Saving Cost: Fit, Form, Function

Saving cost on your component’s design


Conversations with suppliers always start with the basics—the fit, form, and function of your new component. But with other suppliers, the next step is to go straight to quoting your component, with little to no time spent on optimizing your design for manufacturing. With this mindset, precision component projects are stunted before they even begin production.


At Signicast, we believe in a value-added approach to manufacturing your component, and that means helping you to optimize your design for greater value from the very beginning of your project. By partnering with our engineers in the early stages of your part design and utilizing our “design for manufacturing” methodology, you can meet all your form, fit, and function requirements while still hitting your cost targets. And all it takes is a conversation.


In this webinar, our presenters cover:


·       Saving cost by optimizing your design for the investment casting process

·       Adding value with complex features without adding cost

·       Design for manufacturing methodology

·       Part examples demonstrating both cost savings and value addition

·       Past case studies where we did just that!


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Transcript: Saving Cost: Fit Form, Function


Taylor Topper:

Hello, everybody, and welcome to today’s Metal Solutions Webinar, Saving Cost: Fit, Form, and Function, presented by Form Technologies. I’m Taylor Topper, Group Marketing Manager at Form Technologies and your hostess for today’s webinar. If this is your first time joining us for a webinar, I’ll quickly go over a few housekeeping items so you know how to participate in today’s event. For best viewing experience, we recommended using Google Chrome or Firefox.


There is no dial-in for this webcast, so all of your audio is going to come through your computer’s speakers. If you look at your ON24 dashboard right now, all of those widgets and boxes are moveable and resizable. So, feel free to make the slide box a little bit bigger or organize your console in a way that works best for you. I want to point out the list of resource that you’ll see on your console, as well. We’ve provided a white paper, Converting to Investment Casting, as well as a few of our recent blog posts.


For even more resources as it relates to investment casting, I invite you to take a look at our Knowledge Center on our website for I also invite you to submit questions via our Q&A widget. We’ll be holding a live Q&A session at the end of the webinar, and we’ll try to answer the questions as they come in, but if we get to the end of the time and we do have questions left over, I’ll make sure that we have an engineer follow up with you via email afterwards.


So, I do urge you to get your questions in sooner rather than later and throughout the presentation. Just know that we will answer them at the end. Today’s webinar includes several videos. So, if a video pauses of glitches, I recommend you refresh your browser or close out of the presentation and try to log back in. I hope that we don’t have any technical issues, but you really never know how things will go. If there is no sound or slides aren’t moving, you can submit a comment to me via the Q&A widget, and I’ll do my best to troubleshoot that for you.


Like all of our webinars, this is being recorded. So, you can use the same link that you used to access this webinar again in a few short hours if you want to rewatch, or if you missed something, you can just use that link that’s emailed to you. This webinar is presented by Form Technologies, a leading global group of precision component manufacturers, including three major brands, Dynacast for die casting, Signicast for investment casting, and OptiMIM for metal injection molding.


With our world-class technology and processes, we can serve any industry at virtually any volume with superior components and outstanding part-to-part consistency. The Form Technologies group of companies operates 29 design and production facilities in 19 countries worldwide. Together, our entire business is focused on delivering the highest levels of quality at scale. Signicast is a leading expert in precision investment casting and rapid prototyping and delivery, and with the most advanced automation production facilities in the world, Signicast is redefining how today’s manufacturers create, refine, and deliver products.


Today, we have two really great presenters from Signicast with us. They have a combined 25 years of experience within the investment casting industry. I really can’t think of two better people to help me discuss how our customers can save costs through design optimization and collaborative partnership with your suppliers. So, first, we have Konrad Roell. Konrad’s been with Signicast for 10 years, first as a project engineer, and most recently, as a sales engineer.


Konrad specializes in new product development and profits conversion, putting his years of experience as a process engineer to work for his customers, and we also have Craig Learman today with us. Craig has been with Signicast for 15 years, and much like Konrad, got his start as a project engineer. Currently, as estimating engineer manager, he specializes in optimizing designs to be most cost effective for the investment casting process. Konrad and Craig, thank you guys so much for presenting with me today. I think that we can go ahead and get started.


