Removing wrinkles or creases from fabrics, paper, films, foils and the like is indispensable. Even minimal wrinkling on such products may subject them to quality complaints. Expanders or spreader rolls are most effective in wrinkle removal. Ways to remove wrinkles are neither uniform nor simple. Wrinkle removal depends on the physical properties of workpieces, production line's operational conditions, and other factors. From this point of view, I interviewed Mr. Tsuchida, an expert in the production of wrinkle removing rolls.
| What are the most recent trends in your Flat Expander (FE) and MIRAVO roll (MRV)? | |
| Tsuchida: | The specifications that have recently been required for our flat expander (FE) and MIRAVO roll (MRV) are increasingly becoming more severe and rigorous. |
| Please explain more specifically. | |
| Tsuchida: | First of all, 1) production line speed has becomes faster. Speeds of up to 1200m/min. are required. 2) The environmental conditions of production lines are increasingly crucial. These include higher temperatures, higher humidity, a higher degree of vacuum power and the like. 3) Line tension has also increased (up to 200 kgf). 4) The thickness of nonwoven, paper and film has been dramatically reduced (to a few microns). This requires lighter rotational-torque and a reduction in torque variation. Furthermore, a highly adjusted dynamic balance is a must, especially when such a thin web is operated at higher speeds. 5) Lately, we've seen a marked tendency to increase the number of web divisions cut by a slitter (up to 32 divisions). Accurate separation of such a large number of slit pieces is required. 6) Although operational conditions in all phases are increasingly severe, our rolls are strictly required to be improved in the areas of durability and wear resistance. |
| It's just part of going along "with the innovation of Japanese high technology", isn't it? | |
| Tsuchida | Exactly. It's been 28 years since we developed our Flat Expander and 18 years since the development of our MIRAVO roll. These rolls have been used in a variety of production steps by various textile, nonwoven, paper, plastic film, glass fiber, metallic foil and other industries. So, the requirements imposed during the course of technical innovation by the Japanese manufacturing industry are required for our rolls too. In a sense, it could be said that our Flat Expander and MIRAVO roll have been "fostered" by the continuous high technology innovations of the Japanese manufacturing industry. |
| Your Flat Expander and MIRAVO roll are collectively called Wrinkle Removing Rolls. But, I feel that name is a little bit strange for an industrial product. Where did this term come from? | |
| Tsuchida | Our rolls are generally classified into expander rolls, spreader rolls or stretching rolls. At a nonwoven exposition held in Japan, a visitor from the USA was not satisfied in any way with my explanations about web expansion, spreading and stretching. He asked me: "A web is expanded, spread or stretched. OK. So, what? What's the big deal?". Then, I said: "In short, wrinkles are removed from the web." He cried: "Oh, wrinkle removal !? I get it." We smilingly shook hands with each other. Since then, we have used the term Wrinkle Removing Roll for oversea sales promotion. Later, this term has also been used for domestic users because it is simpler and easier to understand. |
| But, your rolls are not only limited to wrinkle removal, are they? | |
| Tsuchida | No. Originally, our rolls were designed to expand, develop, spread or stretch sheet-like workpieces during their production. Wrinkle removal is one of the resulting effects. |
| How is such an expander or spreader roll used? | |
| Tsichida | All around us, there are a surprising number of articles produced in sheet form, such as fabrics, paper, film and the like. In our section of the business world, such sheet-like articles are collectively called webs. In a production line, these webs are formed into rolls, and subjected to a variety of processing steps while being reeled in and out. After passing through all necessary processing steps, the web is made into a final product. However, during each processing step or while being conveyed from one processing step to another, the web tends to move in a zigzag motion, or become looser, distorted, biased, wrinkled or creased. If not dealt with, the final product is judged to be second-class or defective. It is therefore necessary to expand, stretch or spread the web during its processing in order to prevent it from moving in a zigzag motion or keep it from being loosened, distorted, biased or wrinkled. Thus, a variety of rolls generally called expander rolls or spreader rolls have been developed. |
| In the past, what kinds of rolls have been used? | |
| Tsuchida | Conventionally, bowed rolls, generally called bend rolls or banana rolls, have been used. |
| Your rolls are linear and straight. Is there a problem with the conventional bowed rolls? | |
| Tsuchida | Yes. A bowed roll is structurally disadvantageous in that the web is excessively stretched at the center and loosened at both edges. Along with technical innovations, webs have increasingly become thinner, wider and faster. This has increased the adverse effect produced by the use of a bowed roll. Thus, a linear and straight roll for uniform expansion has long been desired. |
| Next time, please explain in more detail the advantages of linear and straight rolls. |
