I learn how to make glass button stems. F project | EP#8
2024 ж. 14 Мам.
10 916 Рет қаралды
The molds were finished; great time to put in some glass and try pressing stems. There is progress, but the journey to a fully functional stem will be longer than anticipated!
Watch "To se vysvětlí, soudruzi": www.ceskatelevize.cz/porady/1...
Interested in browsing the RCA button stem-making instructions? Check the links below and don't hesitate to come back with your findings and ideas!
Big thanks to Jerome from Netherlands for finding and sharing these materials!
www.dropbox.com/scl/fi/zr9n50...
www.dropbox.com/scl/fi/7fjmma...
www.dropbox.com/scl/fi/l56gbc...
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As always, your behind-the-scenes videos are fascinating. I also really liked the Midjourney images given to the client, and then a physical object made of their favorite. Such a cool process.
Great to see you here Ben!
Thank you Ben, I am glad you enjoy them!
I will follow up with a more in depth email but you are going through the same process everybody goes through when developing a new stem. The biggest standouts I see are you are spinning the glass a little on the fast side. It should want to collapse in more. You are going to need to polish those molds. Also you will need a center ring with a stem diameter this large. The inner ring should be taller than the outer ring and you are going to want to heat the inner ring with the torch pointed down and on the inside of the ring to avoid overheating the pins and the outer ring being heated by a softer flame. 3 national N-1 size tips fed with propane and air only and 2 center OX-1 size tip fed with propane and oxygen pointed down at the inside. One of those tips was angled in a way to heat the flared exhaust tube as well. That is the setup that was used for a stems about this size about this when I visited the company who made them for us. They also found they had to pre bead the pins to prevent over oxidation and black seal color. Mullard was able to get away with making the 9 pin stems that fast because they were pretty small and they would introduce a toothed wheel to mash the glass in towards the center, but mostly because the lack of exhaust tube. Makes the thermal dynamics much easier. Sylvania had similar machines. At Toryonic in New Jersey they make a similar stem to the 9 pin noval and they sat me down to show me how they did them. They used a home made machine much like what you are envisioning. After the initial heat they would close the mold enough to hold the pins in place and then paddle in the soft glass with a small graphite rod to coax it towards the center and around the pins then close the mold the rest of the way, then open it back up to reheat to get the oxide on the pins to fuse then press again. Each one tool about 2 minutes, but only one outer ring and no exhaust tube. The larger stems like this were made on modified litton D type sealers with 6 surface mix torch tips and then the big big stuff was made with glass preforms with the beaded and flanged pins sealed individually afterwards or housekeeper type seals. Keep going.
Would a boron nitride mould release be helpful if applied to the top mould? Or would this hinder processing and risk contamination of the pins?
I wonder how it'd go if he put a flat in for the centre rather than a tube, perhaps with the evacuation port already in place as part of it. Then he'd only need to soften the edge of the flat so that the molten outer ring would fuse with it. Might be able to keep the heat down enough not to bother the oxide then.
Charles, thank you very much for all these info! Looks like I really need to use more smaller burners. RCA suggested AGF 1142A burners, they are the same size - I ordered few of them and will give them a try. That exhaust tube makes it much more complex, but the envelope will be a piece of cake ;-) Keep in touch!
And one more thing - I was surprised that the glass already makes nice seals, nice light grey color. There is a lot of black on the bottom, but thats the problem of not enough heat there. Tungsten seals needs much more heat to form good seal. Here I use NiFe alloy 52 which can actually get overoxidized.. I read that NiFeCr alloy (vacovit 511) creates Cr oxide layer on its surface and that doesnt grow with subsequent heating, so it doesnt overoxidize. If we have problems with this, we might try to locate Vacovit wires..
We use graphite as a mold material and use a circular burner assembly to apply even heat all the way around and that way the glass melted more evenly than with two burners
How about erosion of graphite due to surface ablation? And how it plays with forces applied while pressing glass?
First thing I thought of was the material that the mould was made of, ceramic and graphite much better than steel I think ?
Graphite is great, but it wears quickly when exposed to flame. But it might be worth trying..
Have you considered induction heating the dies? Might help with the pin overheating issue
I think that was why the carrousel worked so well. The dies remained hot while cycling around. Also they had a cog wheel that presses the molten glass between the pins and preventing it from flowing over the perimeter.
