Tapping tools
Solid Round Tools - session 3
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Hi and welcome to this knowledge session about solid round tools. This is a film in a series with application tips and strategies for solid round tools. And today we will talk about threading with taps. But as always, safety first. Safety is our top priority at Sandvik Coromant. So we ask you to make sure you're in a safe location and know the safety routines in case of an emergency. My name is Antti Wikström and I work as a training specialist. And with me I have Henrik. Hello, my name is Henrik Liljeby and I work as a solid round tools driver. And in today's session we will talk about threading with taps, both about parts of our assortment and process considerations. As with all our solid round tools offer, taps also have versatile taps, optimized taps and customized taps. Looking a bit at the different product families, we have Crotep 100 with straight flutes for short shipping materials. We have Crotep 200 with spiral point for through holes. Crotep 300 with spiral flutes for bottom holes. And Crotep 400 with forming taps mainly for steel, stainless and aluminum. Another way to look at the assortment and positioning is at grades. In the bottom of the picture you see our versatile offer with Crotep XM, both with the C and B 150, which is uncoated for all materials. But then we also have the steam tempered C and B 145, which increases the performance in steel and stainless. If you want to improve performance even more, you can go for a coated tap like the C 111 and B 111. Then you get the big increase in performance and you also cover all materials. If you want to increase performance even more, you need to go with optimized taps and then you go with material specific. But we have a few new taps in our assortment. Yes, we have. Right, Henrik? In March this year we introduced a new tap for ISOP. This is in our optimized assortment and this is Crotep 200 for through holes and Crotep 300 for blind holes. These new taps also will follow the new code structure that we implemented for taps a couple of years ago. And they will replace the current assortment that we have right now for threading with taps in ISOP. Some improvements in this new generation of ISOP taps are the geometry itself, but we also have optimized the surface treatment, but also the edge treatments. And this is for avoiding shipping and have a higher process security. But also the design in the ship flute is optimized for particular blind holes where we can have problems with bird nesting along the shank of the taps. So we have a better control in the blind holes also with this new design in the ship flute. And this gives us some benefits also in process security. Yeah. So process security, but also we can go with higher cutting speed compared to competition. But together with higher cutting speed, we also see a longer tool life. And this all together will of course increase the productivity and give us a lower cost per component than lower cost per hole. Looking at the industry segments, of course, we cover most of them as long as you are tapping in ISOP. And within the ISOP area, we are in P1 and P2, which are around 330, 350 Brunelian hardness. But as long as you are tapping in this kind of materials, this tap will be the best choice for you. And we have a big assortment here in these taps for different standards and different dimensions. Yes, that's true. But if you want to make smaller adjustments, if you need a specific tap, then we have what we introduced a couple of years ago with what we call tailor-made web. And if you have a user account and a login on our website, you can access this. And now this new tap are also included in this. And with this, you can alter either. You can start from a standard tool and just change what you need. Thread form, pitch, chamfer, lead. But you can also start from scratch and design your tap from the very beginning. And of course, thread forms dimensions. If you want to change a standard going from a DIN tap to something else, an ANSI tap maybe. We can change the lead going from a C or E chamfer if that is a need. We can also change the tolerance of the tap, either sticking to the ISO standard. Or if you know what kind of oversize or undersize you would like, then you can also alter that. We have many different things that you can alter. So as long as you have a logging, this is there for you. And here you get the price and delivery time really fast as well. As long as you make changes within certain limits. Exactly. A couple of minutes, I would say, depending on how much you change. And looking at the performance of these new ICP taps. Here you can see a case against our old or existing ICP tap in CoraTap 300. This is in low alloy steel. And you can see a tool life increase of more than 300%. And to the right in the picture you can also see the difference in wear between the existing tap and the new. Looking at the performance against the competitor, also in low alloy steel. Here you can see in this case a tool life increase of 57%. But you can also notice an increase in cutting data. So besides improving tool life, you can also improve productivity and reduce the cost per hole. But we have more taps in the assortment, right? Yes. One of them we would like to mention here is the quite new CoraTap 100KM for ISO-K materials. And since it is CoraTap 100, it is straight flute for short shipping. This was introduced in 2015 and is for mainly ISO-K materials. We have a number of thread forms, dimensions, internal coolant with axial coolant and radial coolant. And we also have some small assortment in carbide. And these are both for blind holes and through holes? Yes. And could also be used in high alloy aluminum? Yes. If you have a high silicon content then that also becomes short shipping and you have a high strength tap since it is straight flute. And the main difference with the taps, if it is a blind hole or through hole, is the coolant channels. Right. Yes. As many other tools, we have secondary areas where the product itself performs really good or it can be used as a problem solver. In this case, if you have a spiral flute tap tapping blind holes in ISO-P, it can be a problem sometimes with the ship control. You can have like bird nesting along the shank and it can be difficult to solve it with cutting data or another type of tap. So in this case, you can use a straight flute tap, in this case the ISO-K tap. This tap, since it is straight flute, this will