Cutting Pins for F Nixie tube | EP#3
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- Опубліковано 1 жов 2024
- Another version of a mold for manufacturing stems is in development. Meanwhile, I am trying the process of cutting wires to pins - this will be needed once the mold is ready..
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So exciting to follow this new journey; I hope to be able to purchase six tubes for my first clock!
Is it because the copper is so soft they can have very steep/sharp blades?
I think a more blunt blade angle will be able to shear the steel wire and last a LOT longer.
I think so, all cutters for steel were almost flat with ver little angle on the blades..
Looks good so far. The sanding belt is the way most tube companies do it now. I asked some people how they used to do it and I did not get any definitive answers. I saw rod end cutters like in the link I sent you used but those were for expensive pins in military use stems. The high production ones may have been swaged but I have not gotten any confirmation from anybody and might not as most of the people from those days are no longer with us. Good video.
Good, I also think sanding will be easiest and most efficient, lets see! The end cutter seems producing best results, but it is very complex process..
@@daliborfarnythat was my feeling as well. Swaging may be a good option if sanding does not work.
i wonder if you can make essentially a tiny Swiss CNC lathe with a collet the wire runs through and then turn the end clean right next to the collet, push out, part off. probably some minor overengineering though, but it doesn't seem that mechanically complex to build such a simplified cnc machine.
one worry is it would have to work with long sticks of wire, owing to the rotating the wire... but could you build something with rotating tools instead, and still using the same Swiss lathe collet idea?
like, bring in an end chamfer cutter, chamfer the end, push out, then chop off or part off?
.... wait could you post process the completed tubes instead of doing any of this?
7:42 well you will be wanting tool steel and also to select the stainless alloy carefully.
About 20 years ago, I toured Richardson Electronics, a maker of power vacuum tubes near Chicago. One of the most interesting things I learned was that the pins on a vacuum tube, like the ones you're making are made of 3 different pieces of metal, butt welded together with a short piece of Kovar in the middle. Kovar is chosen due to its close match to the thermal expansion of glass. They don't use Kovar for the whole pin because Kovar is expensive. They didn't tell us how this was done. I wish they had, because that must have been a really interesting, and complicated process. And it must have been rather expensive, although cheaper than making the whole pin out of Kovar. I don't remember what the outer ends of the pins were made of, possibly some stainless alloy.
It seems likely that the finishing was some sort of rolling process that may have finished the ends at the same time. It's also possible that a rounded end could be made by a very short TIG arc, just long enough to melt the end.
I recently had a in depth conversation with Ed Richardson. Their tube making operation has really shrunk. They have gotten rid of more equipment than he was aware of. I asked him to look for a few machines for me in their warehouse and he was surprised to find many of them had been scrapped. We really are in the final days of the tube business and soon it will only be a very few rare things left, mostly made in China.
Thats not a very optimistic perspective, but I see the point.. So, we need to try our best to build a good product and preserve the nixie tube technology..
Kovar to metal bond is probably brazed. Kovar can also be sintered. Mass produced rounded ends should be stamped, for small quantities grinding a chamfer is sufficient. Since you probably also want them nickel plated and maybe tin/gold plated, you are probably better off buying from an established supplier
Im not sure which alloy youre going to use for pins I.e. Kovar, or something similar, but I would get some test articles done on that if you can. Steels or nickel alloys optimized for things besides machining can be quite challenging. Theres "Haha stainless is miserable to machine" but it still can be machined well and worked well, and then there's "oh god I think this nickel superalloy is going to be the death of me" Normally Id say you can get some dies made with an inverse of the cone and rather than sheering the wire, pinch it, so youre forming a cone as youre cutting it to length, but Im not sure if that kind of cold work is feasible for the metals youd need to use. I got to see one of our mechanical engineers at work catch hell for specifying mu metal (also a high nickel alloy) for something, and not giving the machinist a heads up or time to buy supplies, because it was tearing though about 1 band saw blade per ~5cm of cut in the sheet metal.
