Thread rolling DIES 2

[personXY]

Hi
I have a general, theoretical, questions for thread rolling dies. Only thread rolling, NO cutting.

I would like to know what is, from theory point of view, hardness of material (steel) of dies for thread rolling? I have found information that hardness should be maximum 32 HRC but this data isn't useful because lower limit is missing.
I called some company in our country who works with dies and they said, their hardness of die material is 64 HRC. I don't know how is this possible. I know this pretty much depends on many factor but I in general, what are the hardness of die materials? I need the actual range so minimum and maximum number within the hardness should be and not just, as I mentoined, "maximum 32 HRC". This data has lack of information.
I don't have any technical drawings and I won't use the answer, for which I want to please for, near any machine because Im not producing any article. Its just for understanding the theory. So I will repeat the question: What is the range of hardness (in HRC) for die material?

Besides this, I would like to know also the suggested dimensions for those dies. Specially Im interested about diameter of thread on dies. But also length and width would be nice to know. Again, I know it depends on some factors but from theory point of view, what are those thread diameters? Do they depend (probably yes) on size (if so, which dimension?) of workpiece?

If any of those two question also depends on which type of articles do I talk about, then: bolts.

Thank you.

 

[TVP]

The suggested limit of 32 HRC maximum is for the workpiece (also called the blank). However, high strength fasteners for aerospace and other applications are rolled onto workpieces with even higher hardness, in the range of 50-52 HRC, but with much reduced tool life.

The dies that form the threads onto the workpiece are made out of tool steels that are hardened to ~ 57-64 HRC. The following are some links to good technical information about the process, including details about the workpieces and tools:

PTG Thread Rolling Tools

http://www.ptgtools.com/Userfiles/reed_rico_EN.pdf

Thread Rolling Machine Fundamentals

http://www.pmpa.org/resource/mbr_services/2006_summary/09-ThreadClass2of5.pdf

Central Rolled Thread article

http://www.centralrtd.com/images/Dies_Last_Longer.PDF

Fette Rolling Systems

http://www.lmtfettetools.com/catalo...ads/2023 Rollkopfkatalog deutsch englisch.pdf

Thread Rolling Technical Papers (lower left corner)

http://www.landisthreading.com/ThreadRolling/

How It Works – Precision Thread Rolling

http://www.todaysmachiningworld.com/how-it-works-–-precision-thread-rolling/

Thread Rolling Comparison Between Technologies

http://www.videx-machine.com/Videx1...ular die; Comparison between technologies.pdf

 

[personXY]

Thank you TVP. Are there any suggested toughness for both materials, workpiece's (bolt) and die's, too? Sure there is two different types of toughness but since we are talking about thread rolling dies, its probably fracturing toughness and not "punching" toughness, right?

 

[MikeHalloran]

What problem are you trying to solve?


Mike Halloran
Pembroke Pines, FL, USA

 

[MikeHalloran]

TVP probably gave up on you for responding to valuable suggestions with a tangential question that seems irrelevant.

Why would you flag your first question as 'theoretical' when you are trying to solve a 'production' problem?

What specific 'production rates' problem are you trying to solve?

What are you producing? At what rate? Using what raw material and what equipment? What part of the process is unsatisfactory, and in what way?





Mike Halloran
Pembroke Pines, FL, USA

 

[personXY]

For unknown reasons, I am a bit sceptical if the following numbers are approximately correct and I would like to ask if anyone can take a look at them and let me know if they are approximately correct or not. Also I have some questions near few numbers for production rates:

Movements of cylindrical die:

RADIAL:

90 threads per minute <----- but for which diameter of workpiece (mark *

for the same questions belows)

AXIAL:

between 20 and 280 threads per minute <----- *

between 20 and 450 threads per minute <----- *

between 25 and 300 threads per minute <----- *

TANGENCIAL:

??, please someone add the data (included time interval & *)

PLANETARY:

between 450 and 2000 threads per minute <----- *

between 250 and 1200 threads per minute <----- *

between 100 and 400 threads per minute <----- *

INTERNAL THREAD:

between 50 and 1000 threads per ??? <----- per what? minutes? + *

Another short question: Is the data that FLAT (!!) die can do thread rolling approximately 10000 to 36000 per hour (workpieces with diameter up to 9,4mm) and 3000 to 12000 per hour (workpieces with diameter between 9,5mm to 13mm) correct?

I think it would be the the fastest if someone just quote and edits my text.

 

[MikeHalloran]

Corn flakes.



Mike Halloran
Pembroke Pines, FL, USA

 

[personXY]

what do you mean? I don't eat corn flakes. I like some other milk food but not corn flakes.

 

[MikeHalloran]

My response made exactly as much sense as did yours.


Mike Halloran
Pembroke Pines, FL, USA

 

[personXY]

Hmm no idea what you mean. However I see you don't know the answer so its two of us already.