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Technical InformationRotary Cutter "NT Die Cutter"

Ryuichi Sakamoto

1. Introduction

NT Die Cutter" is a carbide rotary cutter which cuts contours of various products such as non-woven fabrics or paper that is difficult to proceed with stamping die method at high speed and in high precision. Rotary cutter consists of a die cutter, which has three-dimensional cutter blades on the cylindrical outer surface, and an anvil roll, which has a smooth cylindrical outer surface, and raw material sheets are cut into the required product shape by passing those two rolls. The conventional die cutter is made of tool steel, but it had a disadvantage in product-life cycle due to abrasion.

In order to dissolve this problem, we first applied our original cemented carbides and machining technologies to die cutters. Herewith, the product-life cycle of NT Die Cutter can last about 10 times longer than conventional tool steel die cutter. Moreover, the high-speed operation, excellent cutting ability, and high reliability could be obtained (A patent has been acquired).

After commercialization of the NT Die Cutter, we have continuously improved it to respond to customers' needs. Therefore, it has been accepted by many domestic and foreign customers. From now on, we will be providing NT Die Cutter with high quality as the world brand of Carbide rotary cutter from the ISO9001 (2000) certified factory.

2. Characteristics

(1) High-speed operation

NT Die Cutter is created for our unique material technology and machining technology. Therefore, it is possible to cut at an operation speed about 10 times faster than stamping die method (converted into the operation speed, it becomes 300m/min or more). The reasons are as follows: (1) High knife-edge stress can be generated by the high Young's (2) The conventional stamping die method is discontinuous ( setting, punch/exhaust, work transfer) against the work flow, but rotary cutting method is continuous (Figure 1).

Fig.1 Comparison With Rotary Cutting Method and Stamping Die Method
<Fig.1> Comparison With Rotary Cutting Method and Stamping Die Method
(2) Long life High reliability
Our original ultrafine grain cemented carbide having high hardness and high strength is applied to NT Die Cutter. Therefore, it is achieved to extend tool life cycle, its cycle is about ten times longer than that of conventional tool steel die cutter. Also, our original machining technology and sintering technology improve its reliability and cutting ability with ultimately depressing both defects and dimensional errors that may cause chipping and abnormal wear.
(3) Capability for wide applications and flame unit
NT Die Cutter is usable for wide range of cutting applications. It shows excellent cutting performances for sanitary products, various containers, non-woven fabrics, polymer films, copper or aluminum foils, and those composite films, Also, we can design and produce an appropriate flame unit to suit customer's manufacturing condition.
(4) Actual achievement and experience of NO.1 bland
Since NT Die Cutter was commercialized in 1986,it has been provided to wide various fields and is regarded as No.1 bland. The accumulated know-how and experience of that are effectively used for new customer's needs and troubles. Therefore, we will be able to respond with the best solution to them.

3. Related technology

(1) Ultrafine grain cemented carbide

Material properties required as the rotary die cutter are (1) long product life cycle (wearing resistance), (2) high reliability (chipping resistance), and (3) excellent cutting ability. To satisfy those requirescemented carbide should be harder and tougher. Accordingly, our original ultrafine grain cemented carbide is applied to the NT Die Cutter. Ultrafine grain cemented carbide is made of the WC (Tungsten carbide), as a hard particle, which refined mean grain size to less than 1 micron in order to achieve both higher hardness and strength in comparison with the conventional one(Figure 2). In addition, the finer mean grain size, the shaper cutting edge is obtained (Figure 3, patent pending).

<Fig.2> Comparison with the ultrafine grain cemented carbide and the conventional material (Our company ratio)
(2) Powder metallurgical technology

NT Die Cutter based on our powder metallurgical technology, which allows us to make the complicated products shapes by sintering raw material powders. The manufacturing process is roughly classified as the powder mixing process to sintering, HIP (Hot Isostatic Pressing) and the machining process.

