General Questions In Tube bending process

FAQ 1) Where is your factory located? How can I visit there?

Our factory is located in Suzhou city (beside to Shanghai).You can fly to Shanghai Hongqiao or PVG airport directly. All our clients, from home or abroad, are warmly welcome to visit us!

FAQ 2 ) How does your factory do regarding quality control?

Quality is our culture. We always attach great importance to quality controlling from the very beginning to the very end. Our factory has gained SGS, CE certificate.

FAQ 3 ) How is the training and after sales service?

Please refer to our service policy above.

FAQ 4 ) What is the biggest bending capacity you could offer?

As of now the biggest bending capacity is 220mm outside diameter for cold bending.

FAQ 5 ) What is the machine’s control?

Standard control is PC contorls,  special request is PLC controls.

FAQ 6 ) What is the difference for NC,NCMP and CNC machines?

NC is standard hydraulic pipe bending machines, feeding and rotation are manual, and bending is hydraulic automatic.
NCMP is semi-automatic pipe bending machines, mechanical gear feeding, servo motor automatic angle rotation and hydraulic automatic bending.
CNC is fully automatic pipe bending machines, servo motor for feeding and rotations, and hydraulic or servo motor for bending, multiple tooling stack are available for two and more different bending radius (CLR).

FAQ 7 ) What is the difference for NC,NCMP and CNC machines?

How to choose the pipe/tube bending machines?

You have to inform us following details:
- Max. outside diameter:
- Wall thickness range:
- Bending radius (CLR):
- The pipe material:
- The drawings if possible:

FAQ 8 ) Are you a manufacturer or trading company?

We are a manufacturer, NABOK is our group trade mark.

FAQ 9 )What is pressure die boost, and the pressure assist, also I heard of carriage boost, what exactly these confusing terms are?

Ans.:  Since pipe is drawn around bend die during bending process, its back tangent still-straight section is moving at the same time, while pressure die is supporting against it. Which means, the pressure die has to move together with the still-straight pipe otherwise the friction force will hinder the pipe forwarding.

A following pressure die is moved by friction force from pipe and is returned after bending cycle by spring force.

Pressure die boost(same as pressure die assist), is a hydraulic cylinder mounted above which applies force to the pressure die in the direction of the bend. It tends to push more material pipe into compression, thus reduce wall thinning and collapse on the outside of the bend.

Carriage boost/assist only applicable on CNC Model. It is to apply force to the back end of the pipe by carriage/collet moving forwards. In this way much more force can be applied without slippage because a pressure die boost with excessive force could cause to slip past the pipe or wrinkle the inside pipe.

The carriage boost power coming from the Y-axis feeding action, which is only CNC applicable.

FAQ 10 ) How should I select a CNC or NC bender?

Ans.:  In CNC three axes YBC of material movement are controlled, whereas, in NC, only the degree of bend(C-axis) is controlled.
CNC features highly repeatable bends thus the quality controlled, multiple bends in single cycle and multi-radius stack tooling, carriage boost is a plus.

FAQ 11 ) I heard a lot of tube & pipe, what exactly is the difference between?

Ans.:  Pipe is a circular hollow cylinder to convey gases or fluids. In order to calculate the flow, pipe sizes are measured by ID. Together with wall thickness it is referred in terms of schedule. Pipe size standards different North America from Europe. Usually pipe is formed by sheet rolled and welded, not dimensionally accurate, besides it is not intended for structural use.

Tube, on the other hand, is dimensionally accurate(compared to pipe), and has bright finish, could be rolled welded or drawn seamless. Tube sizes are divided by outer diameter, and wall thickness measured in gauge.

FAQ 12 ) What is a rotary draw bending machine, is it difference from the other benders?

Ans.:  A rotary draw bender is a “draws”(pulling) bending process by making a rotary movement(bending), the forward material is clamped to the bend die(the bending axis), and the pressure die is to support the backward still-straight pipe. Sometimes known as mandrel bending because usually a mandrel is inserted thus the shape is maintained and the bend are not deformed.
Compression bending is a press bending process with a ram to bend a workpiece. Flattening or collapsing on the outside of the workpiece are the most common problems.
Roll bending in which material is fed through a 3~5 roller arrangement. It is a quick and effective method to bend extremely thick wall and large radii that exceed the capacity of rotary draw bender.