PROPOSAL
iNSIDE-OUT FIBER TOW CUTTER
BY:       Lowell Harris
423-288-6644

          

          

          

          

Contents
Introduction:

          There are tons of tows cut each day in the textile industry. Most of the tow cut is over 1/2" or 15mm in length that I call staple. It is usually crimped and is used in the same manner one would use wool or cotton. For this paper I will call any fiber cut less than a natural organic length fiber (.5" or 14 mm cut fiber) short cut fiber. This proposal deals with the cutting of continuous filament in a rope like strand we call tow into short single filaments we call short cut fiber. If you are reading this proposal we will assume the reader is familiar with the industry and knows the terminology used in this proposal. If you have trouble with the terminology please refer to this link for a definition, "Click Here"

          In my 24 years, working in the Textile Industry there has been a need for short cut fiber. Necessity, it is said, is the mother of all inventions. In this instance, when the industry began to manufacture synthetic fiber there was a very large volume of out-of-spec textile waste going to the landfills. Because the properties of synthetic fiber mimicked some of those of asbestos in wet lay products, there developed a strong interest in synthetic fibers cut into short lengths. It was discovered that if one could cut accurately the tow into short length, one could literally manufacture a "silk purse out of a sow's ear".

          At its infancy, it was very important not to have over lengths. Also, the new markets that had discovered the value of this new raw material did not have the experience or technology to use short cut synthetic fiber, let alone inconsistency in the fiber length.

          I was very fortunate to work with a gentleman, Mr. G. B. Keith, who was the father of the Inside-out cutter. He, with a brother and a friend, founded the small company of Mini Fibers out of Weber City, VA. They pioneered the markets where short cut synthetic fiber would be used. I worked as a sales representative for Mini Fibers for thirteen years. When I was allowed to venture out of my office, I would dive into the mind of this inventor. Mr. Keith, a salt- of - the- earth person, loved to discuss engineering whether it was underground homes or fiber cutting designs. These talks stimulated my curiosity and motivated me to learn more about cutting technology. Today, there are vast amounts of synthetic fiber tow cut 1/4", 7mm or less, where it is used in various markets. The quality of the short cut fiber has increased to the point where one can get a fairly good cut (<" fiber) from an outside-in Lummus style cutter and the customers using the fiber can tolerate a higher rate of imperfections. However, the popularity of the short cut fiber (3mm) has increased. As with any cycle of raw material, it has developed new markets or specialty areas where a precision cut fiber is still very much in demand. This proposal is aimed at these markets.

          Patents available for a more detailed study are offered in the "other source of information" part of this proposal.

Objective:

          The following proposal is one to increase the speed and accuracy of cutting various short lengths of fiber with the inside-out cutting design. We want to make it the dominant short cut fiber cutter on the market today. This proposal will allow the Inside-out cutter to be used on line and cut with the precision and accuracy all the prior inventors had envisioned. We have a goal (for now) to cut on line any hot melt extruded polymer 3mm and longer at 750,000 total denier.

Qualifications of the Author:

          I received an honorable discharge from the Army in March of 1968 and came home to go to work at a local factory, which happened to be Mead Corporation. Unfortunately the following year, 1969 I received my layoff notice, and decided to go to our local state college to get a degree. While getting a BS degree at East Tennessee State University, I worked full and part time in the carpet industry. I continued to work selling carpet until a position became available at Mini Fibers. Mini Fibers needed a salesperson that knew something about the textile industry and papermaking so Mr. Keith sent me out on the road selling short cut synthetic fiber. Now, I have over 24 years of textile experience. I have watched the synthetic industry grow from infancy. I have helped customers struggle to use a new raw material on equipment designed for organic fibers. I have seen complaints where over lengths in an old headbox had grown into a huge fibrous snake. I have watched the quality of the cutting go to where the quality of the chemical fiber was more important than the cut length.

          In 1995, I started Renewable Fiber, Inc. to improve on the existing inside-out fiber cutter. To help get the company going financially we manufactured a prototype of the commercial cutter in the form of a lab cutter. I would sell the lab cutter with the new and improved design to finance the work on the larger commercial cutter. After several disappointing run-ins with so called machine shops, fee-crazed lawyers and several delays from the US Patent Office, I was contemplating getting into another profession. Finally in 1998, I met Robert Rutledge of Rutledge Tool and Robert did a fantastic job manufacturing my cutters. I received my patent and I thought I was off to big success.

          The patent I received was on the principle of expanding the fiber while feeding the fiber into the cutter. However, everyone who purchased the cutter automatically wanted to make a commercial cutter out of it. With a large tow size, the blades grabbed the fiber and held it against the blades before the transporter had a chance to work. The first couple of cutters were successful in that they cut small tow sizes but when the customer increased the tow size and increased the cut length to above 14mm the cutter did not perform the way I had imagined. The reason was that the transporter, which was to expand the fiber, was choked with fiber.

          Besides studying and working with the master of the inside-out cutter, I studied patent after patent looking at the different designs. I began to realize several problems that are common to all textile-cutting designs. through the manufacture of these prototypes, I have been able to define the design flaws with the Inside-out cutting design and have been able to address a solution for those problems. I have some answers to some old problems related to the inside-out fiber cutter. For those who have purchased the lab cutters from Renewable Fiber Inc. we appreciate your patience for our knowledge has been long coming.

