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shafeeqah
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Machining

02/08/2012 10:35 AM

How would you go about machining a 20mm hole in a flat piece of metal...the hole must have a very good finish...

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PWSlack
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#1

Re: machining

02/08/2012 10:39 AM

Oh, no. It's "20 Questions" time again!

<sigh>

  • How thick?
  • Which metal?
  • <...very good finish...> Please define.
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shafeeqah
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#2
In reply to #1

Re: machining

02/08/2012 10:44 AM

Sorry for offending you I am new at this still a student...I wasn't told how thick the metal is or anything else...the info I've written above is the only info I was given

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dgibson
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#3

Re: Machining

02/08/2012 1:14 PM

The information induces more questions than answers.

Depending on the thickness of the material, tolerance on the hole size, hardness of the material and exact finish specifications you could try the following:

  • Drill the hole undersized and ream. This provides a pretty good finish if all of the parameters of the machine are set correctly and you provide plenty of coolant.
  • Drill the hole undersized and bore using a boring head. A lot is dependent on how the boring bar is prepared.
  • Drill the hole undersized and use an end mill with circular interpolation on a cnc machining center.
  • Drill the hole undersized then take to a jig grinder and grind the hole. This will provide the best size control and finish if you are skilled enough to use one.
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shafeeqah
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#4
In reply to #3

Re: Machining

02/08/2012 1:38 PM

Thank you for that...I know I wasn't given all the information but I just took a chance...thanks again for helping me you a star

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WJMFIRE
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#5

Re: Machining

02/08/2012 1:53 PM

In most cases the cleanest hole is obtained by punching the metal.

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shafeeqah
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#6
In reply to #5

Re: Machining

02/08/2012 2:00 PM

Wouldn't reaming be the best method?...if we use the reaming method the holes will be accurate insize and have a fine finish...

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WJMFIRE
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#11
In reply to #6

Re: Machining

02/09/2012 7:52 PM

You might be surprised. A high speed punch will deliver an almost perfect hole with no finishing required. Also, (as the OP didn't specify) try drilling and reaming a square hole.

Punching has limits when it comes to type and thickness of metals (again not specified). It is best for multiple iteration machining in sheet and small thickness plate metal.

Thicker bar stock or plate would be better drilled and reamed, albeit time consuming.

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SolarEagle
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#7

Re: Machining

02/08/2012 3:01 PM

If it was just one, I would use a drill press...Smooth the edges with sand cloth or fine mini-file as needed...

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lyn
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#8

Re: Machining

02/08/2012 7:51 PM

Drill and ream.
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ozzb
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#9

Re: Machining

02/09/2012 7:19 AM

Too many holes in the question.

Specs on tolerance and finish need to give a proper answer on how to machine the hole.

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pantaz
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#10

Re: Machining

02/09/2012 6:51 PM

Depending on the material type, required accuracy, cost limitations, part quantities, etc...

  1. Drilling
  2. Punching
  3. Boring
  4. Trepanning
  5. Laser
  6. Water-Jet
  7. Plasma
  8. Broaching
  9. EDM

(In no particular order.)
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Users who posted comments:

dgibson (1); lyn (1); ozzb (1); pantaz (1); PWSlack (1); shafeeqah (3); SolarEagle (1); WJMFIRE (2)

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