I am going to use "Alloy 52" which is roughly 50:50 Ni-Fe alloy. It will be probably very similar to stainless steel which is roughly 20Cr-10Ni-Fe alloy. I would say more Ni means softer metal, compared to Fe or Cr content.. but we will see! Thanks for that experience mentioned!
A wire cutting die should do the trick and round both ends. 9 days production time for a year supply isn't bad. Break it up quarterly and have traceability to process change/improvement after first batch. Very cool!
Brass is a good metal to use for the mold but have you tried high density graphite? You would have to make the mold thicker in spots if you use graphite so it doesn't crack. If you still have glass sticking to the mold try a small amount of beeswax to lubricate it, that's what we use in glassblowing sometimes
The machine is more than sufficient to make the cut, the blades are not. Give the manufacturer a call ... see if they have stainless steel cutting blades.
How about melting the tips to a round shape.
I am afraid that this would create ball at the end - bigger than the original diameter. But good idea to keep in mind.
For that kind of volume, outsourcing it to some metal shop, might be an option. But of course having it in house, could help with these and other future products, plus make it more flexible with lower overheads.
Instead of cutting, using a cutoff grinding wheel, maybe? Would require slightly better holding tho to work.
Wednesdays now have both Wintergatan and Dalibor Farny videos! Twice as good!
There must be some geometry of the cutting blades that would produce rounded cuts, that would be ideal. Like if each blade made one half of a sphere, that pinches and squeezes/extrudes the metal off.
I'm really happy you're doing this project and am excited for the results! The price is basically the only reason I haven't bought any yet.
+1
Instead of cutting, sheering is more elegant. The wire is feed through a hole between 2 block and sheered away by moving one of the blocks. But before starting the process wire at the end can be treated to get the round end.
Really enjoying your videos, I do hope you succeed in your venture 👍🏴
If you dont have one yet, look into buying a mopa fiber laser. You can cnc cut metal, glass, spot weld with them. 60watts run about 6k$ new
We have 50W one, it is good for metals, but I havent tried glass yet.. I know CO2 lasers do glass..
I wonder how vibration and shock resistant the new tubes are? Would be nice to have them as a speedometer.
Thinking about chamfering - it's not an easy task as the pins are short and would need to be fed further, which would require one of usual in manufacturing automation sorting and feeding lines.
It's harder than to make them to dimensions in one step. Single step would require a bit of hacking of the cutting press. Either use a thickening guillotine blades each with u-shaped dent, blunt ones. the u-shape would have a diameter of around 0.4mm (for 1mm wire). They need to meet frontally. Their function would be to not to cut but compress the wire to lower diameter that then can be just broken off. I could design such.
Another way would be to use a rotating cutting blade (from a lathe), the difference being that it would have to be mounted in a rotating holder with adjustable tool feed. It's way harder to make than the compressing blades.
I thought to use some kind of vertical gravity feeder where you put a large amount of the pins and they fall by gravity in between two belts that would bring them on a sanding belt - just like the pencil grinding.. But the idea with a cutting die/compressing blades sounds better - I see what you mean, I think we will go this way. Thank you!
I'm wondering if you could just take around 40k pins, so 200x200 as a block and just sandblast the ends all at once
Maybe heat just the very end in a oxy- hydrogen or acetylen flame to form the round end by surface tension.
возможно контакты стоит округлять с помощью электрохимического травления?
Perhaps the contacts should be rounded using electrochemical etching?
Perhaps a set of blades made of a cobalt alloy might hold up better
Konec lze také zakulatit kartáčováním. Viděl jsem mašinu, kde se "zkulacoval" konec hranaté hřídela. Ta se vždy upnula do držáku a projela (točila se) skrz ocelový kartáč. Rychlostí a přítlakem kartáče se dala nastavit intenzita obrobení. Těžko říct, jak by se to dalo řešit u takhle malého dílce. Ale asi bych neviděl problém - vibrační zásobník, karusel s opánkami a kartáč v jedné pozici... Zkus upnout jeden drát do aku vrtačky, do druhé dát ocelový kartáč a projet jednou skrz kartáč. Třeba to bude tvarovat dobře ;)
To kartáčování je zajímavá technologie, otázka je, jak by se ty piny upínaly a jak by se do toho upínacího mechanismu přiváděly.
