Metalworking newbie here, but accomplished Electrical Engineer....
What would I need if I wanted to punch holes (some small diameter round, and a square hole) with reasonably sharp, or tight radius edges in 0.062 aluminum panel?
The panels measure 2.07" x 8.58", and I'll probably do a whole bunch of them before it's all said and done. (several thousand over the course of 24-36 months)
Option-1 is to just have them manufactured. But, the panels come with the enclosures, and I'd rather not waste them, nor do I want to hassle with low-quantity production runs, as I make continuous orders for enclosures (at 50 to 100 at a time..).
Ideally, I'd like to pop the panels in a big 20-ton hydraulic press or something. Panels need to be reasonably flat when the operation is finished. Can it be done that way, or am I out of my mind?? Is there an easier way?
How much money for something like this?
Holes will be: (QTY-2) 3/8", (QTY-4) 6-32 size, and QTY-1 square, about 1/2" Alignment not CRITICAL, but would prefer to punch all holes at once.
Google for "greenly" or "greenlee" punches. Drill a pilot hole, and then feed the parts on each side of the hole. One side is a cutter and a nut, the other side is, roughly, a bolt and a backer for the cutter to align to. Tighten the nut on the bolt, punch the aluminum panel. Lather, rinse, repeat. Not cheap but they don't wear. Maybe 50 bux each or so.
With that quantity, you'd do better to go to the enclosure manufacturer, negotiate a quantity price without the panels, and have a local tinbender fab them for you.
An electronics sheetmetal shop (AKA tinbender) would be happy to get a job like this and should give you a good price on 100-500 per order.
Most shops will tell you that they can't do it that way. They will want to put a 4'x8' sheet of AL in their CNC punch and let it chop out 200 of them while on autopilot.
A fabbed panel, material included might run $3-$4 in large quantity. YMMV depending on the friendliness of the vendor, yourself, and how hungry he is.
You ought to think about surface finish as well. The punching process will leave small scratches and dings. If this is objectionable, you can call out a grained finish, oriented horizontal. That's just running the part through a big belt sander.
Also be aware that anyone touching the bare aluminum will get their hands dirty. The cheapest way to fix that is to specify a clear Alodyne finish. Clear anodized is more wear-resistant but more expensive.
Hope this helps and isn't too depressing. At least you don't need paint and silkscreen.
For such relatively small quantities, look at CNC punching of the panels. They might nibble the square hole. Setup cost should be negligible. It might be cheaper to remake the panels depending on the finish etc.
It's certainly a possibility with such a simple part. However, if the OP ever wants to change the panel design, he'll likely have to scrap the punch holder, stripper and die plate - basically, it's very expensive to make changes to "hard tooling".
There are some companies that make small C-frame punch/die sets. The frame holds one punch/die, and you build the locators around it. Could be very economical in the OP's situation, esspecially if he spends some time on making the locators for maximum productivity. See
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You can even get them with hydraulic cylinders attached.
Running them would be boring a s**t, but he wouldn't be tied down to massive orders from CNC turret press shops, or the inflexability of hard tooling.
Sounds to me like you ought to get a bid from a water jet shop. Give them a cad drawing and that is the set up they can transfer directly into the machine. Then it is just a matter of stack, clamp and push button.
I have a Roper-Whitney O-5 foot-powered punch (I think that's the correct model #) a 5-ton punch. It has a kind of scissors linkage and a big weight you get moving with your foot to deliver the force. The thing weighs a couple hundred pounds.
It is remotely possible you could set up all your holes on a single platen and do them on this kind of punch, but that is really doing work it is not designed for. If you are doing a hundred at a time, you could set up each size punch and die and have a guide that would align the panel properly for the holes. You could probably set it up so it would align the panel for up to 4 holes the same size. Still, that would be 7 stomps on the pedal for each panel. You'd have ONE TIRED LEG after 700 pumps on that pedal.
That takes a bigger punch. There are desktop-sized versions of the OBI punches that could do this, actually you don't need the "open back" kind at all. You'd need to precision machine the platens to hold the 7 punches and 7 dies in proper alignment.