Konrad Roell:

All right. Well, thanks, Taylor, for the great introduction, and thanks, everybody, for attending today. To pick up where Taylor left off, Signicast does have six worldwide locations, three of them being located in the United States and three of them being located in the EU.


Signicast, from a high view, is the world’s largest commercial investment caster with over 1 million square feet of manufacturing space and over 1,400 dedicated employees. Now, you would think, with over 500 customers, we would be much more well known, but we are the best-kept secret in the investment-casting world, and I think it’s because our customers keep it that way.


We’re their go-to source for the complex geometry and difficult problems. Most of the time, the way we’re solving those problems is through our in-house tooling or our prototyping and additive manufacturing spaces where we can take any design, 3D print it in wax, run it through the full investment casting process, and be able to create a part that has the exact same properties as the true investment casting.


This helps speed up product launch times and conversion times. Now, that’s enough about Signicast. Why are we really here today? So, usually, when we receive RFQs, RFPs, or RFXs, one of the first questions that I ask our customers is if we can set up a design review call or a design for manufacturing call, and most supply managers or program managers think, great, we’re going to either put a stop in our project lead time, or they’re trying to back us up and we’re going to miss all our deliverables.


Well, what we really want to demonstrate here today is how we can have a simple 15-minute, even an hour conversation, walk through your part’s fit, form, and function, and save costs, not only initially, but in the long run. So, let’s get to what we’re going to talk about today. First, we’re going to walk through the process foundation. I think everybody here needs to fully understand the investment casting process and every step along the way, so that when we get into these details later on, we have a good foundation.


Then we’re going to talk about the weight limitations and surface area limitations of the investment casting process. Craig will then talk us through a part example of fit, form, and function being used and how we can add value while saving cost at the same time. After we talk about the part example and the part features, we’ll go on to alloy and heat treatment selection. Very often, this is either carried over from a conversion, or it was one discussed early on in the product design, but never double-checked or thought about again.


Then we’ll move onto machining. Ninety percent of our investment castings require some sort of machining, and there’s ways to design investment casting to help reduce that machining cost. The only thing, besides machining, that will add cost to the investment casting quicker is specifications. So, we’ll talk about specifications at the end of this presentation and how they affect the part cost drastically.


Craig Learman:

Thanks, Konrad. Hello, everyone. We’re going to start off with the process foundation. I want to start off by saying that the investment casting process is a process that many are unfamiliar with. So, with that said, I think it’d be best to start out with a short video explaining the investment casting process, and then we’ll flip through some pictures with a further explanation.


00:08:23.4 Video begins

Male Speaker:

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 dye 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 dye.


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.

00:10:20.8 Video ends


Craig Learman:

All right. So, the process begins with a tool, and basically, our wax tooling is identical to plastic injection molding, except we’re going to inject wax instead of plastic. The wax we’re injecting is a semi-solid, which allows us to hold tight in repeatable tolerances, part to part, lot to lot. Once a pattern is removed from the tool, the part will be assembled onto a tree. This is typically done by heating up the gate and the part area on the sprue, sticking them together, and sealing the connection.


This webinar’s going to focus on that part of the process, how we can maximize really pieces per mold, through some limitations that we’ll get into. Once that mold is assembled, it goes onto a cluster hanger, or in a single mold, as well, we start dipping it into our ceramic slurries where we will build the shell around the wax pattern. Once the shell is built around the wax pattern, we need to melt out the wax.


From there, it will go into the autoclave, where we’ll melt the wax out using pressure and steam so that the mold doesn't crack when the wax starts to melt. From there, we have a shell with no wax inside. So, we’ll put it through the burnout oven where we’ll burn out any residual wax. We fire the mold like you would, say, a clay pot, and then we’re also preheating the mold to 1,800 degrees, so when we put 3,000-degree metal into it, we’re not shocking it when that happens.