@@daliborfarny Na dávkování by se použil obyčejný vibrační zásobník. "Tyčky" jsou nejjednoduší věc na seřazení (jaký mají rozměr? Možná mám doma jeden zásobník na tyčky navíc, tak bych ti ho poslal). Gravitačně by mohli padat do karuselu, který by měl z ve spodní části doraz. Otázkou je aretace, ale to by se dalo vyřečit pružinou, která by se na dvou místech penumatickým válcem odjišťovala (upnutí neobrobeného kusu, uvolnění hotového kusu). Možná by se nemuselo řešit otáčení pinu, ale buď nějaký kotouč, který by se nějakým způsoben otáčel, nebo třeba 2 kotouče 90° pootočené. To by bylo na laborování.
Chtělo by to ale tuto technologii vyzkoušet. Nevím z jakého materiálu májí být finální piny (tvrdost atd). Každopádně kotoučů je obrovské množství a dá se s tím dost pracovat. Pošlu ti nějaký odkazy na DM na Instagram.
Immediately subbed and thumbed-up. I'm really looking forward to see this develop.
UA-cam seems to have removed the 'edit' option. Another rounding method that may have some application is smoothing of bristles (like in a tooth brush). Bristles are bundled tightly, then pushed againt an abrasive pad until they 'bow out' from the pressure. they're then swirled in a rotary motion against the pad. Since they're bowed out, the ends are abraded all the way around. The bowing is critical, though, so may not be possible with little steel rods. Just throwing it out there as an idea.
Interesting idea, didnt know about this process - thanks for sharing!
Zopár zlepšení:
1. máš priveľká vôľu medzi čeľusťami/nožmi. Vidno podľa dvoch zásekov na drôte 8:11 - aj ten napravo (vôľa medzi nožmi možno 0,3 až 0,4 mm).
2. stroj nepotrebuje na 1mm drôt mať taký extrémny zdvih čeľustí. Zredukovať zdvih (medzeru otvorených čeľustí) + znížiť priemer vodiacej trubky.
Stroj by takto mohol strihať oveľa rýchlejšie + menšie opotrebenie nožov trením.
3. zlá geometria nožov, miesto V treba U.
4. čo tak skúsiť vybračne naukladať/nastohovať a upnúť do vyrobeného prípravku/zveráku tisíce ks (desaťtisíce ks) nastrihaných drôtov.
Urobiť niečo ako včelí plást (bunky budú tvoriť drôty) - konce drôtov zarovnať v prípravku a zovrieť. Následne konce drôtov v zovretom prípravku z oboch strán prebrúsiť - tisíce (desaťtisíce) kusov naraz.
Zarovnáš/zbrúsiš tak nedostatky po strihu -vzniknú brúsené kolmé konce drôtov. Bonus: všetky budú mať presnú dĺžku. Následne tumbler.
5. pozri si princíp valcovania závitov (thread rolling). Miesto závitu by bolo možné podobným princípom deliť drôt. Jediným pohybom/cyklom by sa drôt tvárnením za studena zošikmil (alebo zaguľatil) a aj oddelil.
Mám ešte hromadu dobrých nápadov, len som lenivý v písaní commentov.
Díky za tipy, tady ten jednoduchý stroj bude sloužit asi jen k prototypování. Sériově ty piny budeme muset dělat nějak jinak. To válcování závitů je super nápad - už se na to dívám!
I think the pencil sharpener machine is a good inspiration. Instead of two belts and some sanding drum, you probably want to roll the rough cut pins between a cylinder and a U-shaped bore (with the gap between them being just enough to lightly pinch the pins), and have a blade or step on either end that would gradually shear/pinch the ends off as they rotate.
The process I'm developing is much more manual than would be useful to you, but I plan to cut my pins using a diamond cutting wheel and then use a tool intended for sharpening tungsten welding electrodes to chamfer them. I'm using abrasive cutting rather than sheer cutting because it's easiest for me to get tungsten wire, so I'll likely be using tungsten for my pins, unfortunately this means I have to worry about introducing cracks in the wire if I cut it with a wire cutting machine.
