Although the coupling sleeve is a relatively small component, a great deal depends on its faultless performance. These sleeve or tool joints are used to precision-join the casings and delivery pipes with a perfect screw fit, providing an absolutely leak-proof and durable connection of the highest precision while bearing the weight and considerable flexural stresses of the pipes. Production errors or large tolerances on the coupling sleeve can endanger the whole resource delivery process. With this in mind, the main focus is on efficient mass production techniques, with the key question being how an extremely high quality of the production process for coupling sleeves can be guaranteed, especially when the job calls for a single production facility to manufacture millions of these components each year?
An intelligent concept provides a competitive edge
The specialists at EMAG Leipzig Maschinenfabrik provide a very precise answer to this question. The company has specialized in the machining of oilfield components – such as coupling sleeves, tool joints and rock bit cones, as well as casings and delivery pipes – for decades. But it is the production of coupling sleeves in particular that shows how demanding this sector can be, as it covers a multitude of processes from the actual threading operation to the cleaning process and from visual inspections to the final plating operation. The component also features a marking that details the component data (i.e. charge, material, manufacturer, machine, cycle time). This multi-layered production process benefits greatly from the intelligent EMAG machine concept, where process integrity and precision are as good as built-in.
The pick-up principle scores highly
Coupling sleeve production lines mainly use machines from the VSC and VLC series. They are equipped with a pick-up spindle that not only collects the workpiece from the incoming conveyor belt, but firmly holds it vertically while it is complete-machined in the tooling zone. This is of particular advantage where large quantities of these sleeves are to be machined, as Dieter Fischer, Managing Director of EMAG Leipzig, explains: “The component can be produced in a much shorter time, as the various processes are carried out one after the other in cycle times counted in seconds. These processes do not only cover machining, but also additional operations such as cleaning or measuring.” When it comes to the mass production of coupling sleeves in particular, the time savings add up to a considerable competitive advantage for the user, as shorter machine runtimes lead to a massive reduction in component costs.
High processing quality included
In addition to the other advantages, the process chain also guarantees a consistently high component quality. For one, all machining processes are fully automated, circumventing errors that occur when using an unnecessarily large number of workhandling processes. The vertical machining concept also provides for optimal chip flow conditions, preventing the build-up of chips in the machining area, which can interrupt the production process.
Another important focus of the machine builders in Leipzig is the flexibility of their machines. The different frame sizes of the VSC and VLC series machines allow for the complete-machining of coupling sleeves of a multitude of diameters; the VSC 400 has a capacity of 2 ⅜“ to 9 ⅝” and the VLC 800 one of 7” to 24”. Furthermore, the machines are capable of cutting all types of threads, a factor of great importance when it comes to the oilfield industry, as Mr. Fischer explains: “It is, of course, possible to machine coupling sleeves with threads to API and GOST standards, but proprietary threads can also be generated. Larger oilfield technology producers have their own thread standards. We can equip our machines to perfectly suit these requirements.”
Market development opens up new opportunities
The machine builders in Leipzig view the future with great optimism. Already market leaders in machines for the threading of coupling sleeves and the machining of other oilfield technology components and given the dynamic development within the oil industry, there are new opportunities opening up, as Mr. Fischer points out: “When large sub-suppliers want to expand their production capacity, our technology is their first choice. The production processes are very compact, yet flexible and fast. Component costs are reduced. And we offer a global, all-in service. These are all advantages that, in our opinion, will be welcome in this market place.”