Machined Groove In Sheet Metal

[tetwin11]

Hello All,
I came up with a design, but I'm not sure if this particular machining operation will cause issues. We have a 1/8" (3.175mm) thick sheet of aluminum 5052, and we need to machine an o-ring groove 1.96mm deep. Would this be a costly and difficult procedure?
Thanks!

 

[Eltron]

It depends. You can definitely cut the groove, but the cost is likely going to depend upon the design of your part.

Dan

http://www.eltronresearch.com

Dan's Blog

 

[tetwin11]

Good point. I attached a jpeg of the part. Just a plate with holes. Overall 8" x 13".

 

[berkshire]

This would be an easy job for a CNC router. It could nest the parts, cut the grooves and the holes.
B.E.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor

 

[MikeHalloran]

You must do all the cutting on a mill or router.
If someone gets the bright idea of punching any of the holes or shearing the edges, the part will distort enough to screw up your o-ring depth tolerances.

You will probably get calls about the part for as long as it's in production.



Mike Halloran
Pembroke Pines, FL, USA

 

[ajack1]

“If someone gets the bright idea of punching any of the holes or shearing the edges, the part will distort enough to screw up your o-ring depth tolerances.”

Clearly the words of someone who has little or no knowledge of compound pierce and blank tools or fine blanking tools.

Whilst a router or CNC mill is probably the best way to go do not rule out a press tool, especially a fine blank tool if quantity allows for this within the budget.

 

[ornerynorsk]

Agree with Ajack1. As an example, the parts to a proverbial Swiss watch are fineblanked.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[dvd]

In defense of the punching/shearing comment, to shear the blank and punch on a turret machine, then mill the groove while constraining the part flat could be a bad idea. The strains induced in the punching process would be relieved and make it difficult to hold tolerance.

Fineblanking along with semi-piercing might be a good way to process the part, provided that the quantities justify the purchase of the die. The OP does not state quantities to be produced: it may only be one.

 

[mrainey]

What's the width of the groove? If really small, you might have to go around two or three times, which could get expensive.

Software For Metalworking

http://closetolerancesoftware.com

 

[mfgenggear]

Mike's Statement is correct, Punching will be half sheared & half tear in the material, a fine blanking die can be improved but will have sharp burrs,a secondary punch can improve the holes.

Please do not be condescending just state the facts how a punch
will not leave sharp edges. or what can be done to improve punching. I have a few years experience with punching, I am sure
I don't know it all.

secondly It's not wise to criticize an other one statement. milling or routing will definitely be a much improvement but will be expensive for high volume parts.
but can easily be done for R&d or low volume.
Depending on the quality & quantity there can be a compromise.

Mfgenggear

 

[tetwin11]

Thanks for all the input, everyone. This will be a low volume part, and we will carry forward with a CNC router/mill for the machining operation. Hopefully we will be at higher volumes later and a fine blanking punch will be used.

 

[11echo]

So you think "acid etching" is an option?

 

[berkshire]

11echo (Petroleum)
Chem etching is a solution ( A strong alkaline is used for aluminum.). However it would take longer than a CNC mill or router.
The part would also have to be masked, and chem etching is notorious for eching at different rates unless a chem-etch quality material is used.
B.E.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor