how to make hole in transistor can without shavings? - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: February 15, 2024, 08:40:46 am
content: I want to make a hole in a can (sheet metal) but I want to guarantee that there is no shavings inside.What is the best tool for this? Assuming I can flush it out with liquids. This hole is maybe 3/32 of an inch.If I used a standard 2 flute drill I expect possibly curly shavings getting stuck inside.I thought the best ways might be either1) grinding2) some kind of cutting tool with way too many faces running at high speed and low feed to discourage proper chip formation. (dust maker)For 1, is there any tools that might be suitable? I thought maybe some kind of CBN coated grinding rod, perhaps meant for jig grinders? It should be dimensionally stable. I think ideally it would be like a micro ceramic hole saw? Could a diamond core saw work?For 2, recommendations ?

author: guenthert
author_rank: Frequent Contributor
timestamp: February 15, 2024, 09:39:45 am
content: I got no experience with it, but my first thought was to use a laser cutter. For a few mm sheet metal, power requirements ought to be modest.

author: Stray Electron
author_rank: Super Contributor
timestamp: February 15, 2024, 02:33:50 pm
content: How big of a hole and how thick is the metal? I wonder if you might be better to punch a hole in the metal instead of drilling it? A sharp punch should be capable of making a hole and leaving all of the metal attached instead of liberating flakes, shavings, etc. If you must drill or grind then setup a vacuum suction device such as a household vacuum cleaner near the site and run it while you drill and attempt to catch any particles as they're being created.If your transistor is in a metal can, can you de-lid it and then drill a hole in the lid, clean it and then reattach the lid?

author: jpanhalt
author_rank: Super Contributor
timestamp: February 15, 2024, 02:48:18 pm
content: I have used heavy grease when installing a Helicoil in stripped spark plug threads in aluminum heads. That catches most of the chips. Then very carefully clean with towels. Of course, the holes were bigger. Slow speed and decent pressure helps get bigger chips that curl outward and are easier to see and remove.Using more flutes and high speed will only make smaller ships that will be harder to remove and possibly fall into the hole.For your specific problem, I would consider a larger, sharp bit to get through most of the metal. Clean. Then for the very last thin portion, you might use a pick. Alternatively, etch the last bit -- either with acid/FeCl3 or by electrolysis. Since the case is probably magnetic, adding a strong magnet to your drill might help capture chips.Grinding small area to get it thin could also be done. But, I would not grind through to make a hole, if particulates are an issue.EDIT: How about doing it upside down so gravity is on your side?

author: KrudyZ
author_rank: Frequent Contributor
timestamp: February 16, 2024, 04:50:25 am
content: You could try twisting or shearing off the entire can and then replace it with a machined piece with a hole of the desired dimensions.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: February 16, 2024, 05:29:31 am
content: Anything that removes metal - grinders, sanders, mill bits, drills WILL get stuff inside the can with one specific and fairly difficult to achieve exception. The exception is if you grind the top (or saw or mill) to foil thickness and then carefully puncture/tear the remaining foil. Even tearing and puncturing can, but usually doesn't leave flakes inside.Another feasible approach is using a rolling cutter similar to that used to cut copper pipe to cut through the lid. Not totally debris free but better than most drilling/milling/grinding operations.Finally, think about the risk of displacing debris that is already inside the can from a harmless location to someplace that matters. Most are fairly clean inside, but not all, and at least some manufacturing processes have a "mechanical getter", a patch of sticky substance to grab and control anything that has found its way in. Getting such hot while shaking and vibrating the package is likely to release any such debris.The only times I have been involved in such operations they have been small hobby/research type things and involved post de-lidding cleanup and much larger feature sizes than are common today. Perhaps large operations have developed solid processes for this, but I think most of their effort is getting it right the first time. Only the reverse engineering and other spy types really do a lot of this.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: February 16, 2024, 08:12:09 am
content: One option is to use a pipe cutter (the version with a round wheel). Another option is to simply use side cutters and nibble parts away.A third option is to use an iron saw, and then not cut completely through the can, but only "alsmost" though it. Then you can create a weak line around it's perimeter, and do the last part with brute force. Intermediate filings can be removed with compressed air, sticky tape, a magnet or blue-tac.