From there, we have the ability to both robotically pour and manual pour to fill the molds with a wide array of metals. From that, we have the metal filled, and we need to remove the shell. So, we’ll put it in a water blast cabinet where we will blast it with about 8 to 10,000 psi water, removing the shell as much as possible. From there, it would go to maybe a caustic operation to get what remains, and then it’s time to remove the parts from the sprue.


That’s typically done via, like, a big chop saw to cut the parts off, or we will freeze the mold and cryogenically remove the parts from the sprue or the tree. From there, it will go to inspect for quality where every part gets 100% visually inspected, and then it will go onto the subsequent operations. For example, heat treat, plating, painting, machining, pretty much whatever your part design requires.


Konrad Roell:

So, now that we thoroughly understand the investment casting process, let’s talk about some of the limitations of the process, just like any other manufacturing process. The first one to discuss is weight limitations. So, there’s going to be three key departments where we run into these limitations. The first is our wax injection. Second is going to be our ceramic shell building, and third is going to be where we pour the metal into the actual mold.


In multiple steps throughout the process, there are areas where the molds have to be handled individually by our skilled employees. That means that we have safety restrictions on how much the individual mold can weigh. The next area where there’s weight limitations is when it comes to our automation and our robotics. The slurry and shell-building process is very labor intensive, and most modern investment casters use robots to do this job.


However, they still have weight restrictions. The last area where there are weight restrictions is pouring each individual mold. Because we have over 500 customers, and each of them require a different alloy, we like to pour molds somewhere between 100 to 120 pounds, and that’s pretty common in the investment casting world.


The next area where we see limitations is in reference to surface area. Now, some of these are going to be related to weight in one way or another, but the three areas where we see surface area limitations are going to be in our dip cells for our ceramic shell-building process, our dewax where we’re using that steam pressure to remove the wax from the shell, and then our burnout ovens. The first is in dip. Because of the surface area, we have sand and slurry covering the parts.


The more surface area the part has, the more the very viscous slurry can grab onto, thus increasing its weight and its limitations for the robot. Next is going to be in dewax, where, now that we have a fully injected and dipped mold, we have both the wax weight combined with the ceramic shell weight, and once again, there are personnel safety weight limitations. The last is going to be in the burnout oven. Like Craig mentioned, we’re firing these molds to 1,800 degrees, and we have to make sure that that mold at 1,800 degrees and how much it weights is still safely handled.


Craig Learman:

All right. Moving on to fit, form, function. Now, I’m going to take some time to explain to you, the customer, how best to take full advantage of the investment casting process. That process starts with our mold setup. As Konrad explained, the IC process will have geometry, pour weight, and shell weight limitations, and the mold setup for every part will hit one of those limitations.


It is through a DFM meeting that Signicast Engineering will work with you to broach 2, if not all 3, limitations, maximizing the value your partner’s receiving with the investment casting process. So, basically, what I like to tell our customers is to think about it in this way. That your part is renting space out on a mold. Whatever changes or features you can do to the part are essentially free, so long as you don’t increase the footprint of the mold.


As an example, so, if you have a part and you can put holes in it or bosses or features or anything you can think of counterbores, splines, and the overall footprint of the part does not get bigger, we’re going to end up, pretty much, with the same pieces per mold, and the piece price will end up staying the same. So, a lot of that stuff can just go along for the ride. So, there might be a small implications on the tool cost, but like I said, if you can combine stuff together or add things that don’t make the actual footprint of the part bigger, it’s essentially free, but let’s walk through an example so I can show that.


So, here’s a part that we might typically see from a customer. It’s very minimalistic in terms of’s functioning as you need it to function. You know, it’s got a bend. It’s got some holes to bolt something together. It’s got a couple faces to mate things up with, and it functions. It’s very simple for what’s needed. So, a part like this comes in at about 2.8 pounds, and we will be pour-weight limited.