Your "pencil sharpening" idea is very much the way that electrode sharpening works, I think it's promising.
What diameter tungsten are you using and where are you sourcing it from? Tungsten suitable for stem work is typically a special specification. A common problem with tungsten is to have longitudinal cracks in it that can run for many meters due to how it is drawn. These create leaks. It is common to fuse the ends with nickel which in turn are much easier to weld to. It’s a very touchy process and microscopic examination of samples of the tungsten is required before using it in a stem lead or you may very end up with perfect looking seals that are basically straws. If you do make your own tungsten type stems I suggest you make up a leak detector system to verify each stem. It can be as simple as a thermocouple and an ion gauge and valves on your vacuum system with a special flange to seal your stems to test just so you don’t put lots of effort into assembling a tube with a leaky stem. Or just avoid the whole thing and use soft glass with easy to get dumet wire and just build an annealing oven to handle the soft glass. Making seals with borated dumet is much easier.
@@MrSupro Charles! I'm glad you found me here, I had forgotten your YT handle and couldn't find your videos for the life of me, and they're great reference material!
I hear what you're saying about Tungsten, I'm well aware of the problem with cracks. The only vacuum seals that I've made are tungsten-boro so I guess I'm just going with what I know. I want to avoid soft glass, not just because it's finnicky but because my ultimate goal is to make some devices that will be quite small and, consequently, heat cycle pretty wildly on operation, it may be OK to use soft glass in this application, I'm just not sure. Also, since I'm not making them for commercial application, it's okay to do fiddly work and make imperfect seals that leak up over time.
As it stands, my vacuum system can isolate the evac port and leave it connected to its own set of gauges, so I can do some basic leak testing if I just come up with a flange. I also have some Kovar wire coming in to play with (some new from IMI Adaptas and some old from Ukraine) so I may consider that as well, that said (as you touched on in your reply to my comment on another video) it's much easier to prepare Tungsten for sealing.
I may try soft glass and dumet at one point, I want a little more practice with more thermally forgiving hard glass first.
It’s not
“way how to produce”
it’s just
“way to produce”
Thanks for feedback, I hope to rewire this in the brain.. that expression comes from my native language.. ;-)
Hey, you're doing some lovely progress! As for rounding the ends, I was thinking in lines of a sub-miniature lathe for cutting & rounding the wire in one operation.
I think that your wire cutting machine can be upfitted with an automatic pin chamfering mechanism, where the wire end is first fed into a rotating pin chamfering tool (same design as the Click Spring pin chamfering tool) the chamfer is made, wire is retracted to desired length then the pin sheared off.
I'm excited to see what you come up with.
The cutting geometry of the blade will determine both it's life and the finish on the piece you're cutting. Try manufacturing your own blades out of hardened steel and try it with some softer steel pins first. Than try different geometries of blades based on what is available in market
There are pinch cutters, shear cutters, saw cutters... I think a straight shear cutter might do the job better than the v shaped ones
the blade is too fine of an edge for steel
That's an excerpt from "How It's Made" where they manufacture pencils! 😀
It is :-)
I recently found out about these tubes and then I remembered that I used to break the VFD Displays that old VCR and DVD Players used to have when my dad had a workshop.
Thanks to some good people at a certain forum they pointed me here.
Hope to see more from you.
Stainless? Don’t the pins need to be tungsten or Kovar?
The glasses to match those pin materials would be prohibitively expensive and some contain lead. I believe the idea is to use lead free sealing glasses which use other types of nickel iron leads and stainless actually is a good analog for learning hot to process it. It is not a suitable alloy to seal with but is easy to obtain.
The pins should be “roll cut”. In that way, each end has a radius / chamfer.
9:01 rivet style. IE, you need a tube that's almost the height of the pin (bottomed, so a blind hole) that's slip fit, but not loose, and that exposes the pin just enough for a die to come on top. A CNC could drill this from two pieces of steel or one brass one steel (top one has the pin forming end, so that one kind of has to be steel) and you do 50 or more in one run with a press or a big rubber deadblow hammer smack.
