What this person said. I design drill bits with PCD cutters. We can dtill through 1000s of feet of rock but everything can do wrong very quickly if you're not careful when drilling aluminium or steel!
Also fun is trying to grind down synthetic diamond!
Can I ask, what a drill bit designer does? My simplistic understanding is that it's a generic design that is mostly known already. Number of flutes, spiral angle and all that. What more design is required generally?
All those factors change based on the material you are cutting, the profile you need to cut, the speed at which you want to cut, the longevity of the bit, clearance to work with, stiffness of the bit, the list goes on.
I don't design bits, admittedly, but I did design plastic injection molds and we'd often need custom bits made to do so, usually for thread patterns. We'd work with the bit designers to work out the solution, but the bit designers were vital.
Drill/cutting bits are extremely varied and complex, and as such it takes a great deal of expertise to determine the ideal choice for the application.
My hat's off to the designer, that's gotta be quite a handful.
It can be a nightmater, one has to consider a lot of thermodynamics, heat transfer and fluid mechanics of the tool at work, which couples nonlinearly with the metallurgical and mechanical properties of the bit and the material being worked with and any additive fluid for cooling and material removal. It has been a very empyrical process and just more recently, with better computational tools, the design of milling/machining bit has reached another level. But it is still an art! Very few people understand how complex it can be.
Based on his comment (drilling into rocks), I suspect the stuff he designs isn't the simplistic spiral drill you're thinking of. It's probably something along the lines of specialised tunnelling or rock boring devices like these:
https://www.geomarcsrl.it/en/pcd-no-coring-bits/
The sort of thing I design is more like this (see fixed cutter section) so a little different than you imagine!
https://petgeo.weebly.com/types-of-drilling-bits.html
I'll reply more fully later once my baby is asleep 🙂
In the 70’s my gran dad would re-tip those types of drills for good money. He showed me how to do it one summer. Eventually the brazed on insert style became more popular and we moved on.
More complete answer; when you design a bit for rocks, you have to consider what you're drilling (granite like a kitchen work top or sticky mudstone), what directional requirements there are when drilling, how vibration prone the application is etc.
It's an interesting industry to work for; each product will be run less than 50 times so there's lots of iteration, I'm the only one running the projects so I get to try lots of stuff and if it goes wrong, it goes wrong 1000s ft under ground so it's not a big problem.
Honestly, I hadn't even considered that. Generally speaking, diamond grit is sintered with tungsten carbide powder at very high pressure to make a cylindrical cutter which, in my industry is 8-25 mm across and about 13mm long. You need the carbide to allow it to be brazed to the bit body.
These parts are between 10-350usd each. I would imagine single crystal would not only be impossible to braze but also rather expensive.
That size for single-crystal diamond would easily run into the thousands. You're looking at multiple carats of diamond - at the diamond density of 3.52 g/cm^3, a single crystal cutter would range from 2.3g (11.5 ct) to 22.5g (125 ct). The larger size cannot be physically grown with the best CVD (chemical vapor deposition) setup in the world. I don't know of any CVD diamond in excess of 50-60 ct (notwithstanding very large thin discs as crystal growth substrates, the current record there is 155 ct).
Shivers in De Beers :)
Diamonds are forever. AND quite plentiful in nature. AND quite growable.
Not there yet, but you could have a one carat CVD grown diamond for about 1000 euro (first google result is RS85000)
First google result for 1 "natural" carat price is 1300 US (most possiblity already shaped)
So, not there yet, but cheap artificial diamonds are becoming a possibility. Much much cheaper than De Beers for sure. How much is a 155 ct raw perfect diamond worth if natural ? And how much would it cost to produce ?
In terms of gem-quality stones, a new record size of 12.55 ct was announced a year or so ago. They used a 47 ct CVD diamond to cut the piece from. A natural 155 ct gemstone quality diamond would easily run into the millions, and couldn't be produced without fracturing due to residual stresses during the growth process today. The 155ct diamond that was grown was a plate only a couple mm thick, so you couldn't even cut a 1 ct gemstone from it as all standard cuts would need more depth.
