all the control variables related to feed stock formulation, and then how the rest of the process behaves downstream. When you develop feed stock, it is the foundation of the process, and any of these downstream process steps only add variation.

 

So, we have to start out with a very sound and very well-controlled material. Once that material is compounded and validated and proven out, and confirmed ready by our test standards, it is then presented to the molding machines, and these molding machines are basically standard plastic injection molding machines, but they’re modified slightly to accommodate the feed stock material that we utilize, but the molding stage at this point is just like plastic injection molding.

 

The only difference is that the molds that we produce are all tool steels to handle both the abrasion of the metal powders as well as the very high injection pressures that we inject at this material. Then, a set of molded parts is then presented to two stages, what we call the debind and center phase. The debinding ovens are the first stage to help start to break down the binder system, that binder system being the plastic and the wax, and then the parts are moved on to the centering phase, where we finish the process, and this is where we remove the balance of the binder, again, the wax and the plastic.

 

And then, we bond or fuse those metal particles together to get a solid metal component that has a very high densification. We’re talking on the magnitude of about 98 percent density, nearly fully densified. This is just a visual representation of the process of these parts. So, at the molding stage, we call these a green-state part, and these parts at this point, again, have all the binder system and metal powder. These parts at this stage have about the consistency of a Crayola crayon, in terms of strength and density.

 

Once the parts are moved into the debinding phase, that’s when we start to remove some of the binder systems, what we call a brown-state part at this point. And then, once we get to this sintering phase, again, we evaporate out all the binder system, and bond or fuse those particles together. For the MIM process itself, this is some examples of some components. The duller gray components that you see on the screen are actually molded components, next to their sintered geometries, being the shiny parts.

 

The difference, obviously, is the size, and that size difference is that all MIM parts will actually shrink approximately 20 percent or so, depending on this specific material grade that we’re talking about, because each material grade we blend has a very specific and deliberate shrink rate that we control exceptionally well, but we do have to take this in mind as a variable to consider when producing MIM parts.

 

So, as we covered both of our process technologies at a high level, for those of you that may either need a refresher or are new to these technologies, we want to move forward in the presentation and provide some comparisons and so on. We would like to take a moment, though, to kind of reflect on the initial poll that Konrad delivered to you, and review these results.

 

Katie Yarborough:

John, I was going to say, we’ve actually had some really great questions come in. I know we’re going to hold most till the end, but I wanted to go ahead and put a few out there, if you wouldn’t mind.

 

John O’Donnell:

Thank you. Please.

 

Katie Yarborough:

Let’s see. So, one we got was, will the MIM part have a uniform appearance compared to an investment-casted part?

 

John O’Donnell:

The MIM part will have, generally speaking will have a uniform appearance, and the only caveat to that is that MIM parts do exhibit the same characteristics of plastic injection-molded parts. So, when you have a thick-to-thin section and other things that might involve, like, a visual sink or witness, when you’re talking about, you know, visual blemishes, that is not uncommon with MIM compared to plastic injection molding, but you can expect surface uniformity across the part.

 

Katie Yarborough:

Awesome. And then, another one was, do you use special tool steels or something to get high shot counts?

 

John O’Donnell:

Not necessarily. I mean, we obviously select unique tool steels for what we do, but they are off-the-shelf materials. The difference with metal injection-molded tools is how well built the tools are to handle the wear, and how well we maintain them. So, we have a pretty aggressive tool maintenance program at OptiMIM, to ensure that we can get millions of shots out of these tools. That’s a good question, though.

 

Katie Yarborough:

Yeah. And then, I noticed one actually pertains to, I think, where the conversation is going, and so, this may be a good segue. What can Signicast and OptiMIM offer for prototyping?

 

Konrad Roell:

Yeah, that’s actually a great segue. Why don’t we just skip to this next slide? So, we’re often asked about prototyping, both Signicast and OptiMIM do offer it. It’s a great way to avoid large hurdles, or time delays, or missed project deadlines. Typically, a lot of people will ask us to quote a project, we’ll get into the project, and then there’ll be design changes halfway through the actual process. So, prototyping is a good way to avoid that.

