Tube Forming Machines

About Tube Forming Machines and Tube Forming Machine Manufacturers Including: Tube Bending Equipment, Tube End Forming Machines, Bending Machines, Swaging Machines & Tube Swaging Machines.

Tube forming machines include all machines that are used to perform various tube forming processes, such as tube end forming, bulge forming and bending. Tube forming is a secondary process of tube fabricating and is important to many different industries that use tubes and pipes, such as the automotive and aerospace, which require fuel lines, exhaust pipes and brake pipes. Because these tubes often need to be formed into complex shapes, the tube forming machines involved requires a high level of accuracy. Some examples of these tube forming machines are dedicated machines and automated manufacturing cells. Tube forming machine manufacturers can build dedicated machines that are built for a specific job and cannot accommodate design changes, leaving them with little to no value when the job is finished, or they manufacture automated manufacturing cells, which are able to combine the high production rates of dedicated machines with the versatility of CNC machines.
 
One type of tube forming performed by tube forming machines, tube end forming, can eliminate the need for a connector and will potentially cut production time in half. Beading, a versatile end-forming technique, is used to interconnect exhaust tubes or low-pressure fuel lines, dampen vibration in solid lines or increase the effectiveness of a seal. Tube flanging allows the joining of pipe sections without the need for costly welded flanges and is typically used in chemical plants, petroleum refineries, power plants and pipelines. Tubes that are squared, deburred or flared form liquid- and air-tight joints. These are commonly used in hydraulic systems and fuel lines in the aircraft, automotive and heating and cooling industries. Additionally, double-lap flares provide joints that are stronger and more resistant to fatigue and have a better seal than single-thickness flares. These tube endings are used in applications in which joints are subjected to shock, vibration or high internal pressure, and require the appropriate tube forming machine manufacturer to create the particular machine.
 
Another main process for tube forming machine manufacturers is tube bending, which involves creating an arc in a tube with a specified degree of bend (DOB). The appropriate method for the application is determined by several factors: outside diameter (O.D.), wall thickness, bending radius (typically measured from the centerline) and the material of the tube. The first three of these are the most important. Other factors include part configuration and required bend quality. The necessary bending data includes the DOB, distance between bends (length, feed or position) and plane of bend (twist, rotation or orientation).
 
CNC tube benders are widely used, self-sequencing tube forming machines into which data is entered to produce repeatable, complex geometric parts. The tube is fed into the machine by the operator, who then presses the start button and removes the part once it is finished. Automated part loading and unloading is available and can reduce the need for an operator and increase production rates. CNC machining provides maximum accuracy and repeatability, low labor input for production sequences, a high degree of control, quick change-over and versatility. Unfortunately, CNC tube forming machines require capital expenditure, computer familiarity and maintenance department aptitude stress. The tube forming machines may also require amounts of water, air and electrical power. However, after one project is completed, the CNC tube bender can be reprogrammed for other jobs.

Types of Tube Forming Machines

• Bending machines are CNC machines used to bend metal tubes.
  
• CNC machining is a type of machine used in the draw bending process that is quick, reliable, dependable, fast and flexible and produces precise, repeatable high quality bends. CNC machines are simple to set up and program and are capable of having a large quantity of specifications entered into the system to produce complex bending geometries.
  
• Hydroforming is a process in which fluid pressure is used to form the tube to the die, allowing for severe shape deformation. Hydroforming typically produces strong parts of uniform thickness.
  
• Swaging machines use high pressure to permanently join tubes.
  
• Threading is the process in which raised helical ribs are formed on the end of a tube. Threading can be accomplished by either keeping the tube stationary and rotating the machinery or by rotating the tube on stationary machinery.
  
• Tube bending involves using a variety of machines to bend the tube to preset specifications.
  
• Tube bending equipment includes all those machines used to bend, swag, and form tubes.
  
• Tube end forming is a process in which the end of a tube is formed to exacting specifications for a particular use.
  
• Tube end forming machines increase or decrease the diameter of a pipe at its end.
  
• Tube swaging machines use high pressure to connect tubes together at a permanent joint.

Tube Forming Machines Terms

Ampco – An aluminum-bronze wear surface used for mandrels and wiper dies for bending stainless steel, specifically.
 
Ball – A component of the mandrel assembly that supports the arc of the bend of a tube in order to keep it from flattening after it has passed through the point of bend.
 
