This page describes the process flow used to produce NFK products and deliver them to users as rapidly as possible.
01.Rolling sheet steel to create pipes
![](https://en.nfk-jp.com/wp-content/uploads/2018/03/step_01.jpg)
Creating the pipe (tube element) is the most important process in creating flexible hoses and expansion joints.
NFK has a pipe maker for creating flexible hoses of 3 to 350 mm in diameter, and a pipe maker for creating expansion joints of 20 to 2,800 mm in diameter.
02.Forming tubes with forming machine
![](https://en.nfk-jp.com/wp-content/uploads/2018/03/step_02.jpg)
Three forming methods are used.
- Roll forming
– A special wheel is used to form corrugations on the pipe. - Bulge forming (elastomeric forming)
– Pressure is applied to a special resin from the inside of the pipe, and the force of its expansion is used to form corrugations. - Liquid-pressure forming (hydroforming)
– A method similar to bulge forming that uses a liquid (such as water or oil) instead of a special resin to form corrugations.
03.Weaving wire braiding using braiding machine
![](https://en.nfk-jp.com/wp-content/uploads/2018/03/step_03.jpg)
Wire braiding (woven stainless steel wires) is a component that increases the pressure resistance and strength of flexible hoses.
Wire braiding made using a braiding machine is mounted on the outside of flexible hoses.
04.Cutting tubes to production length
![](https://en.nfk-jp.com/wp-content/uploads/2018/03/step_04.jpg)
Flexible hoses are cut to the specified length as specified by the client’s order.
05.Attaching joints
![](https://en.nfk-jp.com/wp-content/uploads/2018/03/step_05.jpg)
There are two methods of attaching joints to flexible hoses or expansion joints.
- Welding
– Joint types such as flange joints and screw joints can be attached to flexible hoses and expansion joints by welding. - Crimping
– Joint types such as flange joints and screw joints can be crimped with a special crimping machine and attached via a special connector.
06.Testing
![](https://en.nfk-jp.com/wp-content/uploads/2018/03/step_06.jpg)
All flexible hoses and expansion joints are leak tested.
- Immersion-type airtightness test method
– Air is pumped into the product to pressurize it. The product is then immersed in that state and leakage is checked for by examining whether bubbles appear. - Non-destructive inspection
– Non-destructive inspections are used to check the solidity of welds of difficult-to-immerse parts such as large-diameter expansion joints.
07.Drying
![](https://en.nfk-jp.com/wp-content/uploads/2018/03/step_07.jpg)
Water or other liquids must not remain inside products.
Products are dried by warming them to evaporate remaining moisture, or pumping warm air into the product.
08.Shipment
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Processes from packaging to shipment also affect product quality.
Suitable packaging is used to prevent damage to products during shipment, ensuring products reach users in the optimum state.