Innovations in Precision Die Casting

Casting may be one of the oldest forms of metal manufacturing, but the techniques being utilized today are far from old-fashioned. In fact, they are continuously being developed and improved.

Download our online seminar where we will discuss the most recent innovations in precision die casting. In this seminar, you will learn about the advanced technologies Dynacast uses to manufacture more than 5 billion components annually for customers across almost every industry.

We'll cover:

  • Advanced casting machines and techniques
  • Tooling and engineering expertise with customer case studies
  • Custom alloys
  • Cosmetic plating and coating
  • And more!

Fill out the form below to download the webinar.

 

Innovations in Precision Die Casting Webinar Transcript

 

Taylor Topper, Group Marketing Manager:

Hello, everyone, and welcome to today’s Metal Solutions webinar, Innovations in Precision Die Casting. I’m Taylor Topper, group marketing manager at Form Technologies and your hostess for today’s webinar. Per usual, before we get started, I’d like to go over a few items so you know how to participate in today’s event. If you’ve attended one of our Metal Solutions webinars in the past, you’ll notice our new platform.

 

There is no dial-in for this webcast. All of your audio should be coming through your computer speakers. All widgets are movable and resizable, so feel free to organize your console in a way that works best for you. You can submit questions via the Q&A widget. If you have any technical issues, no sound, slides aren’t moving, please submit them through the Q&A. I’ll be monitoring that throughout the presentation, and also, utilize our resources list.

 

Download your free copy of our engineering value white paper, “Balancing Design with Cost-Effective Production,” and also, I have there for you our very popular die cast design guide. We’ll still be holding our live Q&A session at the end of the webinar, so I encourage you to submit your questions to today’s presenter. We’ll try to answer them in order as they come, so be sure to get your questions in early. Try to be as clear as possible when submitting your questions.

 

Oftentimes, folks are asking questions to a particular slide, and since we are answering them at the end, it kind of gets confusing if you don’t reference exactly what we’re talking about in the presentation. So, as usual, the webcast is being recorded. If you’d like to re-watch the presentation at any time, or if you miss something, you can view the recording from the link you received within your email in just a couple hours.

 

With that, I’d like to introduce Tim Johnson. He’s our presenter for today. Tim has been with Dynacast since 2017, but before that, he worked as a project engineer for five years at Signicast, which is another Form Technologies company. Tim graduated from the Milwaukee School of Engineering with a degree in mechanical engineering. With Tim’s engineering background, he’s not only been a really great asset to Dynacast’s sales team, but also to his customers.

 

He likes to push the limits on what is conventionally possible when it comes to die casting, whether it be thin walls, tight tolerances, demanding material requirements, or tight timelines. He takes pride in creating a can-do environment for his customers. Tim, it is always a pleasure to have you presenting for us, so, thank you.

 

Tim Johnson, Sales Engineer:

Thank you, Taylor, and hello, everybody. This is Innovations in Precision Die Casting. Our agenda for today is here. The real thing that I want to get across is a brief history of kind of how, you know, we started with our innovations in multi-slide die casting, the beginnings of that, and then just, I really want to touch and build on kind of the way that we’ve evolved. A lot of our evolution and innovations have come from the needs of our customers through time, so that, you know, at the end of this, you can kind of look at some of the projects that you may be struggling with, and kind of see some possible solutions.

 

The Benefits of Die Casting

 

So, as I said, multi-slide die casting is our core technology. You know, we originally developed it to cast the teeth of zippers onto fabric, and zipper bodies and tabs, years and years ago, and now it’s been developed to do so many more things. The bottom line, what it’s so great at is, it’s great at being very precise, very tight tolerances, with extremely fast cycle times, and that is really what has built, you know, Dynacast. The great thing is it requires less cavities, right?

 

So, when you’re looking at not only the PPAT process and approval, you know, but re-qualifications as tools wear, or if you have an engineering change, there’s less cavities. You know, all of that has a cost, and that is something that we’re able to achieve through our precision die casting. Because the tolerances are so tight, you know, we seldomly have to do secondary machining, but you know, of course it is very possible.

 

Male Voice on Video:

At Dynacast, we spent over 80 years perfecting how to make the highest precision die cast components in the industry. Our secret? It’s our proprietary multi-slide technology. This unique approach combines state-of-the-art tooling with the most sophisticated injection system in the world. Simply, this enables us to produce even the most challenging designs with tolerances of just two-hundredths of a millimeter.

 

It allows us to run at six times the cycle speed of traditional alternatives, and it delivers net-shape components with minimal part-to-part variation and greater repeatability. Ultimately, it gives today’s design engineers greater freedom to create more complex, more precise parts, to consolidate multiple components into one, and to do so shot by shot to the very highest quality. You see, there’s die casting, then there’s precision die casting from Dynacast. Dynacast. Solutions made solid.

 

Tim Johnson:

So, that touched on a lot of things that I spoke about as well. You know, that’s a nice video, and kind of shows an example of a part that is typical in multi-slide die casting. So, here I want to talk about the development, right? So, after the original machine, we built the Dynacast A2. It’s called the A2 because the blocks themselves are 2 inches by 2 inches, and was initially very low tonnage, because it was all ran through pneumatic, and that was for speed.