The carroussel is very good because as you say everything gets up to running temperature and then is stable while going around. It needs a lot of tweaking and then you can do a run and make stems. Making a single stems by hand is going to be very hard to do,specifically with softglass. At philips they had a machine to make single seals where they could seal an electron gun to a crt and this was all automated or else it would shatter. Before doing a single tube they had to run the machine a dozen times to bring everything up to operating temperature and then do a single seal. The temperature of the pin where the tubestem rests on is critical , too high or too low and you get radial or tangential tensions that could lead to cracks. It was a very delicate process. This was for very low volume medical grade monitor tubes with high definition and brightness .Larger runs (osci tubes) would be done on a wheel with 12 positions and then an anneal/cooldown wheel next to it.@@SarahKchannel
Thats a good point because you will never get the process tuned when you don't have the mold Temp understood.
Actually, the mold cant be too hot.. when it reaches certain temperature, it will stick to molten glass completely. Something like 300C I guess.
I think that this should be a two-step process. The first step is to mold a glass base blank preform that has the volume and piercings for the pins. This would go into the final press which forms the base to its final form which means the pins can be kept clean and you can control the final draft fit to the final mold tooling.
or coat the pins with a oxidation/heat tolerant material.
@@StephenG__s_i Good point and taken but any coating on the pins can also lead to a bad glass to pin seal. What I was seeing, however, was that the forming process was leaving a glass layer on the pins themselves and that the die-forming process wasn't even. I note that the classical industrial automation process is necessarily more complicated and appears to use longer pins. I'm not sure how the final pin sealing die was applied The automation that he's talking about here is much simpler and designed for a significant but lower volume. My suggestion here is based on that automation idea. (0) Preparation is die forming preformed shaped glass blanks from molten glass with the correct final solid volume and holes for the pins. (1) The preforms are loaded into a first station probably using a tubular magazine form and loaded individually onto a die-base, (2) The die-base is moved to a pin insertion station which loads the pins through holes in the preform, (3) The loaded die-base is moved into the heat die-forming station where it is heated and die pressed to final form (4) The die-base with the formed glass base is moved to a cooling station for controlled cooling after which the finished base part is removed. Notes: 1. The final die-form may have to be insulated or possibly die heaters to ensure that the die does not cause fracture stresses in the part due to premature surface cooling of the molten glass during its formation. 2. The finished component may have to be annealed to alleviate any residual stresse build up.
@@kentswan3230 also good point !
Yep that was my thought too. Make a ring with larger holes for the pins to pass trough, then heat and stamp this one onto the pins.
@@SarahKchannel Yep except I extended the thought to a button shape blank so that the area in the center has the required thickness of glass. When put through the hot die the glass should squish up into the forming die around the pins with minimal excess. You need somewhere for any extra molten glass to go which, in my mind is the center area, not the edges. Effectively the top die closes against the bottom die with a draft angle and an edge that cuts off any squish but most of the squish should go toward the center where the bit of extra volume allowed for it. Dies are complicated. I found that out designing parts for injection molding.
Another advantage to manufacture in-house, which I learned from you: if, later on, there turns out to be a quality issue, it'll be way easier to fix the production line if you control it. Not that I expect any quality issues from your operation -- you seem pretty careful in these videos -- but it happens to the best of us. Congrats on landing a prop job for a TV show! That's cool.
Yes, thats another reason - if you have a problem with a 3rd party product, you really need to be important customer so they dig into it. And thats the problem :-) So better to have it under control. I am careful, but some crap always happen!
I think one thing you haven't mentioned anywhere that I can see is controlling the mould temperature. Given that you are dealing with large metal pieces with equally huge thermal mass - consistent mould temp (of, let's say, 20c below glass melt temp) might help a lot.
I just made a comment saying the same thing and then next one down is yours LOL! and yes I completely agree he has to nail that down
Thanks for the tip, the mold temp will be discussed!
Fascinatingly complex engineering. I love your work.
I absolutely love seeing these videos about the problem-solving process! If I lived in your part of the world, I’d volunteer to work for free (I’m semi-retired) just to be able to be a part of the process 😁
Thats something I would like to make happen one day, create conditions so people can come a spend some time here!
This is one of those mad scientist development projects. You just gotta keep trying more and more creative silly things until it starts going right. I love that you are sticking with it and experimenting freely without getting desperate for trade knowledge. You can totally figure this out and you’re gonna get all the credit, one of the best feelings.
