Rolling process is recommended when threads are required with superior tensile, shear, and fatigue strength. Other processes like turning, milling and grinding remove material to produce the thread form, but thread rolling displaces the material with hardened steel dies. Rolling dies typically have a hardness between a range of RC 58-63 and there is a specific set of dies for each thread size and each thread form.
- Static tensile tests on parts formed through thread rolling show overall increases in strength of about 30 percent.
- Fatigue strength is improved by 50-75 percent.
- Tests on bolts first heat-treated to a hardness of 35-40 Rockwell C and subsequently rolled show even greater fatigue strength.
When parts are produced in larger quantities, single point threading’s versatility is less beneficial. This is because, in order to maximize effective tool life, single point inserts are processed with a limited depth of cut with multiple passes needed to cut to the thread’s full depth. The time needed to take these multiple passes can create a bottleneck. Additional passes may also be taken to deburr the thread, requiring more machine tool time or a secondary operation outside the machine. Although CNC is bringing down the total threading cycle times by making non cutting functions more efficient, these time savings are negated by the added time it takes to single point the thread. Thread rolling on the other hand, produces threads in one pass, reducing expensive CNC machining time.
In addition to doing more work on one machine in less time, thread rolling has many technical advantages over single point threading. Instead of cutting or shearing the material as is the case of single point threading, thread rolling cold forms the profile to be produced. In this process, the component material is stressed beyond its yield point, being deformed plastically, and thus permanently. A hardened die made from tool steel or HSS displaces the material along the contours of the thread profile, plastically deforming the material into the final form. The workpiece material is stressed beyond its yield point, which causes it to flow and conform to the mirror image of the die’s profile
High benefits of Thread rolling process are:
✓ Lower costs
✓ Increased production
✓ Faster lead times
✓ Superior quality and accuracy:
○ Stronger threads
○ Improved finish
○ More accurate profile
- Versatility – with the ability to do both infeed and thru-feed, a standard feature on most of our machines, you can form anything from a bolt or stud to a long-threaded bar.
- Simplicity – With most setups performed in less than ½ hour, our machines can be used for both production and custom thread or form rolling.
- Cost-effectiveness – The ability to tilt die spindles to the helix angle of thread lets our customers use lower-cost, annular ring dies.
- Productivity – Speed-up dies can increase work feed rate while keeping RPMs of the work piece constant. Helical slow feed dies can decrease work feed rate, thereby allowing material to flow and form at a slower pace – requiring less horsepower and pressure than needed for annular dies.
- Maintainability – easy to maintain and service due to simple design and high-quality components.
Our Profimach LOW COST line of thread rolling machines, convinces by an excellent price-performance-ratio, available from 5 ton up to 400 ton . There is more power on request. All models are equipped with PLC control and frequency converter (FU) for infinitive variable speed.
The universal composition of our thread rolling machines allows the application of the machine for all known processes of forming in in-feed or throughfeed. Highest production rates can be realized. Manual loading and unloading is comfortably supported by the generous working space.
The automation of this model range is always possible because of the open construction of the working space and makes the handling easy. This reduces drastically the takt time and simplifies loading and discharging of the work pieces.
High precise profile guiding rails lead to higher quality in through-feed or in-feed are guaranteed process. Thanks to short changeover times, all productions are guaranteed. All adjustments are easily done from the front of the machine.
West Europe :
Call +32 475.736.351 - Patrick (Nederlands, Français, English, Deutsch )
East Europe :
Call +40 722.346.170 - Cézar (English, Français, Română)
or call +40 755.088.805 - Catalin (English, Română)