 

And then, over time, we added what we call hydraulic boosters, so, then, it’s still pneumatically-actuated, still runs very fast, but then once it’s clamped shut, you know, we have hydraulics to add that extra bit of strength. Over time, as the demands of the market, you know, grew, we developed the SIS machines. What those machines do, and we’ll have a slide on them, but they give a closed-loop shot control, that we can control the shot from, you know, temperature.

 

We can control the speed of the shot, all these things that, again, we’ll touch on a slide later, as well as the A3, which, you know, is a much larger multi-slide. We also developed the A206E machine, and that was actually for energy efficiency, and we’ll touch on that a little bit more, but it runs about 40 percent more efficient by using electricity rather than hydraulics and pneumatics, so, for very high-volume parts can certainly have a positive cost impact, as well as friendly to the environment.

 

And then, we also run Techmire. So, Techmire was an offshoot, but is now owned by Dynacast. And so, we run three main sizes, the 4 by 4, 6 by 6, and 8 by 8 are exactly what they sound like, but they use the same tenets, the same shot-control type of technology, part control, automated shot monitoring, that if anything were to go wrong with the shot, machines wear and what have you, that it’s automatically able to reject the parts.

 

Multi-Slide Die Casting Part Examples

 

To give you a couple of good examples of multi-slide parts, here at the top of this picture, you can see the capless gas tank. These were made, eventually went into Ford vehicles. So, if you have a Ford, I know, actually, I have one of these on my car, you can see, this part has to be very precise. It has a gasket O-ring that has to be over-molded onto, and then it’s spring-loaded, right? And then, of course, the environment it’s in, it’s around gasoline and in the elements, so we do a flash zinc coat on it, just to make sure it has the proper corrosion resistance.

 

These are Zamak 5 seat belt latches, again, a perfect A2 part. You know, you can imagine the size of your seat belt and how safety-critical the seat belt latch is, and we use a hundred percent automated and inspection. After this slide, we’ll go into a video showing some of our hundred percent automated inspection, but you know, it’s obviously critical that we maintain the dimensions on these parts, not for each part, but also because they mate together, right?

 

So, both these parts, you know, the variation from our casting has to be limited to make sure that the seat belt functions at all times.

 

Taylor Topper:

Hey, Tim, when we’re talking about multi-slide versus traditional die casting, or what we call conventional, what is the difference in tool life? Like, what does that look like?

 

Tim Johnson:

Well, if you’re talking zinc for zinc, you still get more tool life out of a multi-slide die, and the big reason is, is because you’re moving less material, right? It’s less violent of a process, I always like to say, right? So, for conventional, either, one, the part is a lot bigger, and so, you’re moving a lot more material past the gate area, which is usually the first area to wear out, or you’re using a lot less cavities.

 

Again, the cavities that are getting filled first are getting hit with a lot more force, a lot more pressure. So, your tool life for a multi-slide is significantly longer. So, we’ll go into a quick video here, showing just some automation, the automated inspection. We’re using cameras to inspect for plating defects, as well as some dimensions on the part, just to make sure that, you know, the customer’s getting exactly what they need. The plating defects in this particular case can lead to corrosion issues, so we want to make sure to look for bubbles and things like that.

 

Die Casting Process Control Innovations

 

And you know, they always say, a hundred percent human inspection is 80 percent effective, right? So, you know, the industry has demanded something better than that. So, as I said, we’re going into the SIS, right, that’s the servo-injection system. The beauty of the servo-injection system is, previously it was a hydraulic injection mechanism, which is great and powerful, but you don’t have a lot of control. It’s either on or off.

 

The SIS, you can control the shot, you can have an injection profile that you start fast and end slow, or you start a little slower to get the material in there and end fast. You just have a lot more capabilities as far as making sure the part maintains, you know, a repeatable process, that you’re able to control porosity, you’re able to control surface defects, right? So, we oftentimes use these SIS machines for highly-cosmetic parts, as well as, we introduced a closed-loop parameter monitor.

 

So, we call that our PC9 controller, and as it’s running, each and every shot, it records, you know, the fill time. It records injection pressure, metal temperature, injection speed, right, and all these, you know, injection pressure, for example, if you’re losing injection pressure, that might mean your plunger is wearing out, right? So, not only is it controlling for the part itself, but it’s also monitoring indirectly its own wear and its own effectiveness.

 

So, you can see here, and a great example of where we used SIS to improve a part for a customer, improve the process. So, on the left-hand picture, you see a part, it has flash. You know, the surface is a little bit rougher, and as you can see, obviously, it’s a single cavity, right? So, with the A2 SIS, we’re able to control that shot profile, so you don’t need as much tonnage to hold it shut, to be able to do two cavities. The flash is completely gone in this particular case, but is greatly reduced, you know, in many other cases as well, and the surface quality is much better.

 

And that’s kind of where the SIS shine, as far as, you know, parts that traditionally couldn’t be cast because of the fear of porosity, or because maybe this particular part is seen by the customer, and you don’t want to have a cast surface finished. This is a machine that we have developed over time to really kind of solve those needs. Another great example, as I said, the SIS machine is great for cosmetic parts, right?

