Drilling Protection 1

[Atarek]

Hi everyone,

I have a design challenge here, and i hope someone can help me,
I need to develop a mechanical solution that provide drilling protection of an enclosure,
knowing that i have a constraints in the thickness of the material, to be 2mm max.

I suggested to increase the hardness of a steel enclosure, but i'm not sure,
Is there any method that will assure that not drill will be able to penetrate any further, maybe some kind of trap that will hold the motor from rotating,

Thanks in advance,
ATarek

 

[1gibson]

Like a drill bit collar?

 

[Atarek]

Hi 1gibson,

thank you for your answer,
I mean protection against drilling, drilling proof,

Thanks in advance,
Atarek

 

[btrueblood]

"I need to develop a mechanical solution that provide drilling protection of an enclosure"

Like a safe? They use high-hardness steel, but even that can be drilled with the right tools. At least one type of drill-proof safe door uses a glass plate behind the steel, such that if the glass is broken, it releases a catch that prevents opening of the door...but that still doesn't prevent something penetrating the door.

 

[MintJulep]

Hard material.

 

[racookpe1978]

Try a double or triple layer of thinner metal, between the (hardened, high strength) steel layers put a cloth weave of somewhat loose but strong material like refrasil cloth (fire proof, multi-layers cloth).

When the thief (???????) tries to drill through the wall, he can drill through the outside, but the cloth weave traps the spinning drill bit and jams it before it can cut through the second or third layer.

 

[bobjustbob]

I had a similar discussion with another engineer that I worked with at a foundry. It originally came up when discussing armor but transformed into making a gun safe. Burn-on sand is tough to remove off of the surface of a casting. It really tears up grinding wheels. It is also difficult to burn through with a torch. Our thought was to pour panels onto a poorly bound and packed sand core. The metal would encapsulate the sand grains after burning away the binder. I'm not saying it would be impossible to drill through, but you had better have plenty of bits. We were mostly wasting time so I have not though through how it could be heat treated or processed after pouring the panels.

 

[IRstuff]

2 mm is not much to work with. You could possibly use diamond like coatings (DLCs) or embedded diamonds or sapphires or even quartz. One time we attempted to drill through a wall in our dorm for an antenna feed. It was ostensibly normal concrete, but it apparently had quartz as part of the aggregate. It took us about 5 hrs to drill through 8 inches of concrete and we went through probably at least 6 drill bits.

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[Atarek]

Thank you everyone for all the replies
About the DLC coating, How much does it cost (rough estimation), and if you know a lab or an entity that can provide me with the service of coating samples, for testing purposes,

Thanks in advance,

 

[WKTaylor]

IF this is a one-time need... such-as during installation... a piece of harden CRES or steel shim-stock [0.002 or 0.003 thick, deburred] can be inserted between layers to prevent drill-tip penetration into your critical assy.... then it is retracted.

Caution.
Drill-tip angles are a pain: the flatter the drill-tip geometry, then the better the desired hole-quality will be [IE minimal tapered-shoulder-ring at base of the hole]. However: we would always go-back and 'smooth-down' [drill-thru, deburr, chamfer] the 'ring' left on the end of the hole.

Another approach...
In aerospace we often use 'spot-faces' with precision 'depth-stop' to 'drill-out' spot-welds in the top-layer of an Assy... leaving underlying layers [skins, stringers or doublers, etc] fully-intact. However... we always go-back and 'smooth-down' any 'stubble/flash' left on the underlying layer surface.



Regards, Wil Taylor

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[kingnero]

Manganese steels are very hard to drill. Due to coldworking/workhardening.

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