Cutter types:

          There are rotary cutters, guillotine types, outside-in, inside-out, cutters producing flock, long staple fiber for air lay and short fibers for a wet lay nonwoven. Each of these cutters has their advantages and disadvantages and the markets they go into determine their existence. The three types of cutting that have to do with short cut synthetic fiber (1/4 or 7mm and shorter) are guillotine, outside-in, and the Inside-out cutting styles. The guillotine style cutter produces Flock, the king of the extremely short fiber while the outside-in Lummus Industries' style cutter offers a longer version of the short cut fiber. The bulk of the workload for cutting short cut fiber will be the inside-out cutter. If these cutting style problems can be solved, this cutter will dominate the short cut fiber market. This proposal will be the revival or Phoenix of the inside-out cutter.

Short cut fiber and the inside-out design:

          The study of patents that have been issued notes the limitations to this design. The major problems are related to the heat buildup and unwanted long and short cuts.

          1. The tight fiber tow being pushed through the blades by a smooth polished object. The raised hill concept forced the fiber through inward facing blades. The raised hill was always in contact with the fiber. When the speed of the machine increased to achieve any speeds toward profitability, the heat would melt the fiber.

          2. Fiber cut by squeezing fiber tow onto sharp blades by adding another layer of fiber tow in a confined space forcing the fibers closest to the blades through sharp edges. This left the outer ring of fiber tow to expand to the diameter of the blades. When the tow could not expand, it produced sliding of the tow producing longs and short fiber cuts.

          None of the patents that have been issued has successfully solved the problems related to the inside-out cutter but they have given various ways to control them. I have decided in my experiences that the best approach is to eliminate the cause of the problems. Earlier patents attempted to do this but ran into more problems than just their patent solved. Instead of digging deeper into the design, everyone tended to give up. Util now, there has not been a single patent issued that would make the inside-out cutter the short cut fiber cutter of the industry.

          There are other factors to consider in this proposal. The reason for the inside-out cutter in the first place was to be able to cut shorter lengths than previously had been cut because the blades open up to the outside. The sharp edge of the blades faced inside and the angle of the circular blades opened or fanned out to let the cut fibers pass through the blades. The fewer blades one used, the steeper the angle letting the fiber escape more freely. This limited the amount of heat buildup. However, on the downside, it left few blades to cut the fiber. Hence, there is more downtime changing blades.

          The next problem that has risen is the total denier one can cut due to the Inside-out design. Today the outside-in cutter has a huge advantage in cutting the large rope-like tow of over 4 million total denier at online speeds. The cuts are usually long lengths of 28mm or longer and accuracy is not a factor. However, when a short cut is needed, accuracy and speeds are more critical because the end use is more demanding. Quality and quantity can be achieved even when cutting the shorter lengths. The work I have completed shows that there is a great deal more speed and quality to be harvested with the precision cut of the inside-out cutter.

          There are patents that introduce the fiber into the machine with rollers and patents that use water-cooling. There are patents to use belts taking in multiple tows. While these are good ideas for patents, all of them, including mine, had flaws. However, when the patents are addressed all together, a picture develops that points to one problem that eliminates the problem associated with the Inside-out design.

          This segment should address the market and give evidence to why you need such a machine. We will forgo this section. It is not my desire to address these markets and sell you on the reason why you need a fast, accurate short cut fiber cutter.

Secrets we have uncovered:

          The final proposal is for the people interested in the manufacture of the design. I will list only the highlights.

          The proposal will cover:

          As you can see, the proposal will cover every aspect of cutting fiber. At one time most of these issues were covered but never at the same time and not with the new patented designed product as we will introduce in the final proposal.

The cost of the proposal:

          The figure listed is the cost of manufacturing the cutter if Renewable Fiber Inc. is responsible for all the work. The owner of the proposal and patent may take the authority and responsibility of completing the work if they believe they may be more fruitful than the figures listed. They are welcome to have the work completed by others. This cost does not include any legal fees for attorneys or patent work.

Total for commercial cutter $68,800.

The time line:

          Depending on who is doing what, if I am overseeing the work from my sources, both cutters can be up and running in nine months. If some or all of the work is accomplished in-house by the owner of the proposal, the time line will be determined by the house doing the work.

Legal questions:

          The main ideas have not been disclosed to preserve the patent right to the cutter. None of the work infringes upon existing patents. My compensation can be based on royalties or a fixed amount discussed at that time. The project can be patented by the owner of the proposal at the conclusion of the revelation of the proposal.

Questions regarding the proposal:

           I know that if you are interested in this proposal, you probably have a ton of questions. I have worked on this project for seven years and believe me I have had to work through many questions. The best way to help you with the details is to email or call me. Once you find out how the cutter works, the big picture will become much clearer.

Sources of Information:

          Some patents in this area include:

  • Patent Number: 03485120
  • Patent Number: 03978751
  • Patent Number: 03768355
  • Patent Number: 03948127
  • Patent Number: 03978751
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