 

As-Cast Surface Finishes with Die Casting

 

And so, we’ve used it to get better as-cast surface finishes, right, because all of these parts that you see, you know, they’re exploded out of their key fobs here, are plated, of course, but plating doesn’t hide casting defects. If anything, it enhances them. So, if you have a part that has to get a plating, decorative or otherwise, having a better surface finish on the base material is very important for the end look of your part. So, we’ve also taken our multi-slide and applied it to other materials.

 

I know we had it functioning for plastic at one point in time. This particular scenario’s with magnesium. So, with our die casting, we offer in aluminum, magnesium, and zinc, right, and zinc is stronger than aluminum, but much heavier, right? And so, magnesium is that nice, in the middle. It’s stronger than aluminum, but still, you get to maintain that light weight. It’s very fluid. It’s a little bit more castable than aluminum, a little less corrosive on the machine itself, as aluminum has high silicon content that tends to wear out machine components.

 

This particular one is the die locking force of 60 tons, and it has all the great features of our multi-slide, right? It runs extremely fast, and you know, it can certainly convert either way. And then, as I said, we touched on the E machine as well. So, this machine reduces the energy usage by about 40 percent, but with a real time-controlled electrical drive. So, and you’re able to cycle extremely fast still, right?

 

So, where this really comes into account is high-volume, complex parts, especially if there’s some cosmetic or surface requirements, because we still have the real-time control, like the SIS machine, but then, you know, in die casting, you’re paying for two things, right? You’re paying for machine time, and you’re paying for material, right? So, if you reduce the cost of the machine time, of course, you know, that’s helpful on the parts.

 

Innovations in Injected Metal Assembly (IMA)

 

We’ve also used our zinc technology to do injected metal assembly, or what, I’ll say IMA from here on out, and this is a really cool example. You see on the bottom, the red and the gray that you see are K-Alloy, aluminum castings that we do, and we’ll touch on K-Alloy more, but K-Alloy’s a really cool alloy that we developed with Delphi, and it is known for very high corrosion resistance. So, generally, you know, corrosion resistance is measured in salt spray, which is a fairly arbitrary measurement except for that it regulates all different coatings.

 

And so, this particular alloy, with no coating whatsoever, will get about 480 hours of salt spray, which is pretty incredible, really. It out-performs almost any coating. So, we take those two, for the corrosion resistance, we take those two plates, and they get clamped together. Now, these two parts used to be screwed together with 16 screws, which was, of course, a time-consuming process for our customer. In this particular example, it is used for credit card transactions.

 

It transmits the electromagnetic wave, and one thing about that is if there’s any crease in those two parts, it’s almost like a magnet for those waves. So, not only does it, like, can it accidentally fail because the waves will go in there, but they want to, physically speaking, want to go in there. And so, they were having fallout due to the fact that the screws didn’t always get a perfect feel. So, what we did is we designed, all that bright green area you see is our channels in which we inject zinc into there in an I-beam, right?

 

And metal shrinks as it solidifies, so, I mean, it pulls these two parts impossibly tight, and we completely eliminated that fallout using our injected metal assembly process.

 

Taylor Topper:

Tim, before we go forward, we actually have a really great video on our web site that highlights the IMA process, and I’d be happy to send it out to everybody after the webinar. I encourage you to look at it, because it’s a really cool process, and we’ve been able to do some, I think, advanced, you know, joining through this, and have been able to save a lot of money and time for customers through this process.

 

Tim Johnson:

Yeah, I mean, I totally agree. I mean, IMA, when it’s the right fit, there isn’t a better process to bring two parts together in that way. So, we’ve also gone through, you know, in time, and had many different coating needs from our customers, right, whether it’s just to prevent corrosion and oxidation, whether it’s for cosmetics. Sometimes it’s for feel, and sometimes, you know, like you see on the bottom there, not only does a customer want it, but they want to be able to deliver in a lot of colors, right?

 

Surface Finish Options for Die Cast Components

 

So, down there, actually, what you see is a chrome plate, I believe, over the top of an E-coat for a high-end hair-straightener. So, they wanted to have all these colors, and they had to inject molded plastic, you know, and they wanted to match all that with, the castings with all their various color schemes. So, we’ve kind of gone through many different situations where we’ve developed coating to meet specific needs. You know, I don’t have a slide on it here, but we did a satin nickel chrome for shifter paddles, and a lot of it was the feel, right?

 

It has a different feel than your typical chrome. It looks and feels, I don’t know how else to describe it, but softer, very…

 

Taylor Topper:

That’s interesting.

 

Tim Johnson:

We’ve also had some nickel-free coatings that we’ve developed over the years here. This particular one, we have 18 variations, right, for wearables, you know, because some people are allergic to nickel. Another place that nickel-free coatings, or, we’ve also had some hypoallergenic nickel coatings that we’ve done in the past for medical applications, that have really helped out, right, because, you know, anything that touches the human body, you have a whole new realm of things that you have to consider.

 

So, you know, this particular one, like I said, we have 18 variations of different colors that we can do, that cause no irritation to the skin of folks who are allergic to nickel. Here, I’ll get into some engineered alloys, you know, maybe my favorite, personal favorite part of the presentation, but we have some really cool alloys that we’re able to do. ZA-27 is very interesting. The ZA stands for zinc-aluminum, and 27 is 27 percent aluminum. Now, this particular alloy has to be done using the cold-chamber process rather than multi-slide, but you know, it’s great for weight mitigation, right?