May I give you 2 maybe crazy ideas: 1. Make the mold up-side-down, it is easier to use it as a storage for the glass you are melting (to let it melt into a form) rather than flat table when it tries run away. 2. Have 1 or 2 adjustable induction heaters for the upper and lower molds, to adjust the temperature slightly less than glass melting point. It would help with controllable glass melt process and (if you use 2 levels) keep the molds hot enough for the easier extraction. I was in Czech once in my life, hope I can do it again :) Good luck!
Congratulations on the TV exposure! It's well-deserved 😎
These videos are so interesting, love to see the progress!
Thanks for sharing your progress Dalibor! The design of this manufacturing center is a good illustration that Simple and Easy are not the same thing; in fact they are often opposite: a _complicated_ machine is often *easier* to design than a _simple_ machine. In this case, I would find it easier to design the carousel type machine than a single station machine. With the carousel design, each stage only performs one action, e.g, First Stage Preheat. This makes each stage pretty easy to design. Because the single station design needs to perform every different action, it needs to be much more complex than any of the carousel stages while still fitting in the same size envelope, and thus it is more difficult to design. As a manufacturing engineer, I would much rather design the carousel machine than the single station machine 😀
Thats a perfect summary, the carousel might look complex, but it is easiest to build! Keep in touch!
You gonna end up making CRTs :)
Thank you for the gorgeous cinematography.
I love the iterative design process. Also called empirical design. The 3 clocks for the TV show are sensational as well. I'd never considered AI as a design tool!
Great work as usual! Congrats on the TV clocks. I really like the 1N-12 version too. You should sell it!
This is awesome. I have done a lot of research into making tubes for ham radio mostly. Thanks for the insights
Great work
Hi Dalibor, I think that you don't need a full 24 head carousel production tool. You just need one working position with two or three separately controlled burners, carousel of tooling heads and good automation. In the production carousel, there are positions for pre-heating, re-heating, controlled cooling, that don't require additional tool so your tooling carousel will be much smaller. Though you will be running at 1/24th production rate. It is very interesting project and I might be able to help a little 🙂(I am located in Bratislava). Good job.
Hi, thanks for the tips, I was actually thinking this way first. But it gets complicated when you start thinking about different flame positions (there are at least 10 positions for burners in the RCA procedure) + positioning of the pin loaders, stem extractor etc.. a lot of moving stuff. It is easier to build the system around an indexing table I guess..
@@daliborfarnyI was thinking something like a 3-5 position carousel, with the different flame heads. as you mused in video, the problem with trying to do all the steps in one spindle position is how complicated the space becomes with all the moving parts and active flames. you could possibly do something with say, 5 positions of carousel and 2 sets of flames that switch in and out. distribute the complexity somewhat
You are a fine engineer and an artist, and I wish you every success.
if he succeeds vacuum tubes as a concept will survive
❤a great throwback to my 1980’ies childhood, watching both Arabela and Návštěvníci on german tv broadcast. I am surely going to eatch this new tv series on ZDF in september! Greetings from Denmark
Wait, you could watch Návštěvníci in Denmark? No way.. My childhood as well..
@@daliborfarny I grew up just north of the border to Germany, and watched more german than danish television.
I wonder if the bottom half of the stem mould could be raised up and heated inductively. It could serve as a decent preheating option and it could prevent sticking and as an induction coil is both heating evenly and relatively low profile it could easily fit there in my opinion. It can also be water cooled and it is relatively insensitive to open flames
Nice progress! One thought about the pins melting sooner than glass. How about the pins being on the one side of mold slightly preheated with the form. On the other side you would melt the glass with more powerful burner. And when they are both on the correct temperatures press it together? Problem is that the technical solution would be a pita to make work correctly in vertical position. Also on the problem of glass sticking to the mold. Use brass for molds, polish them and put bees wax on them before pressing. Or graphite. With the graphite you wouldnt have a problems with tighter tolerances after heating (and glass flowing where it shouldnt) and removing of cold finished stem. Also graphite doesnt need bees wax. Proper preheating of the molds before pressing might be critical for smother finish on the glass without wrinkles. Each mold material would have different temperatures for this, choose one with similar temp as ideal sealing temp for the pins. You cant polish the glass with flame or do a second pressing, because you risk melting the pins again. Last thing, with current setup, try higher rpms for glass tube collapsing further from the pins when melting it, centrifugal force is your friend in this case. When you decide to build the carousel machine, that document is a Holy grail!
