Overview of the 5 Program Steps in the IAI Servo Press Programming Cycle

Hello this is Ray Marquiss, Senior Application Engineer with Valin Corporation, and this video is going to explain the five program steps in the IAI Servo Press programming cycle.

There are 5 steps in the program:  approach, search, press, depress-or depression or depressure or depressurization-it's documented differently in different parts of IAI’s documentation. That's basically where you're just going to release the part, and then the final step is the return. IAI uses this graphic a ton to explain their program cycle showing that the approach cycle, or step, the search step the press step. Then you're going to judge. Once you're finished pressing, we judge, and that's not a numbered step. You don't really program that; it's done a little differently. You'll see that in a bit.  And then the depress. The return and then you're waiting for the next program cycle. During this judge step, there's a time you can set we’ll go into that in either in this presentation or later presentations.

But here's the first step in the program. It's the approach. You can see the actuator will start near the zero point at the top and we've programmed it to 125 millimeters a second to a position of 48 millimeters. 48 millimeters is about where our product is, so we're just kind of going getting close to the product. You can see that once we actuated, the actuator will come out and it will go to that 48 millimeter. Position and then it's going to trigger the next step, which is the search step.
In the search step, we start where the approach step ended. We're going to go look for a terminating load. In other words, we're looking for a certain amount of feedback. This 30 is a little high. I'd probably normally set it at about 10 and what happens is we'll go and will push down until we start to see a little bit of force feedback. And once that force feedback back matches this terminating load, then we're going to transition to the press step. Basically, we've just found the part there. If there's no part there and we keep moving, once we pass this limiting position if we haven't seen the proper force feedback, then that's going to cause an error and will fault out. And basically that tells us that we didn't have a part to press on.

Then comes the press step. The press step starts where the search step ended, so we ended around here. That's where we're going to start in the next step, and we have all this criteria that we enter in and the criteria that's used is based on which which press mode you've selected. There are nine press modes. I'll cover those in a minute. In this case, what we're going to do is we're going to move to 75 millimeters and it'll be a good press as long as we don't exceed this maximum load of 80 newtons. So if we got to 70 millimeters and the load was 81 newtons, then we'd fault out and that would give us an indication on the outputs. So we move down a little bit more and we compress that spring. Until we reach the 75 millimeter point. And then here's a little bit more on the press. In this example that I'm talking about, we used speed control, keeping position as an example. So once the press criteria have been met, in this case we have made it to the position without exceeding the force set in our previous slide, the judgment parameters that we program can be checked. These are in the software right above where you set up your move sections or program sections. Once we get to that position, we can say we want kind of bracket it. So let's say our target position was 75. We could say, well, we want the lower limit to be 72 and the upper limit to be 78. So as long as it's between 78 and 72, then we're OK as far as the position goes. We can also fail based on the load, so if we get to that 75 millimeters and we know that we should see about let's say 60 newtons of force, I could set the upper limit to 61 or 62 newtons and the lower limit to 58 so that even though it's pressing and it's got force feedback and it made it to that position, we can detect whether or not it has the proper amount of force feedback to pass that part. Some modes have a target position as a judgment criteria and some have a target distance, so you can change those around based on your application to meet your pass criteria.

Next is the depress or depressure or depression. That's where we release the parts. So we start out where the part’s still being compressed and we move up slowly. I don't believe the software will let you set a speed faster than 10 millimeters a second, but you move up slowly until the load lowers to this terminating load parameter that you've set. Once the load reaches this set level as the actuator is moving back towards its origin position or home position, once it reads this set level the program will move to the next step, which is the return step. So it's going to move up slowly, and that prevents the spring or the part from like flinging out of its press state, you know, it might bounce off or move around as you come up if you come up too fast.  Then once we pass this, we move to the next step, which is the return, and the return’s really simple. It's just the return to the programmed home position, which is in the in the programming parameters. And it's going to move at this speed until it reaches there.

After that, we're done with our whole motion program.

There are nine press modes and I've got this note at the bottom that I'll read first, which is that the terminology is confusing. When I first came across it was confusing to me and it took me a little bit to kind of understand what they're talking about, but “keeping” and “holding” basically means stopping at. Therefore, there are press modes to stop at a position, a distance or a load, or an incremental load. I plan to make some videos of these modes to show them in operation and show the programming and how to set it up and some of the things that you can do with it. I'm only going to do the first 4. modes and probably not do the others. The difference, for instance between “speed control-keeping position”, and “force control-keeping position” is just basically that in the speed control-keeping position whatever speed you set for the press mode, it's going to continue that speed or maintain that speed, and the force will vary.  In the force control mode it's going to use force to move and it's not going to control the speed. So these modes are the same. In other words, speed control is going to stop at a position, force control is going to stop at a position; that's for mode one and mode 5. In mode two and mode six, it's going to stop at a distance after it finds the part. But in mode two, it's going to maintain the speed, and in mode six it's just going to use force to move and not maintain the speed. So look for these videos. There will be some for all four of these modes. The 1st four modes here, and possibly I'll do one for mode nine. That's a little bit special, and we'll talk about that in a different video.

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