 

At Signicast, we do a few different things, but mostly they start with 3D printing materials, whether it’s a wax, SLA, or even a PMMA material, and that just comes down to cost, and how many parts, and sometimes how big the part is. For example, 3D printing wax when parts get much larger than 12 inches will need to use a PMMA material, so that it can actually support itself. So, let’s continue on here. We’ll add up all the questions at the end.

 

I think Katie will have a Q&A at the very end, but let’s continue on, and we will answer some of these questions that are rolling in as we talk about these. So, just at a very high level, let’s compare investment casting to MIM when we’re talking about alloys. As you can see on the screen, a lot of the standard alloys, whether it’s a carbon steel, you know, high or low, or 300 series, 400 series, even your precipitation-hardened materials and your tool steels, both investment casting and MIM can produce all of these alloys.

 

John O’Donnell:

Yeah, when it comes to standard alloys, you know, it’s one thing to have the standard alloys that we offer. It’s another thing to ensure that we deliver, you know, exceptional performance by our materials. The advantage that OptiMIM and Signicast have is that by and large, we’ve developed our materials, we alloy up or blend much of the materials that we actually produce ourselves, in order to get exceptional performance for what we call standard alloys.

 

This is an example of a component that we developed in metal injection molding for a customer, for an application that had obviously demanding, a demanding application, demanding environment that required exceptional material performance. And one of the challenges with this was, you know, brittleness or cracking, and having enough ductility to withstand the application itself. So, OptiMIM was actually one of the suppliers that stood out in this case.

 

In order to produce its geometry that would not only solve the challenge…this was a conversion, by the way, from CNC to metal injection molding, so not only was it a cost-reduction effort, but it was also an effort to improve the product itself, and to deliver something that could, where the MIM component could actually withstand the environment. To elaborate on that, this is an example of a case study of OptiMIM’s 17-4 PH 8 with an H900 heat treat.

 

This is the same material that I just presented in the previous slide for that component. Comparing our material for both the mechanical properties 4A Ultimate and yield as well as elongation, this is a benchmark against kind of the industry standard that is out there for MIM materials. So, you can see the variation in material performance that’s out on the marketplace today, but MIM, with our internal feed stock and our ability to develop these engineering materials, we have exceptional performance with the standard of 17-4.

 

And if you look at not only the Ultimate, but also the elongation itself, it’s tough to develop materials where you can get high strength, but you usually give up, you know, ductility to do that. We found a way to actually deliver both, and on the right side of the screen, the high elongation, that exceptional performance and elongation was really the difference, on that last slide, for us to win the Part of the Year, as well as deliver exceptional performance to the customer.

 

So, as a result of that application, not only did they get a cost down, but actually improved the performance of that product.

 

Konrad Roell:

So, now let’s talk about where investment casting and MIM kind of diverge when we’re specifically talking about alloys. So, one big area where they diverge is in aluminum. Investment casting, we definitely investment cast a lot of aluminum, whereas you would never MIM aluminum. You would use a traditional die cast process for that. Another area where you’re going to see a large divergence is anything that’s a high-nickel alloy, such as, like, Inconel, Monel, Hastelloy, stuff like that, and then even your duplexes and super-duplexes we will pour in the investment casting process, but not MIM those.

 

Vice versa, an area where they kind of share alloys, for specialty alloys, would be in your high-cobalt alloys, like your Stellites, as well as your Kovars, so, where you’re looking for those low coefficient of thermal expansions. An area where MIM actually can create a material that investment casts would be, like, a Nitronic 60 alloy. OptiMIM offers that for specific applications where it cannot be poured in the investment casting process.

 

So, where we see a lot of divergence between the investment casting and MIM is really in those aluminum and high-nickel steels. So, traditionally, that’s in aerospace and defense-type work. Usually, a lot of the parts that we’re going to be investment casting in aluminum are going to be conversions from a billet material. So, they were designed or originally designed to be a 6061 or a 7075 part, and just because of either supply chain or cost, they’re turned into an investment casting.

 

A lot of the advantages is, you know, through the investment casting process, if we do our job correctly, we can make sure that part directionally solidifies very well, and we’ll actually solidify in a pressure chamber, so it has a very billet-like quality as far as the material goes, and you get a lot of net shape geometry basically for free. You’re not paying for all that additional billet material that is just, you know, cut into chips. The other application is those high-nickel steels that I mentioned, your Inconels, your Monels, you know, applications where it’s a very high heat-resistant alloys.

