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Thread rolling: what is it?

Thread rolling uses cold forming to create the deformation of a workpiece under the force of the two rolling tools in motion. This technique is one of many precision parts machining processes. The specialist in precision threading, SMEPI ensures the manufacturing on plans of your parts to be machined in small, medium or large series.

Advantages offered by the rolling process

Roll Threading is also known as Roll Threading. By the deformation of a workpiece, a thread is created under the force exerted by the two moving rolling tools (rotary presses). As the profiles of the rolling tool penetrate the surface of the workpiece, the material is pushed to the base of the threading tools until the nominal dimension is obtained.

To have knurling or threading, there are two categories of techniques: by deformation: rolling without chips; it brings several advantages and by removing material with chips.

As it does not generate chips, the saving in material is one of the first advantages of the cold rolling process. In addition, it increases the mechanical resistance (breaking strength and fatigue resistance) of the thread and work hardening of the part (increase in surface hardness) thanks to maximum compression during deformation. An excellent quality of the surface finish is also obtained although the machining time is reduced.

The use of specific tools - the knurls - is essential for cold rolling. The knurling wheels consist of cylinders made of a very hard metal and having a profile similar to that of the workpiece. When the two wheels approach the part, the latter is driven in a rotational movement at speeds varying from 1 to 60 revolutions / minute. The material fibers are then deformed and the latter matches the shape of the knurling wheels. Besides the absence of chips, one of the great advantages of cold rolling is that it improves the mechanical characteristics but also the surface condition of the part. Subsequently, the resistance to oxidation is found to be reinforced and the mechanical friction reduced. Likewise, the cold rolling process offers an excellent degree of roughness on the sides of the thread and on the radius at the root of the thread.

Cold rolling allows parts of long lengths to be threaded. To do this, we proceed to the sideboard system. On the other hand, if we want to obtain a very precise result, the plunging process is used, the length of the part is in this case less than that of the tool.


Note, however, that thread rolling is only suitable for materials with a hardness less than 1200 MPa and an elongation exceeding 5%. It is most often made with steel (stainless, case-hardened and carbon) and with bronze, copper and brass. Other parameters must also be taken into account before proceeding with the taxiing. These include, among other things, the state of the material and the roller burnishing, stretching or straightening operations to which it has been subjected.

It should also be noted that aluminum alloys, titanium and inconel do not quite lend themselves to this cold deformation technique.


SMEPI, the rolled thread specialist

Endowed with recognized know-how in precision industrial mechanics, our company produces your components including rolled threads by ensuring all stages of manufacture: studies and definition of specifications, production of prototypes, supply of raw materials, production of parts in medium or small series, assembly of mechanical assemblies or sub-assemblies and surface treatments.

We can of course work on different materials such as alloy steels, stainless steels and bronze.

To ensure the quality and performance of the parts produced, we carry out the checks ourselves. These are thus subjected to proof and impact loads, to mechanical tests, and if necessary, to non-destructive tests (magnetic particle inspection, ultrasound, etc.).

We don't just manufacture your parts and deliver them on time. Anxious to meet your expectations, we can adapt our production rate to the requirements of your activity. Deliveries will then be made progressively, which makes it possible to set up a programmed management of your stock. In addition, it is possible to make spare parts without delay to help you out.


SMEPI, a benchmark company in the machining of precision mechanical parts

In the precision machining sector, we are capitalizing on more than ten years of experience, we have succeeded in building an enviable reputation in the four corners of France. For the machining of mechanical parts, whatever their size or format, SMEPI is the essential service provider able to fine-tune your parts. Our achievements are intended for professionals belonging to different trades, in particular: energy, petrochemicals, special machines, chemistry, nuclear power, transport, etc. Our machining company employs a highly qualified team and has a large stock of raw materials in order to meet your quality and deadline requirements. SMEPI guarantees you a complete service including: study, prototyping, assembly, machining, selection of materials to be used, heat and surface treatment ... and finally, a rigorous control of your parts.

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