Bend Data – A term that refers to the basic elements of motion that must be programmed into the controller of a CNC tube-bending machine in order for the tube to be bent.
 
Bend Die – Sometimes called the “bend form” or the “radius die,” it is the primary tool of a rotary-draw tube-bending machine, against which the tube is placed and drawn around to produce a bend.
 
Bend Radius – A general term referring to the arc of the bend itself but which does not precisely specify the radius. Bend radius can refer to the inside radius, the centerline radius or some arbitrary reference point, though it is typically measured from the centerline.
 
Bender – A mechanical device that is used to form a bend or arc in a straight length of material. Bender also refers to a company that performs this service.
 
“C” Style Tooling – A drop-in segmented tooling that has either a set of dies that only reduces or fingers that only expand.
 
Cold Drawing – A tube bending process that does not involve the use of heat. Cold drawing is used to obtain smooth surface finishes, reduce the wall and/or the outside diameter and achieve closer tolerances.
 
Crush Bending – A non-mandrel tube bending process in which the tube is stretched over a crush knob located in the cavity of the bend die, eliminating any wrinkling or buckling that may occur in the tube in the absence of a mandrel. Crush bending is typically used on non-round tube bends.

Degree of Bend (DOB) – Sometimes called the “angle,” it is the measurement of the degree to which the tube is bent. The minimum angle is about 5?.
 
Drop-in Style I/O Segmented Tooling – Six- or eight-segment dies and fingers in a housing, a self-contained barrel, which can be quickly and simply dropped into or removed from a machine to provide a quick changeover to another tool set. The dies are close on the outside of the tube, and the fingers are open on the inside of the tube.
 
“E” Style Tooling – Ram forming tooling that consists of clamping dies and ram tools. The clamping dies are used to hold the tube during the forming cycle.
 
Elongation – The increase of the length of a material during the bending process, expressed as a percentage of the initial length.

Hot Bending – Any tube forming process that uses heat.
 
Inside Diameter (I.D.) – The diameter of the inside of the tube.
 
Mandrel – A part of the tube-bending assembly that provides support to the inside of the tube in order to prevent the tube from buckling or necking.  A mandrel may not be necessary if the wall is thick enough.
 
Outside Diameter (O.D.) – The diameter of the outside of the tube.

Plug Drawing – A cold finishing operation that produces a precise outside diameter and wall tube. In plug drawing, the tube is drawn through a die over a plug.
 
Press Bending – An inexpensive and fast method of bending that is suitable only for applications in which tube walls are relatively heavy and centerline radii are large. Press bending produces reduced bend quality, because it is impossible to fixture mandrel tooling inside the tube or wiper tooling to control the flow of material.
 
Ram Bending – A process in which a tube is placed in a die and hydraulic ram. The ram, containing half of the dies, presses into the tube and pushes it around the radius.
 
Roll Bending – A quick and effective method of bending a tube by feeding it through a triangular arrangement of rollers. Roll bending forms extremely thick walls and large radii from the material that exceeds the capability of rotary draw benders.
 
Rotary Draw Bending – A principal method of tube bending in which the material is drawn around a rotating bend form or die. The forward tangent is rotated, while the back tangent is held in place by a pressure die, allowing for the use of mandrel and wiper tooling.
 
Sink Drawing – A cold finishing operation in which a tube is pulled through a die without using a mandrel. Sink drawing is used to obtain the exact desired diameter and/or to improve mechanical properties of the tube.
 
Sizing – Forming the end of the tube to meet preset specifications of roundness and concentricity.
 
Springback – The response of the tube after the stress of the bending process has been removed. Tubes can be bent over the specified DOB, so that they will open up to the desired degree or bend.
 
Tangent – The excess material on either end of the arc or bend of a tube that can be cut off after the bending process.

Tube Flaring – An end forming method in which the end is formed into a funnel shape so that it is able to be held by a threaded fitting.
 
Wall – The thickness of the tube or pipe wall, usually expressed as “nominal” or “minimum.”
 
Wiper Die – Also called “shoes,” it is used to prevent the wrinkling of the tube during the bending process. A wiper die is necessary when the resistance of the tube to compression is high.
 
Wrinkle – An unwanted fold, crease or ripple formed on the pipe surface during the bending process.