author: coppercone2
author_rank: Super Contributor
timestamp: February 16, 2024, 08:26:46 am
content: I was hoping I could pour out the grindings by putting water in there and ultrasonic cleaner for a short duration to agitate it and pour it out a few times, I figured maybe this makes a bond wire but I never knew there was a mechanical trap in there (glue?) for debris. sounds like its better to cut it off and resolderI wonder if I can cut it with a thin dremel wheel (to-3 package) half way, modify, then replace the cover back in place by spot welding a tab to it for a third hand, filing them so they fit right, and soldering around the perimeter.I don't like the idea of a 'pipe' joint with solder on such a thin can but it should work. 'bridgit' solder should be good for this application.

author: tooki
author_rank: Super Contributor
timestamp: February 16, 2024, 10:30:58 pm
content: Why do you want to open the can anyway?

author: coppercone2
author_rank: Super Contributor
timestamp: February 17, 2024, 12:47:07 am
content: sun roof

author: KrudyZ
author_rank: Frequent Contributor
timestamp: February 17, 2024, 03:54:21 am
content: I just tried it with side cutters along the lower edge of the package.Comes out quite clean with no debris that would interfere with the transistor.It's more of a beach blanket than a sun roof though.

author: tooki
author_rank: Super Contributor
timestamp: February 17, 2024, 05:28:44 pm
content: Quote from: coppercone2 on February 17, 2024, 12:47:07 amCome again?

author: tooki
author_rank: Super Contributor
timestamp: February 19, 2024, 07:41:24 am
content: Transistors don’t need sunroofs. Also, they aren’t cars.

author: Retirednerd2020
author_rank: Regular Contributor
timestamp: March 28, 2024, 10:20:06 pm
content: You could try it upside down to minimize the chips inside. Mount the transistor so it spins in a drill-press chuck and mount your drill pointing upward in a vise that is clamped to the drill press table.Actually, a center-cutting end-mill would work better because the point of a standard drill might contact the transistor die as is punches through.You will need to guard against the end mill being pulled through abruptly at the last minute. Maybe a sleeve on the mill to keep the maximum depth to a safe depth. Go slow, especially just before getting through the inner surface. There is a good chance that a burr will exist on the inner surface so that may need to be dealt with. There is a possibility that the vibration will kill the transistor.

author: DiodeDipShit
author_rank: Regular Contributor
timestamp: April 05, 2024, 04:15:09 pm
content: This could be done in a good drill press, not a worn or cheap loose one. Hold part firm, zero movement, this may be an extensive set up. Chuck a sharp 3 or 4 flute Center Cutting Endmill, descend slowly. Chips stay out. the whole is clean and burrless, but the disc falls through.

author: floobydust
author_rank: Super Contributor
timestamp: April 05, 2024, 04:43:35 pm
content: I have used a hacksaw as the shavings are large, and then a magnet to pick up metal chips.

author: coppercone2
author_rank: Super Contributor
timestamp: March 10, 2025, 08:18:06 am
content: I found some package that has a lens on it, they have TO-style LED and some photo detector chips.I can cut it off and do a swap and solder it back together. some kind of small pipe cutter tool would leave a swage that you can jam the top of the other transistor to make a nice press pre solder fit (and solder well) on and make a nice filet. low temp solder would work nicely to help protect the lenssame for fluid cooling, cut the lid off, modify it with tubes, and solder it to a cut transistor (say florinert pump)TO-3 is still a problem because its not very tall.I can see what transistors do with laser light and stuff like that.

author: nvmR
author_rank: Regular Contributor
timestamp: March 10, 2025, 08:30:01 am
content: why not take the whole head off? using a hacksaw. that way shavings fall to the side.

author: coppercone2
author_rank: Super Contributor
timestamp: March 10, 2025, 08:31:24 am
content: Yeah if I can replace it with something which I can use another head of, especially if its cut like a copper pipe and leaves a slightly narrow diameter swage to fit it onThose lens TO packages interest me too because you can get them in different FOV, to try to focus light on a dieDo you think if you measure reflected light (like VNA), would it be at all modulated by what the transistor is doing? Like if its a power switcher. does the surface the silicone do anything funny like that?I know you can trip some MOS circuits with powerful light, but I wonder if their surface does anything to incident light based on bias? I was thinking about lock in amplifiers in regards to this..Imagine you could see the transistor working because powerful light is reflecting differently when its on or off? Is there even the slightest theoretical basis for this?