Update on Bird's Nest Annular Cutter Issue...

J

Joe AutoDrill 16 years ago

For context, these are two videos I posted back on May 21 that show a larger diameter annular cutter going through thicker steel plate and the resulting problems:

Check out this link for a 2" hole being drilled through a 3/4" piece of steel with the 5160-x series AutoDrill.

formatting link

We haven't quite solved the chip build-up issue yet given the different diameter holes that can be drilled, etc. See the problem here:

formatting link

The issue we have is that with a manual process, the "bird's nest" of chips is not a problem. However, when trying to do this with an automatic or self-feed drill like I provide, the chips just keep building up more and more.

Since some customers will automatically feed parts to the drilling machine (may up to 10 per minute for the worst case scenario), the problem quickly spirals (sorry for that) into quite a big mess that simply damages the surface of the part being drilled, could damage the bearing on the unit doing the drilling if they somehow got in, etc.

The solution is to remove the possibility of a bird's nest of chips somehow.

Some ideas provided were:

Chip breaker next to the tool Magnetic chip "grabber" or comb device Peck drilling to create non-spiral chips, etc.

We chose to try the peck drill idea. After receiving a link to this video from Garlicdude showing a much more sophisticated peck drill process:

formatting link

...we got inspired to build our own.

We built a potentiometer-adjustable peck control so that we could control the forward and reverse stroke from anywhere near zero time to 10 seconds time.

Setting it at it's most inefficient setting but the smallest chip worked for about 1/2" thickness of material. However, after the material got thicker and the pile of "chiplettes" got big enough, they acted like those old toys we played with as kids - the barrel of monkeys with interlocking arms. This setting was roughly equivalent to 1/2 or 3/4 rotation per peck. Like I said, really inefficient since the peck was also 1/2 to 3/4 rotation.

Eventually, the chips grabbed each other and made a ball that was simply tighter wound but more loosely attached. It would be removed manually easier after a shut down but still caused a significant issue.

...so we then tried to blow the chips off the work surface at a regular pace along with the pecking. That way, we figured the chips could not build up. Really inefficient use of compressed air, but it essentially worked.

...Of course, I now have "chiplettes" everywhere within a 50' radius of my test machine... Ptooey there...

So... Essentially, a fix is in the works and a video may be taken early next week for everyone's evaluation.

The peck will probably work in cooperation with an air blast chip evacuation system (or some other more complex set up like a mega-magnet, etc.)... We shall see.

P.s. New Facebook and Twitter links below too. :)

Regards, Joe Agro, Jr. (800) 871-5022

01.908.542.0244 Automatic / Pneumatic Drills:

formatting link

Spindle Drills:

formatting link

Tapping:

formatting link

Site:

formatting link

V8013-R

Vote

W

Winston 16 years ago

(...)

Shop vac rather than blowoff gun?

Yes, please.

--Winston

Vote

V

vinny 16 years ago

Chip break it AND peck drill it.

One line of code chip break drills to -.3, taking an incrimental .025chip break. When it's done it retracts to Z1. Throw in a dwell for 1 second... The next line of code drills to Z-.325. The next line of code drills to Z-.35. Throw in another 1 second dwell here. The next line of code chip break drills to z-.6. Add dwell line. The next line of code drills to Z-.625. The next line of code drills to z-.65. Add dwell line. Then it chip breaks again, drills, and dwells etc....etc...etc...

It'll 10-15 lines to drill that thing birdnest free, but its simple g code, just a break chip g code, a drill g code and a dwell g code. And obviously some carefully aimed external air and a shop vac behind it catching chips.

Vote

E

Existential Angst 16 years ago

Dude,

Very inneresting! Izzat you doing the demo? If so, shouldn't you have flexed your muscles for the camera?? :)

Q's: The first video didn't peck, yet had no bird's nest. The second video pecked, and did have a bird's nest. Why is that?

No coolant?? iirc, those annular cutters are effing expensive!

Also, I noticed that in the second video, altho the retract was fast, re-entry was slow, at the cutting feed. Can you re-enter as fast as you retract? That would greatly speed the cycle time where pecks are involved.

That plug ejection is nice! Did you have to modify the cutter/holder to be able to do that?

Where bird's nests can't be avoided, how bout a sacrificial piece of material on top, if cosmetics are an issue? Even cheap 1/8 paneling, or stiff cardboard, or .020 sheetmetal.

Just thinking out loud here, but what about this: Pre-drill a 1/4" hole, then shoot coolant UP through the hole from the bottom for the annular cutter, and the coolant would then be encapsulated by the annular cutter itself, while cutting.

Ostensibly a 2-step process, but might be worth it, and depending on how fancy your stuff gets, mebbe the drill could be part of the annular ditty (like a regular hole saw for wood), which could retract separately, allowing coolant for the annular cutting.

Even if a 2-step process, might pay for itself in increased feeds/speeds (cycle times), and tool life.

Garlic's MAM process was very inneresting, but it would seem that your first video sort of makes this moot.

Vote

J

Joe AutoDrill 16 years ago

Where's my car?

I think I'm the voice. I'll have to go back and check.

Didn't want to distract the viewers.:)

Again, I'll have to go back and view them again to confirm, but I think the first was an interupted cut - a cut that intersected a pre-existing hole so the chip was never 360 degrees worth.

Through the coolant oil drip.

Yes. We can. It's not a feature shown on that video though. Check out one of the "peck feed" videos here:

formatting link

No and yes. The cutter is stock, the holder is our custom spindle with a rod through to the back and a pressure plate on retract to help the spring if needed.

I'm thinking that the chip build-up is more critical as this is a structural steel hole saw drill thingy if eventually perfected.

I'll try to post a video about the integrated coolant that is already in place. Neat and very simple system.

Vote

Update on Bird's Nest Annular Cutter Issue...

Join the Discussion

Didn't find your answer?