 

Aluminum Die Cast Capabilities

 

Because there’s so much aluminum, it’s much lighter than other alloys. It’s very high-strength. It also has a very high melting point, right? One of the big weaknesses of zinc is the lower melting point in high-temperature applications. The ZA-27 gives you that higher strength, you know, higher than aluminum, and also mitigates some of that weight when it’s important. EZAC is a relatively new alloy, and it was developed specifically to reduce creep, and there’s some really great information out there in terms of the creep curves of EZAC at different temperatures.

 

But I don’t think it’s fair to say it eliminates creep, but it definitely is amazing for reducing creep, the best of any alloy, and as an aside, they also made it very strong, right? If you look at the strength numbers on this, you know, besides the ultimate tensile strength when compared to ZA-27, it is the strongest zinc alloy, and it can be done with the hot-chamber process. And then, ACuZinc came along before EZAC, and it was actually made for a similar reason, higher strength and increased reduction, and ACuZinc does perform very well, though it’s fair to say that EZAC performs much better.

 

And aluminum, I talked a little bit about it before, K-Alloy has spectacular corrosion resistance and good thermal conductivity. So, you know, a heat sink that’s out in the environment would be a great application. Of course, I mentioned the communication devices, you know, that are out on satellites, that are withstanding all of the elements, and then, of course, any part that has to face tough, corrosive environments, K-Alloy can be a good alloy to use.

 

DCA1, developed for thermal and electrical conductivity, it also has a good corrosion resistance, but not as good as K-Alloy. As I mentioned, K-Alloy gets a salt spray of about 480 hours, but the thermal conductivity is a bit better on DCA1, as well as the electrical conductivity, which is something that you usually sacrifice when you move to aluminum from other metals.

 

Taylor Topper:

Tim, and out of curiosity, when you’re talking about, like, a ZA-27 or an EZAC, how does that change castability when you’re talking about engineered alloys? Is there any difference?

 

Tim Johnson:

For ZA-27, there certainly is, just in the sense that you have to go to a cold-chamber process. I didn’t dig into it too much for this particular webinar, but I did talk about it in the last one I gave, so feel free to go back and download that. That’s on our web site, but basically, cold-chamber slows down the process pretty significantly, because you have to scoop the material out and then put it into the shot sleeve, rather than the shot sleeve being submerged in the material.

 

Otherwise, the other ones, they’re very castable. I wouldn’t say that they have significant drawbacks in that regard. And then, another engineered alloy, ADC10 is one we developed. You know, lead is a very small amount of any, well, almost any casting alloy, but still too much for the California Toy Lead Requirements. Obviously, you know, kids put toys in their mouth. I have two kids myself, and I think every single toy, they’ve at least tasted once. And so, this particular alloy was developed specifically for that, to get below 100 ppm, parts per million, of lead.

 

Simulation Software in Die Casting

 

We get into some of the engineering innovations and some of the things that I think really set apart the experience of casting with Dynacast, and what has been done here, and one of the big ones is simulation software, right? There’s two factors. One, not everybody has simulation software. The seats are very expensive, but also, simulation software is only as good as the user, right? Garbage in, garbage out, right, so you need to be trained.

 

You need to understand what you’re looking at, what you’re looking for, but these simulation softwares can offer some very amazing predictive aspects, so that before you cut a tool, right, so, when you’re looking at, okay, simulation software, that’s great. Well, if you cut a tool, that’s the longest part of your timeline in your project, is getting that tool cut. The end of it is finding time in the factory timeline to load the tool up, and run it, right, but that is significantly less than cutting the tool.

 

So, if a mistake is made, or an unforeseen casting defect arises, that can throw your timeline upside down, right, and suddenly you have late timelines, you’re rushing to get things done. It can create a really, really stressful environment for your team, whereas we go through, in every single tool that we make, we go through and simulate, and make sure there aren’t any abnormalities.

 

A great example is shown here. We actually worked with the customer to add feed ribs, to add different features, to make sure that they didn’t have porosity where they didn’t want it, made sure that they understood what all these things did, and wound up, before ever cutting the tool, giving them a much higher-quality casting. There’s another great example, it was actually using K-Alloy, of a part that they didn’t have time in their timeline to change their design.

 

So, we said, okay, there’s going to be some fallout for porosity, and then, you know, when we’re making the second tool, went through the design-change process with them. That way, you know, they could still get the parts they needed on time, and then what we did is we reduced the fallout, these particular parts are a hundred percent leak-tested. We reduced the fallout down below one percent, from where it was at about six percent, when the project launched.

 

Taylor Topper:

How do you think being, I guess, your engineering background and designing, you know, tools for Signicast, now working with Dynacast and die casting, the difference in working with different customers and how they design their part versus how it’s then kind of reengineered for the manufacturing process, can you touch on that, because I feel like that’s something that’s always really interesting to me, and something that I’ve learned, is how, for example, maybe a consumer electronics company will design, and it works for the product that they’re creating, and then they go to manufacture it, and there are design changes that need to be made.

