Roll tapping titanium

[machinedudester]

Does anyone have any experience roll tapping titanium. We have parts made from TiGALV4 and they are trying to roll tap them 9/16"-18 UNJ 3B and the titanium keeps sticking to the tap after the first hole and then the no go starts to go and the threads get rough. They used an oversized drill (.5394") and moly-dee and it became very hot. Any advise would be greatly appreciated, thanks.

[chris m]

Tap drill is definitely a little big so that's not a problem. A form tap that big is going to require some torque so I hope the machine has some sack, though that doesn't sound like the problem either here. We typically use OSG Exo-TAP [NOT HyPro] NRT form taps in tough materials.

[?Mark]

We've done well form tapping titanium with smaller size taps up to 10-32). Good brand of taps and heavy duty (rapid tap or similar) cutting fluid is the key. I think we tried balax and emuge taps with success.

[YoDoug®]

Ive never tried form tapping Ti with that large of a tap. Normally for one that big I would thread mill. I am not even sure that my Haas has the power to form tap a 9/16 in Ti.

[mcpgmr]

Thread milling Titanium as I type. 5/16-18 thread. If and when ever I can I thread mill Ti. It works great and the tool life is awesome. Never tried form tapping.

[Salt4cad]

I agree larger threads thread-mill nice clean thread and great thread depth control

[Ralph@Faustson]

Moly-Dee cutting fluid?.. I'd use way-lube or some kind of lubricant... NOT Cutting fluid.

[Guest CNC Apps Guy 1]

Threadmilling is DEFINITELY the way to go. Threadmilled 2-56 blind holes up to .210" deep. Singlepoint 10,000 RPM, 1.5 IPM, ONE pass. Works like a charm. I would never do it any other way.

[machinedudester]

Hey, thanks all for the information provided so far. This is an aerospace application & thus the tread call out is per AS 8879 "Controlled Root radius" Class 3B So no chance of cutting as MUCH as I'd like to go that route.

The machine we are using is the Haas VF3 4-axis CNC, 40”x20”x25”. I don't think Sack (as someone put it) is an issue Also we tried a steam oxide coated tap from Balax the first time which is a porous coating for holding coolant. Balax rep then suggested a ti-lax coating which was non porous on the second run. BOTH of which seemed to hold on to the Ti. Thanks for the lubrication suggestions also. Do you think I should be worried about heat as when forming? I can tell you it was a LOT without using coolant.

[Mike Whitten CAD/CAM Contractors]

As far as I know, the main deal with the AS 8879 is that you need a "controlled root radius" at the root of the external thread only. The only difference on the internal thread is that the minor dia must be increased to clear the modified root radius. It would be a good idea to just purchase the download of the current spec. I think it is available on sae.org. There is also a spec that I can't think of at this very minute that is used in Aerospace quite often that states that you can't use a Form tap. You may want to watch for that.

 

Mike

[GoetzInd]

Thread mill. At this point it would be cheaper. No buildup issues, pitch dia control and cleaner threads. I would be nervous in the service tappin that big in ti. Especially if it's an expensive part.

 

Mike

[Guest CNC Apps Guy 1]

You can actually control the thread form and size with a threadmill whereas with a tap (roll or cut) you cannot.

 

I still say threadmill REGARDLESS unless there is a specific prohibition on a cut thread.

[machinedudester]

Thanks again for all your input. I appears that we may have miss interpreted the print. It calls for a 9/16"-18 UNF MOD by 8879 because the insert that will mate with the hole is roll threaded UNJ.

[Metals and materials]

Sooo, I have to tap with M8x1.25 STI for helicoil inserts. I asked one of the dealer closer to my location and he suggested to use EXo-Form Tap from OSG.

OSG 1636000708                             We have Ridgid high performance thread cutting fluid. 

I have DMU from DMG Mori 5 axis machine. Should I try? or leave aside form taps at all and start looking only and only thread cutter options?

[JParis]

We rollform tap Ti Al6v4 all day, everyday....0-80 & 1-72

That big I would likely start with a peck tap and go from there..

[Metals and materials]

27 minutes ago, JParis said:

We rollform tap Ti Al6v4 all day, everyday....0-80 & 1-72

That big I would likely start with a peck tap and go from there.

Okay, thank you!!! Peck out all the way out, correct? to dissipate heat generated.

[JParis]

1 minute ago, Metals and materials said:

Okay, thank you!!! Peck out all the way out, correct? to dissipate heat generated.

We do it more to keep the pressure build up down....there are no chips, so it's really all about the heat & pressure.

[Leon82]

On 10/31/2023 at 12:22 PM, JParis said:

We rollform tap Ti Al6v4 all day, everyday....0-80 & 1-72

That big I would likely start with a peck tap and go from there..

What speed do you use. We want to try it on some 00-90 threads

[crazy^millman]

1 hour ago, Leon82 said:

What speed do you use. We want to try it on some 00-90 threads

Speed is one part of the equation. Synchronization of the spindle to the feed rate is the real issue. Need to think about using the Emuge Floating holder and that will make the process more successful. Ream the holes before roll tapping them to provide the most stable surface to allow the molecules the shape and preform needed to make this work. Drill is still be nature a ripping action into the Material and even a triple margin drill is nothing compared to a reamer at providing the base base surface for roll forming holes in any ferrous based material.

Link:

That said I might start at 2000 rpms with a G95 feed. That woulds be .0111 per revolution or 22.2222 ipm feed rate.

[JParis]

16 hours ago, Leon82 said:

What speed do you use. We want to try it on some 00-90 threads

0-80 & 1-72 both run at 800 rpms

 

[jpatry]

22 hours ago, crazy^millman said:

Need to think about using the Emuge Floating holder and that will make the process more successful. Ream the holes before roll tapping them

I like the idea of the reamer.

I'm still trying to convince the powers-that-be to buy at least a couple of those micro float tension-compression holders, but they still think putting taps in standard ER collets and holders is good enough.