Drilling stacked sheet metal

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Cplbooth54618

Plastic

Joined

Mar 19, 2019

• Mar 27, 2019

• #1

We often make these large parts from 1/8 to 1/4 stainless sheets. They typically have 50-400 holes that have a +/- .001 tolerance. I know the best way would be to have a laser or waterjet rough the holes and finish them in a mill, but that isn't an option. Currently we are working on 35"x55" sheets and are really struggling to get enough support under them to drill without massively deforming the sheets. Does anyone have any advice on what else we could try?

 

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lionelt

Stainless

Joined

Nov 25, 2010

Location

Oxfordshire

• Mar 27, 2019

• #2

I had some 4 foot long 3 inch wide strips of stainless steel sheet to drill once with rows of 3/8” holes.

Used double side tape and 1 inch plywood strips as a backing.

 

C

Cplbooth54618

Plastic

Joined

Mar 19, 2019

• Mar 27, 2019

• #3

Maybe I'll see if the boss will go pick up some plywood.

 

H

HuFlungDung

Diamond

Joined

Jan 19, 2005

Location

Canada

• Mar 27, 2019

• #4

Cplbooth54618 said:

We often make these large parts from 1/8 to 1/4 stainless sheets. They typically have 50-400 holes that have a +/- .001 tolerance. I know the best way would be to have a laser or waterjet rough the holes and finish them in a mill, but that isn't an option. Currently we are working on 35"x55" sheets and are really struggling to get enough support under them to drill without massively deforming the sheets. Does anyone have any advice on what else we could try?

Click to expand...

It seems to me that your stated tolerance is far tighter than you can achieve with drills alone. Are you also reaming them all?

 

C

Cplbooth54618

Plastic

Joined

Mar 19, 2019

• Mar 27, 2019

• #5

Circle milling to the finished size

 

michiganbuck

Diamond

Joined

Jun 28, 2012

Location

Mt Clemens, Michigan 48035

• Mar 27, 2019

• #6

QT; [Circle milling to the finished size] with an end mill?

Might you grind the end mill to a drill point. That way having one feed entering the hole as the end mill OD would be in place to circle mill..The time savings applied to drill feed speed so making a better drill hole. Yes a center cutting end mill might also work..(center cutting end mills should have 10 to 15* end clearance.)

Yes the +- .001 is a bugger even with circle milling.

 

C

Cplbooth54618

Plastic

Joined

Mar 19, 2019

• Mar 27, 2019

• #7

These plates have a total of 792 .688 holes to finish. So for.cost savings we typically drill them then finish with an end mill. The problem is supporting them for the drilling. These parts are usually run in only 2-8 piece runs and aren't always the same hole size and location. Ideally I'd like to see the boss either get a water jet or find a shop with one who could rough the holes that way. But until then we struggle finding ways to support the part without deforming it.

 

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DDoug

Diamond

Joined

Oct 18, 2005

Location

NW Pa

• Mar 27, 2019

• #8

I wonder if you could punch the holes ?

 

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Delw

Stainless

Joined

Jan 8, 2019

• Mar 27, 2019

• #9

Particle board works better than plywood, but it will deteriorate with coolant fast, I would use a thicker sheet of plastic its pretty darn flat if not just face mill it.

as far as the fastest way to do them I would think drill and then boring with a boring head from sanvik or kenametal or type of insert style .but you didnt say what hole size. so a carbide reamer might be best. for that matter what ss type. all this is going to make a difference on what type of tooling you could use.

programs simple to run, easy to edit no need for other sizes as well.

 

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memphisjed

Titanium

Joined

Jan 21, 2019

Location

Memphis

• Mar 27, 2019

• #10

like Doug ask, a turret punch? A Piranha laser-punch-drill machine? use a reamer in the drill head for finished hole.

 

Spruewell

Hot Rolled

Joined

Sep 8, 2015

Location

Northern California

• Mar 28, 2019

• #11

I’ve heard issues with machining water jet parts. Apparently the abrasive becomes embedded in the material and causes excessive tool wear.
You may want to consider building a vacuum table to hold the sheet down. A ball end mill may make a nice two in one cutter that can drill through then go directly to opening up the holes to size.

 

D

DDoug

Diamond

Joined

Oct 18, 2005

Location

NW Pa

• Mar 28, 2019

• #12

memphisjed said:

like Doug ask, a turret punch? A Piranha laser-punch-drill machine? use a reamer in the drill head for finished hole.

Click to expand...

I was thinking more on the lines of a finn power punch, or similar machine machine.

How close is a punched hole ?

Size should be very close.

 

michiganbuck

Diamond

Joined

Jun 28, 2012

Location

Mt Clemens, Michigan 48035

• Mar 28, 2019

• #13

The very tough cardboard Alro Steel uses to stack steel might be considered. Agree not so good for water jetting.

 

Dupa3872

Stainless

Joined

May 1, 2007

Location

Boston Hyde park Ma.

• Mar 28, 2019

• #14

What type of machine are you doing this work in ?

I worked as a consultant at a place that made vibration isolation tables. These tables would have hundreds of drilled,C/sunk and tapped holes in 4 X 8 sheets of 1/8 thick stainless. This work was done in a large bridge type milling machine with an aluminum sub plate. The work was held down with clamps and vacuum.

Make Chips Boys !

Ron