So we’re only going to get, I think it’s 18 pieces on a mold, per se, and we’re going to end up with a price of about 23 dollars. So, if we start through that DFM process, we can start to add cover board hex holes. So, you know, this can be convenient where the nut can be retained. We can make little bosses next to the hex that we can coin to put the nut in, coin it to retain the nut in there, and then ship it that way. You can also put it in in a location that you might not be able to get a tool on the backside of a machine or something where this can act as the tool itself.


And you could see the weight didn't change much, but we’re adding hex holes, and you start to see a little bit of an advantage, but our price stays the same. Now, if we take that DFM another step, we could start to lighten the part up. So, obviously, we’re past FDA and everything like that, but you can start to see that, you know, the weight has been drastically reduced, and what that does is that allows us to increase our pieces per mold.


So, the overall piece price then comes down from that 23 bucks to that 18 dollars, and the cost of the alloy itself is not the reason it reduced that price. It allowed us to get more pieces per mold. I mean, that’s the big driver. The cost of the alloy itself in the part, it’s, like, less than 25% of the overall cost. It’s the fact that we were able to get more pieces per mold to get us off that pour weight limitation, and if we take that DFM call one step further to fully take advantage of the investment casting process, we can start to add lettering, lot codes, part numbers, left-hand, right-hand, I mean, logos.


Things that, basically, if you can think of it or draw it or model it, you know, we can put it into the tool and ultimately into the part, and this is a great way to set yourself apart from your competitors. I mean, you could put your logo right in someone’s face if that’s what’s desired, and again, you can see from the previous example, the weight itself does not increase much at all, and the price stays the same, and then you could take full advantage of this process.


So, kind of summarizing this, that initial part, like I said, we were pour weight limited, so we could only get 18 pieces per mold. When we start to reduce the weight of the part, we could expand that pour weight limitation to get more pieces per mold and ending up reducing our cost from 23 to 18 dollars, which is a 20% cost savings, which can be a huge deal to everyone.


Konrad Roell:

So, now that Craig has walked us through a part example, I think it really helps demonstrate the fundamentals. It was a simple part, but any part can take advantage of what was just explained. Let’s move onto alloy and heat treatment selection. So, like I was saying, very often, alloy and heat treatment selection is thought of very early on in the design process and never again. Some of our customers use cutting and grinding tools.


A good example would be this knife blade that we see on the left. It came in as an RFQ in 420 steel, because it was originally machined from solid. After talking about the function of the part and doing a DFM call, our metallurgist suggested a D2 tool steel. The end result is being able to supply our customer with a part that did have a 5% greater cost, but it had a seven times wear resistance, and therefore, extended the life of the part in service by 700%. Another example would be heat treatment. It’s important to think about heat treatment because some parts drastically need it.


If you want a part that’s going to be heavily machined, you definitely want to heat treat it and homogenize that entire material before doing any machining to limit hard spots or broken tools. However, if you aren’t doing extensive machining, you may be able to eliminate heat treat altogether. We have some lock manufacturer customers that design parts that don’t require any machining, and we were able to eliminate the heat treat altogether. This is because the AVCASS material was strong enough to meet all requirements as far as strength and cycle testing


The next area that we need to talk about is machining. Like I said earlier, 90% of our investment castings are machined. You can see the part on the left in the center is very good investment casting. It was originally a weldment, but you can see there are no thick sections, and there are ribs and gussets where are needed for strength. You can also see there’s cast counter bores and through holes. There’s even a cast through hole that then gets capped to eliminate a drill and tap operation and can simply become a tap operation.


Other thing that you’ll see in the center picture is that there’s four raised bosses. This part was originally designed to have those be flat surfaces that require machining as far as location in its final assembly. By simply designing an investment casting to have raised bosses, you can now eliminate the machining and the large cost. The last thing to talk about when it comes to machining that I often see on prints and RFQs are surface finish callouts. It’s very common to have a 32 or a 64 surface finish callout in your title block.