Bees wax would give a hell lot of smoke and i don't think is up for these temperatures. But it certainly could interfere with the glass to metal seal and contaminate that! There is a liquid graphite coating called 'aquadag' that is also mentioned in the RCA papers. You can just brush that on the mold. Dalibor has this aquadag so he can test it. It is merely to prevent sticking which you get when the glass starts to stick/seal to the metal mold which happens when the mold gets really hot. But in this case it is more stuck ie jammed in the mold. No anti stick material would help against that.
In the second half of the video, the mold is already brushed with the aquadag from you- I totally forgot to mentione that. It helps a lot and is simple to apply.
You in fact have 2 problems with this glass base and I'm relying on some anicdotes from when my father worked in these factories back in the 50s. The trick to glass is keeping everything hot and lots of pressure. You're press is ambient temp and do not have enough pressure which leads to rge glass cooling before it's properly formed
Thanks for the info! Will keep it in mind at the next try.
That tv series sold itself to me with the chicken more or less escaping the oven 😅
It really looks like a fun show, it's a shame I don't understand a word of Czech!
@@dariusliadon If they caption it for German maybe they'll be able to translate that into English; I'm happy with a machine translation.
I would consult with a university scientific glass blower. Most have at least one of them, and they tend to be extraordinary problem analyzers and solvers.
I think you need a n ejector mechanism, where each pin has an ejector pin pushing up from below. The same way injection molding often works.
Is it possible to retain the pins in the top part of the mold? Then melt the glass in the bottom part and press the pins in? That would give advantage of being able to heat the pins independent of the glass and possibly controlling how much glass adheres to them.
woah I love the AI generated clock! such a cool idea!
I feel like solid-state electronically-controlled heating would give you greater temperature regulation, so you would not overheat the metal, and being able to apply a heating and cooling profile would carefully control the process for annealing as well. Gas torches seem like a really difficult way to control heat for this process.
What about a 2 step molding process? A first mold that melts a glass tube into a thick ring with holes for pins, then the second mold stamps this thick ring into its final shape with the pins installed? It would let you heat the tube without the worry of melting the pins. This would also allow the batch production of "stem blanks" on the same molding equipment, and then resetting the machine for molding in the pins.
Good vid! Now do one on evap systems haha
I think if the pins were pressed in from the top (press) mold you won't have the issue with glass on the pin contact area. Maybe see if you can find some old videos of vacuum tube construction. or see if you can find an old vaccum tube base press (or dies) as a starting point. Considering CRT tubes were still getting produced in the 1990s, I presume there has to some equipment available somewhere.
Zdravím Dalibore, ta pauza mezi #7 a #8 byla pro mě "nekonečná" 🙂 ale chápu že toho máte na vývoj až až. Moc držím palce abyste všechny problémy vyřešil co nejdříve. Můj obdiv k tomu co děláte neopadá. Mějte se moc fajn a nezapomínejte že je třeba i odpočívat.
Zdravím Vás, moc děkuji! 95% času nám teď zabírá velký projekt, který bude brzy venku.. Tak potom snad bude víc času.. Na odpočinek to moc nevypadá, blbá doba :-)
Fascinating work. What metal are the pins made from?
Alloy 52, it is nickel iron alloy, roughly 50:50
Invert the mold such the bottom is larger diameter cup and top is smaller diameter insert; this prevents glass overflow beyond bottom cup diameter. Control hot gas temperature to well above glass melt point and well below pin melt point; glass will melt slowly but pins won't melt ever. Consider heating bottom cup such that glass flows which may remove need to spin the mold. Think glass casting. Think temperature controlled hot gas source (flame used now mixed with the right amount of ambient air). Think inductive heating the metal mold parts.
Interesting ideas. I am afraid it would be difficult to heat the glass - if you heat it in a metal mold, it will stick to it. Graphite might be a solution, but would wear out quickly I guess..
@@daliborfarny Glass mold release is readily available. You're stuck in a mind set of heating glass just one way. Would you like me to start a document to banter about options? I don't see you controlling process temperatures; accurate temperature control is critical to repeatability. I don't see you considering glass, pin, and mold melting points. The process becomes easy when glass and pin melt points are wide apart so heating with gas at intermediate temperature solves pin melt issue. The cup bottom makes gravity your friend.
@@daliborfarny When building a new mold; heat a pin batch to above the glass melt point but below the pin too soft point and measure pin diameters at temperature and size mold pin holes accordingly.