 

Investment casting, obviously, offers a benefit for net shape, because you don’t have to machine those surfaces, and a lot of them can be used as is, as well as when we start talking about ceramic cores and even soluble cores, there’s geometries that we can form with the investment casting process that can’t even be machined. So, moving on, this is probably one of my favorite slides, and I’ll let John start here, but this might answer a lot of questions, or this is probably answering, you know, 99 out of 100 questions when we start comparing investment casting and MIM processes.

 

John O’Donnell:

Yeah, no question, Konrad. To tack on a little bit to your slides about specialty materials and standards, something to reflect on, again, we alloy up a lot of our own materials for both investment casting and MIM. So, what you see on the screen today is not what we’re limited to. It’s just something that we offer as some standard options. Again, we have the opportunity to blend up or alloy our own materials, and even something that’s entirely unique to your application, whether it’s a standard copper or something that doesn’t even exist today, and we can take that under consideration as well.

 

But with the limited time that we have today, moving ahead to compare some process comparisons with both of our technologies here, starting out with tooling costs. This could be a wide array of costs, depending on what your project is, how complex it is, you know, what the total capital investment might be, but looking from a tooling cost standpoint, the difference between the MIM and investment casting is MIM is, you have tool steels with a lot more precision work, because we’re injection molding at very high pressures with abrasive material, versus an investment casting die, which is a 7075 aluminum, right, and you’re injecting wax all day.

 

So, to that end, you can see that investment casting, you know, has lifetime tooling, because there’s very little to no wear when you’re injecting wax into an aluminum die, compared to MIM, which has abrasive material. But again, based on the way that we produce the steels and produce our molds, with the tool steels and in our aggressive maintenance program, it’s not uncommon for us to get, you know, several million shots out of these tools before they completely wear out and need some form of replacement. But again, we have a lot of different options we can discuss with you.

 

Konrad Roell:

So, besides tooling, probably one of the biggest questions we get asked is part size. So, you can kind of see, there’s a little bit of overlap when you start talking about that third of a pound or quarter of a pound area. There’s definitely some compare and contrast. Maybe a part will fit better for MIM or investment casting, depending on some of the things that we’re going to talk about later today, but typically, you know, that MIM part size, anything under a half a pound is going to fit really well, where investment casting, we do do some smaller parts, but typically you’re going to be anywhere from a half a pound all the way up to 250 pounds when we’re talking about investment casting.

 

Another big area where the two processes diverge is surface finish, and we’ll go into more detail about this later, but just straight out of a tool or straight out of the process, investment casting’s typically going to have a 125 or a 150 RA, where through the MIM process, you’re going to see that, you know, right around 40 RA as far as a surface finish. Another area where we see a lot of difference, or at least some difference, is in tolerances.

 

So, because the MIM process is molding the part inside the die, whereas investment casting process, you’re molding a pattern and then it’s going through subsequent steps, there’s a difference in tolerances. So, investment casting is going to have that plus or minus one percent of a linear dimension, where the MIM process is going to be about half that. So, that’s a, definitely a difference there. Sometimes this really doesn’t matter. If a small internal tap hole, you know, has threads or something like that, the investment casting process, often we can just cast approval, and then run a tap through it after the part has been cast.

 

And so, there’s really no advantage there, but if we’re starting to talk about, you know, coarse external threads, or some other fine details, we’re right on the edge of the tolerance limit, that’s where MIM really offers that tighter tolerance advantage.

 

John O’Donnell:

Yeah, comparing and kind of contrasting these technologies, you know, they really complement each other. I mean, there are times when you get some overlap with a particular component that maybe, you know, fits in the palm of your hand, but that’s even unusual. It’s really leveraging these technologies to figure out what is the right solution for your application, but as we kind of, you know, contrast and compare, comparing some of these, one of the benefits of both these technologies is that we don’t require any draft angle, for the most part.

