Introduction to Soft Limits (0:00-1:04)

0:00-1:05: “Hey, hey, welcome to another training video. Today we’re gonna be talking about soft limits. One, find out what they are, what they do, and what you need to do if you actually trigger one on your controller when setting up and running a program. Okay, so the first question is, what is a soft limit? Well, a soft limit is simply a digital barrier that prevents us from running into the limitation of the machine. So for example, we have three axes of travel for the cutter. We have X down the length, we have Y across the width, and we have Z axis going up and down in any of those axes. Eventually, we’re going to run out of movement, but instead of hitting a physical barrier to stop our movement, which would cause some problems, we have a digital barrier that is built into the system called soft limits. So lemme show you. So if I try to move the y axis here against y negative, even though I’m still holding down the, the control to move the y axis in the negative direction, it automatically stopped and prevented me from um,”

Understanding Work Envelope and Soft Limits (1:04-3:10)

1:03-1:08: “and prevented me from um, running into that physical barrier. Same thing will happen on the positive Y.”

1:12-3:10: “Beautiful, and we can do the same on all axes and limitations. So if I go here to the X, okay, so there’s my X again prevents me from driving off the system and also my Z axis. So we can bring this, I’m gonna bring this slightly over here and I can go all the way down as far as the Z axis can travel, which is that low. And that is, um, well beyond the table surface by the way, so that we can reach vertical workstation, um, parts as well as small diameters and even pass the, the center point of our turning center. Um, if we go up in our Z axis, it automatically stops as well. Okay? So all of these boundaries create a what’s called a work envelope. It’s the physical box that the cutter can travel in, that we can cut parts within this work envelope. The soft limits will protect us from going outside of the box, but they don’t prevent us from hitting anything inside the box. And we’ll have another video on how to do crash prevention so that we reduce the risk of hitting anything inside the work envelope of the machine. Now just like any coordinate position on the on the machine, uh, the soft limits are all tied to the proximity switches when we home our system. So when we perform a startup routine, then our soft limits will automatically activate and they’ll be set up correctly based on that homing routine. Now there are indicators throughout the controller interface that lets us know if we are actually on a limit. So here on the home screen we have here a limit. And you can see my red light is on. Um, that’s because my z axis is lifted up all the way. If I simply move my Z axis down a little bit, you can see the, the red light turns off here on my limit. That same indicator is also on the three workstations. So all three of these are gonna be the same location. Um, right here you have a limit indicator as well.”

Triggering Soft Limit Errors (3:10-5:18)

3:07-5:19: “Um, right here you have a limit indicator as well. So if I lift up my Z axis until it stops on the soft limit, you can see here it’s uh, it says that I’m actually on that limit or on a limit. The one thing about being on a limit that we need to be aware of is the system. The delta systems don’t like to start an actual program. So if we went to load a load a program here and push play, it doesn’t like to start a program while being on a limit at the beginning. So as long as we move it off the limit, we can then make sure this, again, light is turned off, we can then load a program and we can push play and it will be, be able to proceed from there. Now soft limits do a couple of things for us. One thing that we just barely saw is they prevent us from manually, uh, driving the machine into a physical barrier. Um, that doesn’t mean that we can’t drive the actual spindle down into our table fixtures ’cause that’s actually inside this work envelope box. So we still need to be careful of doing that, but if we’re actually just simply driving it all the way to the end of the access, uh, we don’t have to worry about it actually smacking into anything. The second thing it does is it helps us manage when we’re running programs. So when we load a program into our controller and we push that play button, um, it’s going to scan that G code to ensure that any part or any movement of that program is not going to exceed any area of the machine within, again, the x, the Y or the z axis minimum and maximum travels. Now sometimes that does happen, sometimes it’s called triggering a soft limit error. Lemme show you what that looks like right over here. We’ll just load a program and I’ll, I’ll set up a scenario so that you can actually see that and then we’ll talk about why there’s two reasons why the soft limit pops up and how to overcome those. Okay? For this example to get a air to pop up for a soft limit, we’re just going to set up the machine technically incorrectly. Um, I’m gonna tell it to go to XY zero for this sheet that we have on our horizontal table. So it went over the bottom left corner, which is most of the time where we set XY zero for the horizontal,”

Common Reasons for Soft Limit Errors (5:18-8:02)

5:16-6:04: “of the time where we set XY zero for the horizontal, you know, workstation. Um, it’s not required, it just seems to be everyone’s preference. Um, and so that means that the program that we would be running would be all dialed in from this corner and all the coordinates would be from that corner forward. If we move that zero, let’s say over here to this top left corner and try to run that same program, um, if there were any movements within this larger work area, they’d be trying to happen outside of the machine and that should trigger a soft limb air for us. So if we move this all the way over to the other corner, let’s say right there and I zero out my y axis, okay, on my horizontal workstation. And now we load a program,”