have a function to break the ship into smaller pieces. And then with the axial coolant channel, we will flush the hole clean from the ship. Of course, some ISO-P materials behave differently, so it can be in some cases you need to do some testing. But in most cases, you will do the problem solving with the help of this tap. A few words about hole diameter and hole size. Of course, it is really important in tapping to follow the tolerances and the dimensions that we have. But if you can use the largest or biggest hole diameter as possible, but within the standard and tolerance, that will be a benefit for the tap when it comes to predictable tool life. Because with a bigger hole diameter, the tap will have less torque and you have less risk for tap breakages. But of course, you need to stay within tolerances and standards. This is something that you don't calculate. Usually we have charts that you can follow and guidelines in the catalogs and so on. But a simple way to calculate for a metric is to take the thread dimension minus the pitch. Then you have the hole diameter. But of course, there are tolerances for this also. It is not a fixed value. Another thing that is worth mentioning is the tolerances versus the tolerance on the tap. This can sometimes be an area for misunderstanding or confusion. But if you look at the gray chart for 6H, for example, which is the most common one, the gray one is the tolerance area for the thread itself. And the green one is the manufacturing tolerance on the tap. So we can see that it's quite a big difference. So we have a lot of space to the upper limit and the lower limit. What happens when we wear out the tap? It will go down in diameter on the pitch diameter and the go gauge will go to not the right depth or it will be hard to get it in the thread. We can also see that we have 6HX on some taps and that is still within 6H, but it is slightly bigger. The purpose of this is to extend tool life. We have most of them you will see in ISO-K area since that material is a bit more abrasive. But we also have this on our ISO-P taps, which we will have a longer tool life with. The normal tolerance 6H is that standard that all suppliers follow. But the 6HX is up to every supplier to decide themselves where to put it. But still we are within the 6H. We also have ISO-1 and ISO-2 on these gray bars here. And that is something that could be mixed up with the shank specifications. Yes, sometimes it happens that if you read out from the shank of a tap and it is marked with ISO-2 for example, then you can easily maybe mix that up that it is an ISO standard tap or not a DIN tap. But that is the same as 6H, that is the thread tolerance. Also worth mentioning within tapping is the holder. This can be an area for if you have something that is not working properly in tapping, it can be caused by the holder. If you are using the wrong type of holder or for example within rigid tapping, synchronized tapping, it is very common that you have a rigid holder, an ER or something. But the whole system with the spindle, the axis in the machine, the CNC control, for everything to sync 100% okay, that is very difficult to achieve. And something that you might not think of is that we also have a tolerance on the tap. Maybe you have a bit shorter tool life than necessary or you have like tap breakages on smaller dimension. And then the best alternative is to use a synchronized holder like the Corsac 970. This is a micro floating, just a tenth of a millimeter or something depending on size. And this will allow the tap to go on the right pitch. Yeah. And this is a big benefit also compared to a floating holder. Yes, exactly. A free floating. Yep. A traditional floating holder. But one thing to mention is that the Corsac 970 is only to be used when you have a synchronized cycle in the machine. Yeah. Otherwise you need to have a floating holder, a traditional. Here we can see just a short comparison what the force on the thread flanks will affect with different holders. We can see the gray one where we have a rigid holder. We have quite a high force. If we compare to the blue line which is the Corsac 970. And this will reduce the friction, the heat and will extend the tool life. And also you can avoid the sporadic tap breakages. So looking a bit at optimizing and problem solving. We can look a bit at wear types. Flank wear you also have on taps. And as in most areas or machining areas, flank wear is a preferred wear type. Yes, it is. But if we get it too fast and if we want to have a longer tool life, what can we do about flank wear in tapping? First of all, we can look at the do we have the right type of tap. We mentioned that we have uncoated tap. We have steam tempered and we have coated. Maybe you need to go from uncoated to a coated tap maybe to have a better performance. It can also be that you need to have a look at the lubrication or the coolant. Which type of coolant? And with that we don't mean brand. We mean type. Like do you have a synthetical or a mineral based? This is also something that you need to check up if it is the right one. Also cutting speed of course. Is the drilling application okay? Do we have the right type of drill? How long have the, is the drill worn out? So that is the most common cause if you have, if you wear out the tap too fast. Right. Also we could have shipping. Yes. And what can we do about that? As always we need to check if we have the right coolant. If we have enough coolant. Also have to check, maybe this is obvious, but maybe the tap can hit the bottom in the hole. We also need to check for through holes that we have the depth enough. So the lead or the cutting chamfer is going all the way through the hole. Otherwise when you reverse that type of tap you can pull the chip upwards again and you can have chipping from that. And the same here, you need to check if the drilling is okay. So you haven't run the drill too long. Yeah. But we can also have chipping outside of the cutting zone on the tap. Yes. And this is something that is perhaps maybe more specific for taps that you can have chipping on the non cutting area, but the tap will still do its job. But of course you will not, you can never accept the chipping on a cutting tool. So for blind holes, it's most common that you have bird nesting. You have a bad chip control. You need to check with that, maybe cutting data, maybe use the straight flutal or forming tap as a problem solver. Also check the coolant, if we have enough coolant in there. And also again, maybe you