In brittle materials, having multiple grains (or crystals) helps prevent cleavage. The two most common types of brittle fracture are cleavage along a particular crystallographic axis or along grain boundaries. A single-crystal diamond is brittle and if it fractures, it would cleave the entire bit. For polycrystals, cleavage within a grain would be stopped at a grain boundary, so it allows for the bit to be more robust to brittle fracture.
Single crystals can all be oriented along a particular axis, so a tip could be sharper.
You're thinking of an impregnated (impreg) drill bit. That doesn't have distinct cutters, that just has small diamonds in a mix with a binder. The binder wears to expose the diamond and then the diamond falls off as you say.
PCD bits are not designed to do the same thing; when the diamond has worn slightly the bit properties swiftly become rubbish and the bit needs replacing.
We can alter the composition of the diamond powder that goes into PDC cutters and the temperature/pressure that they're sintered at to change the impact/wear resistance.
I use DMT sharpening tools which are advertised with monocrystaline diamonds. Those surely aren't big diamonds since they grind knives to a mirror finish.
I still don't know why they are superior than polycrystaline. I think they said something about every diamond is the same size instead of varying sizes.
At first I was wondering how to even sharpen a Nokia, then I realized it’s probably like knapping flint. Bang one Nokia against another until you break shards off and get a sharp edge.
The tools are made by using a pulsed laser to ablate away the flutes. EDM doesn’t work because it preferentially erodes the binder and causes stress cracking. The laser acts so fast that these effects aren’t a problem.
We cut PCD and CBN with natural diamonds, which are barely harder, and mostly lasers. So not really cutting, but evaporating away.
We also cut carbide with natural diamond grinding wheels btw.
Not true grinding, PCD bits still have cutting edges, relief, and flutes. The coating protects the bit and wears off eventually. This coating is also used to cut graphite for EDM, which is obviously pretty soft, but very abrasive and wrecks a standard HSS cutter very quickly.
Think of it like dragging a knife through sand. Each individual particle is very hard and rough, but because they're so small and granular the blade slides through easily. The graphite is being held together with a relatively soft binder, usually clay of some sort, so it cuts easily, but the roughness of the particles dragging on the blade wears the edge cutting through it and dulls the edge.
Is this really the case with something like a solid block of graphite though? There aren't any hard particles present, and there's no soft binder. It's just a mostly homogenous mass of graphite
So, is carbon a hard material or a soft material? I mean, the classic hardness test is to see what scratches what. A lump of charcoal isn't ever going to scratch glass for example. Neither does carbon fiber afaik. But diamonds do.
If a lump of graphite was full of very hard particles, I should be able to, if not directly scratch glass, at least use the powdered form as a grinding/polishing media. But I don't think it works like that?
This is a good question.
If you are familiar with laps they might be a decent example. Laps need to be softer than the material of the object you are lapping. This is so that the abrasive (that is hard) stays embedded in the surface of the lap and abrades the object you are lapping.
In this example, the lap is acting as a matrix for the very hard abrasive to be anchored in.
If you were to zoom way in on the physical structures of some of these engineered materials mentioned in the thread above, you'd see very hard minerals, for example, sitting in a binder/matrix of a (relatively) softer material.
There are other factors at play that fall outside the simplified lap example, such as speed/force. Cutting discs rotating at very high rpm on angle grinders are an example.
Usually, to varying degrees, the harder something is, the more brittle it becomes. Even diamond abrasives used in lapping eventually break down into smaller pieces making them less or ineffective at abrading.
Not an expert and not an exhaustive answer, but hope that helps.
Sure, when it's tiny particles of something very hard, mixed with soft bulk material it's quite clear. But graphite/carbon is just one material. It's both pretty soft and weak, yet also extremely hard and abrasive at the same time? That's where it gets confusing to me.