An interesting problem. Two ideas for make finished cut ends on pins and could (maybe) be a custom cutting head mods to your existing wire cutter are:
(1) rather than using a V cutting blade, use a V but with a U-shaped bottom, The cutter looks like the double V cutter but instead of a sharp V notch has a radiused cutting notch of between 1/2 to the full diameter of the pin (requires experimenting). The theory is that this radiused style would start the shear cut in a mostly circular compression around the pin by the cutter compressing the pin towards the central axis as it shears. The back side of the cutter would tend to form somewhat of a chamfer
(2) this takes the previous idea to the next level by devising a rapid cycling circumferential blade system that rotates the blade cutting line around the pin as it closes (sort of like a combination of multiple lathe parting tools combined using a simplified partially rotating iris actuator, much like that of a camera) The theory here is that by using a circularly compressing shear cut moving inward from the outer surface of the pin, the cutting action would leave any remaining cut deformation at the pin's center line.
The second is somewhat more complex mechanically than the first.
Note: all self-made cutting blades should be made from suitable tool steel, sharpened, then case hardened, then honed to reduce the rate of blade edge degradation during use.
Yes, the cutter needs to be U shaped - the U just slightly bigger than the wire diameter. I think the best approach will be to stick to a compression die, like your (1) idea. Adding the rotary elements would add a lot of complexity. I am thinking to use some 19XXX tool steel (EU standards), hardenning-tempering the seel or just cementing the surface layer..
@@daliborfarny Agreed. The wire's surface must be in a progressive compressive shear on its entire circumference to eliminate pinch burrs. I suspect that you'll likely end up with a guided compression U/V die that first engages the horizontal surfaces of the wire before the die compresses the wire into the final U-shaped shear zone. This means that the final U is likely to be slightly narrower than the wire which should result in a circular cut with flat pin ends.
Also, I may have found some reasonably affordable production-level desk-top wire to flat-end pin-cutting machines. These appear to be related to automated precision tube and pin cutting in the production of commodity medical tubes and pins for subassemblies. I've got an inquiry in and will report back with info when I get it.
What metal alloy do you intend to use for these pins.
@@kentswan3230 The plan is to use "Alloy 52" that is roughly 50:50 Ni-Fe alloy. Thanks for the info and work in the previous comment!
@@daliborfarny I forgot to ask what the wire diameter is in mm.
I love your work and your videos ! One day I will afford one of your Nixie Clocks 😊
ahoj Dalibor, ak ti muzu doporucit, zkus stejné nože s tím že zmenis tvar kterí bude naspod mít u V-čka radius dratu, pak se líp rozlozí tlak na čepel, taky zmeň uhel na mnohem tupejší aby a čepel víc vydrží, ty abys dokazal udelat ukon strihu tak to dej na treba 10-15 stupnu namisto 45 jako mas teť... samozrejme čepele pak musí bít co nejvíc u sebe aby ten sřih byl co nejdokkonalejsi a pusti to na tíden :D když tak jsi koukni jak se striha armovací roxor o tloustke treba 25mm :) ty čepele vubec nejsou ostrí a ta ocel praskne drív jako med !!! :) taky lovecke noze maji tupejší uhel a vydrzí díl, ty vostří u oceli nepotrebujes jako u medi proto že je mekší a vice se tahá pri strihu.. jasne a pak bych to prohnal pres stroj kterí ostrí ty ceruzky protoze udelat novy stroj kterí ti bude delat zarodek do dratu a pak ho tahat aby tahem prasknul a deformoval se do čepičky tak to je hodne laborovaní a na tu delku asi malo realní.
kdyz tak dej feedback rad te sleduji.
Would annealing the wire prior to cutting help with some of those rough edges?
Yes it would, however the final product would be pins so soft they may not survive insertion into a socket without bending over. The heat cycle from the sealing process makes them soft enough that another round of annealing would be problematic. In high volume production effort was taken to keep the tips of the pins below annealing point by keeping them hidden within the mold until they were out of the flame and pin material with an annealing point as high as practical to give you the most temperature range to work with.
@@MrSupro Interesting. Thank you for the insight. I take it you've done something like this?