I feel like separating the heating of the glass and the heating of the fixture would help a lot. Is it possible that you could drop a small slug of molten glass with high thermal capacity into the center of the mold while using torches to keep the mold and pins at a consistent pre-heat temperature?
Maybe a silly idea or question? Why not use a disc of glass, and make a series of small holes for the pins. Then when the disc is melted, the glass does not have to flow very far to seal against the pins. Two thoughts on how to make the holes: (1) Use something like a small diamond drill bit (if such a thing exists). (2) Or, melt the glass in a mold to pre-shape it. The mold would create holes. Then in a later step, the pins are put in the holes, and the glass is melted a second time. Maybe this wouldn't work, because: (A) If drilling, the process is too slow for production? Also, the drilling process might contaminate the surface of the glass, and cause a bad seal? (B) For various technical reasons, maybe the glass cannot be melted more than once without causing problems? Sorry if these are bad ideas or questions. I know almost nothing about glass work and manufacturing.
Thank you for the tips, I will discuss the ideas.
I have a vague memory of watching a documentary in which the pins came into the stem pressing process already coated with a droplet of glass. I have no idea if that was to make the seal better or to use two glass types (one of which bonds to metal better, the other is better for pressing or something) or what, but perhaps it would allow to use a small disc of glass for the inner part and a piece of pipe for the outer part, while also having enough glass from the droplets to fill space between the pins? No drilling would be needed. And the pin coating process probably would be easy to automate.
Have you thought about using an insulative material, like ceramic, to heat the glass on? I don't know how glass works, but metals tend to be very good at wicking away heat, so maybe that's why the bottom doesn't heat up as well? I don't know if glass would stick to the ceramic, though.
Thought the same.
Cool
It seems to be HOT to me 🙂
Would it help insulating the two cast iron pieces from the mould support structure so that the heat doesn’t just get sucked out of the mould by the surrounding cold mass? Great videos BTW love this channel.
I wonder if you need a reverse draft angle on the top die? So it's almost like a blade then the surface area is small so it shouldn't stick but you can have tight tolerance to keep the glass clear, also maybe adding a mm of movement to one on the dies so they can get themselves concentric with each other during the press?
That mm of movement is something that was planned in the first version, it will be necessary to get the molds concentric.
have you considered making an die to form the glass prior to insert the pins, and then transfering to this machine?
Typicall the stems are pressed twice. The reason is to get better flow, not sure if it is possible to do it in just one press. Between the presses, the stem is lifed up from the lower mold by the pins. if you apply even pressure you can lift them up, and then you can heat both sides to get excellent flow for the final forming press. That is the problem you are having that the glass on the bottom will not flow because the mold will cool it to much and you can't get heat there. From what i know, it will be tremendous more difficult to do it in just one.
Thank you very much for the idea, it make sense. In any of the videos of stem forming I havent see the stems being lifted - but I read somewhere about it. To get flames under the stem.. More presses - thats a must, for sure!
Any chance starting with heating the glass part/shape first then pushing the pins through would be better?
have you considered using a different material for a mold? Maybe graphite?
One step seemed to be a roller that squeezes the glass into the gaps between the pins. Perhaps that is important?
The RCA document could still be useful for a simpler machine: the document gives you a description of the process. Whether that process is carried out on a 24-step carousel or on a simpler machine with only one working position, the process could be very similar.
Hey @Dalibor Farný, I have a question. Are there such a thing as other noble gas nixie tubes? Ones that glow different colors or something?
Hi! Other gases would make a different colors, but very low brightness and extremely low lifespan compared to neon. E.g. Argon is blue/purple..
I might have suggested this before, but my gut instinct tells me to try making the mold from graphite.
Or similar thermal properties maybe a ceramic ?
@@andymouse I think ceramic would bond with glass...
Thats a good point ! however ceramic to metal seals can also be a pain@@SarahKchannel
@@andymouse i worked with metal pass troughs in high temp and vacuum applications about 30 years ago. Back then the metal parts had to be coated in several coats of different glass types. Starting high lead content to low. Where the lead helped to bond to the metal and made the glass flow better. thinking about that makes me believe that just the pressing of glass might not form a good enough seal / bond. For the ceramic, ceramics are often glazed for practical reasons, so glass and ceramic seem quite happy to form bonds. In glass blowing graphite is often used as shaping tools, hence I think it would be a better material. Also graphite is relatively easy to machine and is very tolerant to high temp - only down side its more brittle and messy to machine,
This combo of glass/metal is industry standard combination (Schott 8350 - Alloy 52), so it will make reliable joint. Your are right with lead glass - this flows better, but then we would have Pb in the product (RoHS).