have the wrong type of tap for this material, the helix angle or you have to look up that you have the right tap. Right. And with tool breakages, it's often difficult to determine what actually happened. Yes. And so also in tapping? Same thing here, you need to check more from start, check more often what is causing the tap breakage. Can it be chip jamming or is it the wrong type of tap? Maybe the problem is in the holder or the drilling. But again, you need to start look more frequently and start early to look, follow the tap. But if you break a tap within a component, there could be a chance that you could get it out. Yes, it is. It can be. Usually when you do the threading operation, you have machined the component for a long time or it is the last operation. One solution to remove the tap is to use the hard cut drill. Usually you have that in a manual machine and quite carefully try to remove the tap with the help of that. Then the diameter of the hard cut drill is in that diameter so we don't damage the thread. So this can be an alternative to save the part. Yes. We can also get some built up edge on the taps. And is there something we can do about that? Same here as we talked about at the other wear types. You can go from maybe an uncoated or steam tempered up to a coated tap. Again, same here. Look at the coolant, the type of lubrication, if it's the right one. Maybe something with cutting speed that you are in a built up area. Check that also. But maybe we should also mention that if the built up edge is not really welding on to the tap and it's not affecting the surface of the thread, it's not that big problem. You can have built up edge that comes and goes. Yeah. Not that unusual. No. That can happen. If it starts to affect the thread quality. Yeah. Then you need to remove it still with some problem solving. If you look at the thread quality, which we have on the picture, you can see that the material have smeared on the thread flanks and give it a bad surface quality. So you need to have a look at that. Yeah. But there are other quality issues we could have on a hole or a threaded hole. Many times when you have a problem with tapping, it can be the drilling that is causing the tapping problems. But have a look at the hole quality. Is it cylindrical? Is it tapered? Is it out of position? You can also have like a barrel shape. Maybe not that usual that you have the hole types that we see here, but it can happen. And the message is to also look at the drilling if you have problem with tapping. Right. This is just to illustrate what can happen if you have the wrong type of holder. You can have it over feeding or under feeding. And this comes from the whole system with synchronizing. And as we mentioned before, you can, you will push the tap forward or holding it back. That will give some pressure on the thread flank, which will give higher friction, higher temperature, and that will take down the tool life. Or you have tap breakages. This is something as a rigid holder will cause, but you can also have other problems if you have a floating holder. For example, in blind holes, if you have a spiral tap with a high spiral angle, high helix, quite aggressive geometry with high rake and much clearance, that tap can over feed itself. And a floating holder will allow the tap to do that. So we have a couple of examples here what will happen or can happen. This is quite a big thread, but it is mounted in a floating holder. And you can see here when the taps come into the material, it will start to feed more than the pitch. It will actually feed with the helix angle on the tap, pretty much. It will just make the hole bigger. Yeah. And it's because of the cutting forces with the helix angle that actually pulls the tap into the material. And we can see the chip control here is not the best. No, you don't want that. No. If we just change holder to a core chuck 970, that will prevent this. It will hold the tap back in its right pitch. Yeah. And besides the poor chip control, we don't get the thread we want either. No. With the floating tap. Sometimes it's just a bigger hole. Yeah. So here we can see that when the tap comes into operation, it will go to the right depth. We don't have that bad chip control. It's really good. And when we reverse the tap, we can see when we are up at the start level. If we now would have moved to the next hole, that chip will also be removed. So it's far much better control. Yeah. So besides having the right holder, what can we do about over dimension threads? When we have something that is over dimension, it can either be that you have the wrong tap tolerance compared to what you have on the gauge or the drawing. You can have the wrong type of tap for this material. Not maybe that common, but it can happen. But also you need to check the holder if you have some pitch error that can cause this also. But you can also have a look at the gauge, of course, if you have the right gauge to the thread. Yeah. But it can also be an under dimension thread. Yes. Pretty much the same reasons. We can have both under dimension and over. But in this case, it can also be that you maybe have the wrong type of tap for this material. Some materials close after you have machined it. And then maybe you have this wrong geometry for that kind of material. So maybe also have a look again at the recommendation to pick the right tap. Right. We talked a bit about chip control already. And it can be a big problem. Yes. And this is usually when we have this kind of chip problems, bird nesting. One thing is to increase cutting speed. Then you have like a better ship forming and you have like a more forces on the ship that will evacuate from the tap. But sometimes maybe you cannot go to that cutting speed that you would like to because then you have a tap breakage. And that is not that unusual that that is also connected to that you at the same time have a rigid holder. But if you change holder to a 970, Kortchuk 970, then you can increase the cutting speed where you should be. And then you can avoid the bird nesting. But otherwise check the type of tap, the helix angle or use a forming tap or the straight flute as we mentioned. And that was actually it for today's session. So we'd like to thank you for your time. And if you're interested in more application knowledge in SolidRound tools, keep an eye open for next session. If you would like more information about what we talked about today or for us to contact you, follow the QR code or the web address on the screen.