Just an idea I had, not sure if it's feasible: If you buy a Tig torch, find the right parameters and automate the triggering, you could cut the wire with the arc. Basically replace the cutters in your machine with a TIG torch.
It has to be tested how consistent the lengths turn out to be, but it would automatically leave a rounded end!
This concept was actually used in making multi part stem leads and fusing the ends together. I have tried this method in the past but it would have taken time to make up fixtures and since all of my tubes are experimental I just wind up sanding or grinding the ends to smoothness.
It might be easier to round the wires once they are in the tube
Most efficient way to produce these radius pins at your projected volume and quantity requirements would be on an Escomatic screw machine. Kovar and alloy 52 glass to metal pins are commonly made this way.
Thats perfect, I didnt know these machines - I will definitely take a look at them. Seems like the way to go..
@@daliborfarny I would investigate this as well. It looks ideal.
ED Fagan in New Jersey is the material supplier I used every time I worked with Alloy 52. There are still a few mom and pop screw houses in North Jersey that run these parts on esco's. Their pricing might shock you in a good way. I.e parts are generally quoted in $ per 1k pcs.
I just sent a PO to one of them, in New Jersey.. The price reasonable and turnover quite fast.. In 4-5 weeks the pins should be on the way to us. Have you done glass sealing projects to alloy 52?
In my small sliding headstock screw machine shop I have made alloy 52, bi-metal, and occasionally kovar parts for glass to metal electronic customers. I've never made a pin as simple as yours. Full radius ends, turning reduced diameter, maybe a groove or cross hole. Cold heading and Escomatics fill the niche at quantities higher than what I was making. I can't help with application engineering on an Escomatic, but I can help with swiss sliding headstock cam machines such as a Tornos M4. It will require 12ft straightened stock, they are cheap(valued at scrap or less in the US when found), compact footprint, easy to run on part like this.
I presume the stainless steel wire has the same temperature coefficient as the glass. So variations in temperature are not a problem.
This is not for sealing, just for test…
What material did the older tube companies use? (Tungsten?). What was their glass composition? I am not sure if stainless steel (type ??) is the right material. I remember seeing a sealed glass tube with 10 pieces of 20 cm of (copper coloured) rough (not smooth) wire special for sealing into tubes. What about browsing through the patent or IEEE literature?
Short answer is most products used dumet which was a soft iron/nickel core composite material with brass and copper cladded portion butt welded to plain. Nickel or nickel alloy. They are difficult to get now. Tungsten was and is still used along with Kovar but glasses used with these metals is cost prohibitive. We now use other lower cost nickel iron alloys with lead free glasses and stainless is actually a good analog to those alloys for experimenting with cutting and forming at a significantly lower price.
I used stainless steel here just for experiment - it is available and low cost. The real sealing alloy is different, but similar in hardness and temper..
Hey, i'm sure you love unsolicited advice from people who know almost nothing of your job, but here it is anyway :D
I would put the rounding or chamfering of the pins to the end of the production process, once they are already in the tube, and it has been tested. Advantages I see are:
- you don't need to think about workholding of tiny metal pins
- you don't need to put them into the tube in the right orientation or process both ends
- you don't waste effort on failed tubes.
I enjoy seeing your videos, looking forward to the journey to the finished product.
Thank you for the ideas, they are definitely valid! The first moment when the rounded/chamfered end will be necessary is during inserting the pin into the hole in the mold (glass pressing process). The chamfered pin will navigate itself easily into the hole. For this reason I think it will be necessary to do it right after cutting.
@@daliborfarny Ah, unfortunate for you, but fortunate for us viewers, because that will be interesting to see you find a way to do it :D
Good looking pins!
1. sharpening angle is too low
2. use tungsten carbide
Like too sharp? It is tungsten carbide…
too bad he said they're already carbide right ?
I think that Dalibor said that the cutting blades are tungsten carbide.
Yeah it's very steep angle. It should be more blunt like scissors.
are you sure? Maybe the manufacturer of this machine just says so... by the looks of it it looks more like toolsteel or something, but you never know.@@daliborfarny