Often, this is adding cost where it’s not needed. Many of the features that we machine on the casting are for size, position, or flatness. Don’t call out a surface finish if it needs a 32 or a 64, unless it’s for a sealing surface, an O-ring groove, or a press fit. Very often, you can simply call out a 125 on that same surface and eliminate 1 or 2 machine passes or reduce the cycle time for machining altogether.


Craig Learman:

All right. Lastly, I want to talk about specifications. As the world’s changing, more and more customers are adding specifications to their drawings, to their prints, and a lot of them, they may think what they want on the print, but they’re not familiar with the spec and the specs within the specs. As an example, a very common one we see in the investment casting industry is AMS 2175. That’s an NDT, dye pen, mag particle inspection. Signicast performs that on all of our sample parts for all parts made.


What’s becoming new in the industry, or customers in the world I guess, is we’re seeing that more common, and what it’s driving is the things in that spec specifically call out for the operation to be done in an ongoing production basis, and a lot of times, if not most of the time, that’s not necessarily a customer’s intent. What they want is they want the part to meet that, and that can be done by proving it out on initial samples, and our process gets locked down so that it’s repeatable through the process.


But when it’s just called AMS 2175 with a class and a grade, that requires in-production testing that needs to be done, which can drive up cost. So, some ways to get around that are you can call that spec out, but to put it that it’s on initial samples only, first article samples only, or not required in production. There are some things like that to think about when trying to keep cost on the part low. Another example is the alloy grades. So, we’re seeing a lot more of ASTM alloy callouts.


As an example, ASTM A216, it’s a carbon steel alloy callout, and the majority of the time, when we see that, the customer’s simply wanting us to make it to that chemistry. What they’re not aware of are all the subsequent specs or requirements of that in there, because there might be test bars. Test bars is one that is in that spec, and that might not be something you require for your part, but when you call it the spec, it is what’s required because of the spec. There’s other specs that are buried in the spec.


For example, A488. Basically, we call it, like, a certified welder’s spec. It’s something that Signicast is capable of doing. Those welders have to go through additional training, and then there’s more labor tied to that process and ultimately, to that part, which then is reflected on the cost, and what’s unique here is that spec was more like a boilerplate vessel type spec, and it’s meant for welding, like, cracks and things of that nature. A crack of that nature, it would just be considered scrap, and we would move on.


The type of welding we’re doing would be small negatives. We’re talking 30 thousand to 40 thousand negatives that we’re just pooling a little bit of metal, grinding it flush, and it continues onto the heat treat process and there forward. So, it’s something that’s there, and yes, we’re technically welding, but what’s intended by that spec is not necessarily what we’re doing. So, we like to take exception to that. Another one would be A985, which requires charted furnaces. Now, we have our own way of charting our own furnaces with our own systems, but it doesn't necessarily meet the exact requirements of that spec.


We can do it or have that done, but again, there’s more labor that goes into that process, which is then reflected in the overall price. So, these are things that, yes, we can do, but they are items that I don't know that your part or your design necessarily requires, and that’s why working with Signicast up front on a DFM call, we could help to bring up these concerns or these issues to help kind of design that out before we get too far down the road, so that we can be all together at the same page at the start of the project.


Konrad Roell:

I think, Craig, a perfect example of that would be, you know, last year, I had a customer launch a brand new project with us, and they had, actually, ASTM A216 called out, which you just mentioned, and like you said, that spec requires test bars on every production lot, and then to have those test bars actually pulled and have the results reported, and actually, what we were able to do was, on the first production lot, we did do that. We had test bars pulled and tested, and we also did it on the first five production lot.


And what we were able to do was have our metallurgist work with their process engineers, and we were basically able to correlate the strength in those test bar results back to the actual material certs, which is a much more cost effective type of quality reporting, and on that part, a perfect example, there was a 15% cost savings. So, I think that just is a good example to show how specifications need to be reviewed and make sure that what we’re putting on the prints is really what’s needed for the function of the part.


