Rework of 4000 sheet metal parts-adding a larger hole

[E T]

Plasmacutting them by hand with a jig will give you lots of cleanup work on all the parts.
Even a small plasma will zip through 1.5mm, but at 4000 pieces your travelspeed is going to be all over the place resulting in dross or uncomplete cuts.
And you'll need good fume extraction and ppe. Especially if they're galvanised.

 

[bricol]

P.s. looks like the plate has been galvanised was that done post forming and does the non galvanised edge after reprocessing need to be taken into account?

Looks like zintec to me. Bare edges will stay remarkably rust free due to the galvanic effect of the coating - I have had guillotined and folded bits (actually used as bookcase dividers in our old cataloguing system) standing outside for the last 20 years (as the last place closed 20yrs ago) and they are rust free.

 

[David_W]

Laser but you will need a jig that located on the existing features to allow fast indexing of the part

That's exactly what's happening, about 2 m2 of parts loaded up at a time onto a fixture and some slightly bored person to load and unload. I would complain about the price, but as it's pretty reasonable it would just be covering envy for having a cnc laser

 

[David_W]

Plasmacutting them by hand with a jig will give you lots of cleanup work on all the parts.
Even a small plasma will zip through 1.5mm, but at 4000 pieces your travelspeed is going to be all over the place resulting in dross or uncomplete cuts.
And you'll need good fume extraction and ppe. Especially if they're galvanised.

I tried a couple for self education, and exactly that. I'm sure I'd get better and most people on here would start a lot better, but anything which requires clean up just makes it not worth it.
I've got one of those punch and dies from AliExpress on order, hopefully arriving very late this year. Will be interesting to try that, even if it ends up not used for this problem. Always good adding another string to the bow

 

[David_W]

Looks like zintec to me. Bare edges will stay remarkably rust free due to the galvanic effect of the coating - I have had guillotined and folded bits (actually used as bookcase dividers in our old cataloguing system) standing outside for the last 20 years (as the last place closed 20yrs ago) and they are rust free.

Yeah, you called it exactly right and similar experiences with it, a small edge in a not that demanding application (it's part of an electronics enclosure, unsealed, so anything which will destroy the metal sheet will have already ruined the PCBs)

 

[Pete.]

At 2 quid a pop I'd definitely send it out. Make sure you've specified locational tolerances though.

 

[Beanwood]

Perhaps it’s a good starting project for @Theblackbox and his new toy?

 

[Smallfry]

For 4000 units, wouldn't it be cheaper and less hassle to get someone to cut them from scratch ?

Or get a quote from those nice chaps in China ?

 

[David_W]

So update on this, I ordered the punch tool that @6ply linked to-cheap enough to take a punt on. Considering it's a tenth the price as the one from RS, it works superbly. As we've got time and some people have got some free time, we've got an air over hydraulic press, few hundred quid and sorted.
The tool's clearly designed to be driven with a Greenlee type tool, so I cut down the central bolt, milled some additional flats so it fitted through the existing hole and made a quick spacer out of some 40mm steel bar so the hydraulic press can press on the top tool. Cuts really cleanly, so no deburring needed. If anyone has a similar problem, highly recommend those punch tools!

 

[Tigman]

Let us know the state of the punch after 4000 parts have been through it , very interested !