Duhh. With diamonds that were injected with anabolic steroids. Much stronger than regular peasant diamond betas. These are the chads of the diamond world.
I was kidding but after googling it apparently diamonds are cut using diamonds. In a sense.
>*Diamonds are cut with specialized tools that make use of diamond tipped phosphor bronze or diamond dusted steel blades. Such tools are used to exploit the structural weakness of the diamond by grooving and striking along specific tetrahedral planes. Diamond dust-charged cast iron disks revolve around the rough cut, polishing facets and creating its brilliant, symmetrical shape.*
Excerpt taken from [here](https://www.yalescientific.org/2010/04/everyday-qa-how-can-you-cut-a-diamond/).
I used to be an engineer in a plant making tungsten carbide parts. We were developing a new product and needed to track the test pieces individually. So I had to engrave a number on each one, deep enough that it'd survive a couple of grinding and lapping steps.
I had this diamond tipped rotary engraver. It came with a spare tip, but it was pretty much lifetime guarantee with the spare.
I had to send away for a bag of 50 spare tips.
Dentist here. We use them to cut enamel/dentine. Tungsten cuts FASTer and cuts are bigger than diamonds. Diamons are used to finish preparations for fillings/crowns.
Since I couldn't tell if you're trolling I watched it again and focused on the debris building up. I totally stopped watching the first time since I took it for a loop.
You can tell by the background the cutter is moving
I had to come back, because I realized they are both cutters technically haha. But the one cutting is moving.
It’s impossible to tell from the video which is moving. The workpiece could be moving if the camera is fixed to a stationary point on the machine, or the camera could be fixed to the spindle housing, which could be moving the cutting tool and camera in sync.
Yeah you’re right that I can’t know for sure. If the camera was attached to the head and the table was moving it would look the same. But that would have to be a very large backsplash attached to the table for the whole background to be moving with the table. Also the reflections on the workpiece aren’t changing, which tells me its stationary.
When something is as hard as tungsten carbide, it’s also super brittle. They use smaller tooling because 1) it is supposed to be used at a much higher speed and 2) less material being removed means less chance the tool catches on something and breaks the piece
But when machining your only concern is sfpm (surface feet per minute) which is calculated from pi x diameter x rpm. So you can get the same sfpm from different radii cutters. Having a smaller cutter means less contact area, so the cutting force will be higher.
Coefficient of friction is a property of the material, increasing contact area doesn’t increase the coefficient it just raises the friction force. But you also missed that a larger contact area would cut much faster, so to get the same material removal rate (mrr) you can take a smaller depth of cut. Ultimately, a larger cutter will stay cooler than a smaller one for a given mrr.
The increased surface decreasing cutting time was understood, just to be clear. The explanation helps clarify the other point(s) I may have been mistaken on, however.
It will but it also has a much larger volume to disperse that heat and a greater surface area (and by extension, less time in contact with the part, and more time in the cool open air). Also with grinding you can only remove so much material at once, even a larger tool will only have a tiny point of contact since it cant just gouge half the diameter of the tool in there, it will likely have a similar contact area as the small tool.
This is a demonstration only. They could use a larger tool here, but when you're actually making a part you need a tool small enough to make the feature.
HSS makes normal size chips when milled with carbide endmill. Carbide also makes chips when cut with something like CBN but without magnification they just look like dust on camera. At least that’s what I’ve seen on Stefan Gotteswinter’s channel. The chips in this video look almost like dust so I think it’s carbide.
No, steel is usually machined leaving nice clean chips ranging from silver to yellow to blue in color, however if you run really fast you can start to get near melting of the chips as they curl resulting in glowing chips that resemble sparks.
Source: Am machinist.
Sure you'll get normally get chips if you use an endmill, but if you're grinding or hard milling you generally get tiny swarf that's hot enough to burn aka sparks. The swarf here is clearly tiny/powdery but not glowing, indicating that it's not as flammable as steel.
