O/T Deep Hole Drilling

[chad fisher]

We are faced with drilling 1/8 dia. holes 5" deep in a plastic/polymer called Torlon and another that is called Vesbel and these are extremely expensive. The problem is walking of the drill, we have to reduce the shanks because the Vesbel will shrink around the drill. I am wondering about how a high pressure thru the tool coolant system might work in drilling these. Then finding a company to make the tools for us. We have tried some differnt tip configurations and the best we can muster is a rpm of 700 to 1000 and a feed of .5 or less with .01 pecks. Slow i know but we are having only about 70% success with this.

Any experience on this would greatly be appreaciated..........Thanks

[Rekd™]

chad, most plastics will shrink when drilling. BTW, it's calle VesPel, and it's very expensive, but not bad to work with.

 

Try a .128 drill instead of .125. Also, try 135° drill point instead of 118°, or better yet, a hole popper if it will work in plastics.

 

'Rekd

[chip]

Core Pin......... J/K

 

 

That's a tough one.

[chad fisher]

Rekd

 

Our problem isnt in hole size it is the drill walking off. We have found that if we gring the drill tip in a "bradpoint tip" it stays somewhat strait. What fits in these holes is a electric .120 dia. heater rod. The hole is .050 from an edge, if it walks in theres no problem it is when it walks out when we have a major problem. 135 and 118 tip angles walk severely. The vespel isnt as bad as the torlon. All said done these parts have around 10k in work and material when there delivered. I am dumb but whats a hole popper

[crazy^millman]

I would think that I am correct in that you tried the titex drills wit hthe parabolic drill relief. I would gues that I am also correct in that you start with a screw drill then go to a jobber then go to a 3 different legnth drill to get the maxium effective straightness out of the drills. It may seem like alot but I would think you could fly on the frist 2 drill to make up for tool change time.

 

Crazy Millman

[mayday]

quote:

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I am dumb but whats a hole popper

---

maybe what he meant was jalapeño popper

 

these have been known to burn holes rather than drill. I personally would steer clear of this process

[Rekd™]

Chad, what peck are you using? Feed? Try pre-drilling .12 x 1" deep with a short drill, then finish with the 1/8, peck about .01 to .02, feed < 10ipm or so.

 

'Rekd

[Guest CNC Apps Guy 1]

I've cut a boatload of Torlon in my life and the best way I've found is to use solid carbide diamond coated drills. That stuff is NASTY.

 

HTH

[chad fisher]

Duh..........Ding Ding, i guess if you would said hole burner i would of got is as a edm drill

 

We are step drilling with a cobalt reg lenght to 1"

then going in with the longer drill. Pecking @.01 rpm at around 700 to 1000 and feed of .5 anything more and drill walks worse.

Funny thing is when i first started these a while ago, boss game me this material and I thought to myself piece of plastic huh! No problem Ill run it at 1500 or so and 5ipm. WRONG! Banana's are more strait than that of the hole i got. Live and learn i guess.

[chip]

(*thought*)How about drill undersize half way, flip the part, meet the hole from the other side. then drill to size...........I'm not good with production, just a thought!

[MATT Q]

ahh plastic the ever changing materials you have to love inconsistancy

[Kevangel]

Could they be gundrilled?, that will drill long absurdly deep holes on location, also the thing about using carbide drills as deep as possible is, they do not deflect and walk(more prone to breakage,but you are doing plastic)...I wonder if plastic is building up around drill tip? I know the BIG SECRET to drilling holes "to size and location" is a properly sharpened drill-PERIOD..good luck!

[Surface]

I had a similar problem drilling .02 holes x .625 deep in nylon rod. When the rod is extruded, it also twists and it was the grain of the material which caused the drills to walk-off.

My solution was to use sheet stock instead of rod. The material's grain ran perpendicular to the drill, and the holes drilled fine.

Yours would be some thick sheet, but just something to keep in the back of your mind.

[Kevangel]

To also add; you can gundrill rectangles and wondered if you tried drilling at slower rpm like 250 to eliminate any melting action.

[mike_f]

I'm not sure about the plastic but when I need to drill deep small dia. holes and keep them straight I use aircraft extension drills.

I'm pretty sure you can't hole pop a material that doesn't conduct electricity.

good luck

 

m.