 

The only rare exception to that might be if we have some thin-wall sections or some high aspect-ratio features, that might be challenging to eject from the die, or the mold, or the cavities. We might induce a little bit of draft, maybe a quarter-degree of draft or something to help aid in the release of those features, so that we don’t damage them during the ejection. As far as cast threads are concerned, both internal and external threads is entirely done routinely with both of these technologies, and there’s different ways to approach that.

 

From the metal injection molding side, when you’re talking about internal threads, one of the options that we have if it makes, you know, economic sense for all of us involved in the application, particularly with higher application or higher volume applications, is we can actually do internal threads with what we call hydraulic unscrewing cores. So, that allows us to hydraulically remove the core that produces the thread, and gets you a net geometry without necessarily having to chase it as a secondary operation.

 

Again, that’s limited to the application and the program that we’re talking about, but it is an option, compared to, say, investment casting. You want to elaborate on that, Konrad?

 

Konrad Roell:

Yeah, I mean, when we’re talking about threads, typically the investment casting, if we’re casting a thread through the investment casting process, it’s going to be on an external thread, and it’s going to be on a larger diameter. So, think greater than a 1-inch in diameter. Typically, they’re a driving or a locking feature of some type. You know, they’re not holding any pressure or sealing anything. When we get down to the quarter-inch threads, they can still be investment cast, but typically they’re going to be a coarser thread that maybe has, like, a nylon lock nut on it, but the process can definitely accommodate it.

 

Just real quick, and we’ll move on here, so we don’t run out of time, but just think about any feature that can be made in an injection molding tool, both processes can accommodate. We can also do undercut features. Got to be a little careful, make sure there’s enough room to design, you know, collapsible slides, and you’re not building a tool that’s going to need a lot of maintenance and not be very, very reliable. And then, both processes, we can do soluble cores or ceramic cores to form internally complex cavities.

 

John O’Donnell:

So, and particularly with metal injection molding for undercut features, I mean, we can do, like, a lost core concept, using, like, plastic, and we can do collapsible cores in the tools, but certainly investment casting is far more flexible at delivering that, but go ahead, Konrad.

 

Konrad Roell:

Yeah, so, let’s continue on here. We have another poll we’d like everybody to participate in, and really, we kind of want to know, as we dive into the rest of the slides here, we want to know what processes you guys are very familiar with. Are you very familiar with investment casting, and looking at maybe MIM for higher volume, smaller components? Are you very common with metal injection molding, and you know, need a little bit more flexibility or have larger parts as you continue to work on new designs, and need some investment casting?

 

Or are you coming from the life of die casting, of powdered metal forging, stuff like that, a lot of processes that kind of overlap with both investment casting and MIM? So, while you guys answer that poll question, I think John’s going to touch on this slide and talk about, you know, how we do a lot of DFM and consolidate parts for our customers.

 

John O’Donnell:

Thanks, Konrad, yeah. As you review the poll questions, we’ll reflect on that here momentarily, but to contribute to, again, these technologies and really how to leverage them, it’s not just being able to look at a part at the component level and understanding how to leverage either investment casting or metal injection molding. You’re really looking at it at the assembly level, and keeping in mind that, you know, it’s one thing to convert a component over to try to either get some cost savings or get some enhanced performance with this technology.

 

It's another thing to actually combine several components into a single component assembly and eliminate both the assembly cost, you minimize your supply chain greatly because you’re no longer having to source several parts, you eliminate the risk, you know, mitigation that comes with failed assemblies because you have an assembly failure. There’s all kinds of benefits to being able to consolidate components and get a single component out of it.

 

And again, these processes really excel at this, because the complexity of the component isn’t necessarily in the cost of the part for MIM or investment casting. It’s really in the tooling, which is the upfront capital cost to do that. So, there’s a tremendous amount of benefits by leveraging that. Wow, looking at results here. So, with the quick poll results that we had, the machining clearly stands out in your results that, again, thanks for the participation, and that partly reflects on the previous slide I just presented, talking about, you know, part consolidation.

 

Again, it’s not only converting from machining to investment casting and MIM because you don’t require the draft angle, but it’s also looking at part consolidation. Even if it’s a sub-assembly or full assembly, there’s ways to consolidate that’s really ideal.

