Create Square Notch in Alumnium Extrusion

[MDGroup]

I have a 4-ft long aluminum extrusion, and need to notch out a square cut-out in the one end. See attached images.

The thickness of the aluminum to cut thru is about .020". The tube is about 1" is diameter. The notch will need to be about .45" wide by .75" long.
The back of the tube could get in the way, something could be slid into the tube, but obviously can't be very large.

This is needed for production, not just a few that I could just dremel away. So, I need to find something very easy, repeatable, and consistent.

The dimensional tolerance isn't very critical, but the edges should be somewhat smooth and not twisted, deformed, and sticking up.

I would prefer a hand tool or a fixture for an arbor press. I don't know if there is any type of automated nibbler that could do this, or a dedicated machine that isn't too costly?

Any suggestions? Any additional info I can provide to help out.

 

[MikeHalloran]

That's an extraordinarily thin extrusion.

I'd guess most any toolmaker could make a plier-type tool to nibble out the notch you want, maybe even to notch the full extent in one stroke if you can actually get the part extruded as shown.

I.e., a punch would descend between the outer grooves to punch through the flat web, backstopped by a die that is custom made to just barely fit in the lumen.

There probably isn't room to make any part of the tool easily replaceable, e.g. with inserts of simple geometry, so you should start with at least two and budget time and money for occasional replacements.



Mike Halloran
Pembroke Pines, FL, USA

 

[ornerynorsk]

This is a very easy tool for any toolmaker. A unitized die set could be made that fits into an arbor press or benchtop press. Top half is a punch, heeled or skewed to reduce tonnage, bottom half is a horn mandrel with a guide collar for orientation and stripping.

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.

 

[KENAT]

Does it really need sharp corners or can some kind of corner relieve be employed?

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[MDGroup]

Corners can be relieved, or they could be rounded off.

Would I be able to make a custom die set for a ratcheting pair of crimpers. I have used ratcheting Paladin crimpers in the past for crimping wire terminals. Do you think they would be strong enough if I made a custom punch set, kind of like Greenlee punches. Thoughts?

 

[ornerynorsk]

Operator fatigue is a major concern with production volume parts. I would not want to be the guy to be handed a pair of pliers and set before a cart of several thousand parts. A hand tool is not made to withstand that kind of usage, it will begin to wear out with subsequent mismatch between the punch and die, which you don't want on 0.020 thick material. Your clearance is only going to be 0.001 per side between punch and die.

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.

 

[KENAT]

If you can have rounded corners/corner relief then would a router be a possibility.

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[dvd]

Is it allowable to simply cut in on the two parallel side and then fold the tab inside of the tube? You might make a simple double-cutting notcher.

It seems like burrs may be an issue with any hand-tool. The clearance between punch and die, blades, etc. will result in burrs. What are the consequences of sharp edges? Will you be following up with deburring? If so, it may be cheaper to machine or laser-cut or otherwise produce on better tooling. It looks like a simple little job which requires minimal tooling, but the people who are performing the work might spend more time on this than you want/anticipate.

 

[MDGroup]

A router would work, but I really want to avoid all of the chips and the mess that it will create. We would have to blow out the tube and chips would get all over the place.

Cutting the edges and folding it in is a good idea, but wouldn't work.

Small burrs are not an issue, especially if we could control them so they are always on the inside edge of the tube. Big burrs on the outside would be a problem. Hopefully a quick swipe with a de-burring tool around the outside would clean that up sufficiently.

It seems like such a simple task, but I can't come up with a simple way to do it.

For now, it seems like the best way to do it would be to have a tool shop make a set of tools that could be fitted to an arbor press. Make a small fixture that the tube can slide on to and fully supports it on the inside. Push the tube on, pull down on the press and out pops a single chunk of material. Hopefully.

Thanks for all the input. Let me know if anyone can come up with something different.

 

[berkshire]

MDGroup (Mechanical)
Ornerynorsk said it, you need a horn punch, either in a die set on a punch press, or a self contained die set, that can be placed under an arbor press.

As an apprentice I would get the job of just making something like that. These days, most apprentices are not trained to do that, so you may have to send the job out to a toolmaker. how elaborate the tool is , depends on how many you have to do.
B.E.

You are judged not by what you know, but by what you can do.