 

Tim Johnson:

Yeah, I mean, I’m sure there’s a lot of engineers on this call, and maybe not every engineering school’s the same. You know, I love Milwaukee School of Engineering, great school, but I spent one semester and covered every single, in one class of one semester, and covered every single manufacturing process in one class.

 

Taylor Topper:

Wow.

 

Tim Johnson:

And really, I mean, new designers, they don’t come out of college equipped that way, right? And so, what I would say is they design the perfect part for their function, but unfortunately, that perfect part will cost an arm and a leg to manufacture, have quality issues, many of these other things, right? I think as engineers become more experienced and comfortable with different processes, that becomes less and less of an issue, but you know, engineers spend a lot of time designing a part, and a lot of time building the print, and getting everything to work just right, making sure all their tolerances stack up.

 

I mean, there’s a lot of effort that goes into that. So, then, when they go to launch their part, being asked to change that right out the gate can be tough.

 

Taylor Topper:

Yeah, I imagine.

 

Tim Johnson:

So, yeah, it’s definitely part of the process, though, and it’s very important, at the end of the day, that they get a quality part. So, another thing that we did, we used a three-plate design to cast internal threads. This is something that the first time I saw it, I seriously had a hard time believing it, just knowing what I knew about tooling, but it is something we do, and we’ve gotten up to 13 cycles a minute. I mean, we also had the auto degating function, right?

 

Tool Design

 

So, in our tools, what we oftentimes do is we add a little undercut somewhere that holds the part in, and we can eject the gate separate, and then we can eject the part, right? So, you know, the less times you touch a part, right, the better the cost is, the less chance for quality issues, right? It’s just general rule of thumb. And so, that’s something that we’ve been able to do with our tooling and engineering expertise.

 

I love talking about vacuum casting, for the simple fact of, if you go to the die casting engineering party, and you bring up vacuum casting, there’ll be very split opinions on whether or not vacuum casting is necessary, or whether or not proper gate design and proper overflow design can alleviate vacuum casting, an argument I understand, but I have seen times where it does matter, right, because in our multi-slide process, the injection mechanism is submerged down in the material.

 

So, the porosity that you see in a casting really is the failure to evacuate the air from the cavity as the metal is injected. So, if you vent it properly, if you have proper overflows, if you have these things, sure, the argument could be made that you can not really need vacuum casting, right? But over time, for example, vents can get clogged. Over time, you know, the overflows can wear out. And so, the vacuum casting creates a vacuum, so that as the metal comes in, it pulls all of that air out, and you can see, this is a great example of when we used vacuum casting.

 

I mean, if you look at this heat sink and imagine how in the world you’re going to get that air out of there with vents, it’s going to be pretty tough, right? So, part design has an effect on that as well.

 

Taylor Topper:

And Tim, is this something that you would add onto, like, or add in during the design process? Like, at what point does vacuum casting become a thing? Like, it’s not that all the machines come with it, and you automatically get vacuum casting.

 

Tim Johnson:

No, I mean, it slows down the process a little bit, right? So, you only want to use it if you need it, right? That’s the trade-off with manufacturing in general, is the more different things you add can oftentimes slow it down. So, a lot of times, you enter a project knowing that that might be the case, and our engineers do a really great job of taking the time to prove out the machine, to do capability studies, to understand the defects that present themselves, and communicating that with the customer, right?

 

You know, if in this particular case, if the customer wasn’t worried about these defects, if they had, then why add the vacuum casting, right? But when you go into that with that open communication, like, hey, we’ve seen this in our simulation, we may have to add vacuum, and so, we’ll walk down that path as we get there, and that’s kind of how our program managers and our engineers approach it.

 

This is a really cool design, and one that I dealt a lot with when I was in engineering, you know, and hopefully one day in sales I see a design like this, because this is really cool. What this part does, it’s a NADCA-winning design, it actually is cast with the intent to break. So, on the left-hand side, you see the part in its as-cast state, and then it’s installed into the seat belt mechanism, as you can see, and then it breaks, right?

 

And in this corner, where you see the left-hand blue, you can actually, if you hold that casting up to the light, can see through it. It’s really cool, how we move the material across there. And so, this is for a table guide for seat belts, so, one, our precision allows for robotic assembly. That’s something I want to touch on, right, is multi-slide casting lends itself extremely well to automation, because it is so repeatable. The CPKs are so good that your robots will always recognize the parts. They’ll grab them easily, right?

 

If you have a lot of variation in the parts, it can shut down your robots, because the failure to grab or failure to recognize, there’s a lot of things that robots are doing in the background that inconsistency in the parts can cause. So, it allows for that, but it also took three separate parts and turned it into one. So, they install this in, they press down and it breaks, and you can see the two little blue nubs that come through, and then, those are orbitally riveted into place. So, it holds the cable in place for the seat belt, and was a major cost reduction due to reduction in labor, was a very cool project.

 

Thin Wall Aluminum in Die Casting

 

Another thing that we’ve been pushing the limits on is thin-wall aluminum. You know, we can get as low as about, we’ve successfully gotten to as low as about .35 millimeters. You know, you can see, in this particular part we have .6 millimeters, and .7 across the span, .6 localized, right? And so, you know, of course, lower material cost, as I said, you’re paying for two things. You’re paying for machine time, you’re paying for material cost. So, you got lower material cost and less weight, and in this particular one, was to replace a plastic part.