 

Konrad Roell:

Yeah, I think, you know, we’re seeing more and more machining conversions nowadays. Here’s a great example. You know, we’re seeing not only cost for billet and raw material, but supply really dry up and inflate costs as well as extend lead times. So, we’re seeing a lot of conversions from not only machine products, but stamp products as well. So, here’s a great case study where we took multiple components that were machined, and even one that was stamped and formed, and consolidated that from, I believe it was about five parts down to three.

 

And we’re able to do that sub-assembly in-house at Signicast. We offer that service for some of our customers, and here’s a good example of where maybe the original product, the way it was designed or the demand made sense to machine it from solid, and as demand increased, or maybe supply decreased, or a combination of both, they looked at another process, i.e. investment casting. So, here’s an example of a 17-4 part, where there’s a large cost reduction of 26 dollars, as well as that weight reduction.

 

Kind of going back to the point that John made, you know, once you’re paying for the space on the mold, any features you want to make, you’re paying for in upfront tooling. So, we can do a lot of weight reductions, and even add additional features that maybe bring more value to your guys’s product.

 

John O’Donnell:

From that poll that we just looked at here, there was, you know, quite a few users that use metal injection molding today, and if I reflect a couple slides back, or several slides back, when I talked about the bar graph showing the material performance variation within the MIM industry, this was actually an example of a component that was brought to OptiMIM for review, and really helped kind of rescue them from some challenges.

 

This is a component that was previously MIMed by another supplier, and they had some issues, some quality issues, and particularly with product failure and cracking, and one of the differences to solve that challenge with OptiMIM’s metal injection molding process was using our enhanced material with our high ductility to solve those, and actually dramatically improved the reliability of this product. And while it’s not noted here, this was something that was recognized within our industry during an MPIF, Metal Powder Industry Federation, event back in 2020, which we won an award for this program.

 

So, again, it makes a difference in what you’re working with, in what your needs are and how we can help you. That’s kind of where we excel, is in the front end, not only with our DFM work, but also with our material performance offerings.

 

Konrad Roell:

So, let’s continue on with some of these poll questions. I’ve seen a few of the Q&A questions coming in, and people are definitely asking about envelope size for products. So, the first poll question is, you know, what envelope do most of your guys’s products fit under? Are they smaller than an inch, or are they greater than 6 inches, or maybe somewhere in between? This is definitely something that we’re asked a lot about when we’re comparing investment casting to the MIM process.

 

The other question that comes in quite often is volumes, and we’ll talk about this. There’s a great slide coming up which I really like, but are you guys, you know, working with products that are less than 10,000 a year, more than 100,000 a year, or somewhere in that in-between range? Typically, we’re going to have a little bit more flexibility with investment casting than MIM, but that’s not always true. Kind of goes hand in hand with the envelope size, and a little bit of the weight.

 

So, here’s probably my favorite slide of the entire presentation, and this does a really good example of showing where all those people’s that answered the questions about what processes are they currently using, and it was machining, here’s a great example. As, you know, as the part gets really, really heavy, investment casting, the lower the volume can be for the investment castings. There are castings that we pour one of a year, or even two of a year.

 

They tend to be hundreds of pounds, and they tend to be a very exotic, either nickel or cobalt alloy. But then, you can kind of see the curve of investment casting slopes up all the way to that, you know, half to even a third, kind of quarter-pound range. That’s where we start seeing MIM overlapping with investment casting. So, if you have a part that’s a half a pound or more, it’s high volume, investment casting is the way to go, because that volume really fits investment casting versus a machine-from-solid product. And John, you probably want to touch on this a little bit.

 

John O’Donnell:

Yeah, you know, relative to MIM process, it’s really ideal for smaller parts, parts that fit in the palm of your hand down to something closer to a grain of rice. But also, MIM is run in larger batch quantities, typically, because we’re using furnaces that are about the size of, you know, a vehicle, that can load a lot of small components into a furnace to establish our lot size. So, we’re generally dealing with a much larger lot size than what you see with the investment casting process, but we also do smaller parts, and are limited to those, for a variety of reasons.

 

One of the things about metal injection molding is the ability to scale. Well, both of these processes scale well, but from a high-volume standpoint, MIM can certainly do that exceptionally well, and I want to kind of give you a extreme example of that. We have a success story that we worked with in the past, for a customer that had an application that started out with a couple of, with three different components. They were certainly challenging and demanding on the requirements, and the profile, the expectations and so on.