Craig Learman:

Yeah, Konrad, that’s a great example, and this isn’t specific just to ASTM A216. It’s pretty consistent across all ASTM alloy callouts. There’s a lot of different things that are buried in these specs, when, the majority of the time, it’s simply you want the chemistry. So, I guess when putting prints together, something to consider is, you know, make sure you understand the spec or what part of the spec you want to involve, and what we’ve been seeing lately, we can call it out to say, like, chemistry per ASTM A216. So, that would apply just the chemistry for that requirement, not necessarily the rest of the spec.


Taylor Topper:

Thanks, guys. I am assuming that was the last of that slide, but I really appreciate you all presenting for us. I know those design videos do take a lot of time, so I appreciate you putting in your time to not only create those, but just be thoughtful in how you’re presenting and sharing that information. So, I really appreciate that. We do have a few questions here, not too many. So, we’ll just, you know, keep going with the webinar until we run out of questions, and the first one is how long does your average DFM conference call or meeting take?


Konrad Roell:

Yeah, that’s a good question, Taylor. Typically, it depends on the complexity of the part and where there’s areas for improvement. I would say, on average, somewhere between 15 minutes to an hour, we’re able to have a full DFM call and leave with action items and be able to update the quote or RFQ, you know, later that week. So, not very long. About a half an hour, 15 minutes is probably average.


Taylor Topper:

Great, and next question. What advice would you give a design engineer working on their first investment casting?


Craig Learman:

I think the advice I would give would be to, basically, take the function of the part in the scope and make sure that’s what you’re gathering first, and then, from there, we like to see a customer start to weight-lighten parts, and to really do that, you need to understand where the gating’s going to be, and until you’re really familiar with the process, that can be difficult. So, I think the scope is to really understand your part designs, the function, and then to, you know, give us a call, and we can step through that, tell you where we think we need to gate it, and then design some of that into the part, those weight-limiting pockets or holes or features into it.


Taylor Topper:

Thank you, Craig. _____ 00:32:57.4 dimensional requirement and capabilities, how do you, or how does your team, ensure your customer long-term capability compliance?


Konrad Roell:

Okay. Yeah, so, typically, if we’re worried about certain features and long-term capability, we will suggest that those features be called out as critical features on the print, and traditionally, for any critical features, upon the FEI inspection, Signicast would do a full capability study on those features. If we prove out capability, then we’ll go forward with just a sample plan with, you know, very few checks into production. If it proves that that feature cannot be capable or have a very good CPK as far as the investment casting process goes, what we’ll do is we’ll implement functional gaging into the parts, and you either have a sample plan for the functional gaging or gage the parts 100% for those critical features.


Taylor Topper:

Thank you, Konrad. This next question, I think we probably get on every webinar, and we do have this information on our website, but what dimensional tolerances is the processing investment casting capable of?


Craig Learman:

Well, as a general tolerance, you know, from a half-inch to an inch, it’s pretty much plus or minus 5 thousandth, and from there, it’s real fun. It’s about plus to minus 3 thousandths inch per inch thereafter. There are some things we can do to tighten that up, if need be, on local areas or holes. We can do some tool reworks to dial some dimensions in, but otherwise, we do have processes, like straightening or machining, that we can utilize to accommodate those tighter tolerances.


Konrad Roell:

Yeah, I think, Taylor, just to add to what Craig said, a lot of RFQs we see have standard, you know, title block tolerance plus or minus 5, plus or minus 10, plus or minus 15, and just because of the way investment casting works and the way the metal solidifies and shrinks as it solidifies, the larger that feature is, the more tolerance that’s needed to prove capability. So, the best way to, you know, save cost on the initial RFQ is really go back through that print and not just apply general tolerances and apply tolerances that are needed to make that part function.


