Over 50,000 Threads with Thread Forming – What Really Matters
30,000 threads per tool had been projected. That was the expectation with which the customer started the application. Not an unrealistic figure, but rather a solid, cautious estimate. A practical case that shows quite clearly what really matters in thread forming.
In the end, the counter showed more than 50,000 produced threads.
That is neither an outlier nor a coincidence. It is the result of an application in which several things were simply done right.
The starting point: Classic series production in die-cast aluminum
The parts were produced in die-cast aluminum, more precisely in ADC12 alloy. A material that is often used in practice and is known for its good formability. With a maximum tensile strength of around 240 N/mm², it is one of the materials that is very well suited for thread forming.
A VÖLKEL thread forming tap (also called a fluteless tap) M6 with lubrication groove and TiCN coating was used (Item No. 90938). The thread length was 12 mm, which is about twice the nominal diameter. This already puts the process in a range where even small design errors become noticeable immediately.
Production was carried out on a CNC machine, with coolant lubricant and a cutting speed of around 20 m/min. So not an exotic setup, but a clean, practical standard application.
The decisive difference is not down to chance
The fact that more than 50,000 threads were achieved in the end, while a comparable tool reached around 30,000, can be explained quite clearly. It was not a single factor, but the interaction of several points that are often underestimated.
One example is the pilot hole diameter. In this case, it was selected exactly as recommended at 5.55 mm. That may sound trivial, but in thread forming it is one of the biggest levers of all. If the pilot hole is too small, the forming forces increase significantly and the tool wears much faster. If it is too large, thread quality suffers. Here, the coordination was right, and that has a direct impact on tool life.
Equally important is the decision to use a thread forming tap (also called a fluteless tap) with a lubrication groove. With a thread length of 12 mm, or about 2×D, it is no longer enough to supply lubricant only from the outside. The lubrication groove ensures that the coolant lubricant reaches the forming zone. This reduces friction, lowers the temperature, and noticeably relieves the load on the tool. Without this support, the achieved tool life would hardly have been possible in this form.
Coating and cooling must be considered together
Another point that is often underestimated is the interaction between coating and process control.
The thread forming tap used is TiCN-coated. This coating offers very good wear properties and reduces friction. At the same time, however, it has one clear weakness: high temperatures.
That is exactly why coolant lubricant was used consistently in this application. Not as an add-on, but as an integral part of the process. If a TiCN-coated tool gets too hot, the coating quickly loses its effectiveness. Tool life then does not decline gradually, but significantly.
In this case, the cooling was right, and so was the performance of the coating.
Speed and machine: Two factors that are often underestimated
The selected cutting speed of around 20 m/min also suits the process. In thread forming, higher speeds are possible than in conventional thread cutting, which not only increases productivity but also stabilizes material flow.
At the same time, the process ran on a CNC-controlled machine with precise tool guidance. That may sound obvious, but it is crucial. Thread forming involves high forces, and even small deviations in guidance lead to additional wear or, in the worst case, tool breakage.
Here, process stability was ensured, and that is reflected directly in the tool life.
What this application case really shows
When you look at the overall picture, it quickly becomes clear: the more than 50,000 threads are not a “best case,” but the result of a precisely coordinated application.
The material suits the process. The tool is selected correctly and designed correctly. The parameters are right. And the process conditions are maintained.
It is exactly this combination that creates the difference between solid tool life and truly high tool performance.
Conclusion: Tool life is predictable – if the details are right
The jump from 30,000 to more than 50,000 threads seems large at first glance. In practice, however, it is logically explainable.
Anyone who looks only at the tool when thread forming is leaving potential untapped. What matters is the interaction of material, pilot hole, lubrication, speed, and machine environment.
When these factors fit together, high tool life is not the exception, but what you can expect.
And this is exactly where we focus in practice: VÖLKEL’s application engineers take a close look at existing processes and help optimize the setup. Often, it is not major changes, but small adjustments that make a noticeable difference in tool life and process reliability.
If you want to get the maximum out of your process, take a closer look at your setup. Our application engineers will support you – practically and directly in your application.
FAQ: Thread forming in die-cast aluminum
How many threads are realistic in thread forming?
That depends heavily on the setup. In many applications, tool life is in the range of 20,000 to 40,000 threads. As the practical example shows, however, more than 50,000 threads per tool are also possible with optimally coordinated parameters.
Why is the pilot hole diameter so important in thread forming?
The pilot hole diameter has a direct influence on the forming forces. If it is too small, the load on the tool increases significantly and tool life drops sharply. If it is too large, the thread profile will not be formed cleanly. Following the recommendation is therefore crucial.
When should a thread forming tap with a lubrication groove be used?
As soon as the thread length reaches around 1.5×D or more, a thread forming tap with a lubrication groove makes sense. The lubrication groove ensures that the coolant lubricant reaches the forming zone in a targeted way, thereby reducing friction and wear.
What role does cooling play with TiCN-coated tools?
TiCN coatings are wear-resistant, but they are sensitive to high temperatures. Without sufficient cooling, the coating quickly loses its effectiveness. The use of coolant lubricant is therefore crucial for tool life.
Is thread forming faster than thread cutting?
In many cases, yes. Thread forming generally allows higher cutting speeds, which reduces machining time and can also ensure a more stable process.
Why does the thread sometimes tear out during forming?
This is often caused by a pilot hole diameter that is too small or by an unsuitable material. Missing lubrication or excessively high forming forces can also cause the material not to be displaced cleanly, but to become damaged instead.
Why are the torque values too high in thread forming?
Excessively high torque values are usually caused by an incorrect setup. Typical causes are a pilot hole diameter that is too small, insufficient lubrication, or a cutting speed that is too low. In many cases, the forces can be significantly reduced through small adjustments.