 

And by the time we were actually able to scale this program within our own footprint, we ultimately got up to something in the magnitude of about five million sets of components a week to do this, and based on the automation and everything that we had in place, the goal was to achieve zero PPM, and which we did with this particular program. So, this is kind of an extreme example of what is possible with metal injection molding. Now, comparing these technologies of MIM and investment casting, of course, investment casting can do much larger parts, but because they’re all, they’re banked up on, you know, trees, they generally run smaller batch sizes.

 

So, this is where the technologies really kind of complement each other, and it is not uncommon for investment casting, for both Signicast and OptiMIM to be working with one customer on a single product, where perhaps we’re doing an investment casting housing with some MIM components that go inside of it, just for example. So, in addition to the poll questions that we covered on the annual quantities and part size component, another area to consider is what you might require for surface finish.

 

So, we have another poll question here for all of you, again, to participate in, and thank you for all of your participation with all these poll questions, but it helps us answer some questions as we get to the Q&A at the end here. You know, but what kind of surface finishes do you require? Are you looking for something like 16 to 32, you know, RA or better, or are you satisfied with something that’s 125 RA-plus? You know, do you have an application where you want surface roughness for, maybe you’re over-molding it and you need surface adhesion, or do you want something that’s more cosmetically polished?

 

And when we look at these poll questions, with some of these, you know, ranges in between here, this is kind of where we can potentially get into the overlap between metal injection molding and investment casting. But again, it depends on what your requirements are, if it even does matter. You want to contribute anything there, Konrad, before I move on?

 

Konrad Roell:

Yeah, I mean, typically, we mentioned it on one of the earlier slides, but typically, you know, investment casting is going to be that 125 or higher, and if it’s a critical surface, if it’s going to be machined anyways, then that 63, 32, 16, depending on the type of machining, is achievable in specific areas. Where there’s really overlap, where, you know, maybe the product could be an investment casting or the product could be a MIM part, is usually where the entire part has that high surface finish.

 

So, here’s a great example John has in medical industry, where, you know, the part needs to have a high surface finish in one area, and maybe lower in others.

 

John O’Donnell:

Yeah. In this component, while we were combining…this is a case where we not only consolidated multiple components into one, but there were some areas where we needed to have a rougher surface finish. So, we actually had to texture the mold to produce a rougher surface finish, because this customer ultimately wanted to over-mold this component in plastic, and they wanted good surface adhesion to do it. So, you know, we can control, in this case, you can control surface finish by feature as well.

 

And that can, again, be textured in the mold to get a higher roughness where it might be needed. So, reflecting on our results, why don’t you go ahead and elaborate on this, Konrad?

 

Konrad Roell:

Yeah, so, it seems like a lot of people really need those higher surface finish. So, if your part really requires that 16 to 32, you know, MIM is really the way to go, even to the 32 to 63, MIM is going to be the surefire bet. It’s going to come out in that, like we mentioned, around a 40 RA, just from the tool, but that doesn’t necessarily mean that if you guys require a better surface finish, that maybe investment casting isn’t the process you’re going to go with.

 

The reason I say that is because there’s lots of applications where we talk about surface finish, the way it comes out of the process or as cast, and typically, a lot of our customers are doing other operations to that finish to meet their market demand. So, for example, you know, recreational vehicles or motorcycles, a lot of those are going to be powder-coated or chrome-plated, and it really doesn’t matter what the surface finish of the casting is, because those surface coatings are going to cover that entire part.

 

An area where it’s kind of like an in between would be on some, like, recreational goods, consumer market. You know, this is a good example of a mountain-climbing application for a cinch, where the customer wanted to demonstrate a premium product on the shelf. So, all that we did was we took this part, we did a blast to it, and then electropolished it, and it gave that very good premium luster without adding a lot of cost or something like manual polishing.

 

And then, on the very, very high end, you know, as we approach that 60 RA, or, I believe this dental application was around 80, we can do some very, very fine glass bead blast or even media blast on a part on a part, and then do an acid vibratory. Typically, if we’re doing a medical application, we can already assume that the part’s going to need a fine media blast and a acid vibratory for one to two hours.