Craig Learman:

Yeah, and Konrad, even to expand a little bit further, when know, we see a lot of conversion parts, and when we get a machine from solid print, a lot of everything we see is, like, plus or minus 5 thousandths, which, in that world, can be very easily held, but then you put it in our process. If we have to hold plus or minus 5 on every dimension, that part might not make sense. So, what we need to really understand is the function of the part so we can help determine what tolerances or what dimensions we could hold as cast to help eliminate that and only machine what’s required, and that’s both from a dimensional standpoint, and like you talked about earlier, even a surface finish standpoint.


Taylor Topper:

Thanks, guys. Next question. How thin can walls be in casting?


Craig Learman:

Yeah, that’s a great one. As a rule of thumb, we like to say 100 thousandths, but it really depends on part geometry, part design, how big the area of that wall’s going to be, and what’s feeding up to it, and where’s the gate in relation to it all? We do some parts that go down into the 40 thousandths, I believe. We have some parts that, you know, have areas that get that small, but as a rule of thumb, it’s about 100 thousandths, and with some special feeding or ribbing, we can get down to that 40, 50, but that’s pretty much the limit there, and that’s on specialized parts.


Taylor Topper:

Can surface textures be added to the tooling to create custom surface finishes or appearances?


Craig Learman:

Yeah. Absolutely. We’ve had a unique case once where we used to make a part out of plastic, and what they found is that _____ 00:37:36.2 would try to break into their equipment, and it would break. So, when they came back to us to have this part made out of metal, they asked us if we could rough up the cavity of the tool so that it looked more rugged so that people would stop trying to smash it. So, yeah, on the geometry side, you can design, and we can tool. Yeah, we can put it into itself and also made into the part. I mean, honestly, if I went in wax right now and put my fingerprint on the part and I checked that same part at finishing, my fingerprint would come out. I mean, that’s the kind of detail that is capable with this process.


Taylor Topper:

Awesome, Craig. Thanks. Next question is what’s the max number of parts that can fit on a sprue?


Craig Learman:

Yeah, I don't know that there really is a max. We have parts that are one per mold, and we have parts that are, I want to say, a few thousand per mold. It just really comes down to the limitations that Konrad talked about, and we’re going to push that mold to one of those limitations, whether it’s geometry, pour weight, or shell weight, and however we get there, we get there. You know, we have single-gate contacts in the sprue, and we have parts that are multiple gate. So, we’ll have one connection to the sprue, but it might have a runner with eight parts on it. So, we do what we need to do to hit one of those three limitations.


Taylor Topper:

As it relates to sprue, we have two questions around material, and I’m going to kind of try to combine them into one, but does the type of material make it possible to add more pieces to a mold or sprue? So, you know, if you had aluminum versus stainless steel, does it matter?


Konrad Roell:

Yeah. Absolutely, it does. So, if we just stay in the steel world, carbide steels, the alloy steels, even the 400 Series stainless steels, those can all be cryogenically removed from a mold. The 300 Series, or if you have really big gates and even the aluminum, they can’t be cryogenically removed. So, what we have to do is basically use a chop saw to cut that off. So, for those that’ve used a chop saw, you have to be able to get at that gate without cutting through another part, and that’s really the big difference between those, in general, to the part removal. You just got to be able to get a saw blade in there to cut it off.


Taylor Topper:

What are the size limitations for an investment cast part? I know you mentioned that sometimes you just have one part per sprue.


Craig Learman:

Yeah, and specifically for Signicast, as small as you can think of probably, we can really do. So, you’re talking grams, and then, typically, we used to say it was 150 to 200 pounds, but I know in the prototyping world, I think we got some stuff we’re pushing 300 pounds, and then our Texas facility, I think they can go up to even 400 pounds. So, if it’s the right geometry, if it’s compact, there’s usually some other limitations that the part has to still process through the plant and not just wait, but it’s, you know, we’re probably up to 400 pounds in a 2-foot cube, 24-inch cube. You know, that would be a big part.


Taylor Topper:

Great. Thank you. Next question we have is do castings heat treat as well as parts machined from solid?