I wonder if a thicker tubing wall would help with the lack of infill?
Yes, that will be discussed in the next one!
Maybe if the pins were placed in the upper part of the mold. Then glass could be melted on the bottom piece, snd rhen jam the pins through the molten glass.
Have you tried to first make something like a small disc with holes where the pins need to go and in second phase put this disc together with pins in the mold and make final part?
This would be very slow - but I will dicuss it next time.
Isn't it the issue with how glass curls after being heated? From the old clips it seems that one glass layer should be enough, provided it curls properly. Besides observation that gas torches seem to be crucial as well, I can't come with any smart solution. Actually, I'd enjoy joining your effort even for a while to play with this problem - sadly I can't.
Do you plan on making triodes in the future?
Nope, laser focus on nixie tubes..
@@daliborfarny I see, I hope you succeed in manufacturing the stems
will it be possible to make a keyboard the font light with nixie lights
It seems that in the documentary they used much longer pins and much thicker glass tube.
Yes, they use different type of feedthroughs.
Not hindered by any form of knowledge I would like to offer my 2 cents: How about to make the glass ring and drill the holes for the pins in the glass ring and then secure / seal them by melding the glass.?
Uninformed comment from left field: is an epoxy base possible with an epoxy-based bond to the glass? Control of the epoxy would be much easier and more predictable.
I wonder if you could heat up the bottom mold. Not hot enough to make the glass flow, but enough so that it won't cool down so quickly. The 3D printer folks do something similar.
too hot mold makes the glass stick to it, but hotter mold draws less heat from the glass..
@@daliborfarny yeah, clearly there is a lot of art to this stuff.
May be a different mold could help.
Just wondering if you are still using boro Schott, or trying any of their leaded stuff? My boro supplier is UST in America. They claim they are the only Schott importer in my country. I want a few cases of leaded crystal for it's acoustic properties, but they'll only supply it unless I buy the whole shipping container 🤦
Leaded would be best, but we wouldnt pass RoHS. So, I use Schott AR (8350) which seals well to Alloy 52. Glass to metal sealing will be discussed later.
Вы не думали попробовать сделать форму из графита? Мне кажется, он лучше подходит для данной цели. Стеклодувы используют графитовую оснастку для производства сложных химических реакторов.
yes, graphite is a backup solution.
Maybe you came up with the solution yourself, but to counter the "overflow" just remake your molds, so that the bottom mold has the outer lip that stops the glass, or make a spring loaded two part top mould.
Dali can you share a link to that friend of yours who is trying to revive CRTs? Because I really wanted you or someone of your caliber to tackle that problem next! :D
Hopefully Jerome will get them to working state one day!
@@daliborfarny What's his channel name, Dali? I made a typo in the comment. I wanted to know where I can see his progress. :)
I wonder if there's an old carousel machine sitting in someone's shed, waiting for you.
Me too, I secretly hope for it. I was able to obtain some machines already this way, I am so grateful for reach of the videos..
jedine co ma napadlo bolo pouzitie elektro indukcie k ohrevu tej spodnej casti na zvolenu teplotu..nebolo by to jednoduche ale mozne
No hlavně v tom videu z produkce je jeden hořák, co žhaví do skla a další tři, co žhaví formu ... pokud se dobře dívám.
právě ono to vždycky ohřívá to sklo, forma se ohřívá jen jako vedlejší efekt - jinak by se lepila..
A bit of 'Fringe' and a dash of 'X Files' maybe ?....cheers.
Maybe you could just use a lot more pressure? With a hydraulic press or something to force the glass to flow into the centre. A shallower draft angle and tighter clearances might be workable if you add ejection pins.
Can you really sell 20000 tubes/year? They seem like an extremely niche product.
If the tubes are cheap enough maybe !
Honestly, this is something I dont know, but I am determined to try. We used to sell 2000 tubes per year for a price of 145 EUR. With this kind of automation, we have a potential to go below half of that price, which might help to get the tube among engineers, hobbyists..
It’s “a way to” or “how to.” It is grammatically awkward to say “a way how to.”
I am afraid I won't be able to get rid of that, my brain is already too rigid :-)
Amazing progress! Is preheating the glass in an oven to just below melting an option to make it melt better? Or making a preformed glass blank like @kentswan3230 mentioned.
Hi! Probably not, it would make the process more complex - the flames do the job well..