 

John O’Donnell:

Yeah, when it comes to surface finishes, too, keep in mind, with both of our technologies, you can do anything to the surface in terms of plating, coating, you know, things like that. But go ahead, Konrad.

 

Konrad Roell:

Yeah. So, I know we talked a lot about technical data, and that’s probably what most of you had questions about, but just real quick, for anybody that’s curious, let’s just talk about our companies really quick, John. So, first, just Signicast. You know, we have six facilities in four countries, mainly our headquarters here in North America in Hartford, Wisconsin, and then we have three facilities over in Europe.

 

A lot of the customers we’ve been doing business with recently are working on, you know, aerospace parts that require AS9100, whether it’s aluminum 15-5, 17-4s, or even your nickel alloys, like I mentioned, like your Inconels, and Monels, and Hastelloys, as well as a lot of those products in the defense sector that require your ITAR and your NIST compliance that Signicast has. And then, lastly, we did talk a little bit about medical parts. So, Signicast does have our ISO 13485 for any of those medical applications.

 

John O’Donnell:

Yeah, similar to Signicast, we have our, with Portland, Oregon being our primary location here for metal injection molding, we are also ITAR and NIST-compliant. We do a fair amount of work with the aerospace, military, and in defense, and certainly compliant to that, and some examples of which I showed you in this slide deck already. In addition, we do quite a bit of work in the medical space. We are ISO 1345-certified to that medical standard, and again, have quite a bit of experience in automotive as well.

 

So, we are IATF 16949-certified as well. So, again, with all of our technologies and our certifications, we’re certainly here to help with any of your applications in really any industry, frankly. So, thank you again, everyone, for joining us today, and thank you for your time. Over to you, Katie.

 

Katie Yarborough:

Thank you both so much for a really great, informative webinar. Lots of great information, we hope you all found it useful. We are going to get to the Q&A in just a minute. I just wanted to inform everyone, though, that this webcast is being recorded, so you can actually use the same link you used to log in initially to get back in, just in case you want to rewatch, or you missed anything. Just give it a few short hours to upload, and then the recording will be available later today.

 

But the first question, I’ve pulled a bunch, and so, we’ll try to get to as many as we can. If we’re unable to get to your question, though, we will have an engineer follow up with you via email after the webinar. But first question we have is, have you heard any talk from people in the US military or a DOD supplier about switching from investment casting to MIM for triggers, hammers, and other small parts for US military rifles?

 

John O’Donnell:

I think I can start off on that one. That is a common conversation, really, in that industry between investment casting and MIM, and we actually have a number of customers, and actually utilize both technologies, depending on what the geometry and what the requirements and the material and the demand is. Anything to add, Konrad?

 

Konrad Roell:

Yeah, I would just say, we’re definitely asked about it a lot, you know, any time someone talks about mil spec, that term’s kind of thrown around loosely. I think the resistance for the US to start using MIM products in the fire control groups is just, we’ve seen lots of recalls, whether it’s firing pins, or other components inside pistols that are MIMed, and they didn’t go through the correct quality process, quality controls like OptiMIM has, and you see those failures, and they’re pretty random.

 

So, I think that’s why the US military has stuck with investment castings for those types of components.

 

Katie Yarborough:

Okay, and this next one, can you modify any materials?

 

Konrad Roell:

Yeah, I’ll take this first. So, we alloy up all of our materials. Very often, we’re asked about supply for metal. So, we start with a lot of stampings, forgings, or even machining scrap, and we’ll alloy those all up and add in your chrome, your moly, your silicons, anything that’s needed to hit the correct alloy chemistry. So, really, there’s any alloy we can do, if you guys dream it up. If there’s something as far as the grain structure, you want it to be more martensitic or something like that for a certain advantage, we can definitely do that and work with you to make any alloy.

 

John O’Donnell:

Yeah, that applies to MIM as well. I mean, we obviously source our own powders, and so, we can actually, you know, we can mix powders together to create a unique alloy to solve some challenges, and we’ve done webinars in the past talking about some examples of things that we’ve done with custom alloys that we have developed for unique applications, for which there was not a material off the shelf to solve the problem. So…

 

Katie Yarborough:

And on that same note, given the challenging supply chain environment, what’s the most common or most available raw materials to help indicate what might be the most available long term to guard against delays?