 

You know, so, of course aluminum is much stronger than the vast majority of plastics, and also, you know, you can still replace cosmetic magnesium components as well. This is really cool. This is touching back on some of the key fob stuff we do. Our tooling engineers are extremely creative in the way that they look at parts and the way that they approach the tool-design process, and you know, they look at a part like this, which has multiple undercuts, right, the tabs at each end, if you will, of the horseshoe are undercuts in and of themselves, and then you have an undercut for this little snap tab at the base of the horseshoe, and then these little nubs on either side are both undercut, right?

 

And when I say undercuts, you imagine looking at it from the bottom. If any part of the part is hidden, that’s an undercut. And so, you know, they go through, in order to reduce, or eliminate in this case, CNC operation, they found a way to get this cast in, all these undercuts, right? I count one, two, three, four, five undercuts that they’re able to go in and cast.

Developming Automation for Multi-Slide Machines

 

Automation, as I said before, is a big part of what we do. You know, this is just one example. You obviously saw the automated vision system inspection, before.

This is the automated over-molding process we do, where we cast the heads of these screws on, so we have an automated feed-in system that then goes into the loading, loads those in, each shot into the die casting system at a rate of 7200 parts an hour. So, you know, the big thing with automation for us is our machines are running so fast, our multi-slide machines, is to develop automation that isn’t slowing down that machine. And then, another great thing that we developed over the last few years is ring-gating.

 

Ring-gating is great for circular parts, as the name may suggest. It gives you a great ability to have almost no draft. You can hold tighter tolerances on these circular parts. It also, the way that it flows, right, in casting, you know, depending on the type of casting you do, there’s always shapes that are, I don’t know, I won’t say taboo, but that are more difficult, right, and circular shapes can be for tight casting, because essentially, one side’s going to have the gate.

 

You’re going to have to feed, and then feed it back out, right, and there’s many ways to go around that, but one really awesome way is ring-gating, because then you make one continuous flow through the part. So, this one had to have cast external threads, as I said. Because the tolerance is so tight now, we don’t have to have any reaming operation, and we set up our ring-gating process with an auto degate, so we eliminated also the degating process.

 

So, you see my information there. I just want to say, if any of y’all have questions now, please bring them forward. Also, you know, afterwards, feel free to reach out to me any time. You know, I’d be happy to assist you.

 

Frequently Asked Questions

 

Taylor Topper:

Perfect. Thanks so much, Tim, and we do have quite a few questions in the question widget. So, continue to ask those questions. We’ll start with this question, actually, which is about the undercuts. So, I know traditionally that was more of a conventional thing. Was that cast with the multi-slide? Or…that was a question for me, sorry. The undercuts from that key fob, that’s a multi-slide project, correct?

 

Tim Johnson:

Yeah, I believe that’s done on an SIS. Many of our key fobs are done on SIS machines.

 

Taylor Topper:

Awesome. So, going back probably to the way beginning, and maybe this person missed the video. However, is multi-slide referring to the tool design, or a permanent part of the die cast machine?

 

Tim Johnson:

Yeah. It is a permanent part of the die cast machine in the sense that it’s set up to run multi-slide tools, if that didn’t confuse it any further. But the multi-slide tool essentially, instead of having, you know, in a traditional, either injection mold or traditional, conventional die cast, you have two halves of the die, they come together. Multi-slide, we use four separate actions to create the part, right? So, it just gives us an ability to run the tool even faster, because you don’t have to wait for the actuation of slides, or different things. It’s all moving in unison.

 

Taylor Topper:

And what was the shot speed for multi-slide versus conventional, the difference?

 

Tim Johnson:

Yeah. So, a multi-slide is going to run you somewhere between 12, upwards of 60 shots in a minute. Conventional, if you have it really dialed in, you’re looking at, you know, at a max of about 12 shots a minute. I mean, that’s if you’re really humming.

 

Taylor Topper:

Next question is related to IMA. How do you prevent galvanic corrosion at the interface of the two metals in IMA due to the material mismatch?

 

Tim Johnson:

Yeah, and I’m certainly not an expert of the galvanic chart, but as I understand it, I don’t believe that zinc and aluminum are very far apart on the galvanic chart. So, you don’t get a ton of that corrosion.

 

Taylor Topper:

I know that cost questions are typically difficult to answer, because it’s completely project-dependent, but this question is related to the percent of cost increase with vacuum casting versus non-vacuum casting.

 

Tim Johnson:

Yeah, I really hate being the it-depends guy.

 

Taylor Topper:

Yeah. I mean, but it does, right? It all depends on the complexity, the part size.

 

Tim Johnson:

Yeah. What I can say is it does slow it down. If I had to take a stab in the dark without seeing your part at all, or knowing exactly what we’re trying to do, you’re probably looking, goodness, probably about a 20-percent to 30-percent reduction in machine speed. That doesn’t correlate directly to price, but that’s a fair estimate.

 

Taylor Topper:

What is the maximum regrind of your material?