6:11-8:02: “Let’s say the V table G code, and this program is all written from the bottom left corner. Um, but we made the XY zero in the top left corner. So again, all the coding is gonna want to go that way off the machine. So if we actually push play here on our controller, you can see that we get an error 2002. So there’s six soft limits because there’s three axes and there’s a positive and negative direction for each axis. So that makes six soft limits. So you’re gonna have 2001 through 2003 are gonna be your positive soft limits. For example, 2001 is X positive direction, uh, 2002 is y positive, 2003 is Z positive. And then if you have soft limit cord, um, errors that pop up from 2011 to 2013, those are all negative soft limit coordinates. So for example, 2011 is negative x axis direction 2012 is negative y axi direction and 2013 is negative Z axis direction. Um, so here we’re running into a 2002 error. So that is a positive y axi soft limit error that we’ve run into, which is exactly what we said would what would happen. Um, the positive Y is in that direction, um, and we said that the, the coordinates are gonna want to go off the machine in that direction. So that’s exactly what we had set up. So if we came and actually, um, zeroed our, our Y axis here instead, this would then run successfully. Now there’s two reasons soft limits are triggered. One is because you have set up your work offset your XY, Z zero incorrectly, um, or it hasn’t been completed yet. For example, maybe you set up XY in the corner,”

Error Codes and Their Meanings (8:02-10:11)

7:59-10:14: “For example, maybe you set up XY in the corner, but you didn’t set the Z axis yet. Okay? So you’ve set up some but not all of them correctly. Uh, so that’s something you need to check, verify your x, y, Z zeros on your parts, especially your job sheets, um, to verify that your machine is set up correctly for the program that you’re trying to run. The second reason why you’re gonna run into a soft limit error is if your program is actually programmed incorrectly to go beyond the parameters of the machine. Uh, let me show you some of those in the cadcam software that are very common that you can run into. So we mentioned there’s only two reasons why soft limits come up as an error on your machine. The second reason is because your tool paths have been programmed to exceed the limitation of the machine itself. And so here I’m gonna cover a, a couple of common mistakes that take place, um, with those that are new to CNC and, and this will hopefully give you some guidance on things to be aware of. So the first thing that we’re gonna pay attention to is orientation. So if we actually zoom out, you can see this, this large, um, cross section that represents the center of this grid or graph. And we’ve positioned this technically in the bottom left corner of our part. And the other thing we’re gonna notice here is that the part is oriented vertically. Um, and that may seem intuitive because we actually stand at the end of the machine and look down the length of the machine. Um, so it may look correct, but this is actually incorrect according to where the front of the machine really is. If we actually look at this rectangle here, this would represent, um, a work envelope of the actual system that we’re working with. And so the length of the machine, um, goes along the x axis or from left to right on our screen. And because the part is oriented vertically, we can see that, um, it, the tool pass would go beyond the work envelope of the actual machine itself. So if we simply change the orientation, um, I’m gonna do it actually this way. Just to point out one other thing, we’ll put this corner in here and let’s go change the orientation here as well.”

Avoiding Common Mistakes in Programming (10:11-13:05)

10:10-10:19: “and let’s go change the orientation here as well. Just swap the X and the Y parameters 49.”

10:22-13:06: “Very good. Okay, so now our part is oriented correctly, um, to go along the work envelope of the machine itself. Uh, the other um, common mistake is actually drawing tool pass outside of the work envelope. So again, if this was the work envelope of the machine, even though our part is oriented and fitting within the work envelope itself, we actually have sections of tool pass that are, um, going beyond, um, the edge of those soft limits. Um, and so you would need to accommodate by moving those, those tool pass and pockets to make sure they don’t exceed the limitations of the system. Uh, that I’ve actually already done that in this drawing. I just flipped it around the other side so you could see a demonstration. But here if I plop this back in this corner the way it should be, okay. So we can see that even though the vectors are still exceeding beyond, let’s say the bottom edge of the part beyond the soft limits, um, this particular tool path that does the pocket, okay, the vertical pocket, you can see that the center of the cutter actually never goes beyond the edge of my material. Um, so this will actually work just fine as long as long as again, the center of my tool doesn’t exceed the soft limit edge if I am putting the part right on the edge of the work envelope of the of the machine. Another common one is our setup of our home positions and our safety clearances. So after you’ve created, created Tool pass or even before you create tool pass up up here in this particular software, the TRIC software, we can do a setup of how we want the cutter to be at the beginning and end of the program and how high we want to clear above the material when it’s going from one cut to the next. So if we click on set here in the Tric software, we can look down here in the Z gap. So this is how high it lifts above the material, okay, between each cut. So this isn’t a problem, this isn’t lifting very high, so that’s not creating a problem. But if I look at my home and start positions, the X and y zeros are fine, but here, my Z axis at the beginning and end of the program is at eight plus inches. Um, meaning that it’s, it’s programming the cutter to start the, the program and end the program eight inches above the surface of the material. So if I don’t have eight inches above the material on the machine, just ’cause I don’t have that much Z travel, then this will also trigger a, a soft limit warning as well. So if we simply, um, pull this down, let’s say only two inches above the material, and then it’s gonna ask us to recalculate our tool path. ’cause that has to be, um, incorporated into every single tool path to have those homes start parameters.”

Conclusion and Additional Resources (13:05-13:56)

13:03-13:56: “to have those homes start parameters. Now, when we save out our G code, we’ve accommodated all the, um, most common mistakes that you can make to generate tool pass outside of the work envelope of the machine. Hopefully we’ve kind of brought up some of the reasons why a soft limit is triggered on your controller. And the two things that you need to check is your work offset. Your XY, Z zero on your machine needs to be set up correctly and your code needs to be written correctly. And we showed hopefully some scenarios on some common mistakes on where those those take place. Now we do have another video that shows specifically in the turning center if you have a Z axis soft limit, um, how to overcome that by touching off the smart tool pad using the execute MDI field. So I recommend that you watch that video if you’re specifically running into that issue in the turning center.”