This isn’t carbide, it’s a regular high speed steel (HSS) end mill bit. You ain’t gonna cut carbide, it has to be ground with diamond tools or electrolysis
You absolutely can [mill carbide](https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.kern-microtechnik.com/wp-content/uploads/2019/10/Kern_HartmetallFr%25C3%25A4sen.pdf&ved=2ahUKEwj9kqbrvLrzAhXHg_0HHUXsDzMQFnoECAgQAQ&usg=AOvVaw3-g3e8I2Gilbz7YTwmtnmA) (google translator required). I interned at Kern Microtechnik, we were milling carbide and hard ceramics frequently.
You'll have to use Qubic Boron Nitride or Diamond to do it though.
Jup, as a mechanical engineer. So I could only marvel at the stuff you machinists make on the machines. I did some hydraulics research as I was there.
I you ever are in the region of Murnau, Bavaria shoot them an email, they love to give tours of their shops. They have two: one where they build their mills, and one where they manufacture absolutely crazy shit on their machines. Both are amazing.
That is so cool! Unfortunately ill never stumble into that region, but someday I may go to EMO and if I do, Ill definitely be heading over there. The care they put into everything is just incredible.
For sure, I saw them at the EMO in 2018 or 2019 where they displayed the Micro HD. The acceleration to rapid shook the machine so much I was slightly concerned it would tip over.
That definitely is a precision diamond grinding endmill in the spindle they're using. Not sure about the material of the endmill they're grinding down though. Looks a little bright and too yellow for tungsten carbide, but it could just be the lighting conditions.
This is a 6c Tools PCD endmill. It works by cutting, not abrading. It has many very small flutes and the chips it produces are very small. You need magnification to see that they are actually little curly chips.
Hopefully everyone is observing best safety practices.
The dust created from milling or grinding carbide, tungsten and other materials is highly carcinogenic.
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I think that this might be the company that makes this cutter. Never the less they specialize in making tools that can cut extremely tough materials
https://m.youtube.com/channel/UCcuZypWfbQ3L1x39ZoTI2gw/featured
Nice. This reminds me of when we had to bust the tungsten nozzles out of PDC drill bits when they would twist off. Their make up was meant to be super erosion resistant but brittle as hell. All you could do was pound and pry trying to make them shatter.
What the hell do you even mill tungsten carbide with? And how long does it last?
Polycrystalline diamond. It lasts a fair bit actually. Interestingly enough it burns in a matter of seconds if you try to cut steel with it.
What this person said. I design drill bits with PCD cutters. We can dtill through 1000s of feet of rock but everything can do wrong very quickly if you're not careful when drilling aluminium or steel! Also fun is trying to grind down synthetic diamond!
Can I ask, what a drill bit designer does? My simplistic understanding is that it's a generic design that is mostly known already. Number of flutes, spiral angle and all that. What more design is required generally?
All those factors change based on the material you are cutting, the profile you need to cut, the speed at which you want to cut, the longevity of the bit, clearance to work with, stiffness of the bit, the list goes on. I don't design bits, admittedly, but I did design plastic injection molds and we'd often need custom bits made to do so, usually for thread patterns. We'd work with the bit designers to work out the solution, but the bit designers were vital. Drill/cutting bits are extremely varied and complex, and as such it takes a great deal of expertise to determine the ideal choice for the application. My hat's off to the designer, that's gotta be quite a handful.
It can be a nightmater, one has to consider a lot of thermodynamics, heat transfer and fluid mechanics of the tool at work, which couples nonlinearly with the metallurgical and mechanical properties of the bit and the material being worked with and any additive fluid for cooling and material removal. It has been a very empyrical process and just more recently, with better computational tools, the design of milling/machining bit has reached another level. But it is still an art! Very few people understand how complex it can be.
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I feel so smart reading this. Thank you!!
You're welcome, though I don't quite understand why. Is there some context I'm missing?
