Drilling .02" holes for vacuum tool

[Sandybar]

Help I'm pulling my hair out trying to drill .02" holes and breaking many drills for a aluminun vacuum forming tool. All vacuum holes are pre-drill with a #30 drill (.1285). then I drill the .02 hole .05 deep inside the #30 drill hole. Some of the pre-drill holes are as much as 2.125" deep. Using a .02" drill soldered on a 1/8" shank drilling @ 10,000 RPM 2.0" FPM .005 pecking cycle. I even centered drill all holes after predrilling them. I have approx. 320 hole to do and I can get about 20 holes done before I break one.

 

How does the rest of the industry do this?

 

Thanks

[Gary]

can you drill it in like 2 pecs? I think runout is giving you the most trouble. I would run about .7 ipm feed and one pec to start.

[Sandybar]

Let me see if I got this right. Make it two pecks at .025 each peck to complete the .05 total?

[Slixmix]

The 1st shop I worked at used These drills in aluminum all day. High RPM, short pecks!

[Carl Anderson]

+1 for the Tulon PCB drills. These drills are stronger than you might think and can take .0005-.001 chip load with a .002-.005 peck in alum.

[Rick Henrickson The Boeing Co.]

sphinx drills come on 1mm shanks very good drills

[Gary]

I have had bsd luck with chips falling into the hole is why I try to keep the pecks small on small dia drill and short depths. Chips fall under drill tip and spin with the drill not allowing it to cut. Small drills deflect very easy and bust. If you can get rid of the chips for sure then short pecs are safest. A chip break cycle might be just the ticket.

[Psychomill]

quote:

---

Some of the pre-drill holes are as much as 2.125" deep.

---

 

I don't think anybody makes a .02 drill to go that deep to finish. You'd have to have one custom built. Even a carbide micro drill would have some trouble. Are the holes thru holes? Can you flip it over and drill from the other side?

 

If not, you could give these a shot too... Whitney Mini Drill extensions. These run pretty true and are only 1/8 OD shank.

 

[Rick Henrickson The Boeing Co.]

Gary is right if you are using a peck drill cycle you will have to adjust your retract and return parameters to keep chips out

[Bruce Kanzelmeyer]

We've had good luck w/.025" taper drills from Michigan Drills for vac holes in alum. Create your points on the tool surface and cut from bottom of tool first with larger drill, peck .06-.1", peck clearance .02, depth of say +.06"(incremental). Don't forget to uncheck tip compensation. Then copy that operation for vac holes and change to smaller drill, peck .02" w .01" peck clearance, depth (incremental) of say -.02" to -.03". Your top of stock becomes (incremental) .06" and retract (incremental) .1" We use flood coolant and spindle at 8000-10000 RPM, drill feed is 10 ipm, retract can be rapid. I've cut tools with over 200 holes with this setup with good results. Make sure your collet is good and don't overtighten. Good luck.

[Matthew]

Maybe you could add a secondary drilling operation. The first operation would drill all holes as deep as you can with no pecking (maybe you can get .020-.040". The second operation would use a retract height to keep the drill in the hole. This might stop the chips from falling into the hole when the drill retracts.

[Keith Graydon]

make sure that your extended .02 drill has

MINIMUM run-out. .0002 - .0003 MAX! Try drilling with no peck cycle. 2 1/2 depth to diameter is not that much.

 

-Keith

[Kevangel]

I have also found brushing something like "alumni-cut" fluid can help reduce the Alum. trying to seize to the small drills or tap, but it "stinks" etc. (I use a small acid brush)

[Sandybar]

Thanks for the input. I will try to give it a bigger peck cycle and try to keep the chips from getting back into the holes.

 

 

Somtimes I break the tool completly off and others the tip is broken. What is the cause of each?

[Jack Neelands™]

Im not sure if you have tried this but we had a whole lot of success with an insert vent that we made out of ali and had wire cut ...we broke drills constantly with the cast vacume moulds at 1 inch thick so we ended up drilling and reaming 1/8th holes or 1/4 holes when needed and inserted our vents ...In a sideskirt mould for a car your looking at something like almost a thousand holes...so we considered that expence and had someone tied up for like a week wirecutting 10,000 of these and wow....you pound it in and machine or grind to suit ...no more broken drills or downtime

[Jack Neelands™]

you can just drill the holes in the insert as well...sorry forgot to add that little tidbit

[Kevangel]

quote:

---

Here's mine. Hope to start construction this year.

 

---

aluminum loves to "seize" to cutting tools (galled)

[Kannon]

Kevangel,

you wouldnt have happened to be visiting the off topic "show us you dreamhome" thread were you?

[John Summers]

How about a porous surface? No holes at all.

[Kevangel]

quote:

---

Kevangel,

you wouldnt have happened to be visiting the off topic "show us you dreamhome" thread were you?

 

---

gotta be more careful, but to add I would not use water based coolants to do those small holes, but rather aluminum tap magic or something, JM2Cents.( I might take a aluminum block and do some R&D test drilling first and try to solve, like diff. fluids, drills and if lower RPM might help or watch visually what is happening by not being hidden down in a c-bore.)

[Mark V.]

[How about a porous surface? No holes at all.]

 

We have used metapor aluminum here and you dont need any holes.Worked real good but kinda pricey.

[Jack Neelands™]

we did try an epoxy as well and had to build a kiln for it to cure in .... but sadly the corners would not fill properly when we tried to draw the sheet over 8 inches deep ..internally we couldnt keep the heat even throughout the mould due to variations in the thickness so we went with ali cast and solid billets

[edmBosto]

One Can hole blast the .020 holes with a brass electrode they even have flush down the middle

We purchase these 12" in length.

I can blast thru a 1" thick piece in about 2 minutes.

Maybe your company doesn't have the machine I speak of but it's quick. We use to create small start holes for our wire machines.

Just a thought.

[edmBosto]

Sorry about that last reply as it seems the holes you need are not thru holes.

I was pertaining to that.

[edmBosto]

Sorry about that last reply as it seems the holes you need are not thru holes.

I was pertaining to that.