In the sintering process, our original powder metallurgical technology is applied to obtain both high material property and stable quality. Specially, HIP (Figure 4) is a special process to ultimately depress material defects, such as remained pores (vacancies) and small cracks, with treating under high temperature and high pressure. Therefore, HIP-treated carbides can be brought out its material-essential high performance.

(3) Machining technology
The performance of NT Die Cutter depends on its machining precision. The NT Die Cutter is guaranteed micron-order dimensional precision as a result of our unique high precise grinding machines and measuring devices (patent pending).
(4) Material & Mechanical design engineering

We can offer the appropriate material design and mechanical design to meet every customer's needs. For the material design, the appropriate cemented carbide material combination is designed according to the driving method and the work, Also, for the mechanical design, the appropriate knife-edge pattern and shape is designed according to the FEM analytic result (patent pending).

Also, We designed three carbide assembling method, sleeve type, separate type, and segment type, to enhance cost performance with using expensive carbide effectively (Figure 5).

<Fig.3> Structure model figure of cemented carbide

<Fig.4> Effect of HIP treatment

<Fig.5> NT Die Cutter assembling (screening parts are cemented carbide)

4. Application and Evaluation

At present, 17 years have passed from its birth in 1986, NT Die Cutter has been used in various applications in domestic and foreign customers. The following paragraphs introduce the trends in each application.
(1) Sanitary products

In the sanitary products industry, the production speed has kept being improved. At present, due to efforts for improvement in the converter-line manufactures, the production line speed has become over 300m/min. Due to realize such high speed processing highly rigid flame unit with loading system and excellent cutting performance are required. In addition, at the 24 hours continuous operation, the long tool life and high reliability are required for the die cutter to reduce tool change. NT Die Cutter has realized the customer's requests through utilizing its cemented carbide property.

NT Die Cutter not only achieves the high speed processing but also saves running cost and maintenance time. Therefore, NT Die Cutter is highly valued in this business field.

(3) Wide range of applicable material (processed material)
Package materials are made of paper, nonwoven, organic film, etc, and their cutting forms are various. In addition, the cutting methods are also various such as complete cutting, perforated line cutting, half cutting, etc. In order to respond to those requests, optimal design is suggested through the discussion with a customer, and feedback the actual performance to satisfy customer's needs.
(4) Metal Foil

Recently, since small and thin electric devices are demanded, the metal foil less than 10 microns is utilized in the industries. To cut those foils by stamping die, extremely precise clearance is required. Generally, it is known that the clearance should be 3-12%(1)of the work thickness is required, then, in case of 10 micros thickness work, its clearance should be about 1 micron. However, because stamping die having such narrow clearance is hardly produced commercially, It can be said that stamping die method for such thin metal foil is difficult. 0n the other hand., Since there is no problem concerning the clearance in the rotary cutting method die cutter can have high cutting at high speed.

In addition, the zero rim, which method has no trim space in the web for direction, is easy to realize by utilizing rotary cutting method. That is effective in raw material cost reduction. Therefore, it is a very interesting cutting method for the customer using expensive materials.

Also, in the case of cutting hard metal material by the conventional steel die cutter the tool life is excessively shorter than that of non-woven fabric cutting. Therefore, the need of carbide die cutter come to increase recently.

(5) Others

On one hand the customers who have already used the steel die cutter are attracted to the performance of the carbide die cutter, such as long life, low maintenance frequency applicability for the hard cutting materials, etc. On the other hand the customers who haven't used die cutter are attracted to the performance of rotary cutting method itself, such as the quality of cut surface, complex contour cut, etc. We have been receiving a lot of inquires and requests through our homepage.

We work actively for sales and technical service to respond customer's needs. Also, the research and development are done to cultivate our material and machining technologies further, and we focus on prompt commercialization of new technologies and new materials.

