Travelling-Table Extrusion Up-Cut Saw Delivers Better Accuracy
With a servo-driven table and variable speed saw motor, the NS-6 offers 50% better accuracy than pneumatic tables and much faster and safer setup.
Narrator: And we're back with Rich and we're at the NS6 Up-cut saw. Rich, your saws are standard with servo table travel. Why?
Rich: Well, the industry has a standard of a pneumatic and we found that the servo actually gives a tighter control on the tolerance and rather than having it as an option, again we made that as a standard.
Narrator: What kind of accuracy increase can you expect from the pneumatic style saws?
Rich: From the pneumatic saws, we can actually estimate that it's going to be 50 percent the cut tolerance as when we're using the servo.
Narrator: How does it work?
Rich: Well, the way that it's set up, the table travels and as the table's traveling with a pneumatic saw, the clamp comes down on the products and the product actually moves the table with a pneumatic assist. With a servo, the servo motor moves the table with the product first and then clamps. What this means is now we don't have to have a high clamp pressure. You're not taxing the product being pushed into the saw and everything works smoothly and because of that you have less slippage and higher accuracy.
Narrator: Why don't you tell us about the handrail with pneumatic clamp?
Rich: Since we introduced the saw, we've updated the clamp mechanism. It has a clamp plate here with a smooth, flat side and a v-shape side for doing different sizes and shapes of products. It's a hand wheel with the bottom having a half-inch stroke with a pneumatic cylinder. The reason that we did that, it gives you ease of adjusting this when you're setting the machine up. One of the biggest problems people have is when you adjust for the next product, you have to change the clamp to fit that, which means you have to start the machine, you have to start the motor, you have to move the blade through the product to make a cut. On ours, it's a simple press of a button here to clamp the product with the last half-inch of the pneumatic cylinder, and then to unclamp it you simply hit the button again. So that gives you a very fast, simple and safe clamp adjustment.
Narrator: Great. Rich, what is the advantage of the variable speed motor?
Rich: The variable speed motor is a big advantage over people with fixed motors because the fixed motor has one RPM level that you can cut with. Obviously different materials require different RPMs. One of the things that we put in ours is a very wide spread of RPM range. It's 2275 to 3500 RPM. That gives us a wide range to adjust for materials, thicknesses and that sort of thing abd also when you change a blade for different types of materials, such as acrylics, that gives us an advantage again.
Narrator: Is the shrouded blade an advantage?
Rich: Yes it is. One of the biggest issues with the old style saws is, what happens to the chips once you cut the product? They fall down underneath the table, they make a big pile. It creates a problem. Ours is a fully shrouded blade and the blade chip collector comes out of this tube here and then you take it off with a vacuum system.
Narrator: How do you adjust the blade stroke for different size products?
Rich: Well, that's another thing that we did that we think is an advantage for our machine. Many of the others have a below-the-table adjustment which you have to get into with tools and make that adjustment. Ours is on the back side of the table and it's simply adjusting a sensor with a thumbscrew.
Narrator: How do you connect the table to the servo motor for the travel?
Rich: On this machine, the way that we connected it is we used a steel-lined tooth belt connected to the bottom of the table and it makes a loop under the machine with the servo motor and that actually actuates the table.
Narrator: Terrific. I see here that the saws are equipped with PLC and HMI.
Rich: Yes. Just as the other machines that we have in the puller lines and the cutter lines, we utilize the same PLC and we just customized it for the saw application. For instance, we have a saw blade start and stop here and you can adjust the speed right here on the fly.
Narrator: The NS6 is pretty big, but I understand you have another one that's a new offering. The NS4. Why don't we go take a look at that? We're back with Rich and here is the newest product, the NS4. Why don't you go through the differences between this and the NS6 and why it's an advantage to the customer?
Rich: OK. Paul. Our standard in NS6 uses a solid table and that table is moving back and forth outside the base frame itself. That obviously means it's a very big footprint. That footprint can be a problem for some customers. So what we did on this machine is we actually developed with a soft table, and the table actually stays inside the base frame as the table is moving back and forth. We also designed a unique guide system. We have a metallic guide on the infeed and we use this belt on the far side so you can quick-adjust for the belt tensioning.
Narrator: That’s It. All right, that's an awful lot of information. We do appreciate it, Rich. If you need any more information on this particular area of downstream extrusion, visit www.novatec.com.