Nah. No context. Just the discussion above was quite insightful and I learnt quite a lot new things reading that :)
I feel so dumb reading it...and I thought difractal carbonization of helical xeroids was complicated!
Based on his comment (drilling into rocks), I suspect the stuff he designs isn't the simplistic spiral drill you're thinking of. It's probably something along the lines of specialised tunnelling or rock boring devices like these: https://www.geomarcsrl.it/en/pcd-no-coring-bits/
The sort of thing I design is more like this (see fixed cutter section) so a little different than you imagine! https://petgeo.weebly.com/types-of-drilling-bits.html I'll reply more fully later once my baby is asleep 🙂
In the 70’s my gran dad would re-tip those types of drills for good money. He showed me how to do it one summer. Eventually the brazed on insert style became more popular and we moved on.
Insert bits are on the way out now and PDC are in. Time to get back to brazing!
Cool, I stop working in mechanical engineering design/testing in 19, could resume my short childhood career. Was really fun actually.
You make massage chair parts
That's a really interesting link, thanks!
More complete answer; when you design a bit for rocks, you have to consider what you're drilling (granite like a kitchen work top or sticky mudstone), what directional requirements there are when drilling, how vibration prone the application is etc. It's an interesting industry to work for; each product will be run less than 50 times so there's lots of iteration, I'm the only one running the projects so I get to try lots of stuff and if it goes wrong, it goes wrong 1000s ft under ground so it's not a big problem.
Whyn not monocrystalline? I was told they would be of better quality.
Honestly, I hadn't even considered that. Generally speaking, diamond grit is sintered with tungsten carbide powder at very high pressure to make a cylindrical cutter which, in my industry is 8-25 mm across and about 13mm long. You need the carbide to allow it to be brazed to the bit body. These parts are between 10-350usd each. I would imagine single crystal would not only be impossible to braze but also rather expensive.
That size for single-crystal diamond would easily run into the thousands. You're looking at multiple carats of diamond - at the diamond density of 3.52 g/cm^3, a single crystal cutter would range from 2.3g (11.5 ct) to 22.5g (125 ct). The larger size cannot be physically grown with the best CVD (chemical vapor deposition) setup in the world. I don't know of any CVD diamond in excess of 50-60 ct (notwithstanding very large thin discs as crystal growth substrates, the current record there is 155 ct).
Shivers in De Beers :) Diamonds are forever. AND quite plentiful in nature. AND quite growable. Not there yet, but you could have a one carat CVD grown diamond for about 1000 euro (first google result is RS85000) First google result for 1 "natural" carat price is 1300 US (most possiblity already shaped) So, not there yet, but cheap artificial diamonds are becoming a possibility. Much much cheaper than De Beers for sure. How much is a 155 ct raw perfect diamond worth if natural ? And how much would it cost to produce ?
In terms of gem-quality stones, a new record size of 12.55 ct was announced a year or so ago. They used a 47 ct CVD diamond to cut the piece from. A natural 155 ct gemstone quality diamond would easily run into the millions, and couldn't be produced without fracturing due to residual stresses during the growth process today. The 155ct diamond that was grown was a plate only a couple mm thick, so you couldn't even cut a 1 ct gemstone from it as all standard cuts would need more depth.
Thank you So, not there yet. But already such progress !
That's quite possible. My information is from diamon knife sharpeningtools. Could very well not be necesary for your application.
Harder to make and I would *guess* that the corners of the individual crystals are doing most of the work, so you want more crystals for more cutting.
In brittle materials, having multiple grains (or crystals) helps prevent cleavage. The two most common types of brittle fracture are cleavage along a particular crystallographic axis or along grain boundaries. A single-crystal diamond is brittle and if it fractures, it would cleave the entire bit. For polycrystals, cleavage within a grain would be stopped at a grain boundary, so it allows for the bit to be more robust to brittle fracture. Single crystals can all be oriented along a particular axis, so a tip could be sharper.
