Precision Tubes

High-precision deep drawing for seamless tubes

Seamless tubes are made from metal blanks in multiple deformation processes. They can be used for different industrial purposes and the manufacturing of metal bellows.

Metal sleeves (metal cups) and seamless tubes are intermediate products in the manufacturing process of formed bellows, corrugated tubes or expansion joints but also find application in many other fields, such as deep-water sensor housings or closed end stainless steel casings for vape devices (electronic cigarettes). The production of a seamless tube starts with a metal strip that undergoes a sheet metal forming process known as “deep drawing”. A piece of metal is considered deep-drawn when its depth exceeds its diameter. Depending on the used material and the designated final size of the tube, it has to be redrawn through multiple dies with decreasing diameter. After each plastic deformation process, the thin-walled seamless tubes have to be annealed to restore the elasticity of the material. Without annealing the material in vacuum furnaces, it would not be possible to continue processing the now very hard material. Using either soap or oil as lubricant requires special washing machines in order to achieving an immaculate surface. In the case of seamless stainless steel tubing, our customers benefit of efficient multi-drawing technologies.

Advantages of seamless thin walled tubes

We are specialized in manufacturing seamless tubes with extremely thin wall-thickness. If the tube has to be welded in an automatized assembly process on customer side, a consistent dimensional accuracy of the cups (tubes) wall is needed to guarantee a leak-free welding line with the “weld-end” As an experienced precision bellows manufacturer, we are able to hold such very low tolerances, ensuring max. 0,1-0,4mm tolerance in diameter and 0,004- to 0,015mm in wall-thickness, depending on design. The hydraulic presses allow maximum production lengths of up to 450mm and diameters of ca. 70mm. The closed bottom of our seamless cups and tubes can be designed in customized shapes and also the open side may be formed to meet individual requirements. It is furthermore possible to stamp holes in the closed bottom end – for example in the case of stainless steel cups (bonnets) for measurement and controlling devices. Because of their versatility, deep-drawn metal sleeves (cups) and tubes are used in many industries.

Precision tubes for demanding technical requirements

While it is often difficult to distinguish a welded- from a seamless tube with the bare eye, there are some significant differences that matter when it comes to ultra-precise applications. Welded tubes are produced from a roll formed metal strip. The welding process results in an inhomogeneous tube wall that has to be reworked first. Due to different working standards, the quality of the weld area can show great variances in the final product, resulting in a lesser reputation for welded tubes compared to seamless deep drawn tubing. Since seamless tubes are intermediate products in our manufacturing of metal bellows, we do only provide results in a smooth and homogeneous surface. Our seamless precision bellows are key components in highly sensitive systems. Their spring rate must exactly meet the requirements, e.g. for actuators and sensors in cars and aircrafts around the world.