 

Tim Johnson:

Yeah, so, we don’t use a lot of regrind. We take our scrap parts and our gates and actually send them back, generally speaking, to our alloy suppliers. The vast majority of what we use is Ingot, and certified there, just because our gates are very small. You know, I guess he didn’t have any size reference on some of the parts here that had gates, but if you look at the little tab on your pen that, you know, you can hook it into your pocket, that’s about how big the average gate is.

 

And so, you know, we don’t gain a ton by recycling those. We tend to send those back to the alloy suppliers, have them re-alloyed and recertified.

 

Taylor Topper:

What is the maximum weight of a part that can be cast in an A2 machine?

 

Tim Johnson:

Well, it’s not limited by weight as much as limited by size. So, two factors, one, projected area is a big limiting factor, to be able to hold the machine shut, but your part has to be within the 2 and a half inches by 2 and a half inches that the blocks are in an A2. Seldomly do we have a situation where a part is big enough for the weight to be the limiting factor. It’s, generally speaking, the overall size.

 

Taylor Topper:

And then, going back…this is another cost question, unfortunately, conventional versus multi-slide tool cost. Again, I know that it’s definitely design and complexity. Maybe a better question is how, when talking to customers, how would you approach the tool cost question? I think a lot of our questions kind of go back to cost when we’re talking about multi-slide and advantages of it. How would you approach that?

 

Tim Johnson:

Yeah, I mean, at the end of the day, manufacturing has a lot to do with cost, right? Cost is a big, big, you know, three-legged stool, right? Cost, you got quality, and on-time delivery. You know, that’s very important to maintain a manufacturing project. Generally speaking, multi-slide dies are quite a bit less costly than conventional dies. It does depend on the size of the part, but depending on your size of the part, you’re going to see a multi-slide die, you know, probably be 25 to 50 percent of the cost of a conventional die.

 

Taylor Topper:

Designing for gates and runners, multi-slide versus conventional, how do parting lines differ?

 

Tim Johnson:

Generally speaking, the parting lines on multi-slide are significantly smaller, and the flash is a lot less and a lot less heavy. The reason that is is because we’re either injecting much smaller parts, or with much fewer cavities, right? So, the force of the material coming in is doing less to fight against the closing force of the die. We also, essentially, split your parting line in four ways, right, so that also reduces the force on each individual slide being held shut. So, the parting line and flash of multi-slide is much less than conventional.

 

Taylor Topper:

Going back to IMA, can you only join two castings, or can other materials be joined?

 

Tim Johnson:

Yeah, I mean, we use our IMA for a wide variety of different applications. Another great application is wire ends. So, they take a steel cable and fray the end of it, or untwist it, not so much fray, but untwist it, and then inject zinc around it so that the zinc is intertwined with that steel cable inside. So, I guess the simple answer is yeah, it can be used for other things. We use it a lot for casting, but it can be used for other things as well.

 

Taylor Topper:

How does tool life compare among the various alloys in the die casting process?

 

Tim Johnson:

Sure. Well, if we’re talking about, I think it’s better to talk about zinc versus aluminum in this case. Zinc alloys, it’s more or less the same. In Dynacast’s particular case, we guarantee all of our tools for life, but you know, it’s fair to assume that a typical multi-slide zinc tool can see a million shots or more, and for the most part still be in good shape. Zinc isn’t very corrosive because of the lack of silicon, and because of the lower temperatures it runs at. It doesn’t wear the tools as much, versus aluminum, you know, somewhere between, depending on the alloy, a hundred to 200,000 shots is what you can expect.

 

Again, we do guarantee those for life, but it’s far less shots. So, when you compare, those are the significant difference. If you’re comparing, you know, the aluminum B390 is known to be, for example, extremely corrosive. So, it will be closer to that hundred-thousand shot range, where your typical A380, great casting alloy, you know, very stable, will be higher, more towards the 200,000-shot range. But if you’re comparing zinc alloys, for the most part, you’re splitting hairs, is what I’d say.

 

Taylor Topper:

Are trim dies required for gate removal with multi-slide zinc casting?

 

Tim Johnson:

They are not. You know, oftentimes we do it, I’d say, out of the gate, but a zinc gate is very thin. It’s about 50-thousandths wide, and you can break a zinc gate very easily off a part, and cleanly, with your fingers.

 

Taylor Topper:

Wow.

 

Tim Johnson:

Just, you know, quick little twist, and it’s off.

 

Taylor Topper:

In relation to casting alloys, zinc, magnesium, and aluminum, which alloy can be cast with thinner walls, with thinner wall sections? Or what is the best for thin walls?

 

Tim Johnson:

Yeah, I guess my gut feeling on that, I would want to follow up with you, but my gut feeling on that is zinc. Zinc is the most fluid of the alloys, and generally speaking has the best properties when it comes to flow, as well as heat transfer, so you can control it a lot easier. So, I would say zinc, probably, if you have a thin-wall program, that zinc is the way you’d want to look, as long as it’s not seeing temperatures of above about 200 C in its application.

 

Taylor Topper:

Next question, do you make parts for pressure vessel with tight tolerance requirements?

