How to tap 1000 2-56 holes in Aluminum?

[Karl V. Schuler]

solgood,
Sorry obout my ignorance, Ive never been around a macine that was capable of it.
Karl

[solgood]

Karl

No offence taken, we all work with dif. machines and dif. parts. We can all learn from each other, great to hear from you and all on the Zone.

This if for all you Machinists

Yes, we do have an extensive array of state of the art, high tech, computerized machinery, but as anyone who has ever cut chips will tell you, "the machine is only as good as the person behind the wheel!"

I wont take credit for the quote its from a good friend.

Chad

[psychomill]

Chad, Karl..... and others....

"Ignorance" is the first step in learning and understanding. Otherwise, we'd all be "know it alls" right?

I think some of these guys or gals are afraid of using there synchro tapping machines to there fullest

There's some truth to that. Many could debate on the affects of "high speed tapping" to a machine. I've heard everything from early wear on the guides (linear or box) to stretching out the ball screw. I've been rigid tapping from 3000 to 10000 rpms for many years. I've never seen either happen on hundreds of machines I've programmed. The only misfortunes I've seen from tapping is when some operator fat fingers a tool length or a Z depth, uses wrong sized drill, incorrect feed, etc.

Taps can and do break. Depends on your set up, material, coolant, quality of the drilled hole, tap type and speeds. In the case of aluminum, I've found that more speed is better. Powdered metal taps work well. The TiN coat does fine in aluminum. It's not as bad as say TiCN or something which works with heat. But I've used uncoated as well at those speeds.

Since 1000 holes is quite a "few", if you only have to do one plate, being somewhat "conservative" is probably wise. But in production, I say "hit the button..... its pucker time".

[Trapper14]

OMG 1/2-13 at 10k!!! Form or cutting? I would pay a dollar to see that!! I usually don't go over 500rpm lol call me a baby

[ajl6549]

Originally Posted by psychomill Many could debate on the affects of "high speed tapping" to a machine. I've heard everything from early wear on the guides (linear or box) to stretching out the ball screw.

I agree, I've never witnessed any abnormal wear etc. from sync. tapping and have been doing it for years. Since the feed and the spindle "ramp up" (and down) it's no different than anything else the machine does under normal conditions. Since we'er on the thrd. cutting thing, who all thrd. mills larger size thrd's? It's a viable opption where horspower is at a premium.

[kalmah]

Originally Posted by Driftwood Hello all... I need to tap about a thousand 2-56 holes in several aluminum parts, blind holes, 1/4" deep. I'm a little new to this all, so I wanted to run this by you all for a second opinion. I can't scrap any parts, so I can't break any taps. If that means going with a slightly less complete thread, then we'll take it. I planned on going with a roll form tap and drilling with a 2mm drill, catalog tells me that should still give me 60% thread. Maybe I should go bigger? As for speed, i was thinking around 600 rpm on my vertical machining centre with rigid tapping. Its an older machine, so I don't want to push it. Hows that sound? Any suggestions? Should I use tapping fluid? Thanks in advance...

Use thread mill. If a thread mill breaks, your can remove the broken part of tool without problem. The programmation is just a little bit more difficult.

[psychomill]

OMG 1/2-13 at 10k!!! Form or cutting? I would pay a dollar to see that!!

And worth every cent! Form or cutting.... I've done both.

It definately looks wicked. For the most part though, I don't program it to run at that speed. If the part only has 3 or 4 holes to tap, you don't gain much for a 1/2-13 at 10k. My only point is that there are machines that can do it. Keep in mind, the spindle has to synchronize and make the speed. Its a little different than just simply programming a G1 move to go 769.23 IPM. Many machines have the acceleration to make that feed in a very short distance of travel. But the same machine won't make it to top speed in the distance of a thread. However, if you program a 4-40 or 6-32 at that speed, now you might make a difference.

Also keep in mind of cutting forces, which brings up the next comment on thread milling. Many machines at a conservative speed, say a couple hundred RPMs can tap a 3/4-10 thread. But the same machine might not be be able to tap it at 2000 RPM. The momentary spike in force at tool entry make cause the spindle to overload. In these cases, thread milling is an option to pick up cycle time. I acually thread mill quite a few threads large and small diameter. My reason has more to do with dedicated tool magazine issues though and not horse power. But the taps I do have in the magazine all run at what most would consider "fast"....

[ajl6549]

We generaly don't thrd mill as a rule on production jobs. When we do it's because we have some thrd. size like 2.5" - 6" that is a one piece job and dosn't justify buing a new tap and holder when we can just thrd. mill it. I've used single point tools from the CNC lathes. We have to do this when we don't have the correct pitch thrd. insert. It's usually a slow deal in hard steel not as bad in iron or alum. though.

[kalmah]

Originally Posted by ajl6549 We generaly don't thrd mill as a rule on production jobs. When we do it's because we have some thrd. size like 2.5" - 6" that is a one piece job and dosn't justify buing a new tap and holder when we can just thrd. mill it. I've used single point tools from the CNC lathes. We have to do this when we don't have the correct pitch thrd. insert. It's usually a slow deal in hard steel not as bad in iron or alum. though.

I understand your opinion.
The tool path for threading is very long to programm. It's a pity that any CN don't have thread cycle.
I have a positive case when threading tool is better. A very expensive part with a lot holes to thread. It's impossible to have a tap broken in the part due to the cost. The workshop have a CAD/CAM and it's very easy to programm the threading of hole. If a thread mill breaks, you remove the broken part, you change the thread mill and you repeat your programm.

But if I should make a lot of part with few hole to thread, I would choose thread former. The advantage: The material around the thread is work-hardened and you don't loose time !!!!

[ajl6549]

Originally Posted by kalmah The tool path for threading is very long to programm.

It's not so long to program. It can be a lot of cutting if you single point thread with a lathe type tool (i.e. the lathe's tool is fairly fragile, not for intrupted cutting) but still cheeper for a one off run.