5. Recent approach

(1) Superfine again cemented carbide
As above already mentioned, the fine WC grain size makes it possible to provide cemented carbides with, the higher strength and hardness. The new superfine grain cemented carbide material to be extremely fine-gained has been developed successfully through our continuous innovation of technology concerning powder metallurgy2). Hereby, it becomes possible to realize at the high level of hardness and strength. At present, this new material (superfine grain cemented carbide) is mainly applied to the die cutter application that has a problem in case of cutter, which enables to solve the problem successfully. In the future, this new superfine grain cemented carbide is expected as a material to improve the performance of NT Die Cutter more (patent pending).
(2) Improvement of cutting quality

In case of cutting the highly ductile material such as metal or resins by using rotary cutter, the burr at the cutting part sometimes come to be a problem. This burr is generated by crushing a material by the top flat area on the knife-edge. Therefore, while it is possible to prevent from the Generation of burr by eliminating the flat area on Knife-edge, at the same time the other problems such as high frequency of chipping may be occurred.

We basically researched cutting mechanism of metal on rotary cutting method, and obtained the knowledge of the burr generation mechanism. From this product of basic research, the die cutter to enable to satisfy both control of burr generation and high cutting was developed (patent pending). We have been applying this technology to the die cutter for metal foil cutting application, and receive high evaluation from customers.

(3) Regrinding service
Today, NT Die Cutter has been used not only in Japan but also all over the world. In order to respond to customers' regrinding needs rapidly, we have established regrinding sites in Europe (German), US, Southeast Asia (Thailand), and China (Shanghai), which make it possible to provide customers all over the world with our continuous regrinding service.
(4) Trial cutting service
For the customers who want to know the performance of rotary die cutter itself in advance of the first installation or to evaluate the cemented carbide die cutter, we can offer trial cutting test with in-house cutting test machine. The raw material received from the customer is cut in practice, and the cutting quality and the cutting characteristics are reported to the customer. Also, when business inquiry is received, the result of trial cutting test can be reflected into the design of die cutter.


As mentioned above, it is presented the Characteristics of the NT Die Cutter which is the Carbide rotary cutter, but the possibility of NT Die Cutter does not reach the limit yet. Since the development, it has become almost matured technology in sanitary products. However, it is still in the first stage about the development to other business fields. At present, it is positively continued the research and development of NT Die Cutter, and the development for expanding the limit of manufacture is also being carried out. It would be greatly appreciated if you find some interest in carbide die cutter or rotary cutting method. For the reference, main product specification of the NT Die cutter is shown in table 1.
Table1 Main product specifications of the NT Die Cutter
Item Specificattions
Work size
(Cutting area size)
Max. 1,100×400mm(Sleeve type*1)
(Max. size of carbide part:ODφ360×1,500mm)
Max. 1,600×1,000mm(Separate type*2)
(Max. size of carbide part:ODφ500×14500mm)
Mterial of die cutter Ultrafine grain cemented carbide FND30 (HRA=90)
Material of anvil roll Ultrafine of fine grain cemented carbide or dice steel *3
Product shape
(Pattern of knife-edge)
Radius R0.1mm and more
Recommended value : R10 or more
(on development drawing)
Spacing between blades 5mm or more
(on development drawing)
Joined pattern
Angle θ=20° or more
Blade apex angle According to requirement
Thickness of carbide Standard value : 10mm (Min. 8mm)
Vacuum hole
Hole diameter : φ3-10mm
Spacing of hole on internal surface, L : L≧2・d
Distance from root of blade : 5mm or more
Manifold Installation of manifold for suction and blowing is available.
Driving method Die cutter : driven
Anvil roll : Gear driven or free (driven by friction)
Loading method Pneumatic or Hydraulic or Mechanical loading
Flame unit According to requirement
Other For further information, please feel free to contact us.
*1,*2) Refoer to Figure 2
*3) Selected according to requirement.

1) Japan Cemented Carbide tool Manufacturers 'Association: Cemented carbide tool hand book1998,P.283
2) Nippon Tungsten Review, Vol34


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