Craig Learman:

Yeah, I would say the same. I mean, the alloy’s the alloy, and the heat-treats that go along with it are the same. I’m not a process engineer expert. I’m not going to pretend that I am, but the published numbers on this stuff is what they are. So, the ability to do it is absolutely there to meet those requirements.


Taylor Topper:

As far as a DFM conversation goes, is it possible to start DFM or have that conversation if we’ve already made prototypes?


Konrad Roell:
Yes, it is. Very often, we have customers that will, you know, make a part and it didn't perform how they wanted, and they’re basically back at square one, and they need our assistance. So, like I was saying early on in one of the first slides, is our customers really utilize us for those very complex parts and the very, very difficult problems.


Taylor Topper:

Thanks, Konrad. Our next question here is, for the same material, are the mechanical properties of investment casting equivalent to other casting processes?


Konrad Roell:

I would say yes, and even better, in some cases. A good example for steels would be like sand casting. Through the sand casting process, you’re going to end up with much more porosity through melting gases and trapped airs, and in order to get those types of defects out of the castings, it requires, you know, perfect placement of any risers. Through our process, our ceramic shell, when it’s at that 1,800 degrees, it’s very porous and allows all that trapped air and gases to escape.


Another example would be, like, aluminum, where, if you’re using the permanent mold process for aluminum, once again, you’re going to have that trapped porosity and trapped air in your aluminum casting. Through the investment casting process, that air is able to escape through the shell, and we’re able to get much better densities through the investment casting process, whether you’re looking for conductivity or heat transfer from the aluminum. Investment casting process will be better than the permanent mold.


Taylor Topper:

Next question. What is the smallest text size that can be cast on a part?


Craig Learman:

Yeah, I’m going off memory here. I do believe it’s really 1/8th inch tall, is kind of like where we like to begin. I do believe we can go a little bit smaller, but if the part can accommodate, I’d like to stay about 1/8th inch tall, and ideally, what we really like is to take the surface and make, like, a pad. Reduce that pad into the casting, say, like, 20 thousandths.


And then we’ll take that lettering and make it stand 10 thousandths proud or 15 thousandths proud off that surface, but what that does, it allows us to kind of protect the lettering through the process. So, when you have faces, the shell starts to kind of fight, and it wants to sheer things off. So, when we make that little pocket, if we build a little extra slurry in that area, it helps keep that lettering protected throughout the process.


Taylor Topper:

Craig, as it relates when you add, you know, text or a logo or something onto a part, does that affect the part function or strength at all?


Craig Learman:

I mean, you’d be a fool to say no, right, but we’re taking a small area and going 20 thousandths deep. I don’t think anyone’s design...and if they are, they probably shouldn't be that close to the edge. I mean, we should have some built-in safety factors in general when we’re designing, and a 20 thousandths recess shouldn’t be on the borderline of a good and a bad part. That’s my opinion.


Taylor Topper:

Thank you. We have just a couple other questions that seem very part specific, so I’m actually going to have those questions be followed up with offline. I think that that’s probably fair in that sense, and thank you, everybody, for joining us today. That is all the questions that we do have. Craig and Konrad, this is a really great presentation. I know it took a lot of time to put together, so I appreciate that, and then everybody else on the call, just a reminder, this is recorded.


So the link that you used to enter the webcast is the same one that you can use in a couple hours, once the webinar has processed. You can rewatch the webinar. Send it to colleagues if you want to share the knowledge, and additionally, we can do one-on-one seminars if you wanted to incorporate some of this information with your internal team. We’re happy to do that, as well. I invite you to check out our website. We have so much knowledge on there for material properties, to our past webinars.


They’re super easy to download and watch on demand, and then our blog section, as well. So, everyone, thank you so much for your time today. We do at least one webinar a month as it relates to Form Technologies and either Dynacast, Signicast, or OptiMIM. We have a Dynacast webinar coming up shortly in the coming weeks on the die casting. So, look for that invitation in your email. Konrad, Craig, thanks again so much, and I hope everyone joins us again.


Konrad Roell:

Thanks, Taylor.


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Last updated 12.07.2022