Proper setup of the punches and dies, and a proper stripper plate will leave the panel quite flat and smooth on one side. There may be a little "flash" raised edge on the back. If you specify the punch-die clearance for the material and thickness, they can meake them to produce practically no flash, so the panels need no deburring.
Alignment is critical between the punches and dies, if you put multiple punches on one platen.
It's only 1/16" AL, the die could be made of 1/2" AL with O-1 button die inserts and the stripper would be 1/8" with some springs or just a stand-off. The punch holder could be the same with short simple punches. I wouldn't even put them on a shoe. The payback would be very quick doing even 50 to 100 pieces at a time because you could bang them out in minutes. If the design changes, so what? Make another pair of holders in a few hours with $20 in materials.
WIth due respect, have you ever made a die like this?
A 1/8" aluminum stripper? The thing would be be bent like a banana with the stripping forces required by aluminum - it's very stick to punch.
Aluminum die plate? I've never heard of such flimbsy die construction. I'd hate to see a miss-hit - the bloody thing would crack in half. Sounds like a huge mess if anything went wrong. Not to mention the fact that you've got similar metals (aluminum part and aluminum die construction) of the same hardness, sliding against each other under immense force. Aluminum gawls *readily* (very evident after that first run of 500 parts - the punches will be covered in aluminum and will require polishing).
I've built a coupld of panel dies for aluminum body panels. They were of not of significantly less rigid construction than their steel panel counter parts. I would strongly caution the OP against following your advice without some references. The only time I've ever heard of aluminum in die construction is using aluminum upper and lower shoes in very light punching applications (with the use of hardened backup plates to distribute forces from punches and die sections)
Well ... it depends on the quantity, and the speed you wish to get.
Slowest would be a Greenlee Chassis punch for the square -- if they make one that small.
Hmm ... with several thousand, I would personally look for an old DiAcro turret punch (I think that the company has gone away -- at least as far as making the turret punches is concerned -- but the machines are still out there on the used market, and there are still makers for the dies for them.
The trick with that is keeping the punches aligned with the dies. But you might be able to have a self-guiding assembly -- punches, dies, guide rods, and springs all built together, so you just put it on the press, feed in the plate, and punch a button. *But* -- if you need to change the location of something, or add a new hole -- that means paying to have a new assembly built.
With the DiAcro turret punch, yes. With three separate punches, yes (though I would probably use a drill press for both the 6-32 and the 3/8" both round. And I would probably actually use a Unibit step drill for the 3/8" holes. That leaves you with only needing a single punch for the square hole in each. That could be done with the step drill to make the pilot hole and a Greenlee square chassis punch at some cost of time. Since I do things on a hobby level, I don't know the prices which a commercial shop would charge.
With the turret punch, you simply raise a lever and rotate to the next set of dies -- but I would probably do all of one size, rotate and do all of the next size.
With your quantities -- if you can get them all together in a single bunch, I would consider a CNC water jet system to punch them all out. With that, you can do a stack of several sheets of metal at once. The problem is that the setup time for that first sheet is what costs the most -- which is why I would do all of the sheets in one run if possible.
The turret punch is used -- and it will depend on your luck and bargaining skills. If you are *reallly* lucky, you will get it with all the punches which you need, plus extras for things like the keyed hole for toggle switches, D holes for fuse holders and some pilot light assemblies and such. If you have to buy them -- and they are not standards (I think all of these are standards) be prepared to pay a lot.
Find someone in your area who does CNC water jet cuting. You feed him a DXF file showing where the holes need to be cut, he massages the file a bit, stacks the plates on his machine, and punches the go button. Quite soon, you are handed a stack of complete plates while he does the next stack. (At a guess -- you might get as many as eight or ten per stack.) As for how much -- you'll have to talk to him. Also -- if you did not have pre-cut panels from the assemblies, you could have a bunch of them cut from a stack of standard sized sheets of aluminum (4'x8' IIRC), so you get more finished panels per load of the water jet cutter. Or -- you might be able to load it with multiple stacks at a precise spacing, and have it make all of them at once.
