Where's the Beef?

[00:00] Hello. This is John Moore, and I'm with JHM Technologies.

[00:05] Here today, we're gonna talk about, where's the beef? Nah, couldn't care less where the beef is. We're gonna talk about, where's the resin? In fact, likely we're gonna talk about why there's so much resin. So, let's get into that, just talking about why this is a concern to us. Our two biggest concerns in our molding process is rework and mold life. If you do a poll, those are gonna float right to the top as the number two things that the... One and two... that the molding community is most concerned about today. So, how has that got anything to do with resin and resin volume?

[00:42] Well, let's think about that. If we've got a part, and just make an example part, say that part's five pounds. Five pounds in resin weight. So, when we consider the mold cavity for that part, we put the dry fiber in the mold, we close the mold. The volume left in that part area of the cavity of the mold is equivalent to five pounds of resin. Now, if we fill it with five pounds, everything's copacetic. Mold's held closed, all at the right shape and size. You've got what you want. But let's say we put in extra counts, extra resin volume. Something's gotta give. The mold's gotta move. You can't put six pounds of material in a five-pound bag. Right? So, there we see one prominent reason that we're seeing stress on those tools, cracking and distortion.

[01:34] But there's more. So, if we've got a problem with putting too much in, we also have to consider how we're feeding that resin into the mold. And that's a secondary point to the volume of resin. That mold cavity is designed to accept the resin at a given rate. So, each of our molds may be filled at a slightly different speed, or maybe injected quick in the beginning and then slow down. The point is, we have variables that must be controlled. Let's stay focused for a moment on that volume. What is the impact on cost? Well, let's go over and look at that.

[02:14] A professional meter mix injection system is going to put out about 100 ccs of volume per stroke. So, what's a stroke? We're talking about piston pumps, so every stroke down, every stroke up. Those are 100 ccs each way.

[02:34] So, when we talk about counts, one count is from the top to the bottom, or from the bottom to the top. So, down and up, that would be two counts, or 200 ccs. Each count is roughly 110 grams of mass or volume, 'cause resin's specific gravity. So, you could say one count, pretty close to a quarter pound. So, on that basis,

[03:05] once down, once up, once down, once up. That's four counts. What would that equate to? One pound of resin. And today with the shortages, two pounds... Or $2 a pound, not uncommon. In fact, some are paying a lot more than that, depending upon the resin you're using. So, just remember, each count is about a quarter of a pound. So, cost... You know, inventory variance. Counting runs around e- each quarter, or each six months that you do your inventory check and you compare it to the bill of materials against all the production, and sure enough, there's a lot of resin missing. You're not un-... [laughs] It's not uncommon. The same thing goes for the purchasing person. They've come to know, okay, we've gotta forecast how many parts we're gonna make. Here's what we've been running each month, so this is how many parts we're gonna need. They're working out the bill of materials. Oh, yeah. That's fine. But then they pull out the cheat sheet, and they know how many drums of resin they're really gonna need to order, because there's not a control on the floor. Why is that? Well, how are we asking the molding operators to put the right pounds of resin in the mold? What prevents them from putting six pounds in a five-pound bag? Years ago, the way it was done is we would take the mix head, static mixer, point it into the mold orifice, the injection port, hold it in there, start the pump pumping, and the operator would listen. Ch, ch, ch. Every time he heard that, that was a stroke. He'd look over on the mold, usually with black magic marker, the number of strokes... The last opinion was of how many strokes goes in that mold, and that's what he targeted. Course, he may or may not feel that's the right number, but irregardless, that was the method. Somebody said, "We could make this a lot easier." Sure, okay. Let's put a batch controller on it. So, it doesn't matter who the manufacturer is. Up to today, they still are using the simple batch controller. They're efficient. They're effective. How do they work? Well, let me show you. Have you ever asked or looked down to see what you're asking the operator to do? So, let's just give a number. Let's say that mold took 26 counts. Simple enough. So, what you're asking him to do... Now, mind you, this is mounted in the front display of the machine. Ask him to come over here, hold down the control, and then the second digit, he's gotta push at least twice. That's assuming it was at zero to start with. Realizing that these numbers scroll around, zero to nine, every time you push the button. So, at least twice on that one, and at least six times he's gotta push this last digit here. That would give them 26. Okay, it's set. They hit the start button. Ch, ch, ch, 26 times, machine shuts off. Beautiful. Now, you saw what it took to change that. If all we ever did was run that same mold every day, I suppose that's effective, 'cause all they'd have to do, end of the cycle, hit reset.You go hit the start button again, 26 counts it's shut off. Everything's fine. The problem is

[06:14] molders across the board, including yourselves likely, don't make just one part. Make a variety of parts. So what you're saying is you're asking the operator to come over every time he changes from mold to mold. He's supposed to come over here and set the exact right counts, realizing every time he pushes, it's about a quarter pound.