 

Tim Johnson:

Well, I’d have to understand a little bit better what you mean, but we do quite a few parts, in aluminum especially, that do get pressure-decay tested. The ones that I’m thinking of off the top of my head aren’t necessarily pressure vessels as much as it’s just a way to make sure that moisture from the outside environment won’t get into the inside, but certainly we have the ability to do leak testing, you know, pressure-decay testing, to make sure the part can hold air.

 

Taylor Topper:

In regards to heat sinks, do you ever cast heat sinks using zinc and/or the multi-slide process?

 

Tim Johnson:

All the time, every single day.

 

Taylor Topper:

Awesome. Can you cast parts that are flash-free, or does flash need to be removed after casting?

 

Tim Johnson:

All right, all my engineering friends on this, in casting, close your ears. No, I’m just kidding. There oftentimes will be a little bit of flash, but what we do is we use a process called thermal deburr. So, we bulk-load the parts into a basket, and there’s an explosion that happens. The flash is so light with multi-slide zinc die casting, if it is there, that it just blows away from that process, and then a quick rinse to get the residue from the thermal deburr kind of, you’re all good to go.

 

We also oftentimes have bulk processes, whether it’s in plating or just a wash, or what have you, for different requirements. Pretty much any time that you bulk-handle the parts, the flash will come right off with the multi-slide process.

 

Taylor Topper:

Is there a difference with minimum order quantities with the multi-slide process versus conventional?

 

Tim Johnson:

Not sure I know the answer to that question, to be quite honest. I will say this, when you compare…I would say, generally, the minimum order quantity will probably be a little bit lower for the multi-slide process, and the big reason for that is, the tools are much easier to set up. A conventional tool can take half a day to even upwards of two days, depending on how big and complex the tool is. You know, a multi-slide, in a worst-case scenario, is going to take you four hours to get set up and running.

 

Taylor Topper:

How does the price of a zinc multi-slide part compare to screw machine brass?

 

Tim Johnson:

So, in fact, I partner with quite a few different screw machine houses, and especially when their parts are brass, just because the material properties compare pretty well between brass and Zamak, the typical zinc casting alloy. So, it depends on the part, in the sense that there’s much more waste that can be had in the screw machine process. So, whatever your widest diameter of the part, everything inside of that is wasted. It’s thrown onto the ground, and you still pay for that when you pay for screw machining.

 

With our process, there’s much less waste. So, especially in high-volume applications, I partner with quite a few different screw machine houses to actually reduce, give them cost reductions on their internal cost. So, that’s not even purchasing the part. So, generally speaking, if you have a smaller screw machine part, it’s probably a wise idea to investigate multi-slide die casting as a possible conversion.

 

Taylor Topper:

This next question, it kind of came in towards the end of the presentation, so I’m guessing it is referring to the…slide 26 is about timing. They’re asking if this is zinc, is the pen tip zinc for the ring-gating?

 

Tim Johnson:

Yes.

 

Taylor Topper:

Think that’s our answer. If you were referring to a different slide or different part, follow up with another question, and I’d be happy to go back to that slide. We have time for just a few more questions, so if you have any, please get them submitted. If we don’t get to them in the next three or four minutes, we’ll be glad to follow up offline, and again, all of our webinars, past webinars are all on our web site. Last webinar we did on zinc, which was really great, Tim presented.

 

On the web site, you can download it immediately from our knowledge center. Last few questions here, Tim, does a raw zinc casting offer corrosion resistance?

 

Tim Johnson:

Well, it depends on what you’re comparing to. Raw zinc casting will corrode. Zinc corrodes much differently than steel, and steel differently even than aluminum. You know, I have a trunk full of castings. I always say I would probably have about 2 miles per gallon if I didn’t have so many castings in my trunk, and generally speaking, aluminum castings in my trunk tend to show corrosion before the zinc castings do in my trunk, as an anecdotal evidence.

 

But the type of corrosion zinc sees is much different, but to say it has corrosion resistance, not really, but a lot of what we do, just for, like, a standard is a zinc flash and clear chromate, which gives you that basic layer of corrosion resistance, and is extremely affordable, in the world of plating, especially. And you know, so, if that is something that’s only a small concern to you, if you don’t have severe, 200-plus-hour salt spray requirements, then a zinc flash/clear chromate bulk process will get you where you need to go.

 

Taylor Topper:

Thanks, Tim, and since we just have a minute left, I do want to mention a few resources on our web site. In our knowledge center, you’ll find a few other white papers that you can download, in addition to all of our past webinars. So, if you missed one, feel free to log on there, and download and watch those, and our next webinar will be November 20, again, same time, 2 p.m. Eastern time, and it’s Prototyping for Production, and it’ll actually be hosted by two of our engineers from Signicast, another Form Technologies company.

 

And we’ll be running through prototyping, different types of prototypes, and how they relate and work with the mass production process. So, look out for that email with an invitation. If you received an invitation to this webinar, you surely will receive the next. I hope you all enjoyed the webinar today. Feedback is always welcome. Feel free to email Tim or myself. My email is in the presenter tab there, or reply to the email where you received your reminder for the webinar today.

 

Thank you, everyone. As always, it’s been a pleasure, and Tim, thanks so much for being here with me today.

 

Tim Johnson:

Thanks, everyone. Have a great day.

 

 

 

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Última actualización 06.10.2020