Find a local shop with a laser or abrasive water-jet cutter system. You get the next shipment of 100 enclosures, strip off the front panels to be punched and deliver them to the shop. Go back a day or two later and pick them up slightly lighter than when they arrived.
You could make up press tooling to punch everything at once, but it would cost a small fortune for the dies. And if there are any changes, you pay almost as much to get the dies reworked.
With a CNC cutting system if you need running changes you just modify the programming - a lot less expensive. And they can engrave logos and serial numbers, too - just turn the laser power or water jet pressure down so it etches instead of burning through. For very low production runs of a few dozen, you could make a jig in a drill press to drill the holes +/- 1/16" on position, and a Greenlee punch for the square hole.
For several hundred thousand and no chance of running changes, you make a punch die.
But for several thousand (and to allow for easy redesign if needed) go to someone with the right gear and have them cut - unless you really want to buy a new toy and don't want to chance a "machine busy" or "machine broken" delay at the cutting shop, then go get your own water-jet cutter for your shop.
I didn't communicate well. The O-1 button dies are inserted into the plate. The stripper would be steel of course...might make it thicker. The blanks would have to be lubed. I have a bunch of dies like this construction for
19 ga steel and they run higher production rates and they are bolted on a heavy steel bolster plate. Look again at the holes he needs, no big deal. My smallest press is 30 ton and has plenty of steel real estate. It depends on where in the blank the holes are as to what you can get away with. If they are spread out over the whole blank, I think the die plate would have to be on a shoe.
I'd ask the manufacturer for a quote with the holes. I bet they have the capability to do it economically. To keep things easy, I'd get a quote for all the panels or half depending and then see if you can buy the enclosures w/o panels in quantity as you go. I don't know what your start up budget is so initial outlay may be an issue.
If having the manufacturer put the holes in isn't an option. Find someone with a cnc turret punch press. They do a fine job of taking a sheet of metal and making repeating patterns replete with holes. They would not want to reuse your panels since munching out of a full sized sheet has less material handling time.
Sorry, like I said, "new" to this group. But to address your concern: South Florida.
I just remembered my neighbor owns a large CNC shop. In the past, he's offered me $50/hr any machine (including his wire EDMs), plus any materials I might consume. Maybe that's the right way to go.??
Still, if I can just pop these in a press, we certainly have room in our workshop......
Why can't one say "big" and "20-ton" in the same sentence? Am I to take it that 20-ton is "lightweight"? Just wondering....
Thanks for all the replies. I am still sifting through them.
It's always a great thing to be self-sufficient for doing your own work. A company I worked for did the same kind of thing you are talking about, buying the stock enclosure and modifying it for the purpose. In your case, if the manufacturer is supplying an all-metal enclosure, chances are they will be able to give you a good price on making the flat panel the way you want it. If you are buying a molded plastic enclosure, with aluminum face panels, it might be a different story on the supplier's end. The bottom line is whether you think your rate of production and sales return will cover the cost of setting up, and what those choices might then entail. Your expressed rate sounds like you'll be making these units about 25 per week for several years. Definitely not a hand-held tooling kind of job. You really only need the punch for the square hole in the panel. You could easily get a decent drill press and a used Di-Acro or similar type of manual punch press, buy an off-the-shelf die set from Roper- Whitney, pay your CNC shop friend to make you a drill jig, simple or more sophisticated, and be in operation fairly inexpensively, say for about $1500 if you find the right auctions or used equipment. If you pay the mfr. to do the work, your outlay over 3000 panels is going to be probably $10K+ at the per piece rate and any setup charges. If you look at your labor and decide that it is worth it, then when you are done with this, you have additional paid-for equipment and capability if you do it yourself. Otherwise, you just throw the money away on a service. The choice is based on what you want to do in your own business development, to some extent.
There are lots of different ways to do this, and the other posters have mentioned a number of them. I wouldn't necessarily go with production at your friend's CNC shop, unless you are talking CNC sheet- metal processing. CNC machining would be less economical than punch processing. There is definitely a benefit, though, in changing a program vs. changing hard tooling design, all other things being equal.
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