[06:33] Starting to see why we're getting the variance on the floor, aren't we?

[06:38] So what's, uh, what's the impact of this? Well, we're talking about rework. We're talking about mold life. It's easy to understand if we overpack the mold, something's gotta give. So that mold takes stress. Why does rework come into play?

[06:55] That amount of resin that goes in the mold, if we open the mold by putting, again, that six pound in a five-pound bag, well then we've now changed our glass to resin ratio. We've got heat shrink and radiuses. Oh, you've seen that. We've got various problems. But here's the other factor. And this is the chalk and cheese difference in the injection systems. We talked about volume. That's important. How fast we feed that mold is critical. And the other interesting thing about what I'm gonna talk about here is every machine out there has got a pump speed control.

[07:36] If they do anything, they'll set a stroke counter. But that poor speed control is left never to be touched. The day that machine was set up, it was turned, set, bang. That's where that pump speed's left. Yet that pump does not always pump at the same speed. Viscosity changes in the resin caused by temperature, batch to batch. A variety of factors affect the speed of the pump. So go back to the mold. We're now not really controlling the volume of resin we put in and we're not controlling the rate we feed the mold. See, a thinner mold, one of a shorter cross-section, say six millimeters, is relatively thick. But maybe we're talking more common, three millimeters or eighth inch parts. Well, an eighth inch part is gonna flow at a much lower rate than a six millimeter or quarter inch part. And there's variances across between the thicknesses. Different fiber loading, cores, no cores. So each mold not only gets a different volume of resin, but it also can accept the speed in which it's injected. Well, well how do we, how do we control that? The machine has to be smart enough to control its speed based on what you programmed into it to do so. Pressure. Yes, of course pressure's critical. But what is pressure? Pressure is a measurement of the resistance to flow. You don't run your process by pressure. You monitor pressure to make sure your process of injection is running the way it should. So we use pressure as a governor or a feedback to what's going on in the cavity. We prescribe a given flow rate that's critical, that may even change on the programming of the machine. Various sized parts may inject faster then slow down in the end.

[09:31] But let's go back to the volume. How's an easy way, if that stroke counter

[09:38] is just not getting used for a variety of reasons, what would get used?

[09:44] Simple.

[09:48] An RFID tag

[09:50] connected to the mold. So how does that work? Well, RFID tag has a specific number that's programmed into it. There's no programming going into the tag beyond that. It already comes programmed with a number. So it's just like a cell phone or a, yeah, cell phone, an iPhone. You, you create a recipe. Well, that's no different than creating a contact. Address, email address, right in your cell phone, right? So that's your recipe you're gonna create for your particular part. So many liters a minute flow rate, such maximum pressure, various other variables that we can put in there. Simple as, all right? Then we take the RFID tag and the number of that tag, it's associated by reading the tag into the reader, and the re- the machine says, "Okay, I see that number." It's kind of like saying, "Well, that phone number goes with that contact." It's that simple, right? So, the tag's been preset, right?

[10:50] Now, he switches, takes that tag, puts it on here, pushes the start button. Boom, pulls that recipe up. Goes over to the next mold. Pulls a tag off that, slips it into the reader, hits the start button, goes through the reading process. Bang, that's the new recipe. There's no going in and selecting recipes. Well, you can do that. If you don't use the RFID tag you can go in and select ar- automatic recipes.

[11:15] But we gotta get past putting all the burden on the operator. They've got plenty to do. Teach them how to load the fiber, how to identify other variables that are affecting your rework concerns. Let the machine do the proper injection of flow rate managing pressure, and then use the RFID tags to be certain they've got the right recipe and the right volume going in the mold. It's that simple. Friends, we've got to get away from the basic things that can really solve our problems in the industry.

[11:53] Rework. Mold life. We don't need the team of people outside the molding area reworking our parts. Load the fiber correctly, inject it at the rate the mold can accept the feeding. Don't let it get overpressurized, and don't ever put five pounds of resin

[12:11] beyond what that mold can handle. If you're gonna put five in, that's correct if that's what it's designed for. But you can't put six pounds into a five-pound bag. That's a tip for today, friends.