 

Konrad Roell:

Yeah, I would say, any of your carbon steels, that first slide, all the standard alloys, any of your carbon steels, your 300 series, even your 400 series and precipitation-hardened materials, very common alloys that have been along for a long time, and are going to continue to be used. I’ll even throw aluminum in there. I think the ones that see the most volatility are your very, very high nickels and high-cobalt alloys, and even alloys that maybe have a lot of titanium in them as well.

 

John O’Donnell:

Yeah, perhaps even some of the specialty materials, but yeah, even from a MIM standpoint, you know, the stainless steel 17-4, obviously, is a high runner for us for much of the medical and other applications that we run. But this is something that obviously is a challenge for everyone, but our company does an exceptionally good job of managing the supply chain, particularly as lead times and all that get pushed out. So, from a company standpoint, we’re actually in really good shape.

 

Katie Yarborough:

And what are the lead time differences between casting and MIM?

 

Konrad Roell:

You can take that first, John.

 

John O’Donnell:

Yeah. From a lead time standpoint, there’s really two aspects to it. There’s the tooling lead time development. So, once we go through a DFM review and get the files that we need to kick off a particular project, there’s a lead time development for developing the tooling and kind of the components. The second phase of that is the qualification or the validation requirements that we have to go through. So, really, comparing the two technologies, from a MIM standpoint, you know, tooling lead time really depends on the complexity of the component.

 

If it’s a relatively simple geometry that might require one cavity, versus a multi-cavity, highly complex component, the tooling lead time might range in the, you know, ten to 14-week timeframe. And again, it just depends on what your application is, and it’s probably a fairly similar, I’d say, for investment casting. Konrad?

 

Konrad Roell:

Yeah, so, for investment casting, because we’re not building a tool out of tool steel, we’re just doing it out of aluminum, our tooling lead time is much less. So, usually to launch a product, like John mentioned, from PO, print, model, everything squared away, to having, you know, parts in your hands to validate, run through inspection, it’s typically ten to 14 weeks, closer to ten weeks if it’s just a simple casting that gets heat-treated, maybe a media blast.

 

But if it gets machined and plated, and there’s other operations after casting, we’re going to be closer to that 14 weeks for validation.

 

John O’Donnell:

Yeah. It’s really application and program-specific, so, invite you to bring your project to us.

 

Katie Yarborough:

I think we might have time for one more, and then we’re going to have to wrap up. Again, we’ll try to follow up with all of you, you know, after the fact, and provide answers, because there were some really great questions we didn’t get a chance to get to. But quickly, why isn’t draft required for injection of patterns and green parts?

 

John O’Donnell:

Good question. Go ahead, Konrad, please.

 

Konrad Roell:

Yeah, I’ll talk about investment casting first. So, the reason we don’t need draft is because we’re using that wax, and that wax is actually engineered to be a lubricant. So, we engineer our wax internally at Signicast, for really tight dimensional control, but one of the things we can do by engineering our own wax is making sure that it has that very high lubricity. So, you’re not going to get that cavity erosion in the investment casting tool, and that’s why we’re able to make it out of 7075, a set of tool steel, is because we’ll continue to inject that lubricant, and it will basically last the lifetime of the project.

 

You know, at Signicast, we still have dies built in the ‘70s that are still being ran full-production today.

 

John O’Donnell:

Yeah, from a MIM standpoint, in similar fashion, even though investment casting has wax as a base for its component, the wax is a constituent in our feed stock, as I mentioned earlier. So, the wax acts as a mold-release agent. So, we do not have to provide mold-release agent into the tool, and also, we have minimal shrinkage at the molding phase for MIM. So, we can actually release the parts with the wax inherent in the feed stock, and eject it directly from the tool. So, both these technologies, they rarely require draft. Good question, though.

 

Katie Yarborough:

And I think that is all of our time for today. Thank you all for attending. Big thanks to John and Konrad for leading us through a great discussion, and we hope all of you have a great week. Thanks again, guys.

 

John O’Donnell:

Thank you, everyone.

 

 

 

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Last updated 05.19.2022