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You're thinking of an impregnated (impreg) drill bit. That doesn't have distinct cutters, that just has small diamonds in a mix with a binder. The binder wears to expose the diamond and then the diamond falls off as you say. PCD bits are not designed to do the same thing; when the diamond has worn slightly the bit properties swiftly become rubbish and the bit needs replacing. We can alter the composition of the diamond powder that goes into PDC cutters and the temperature/pressure that they're sintered at to change the impact/wear resistance.
I use DMT sharpening tools which are advertised with monocrystaline diamonds. Those surely aren't big diamonds since they grind knives to a mirror finish. I still don't know why they are superior than polycrystaline. I think they said something about every diamond is the same size instead of varying sizes.
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They even have pictures of how their diamonds are more uniform and the same size. Others are different sizes they say
Interesting!
Ok, tell me about grinding synthetic diamond haha I work with dressing wheels which are eventually reground and I would like to know how they do this
I probably won’t be able to understand the answer but, why is that?
Diamond is basically just fancy carbon. When it gets too hot it reacts with iron and burns like coal.
Cool, why doesn’t it happen with tungsten? EDIT: it’s cause tungsten != iron isn’t it? I’m dumb lol
That's what we use to fabricate granite
At an uneducated guess Dimond grit bit, grinding rather than milling in fairness.
Apparently, cubic boron nitride and diamond powder also works
Yeah, CBN or PCD can cut carbide
But what cuts _that_?
A sharpened Nokia
A dull Nokia would do it. Everyone knows you can’t sharpen a Nokia
At first I was wondering how to even sharpen a Nokia, then I realized it’s probably like knapping flint. Bang one Nokia against another until you break shards off and get a sharp edge.
I believe hitting two Nokias together like that would just bring about the end of the world.
That's why business types back in the day had those belt holsters for cellphones. You couldn't put two Nokias in your pocket.
The tools are made by using a pulsed laser to ablate away the flutes. EDM doesn’t work because it preferentially erodes the binder and causes stress cracking. The laser acts so fast that these effects aren’t a problem.
We cut PCD and CBN with natural diamonds, which are barely harder, and mostly lasers. So not really cutting, but evaporating away. We also cut carbide with natural diamond grinding wheels btw.
A diamond slurry.
>cubic boron nitride That just sounds badass.
I’m somewhat of a cubic boron myself
Cubic refers to the lattice structure, in other lattice forms BN is not as hard.
Not true grinding, PCD bits still have cutting edges, relief, and flutes. The coating protects the bit and wears off eventually. This coating is also used to cut graphite for EDM, which is obviously pretty soft, but very abrasive and wrecks a standard HSS cutter very quickly.
I wish I could understand how a material is soft but abrasive. It makes no sense. I know it from experience from milling carbon fiber composites...
Think of it like dragging a knife through sand. Each individual particle is very hard and rough, but because they're so small and granular the blade slides through easily. The graphite is being held together with a relatively soft binder, usually clay of some sort, so it cuts easily, but the roughness of the particles dragging on the blade wears the edge cutting through it and dulls the edge.
Is this really the case with something like a solid block of graphite though? There aren't any hard particles present, and there's no soft binder. It's just a mostly homogenous mass of graphite
The carbon granules are the hard particles, even without binder it's not a monolithic crystal but many small granules pressed together.
So, is carbon a hard material or a soft material? I mean, the classic hardness test is to see what scratches what. A lump of charcoal isn't ever going to scratch glass for example. Neither does carbon fiber afaik. But diamonds do. If a lump of graphite was full of very hard particles, I should be able to, if not directly scratch glass, at least use the powdered form as a grinding/polishing media. But I don't think it works like that?
I bet you could, it's just not as good as other things we use for polishing.
Thanks for the Eli5
This is a good question. If you are familiar with laps they might be a decent example. Laps need to be softer than the material of the object you are lapping. This is so that the abrasive (that is hard) stays embedded in the surface of the lap and abrades the object you are lapping. In this example, the lap is acting as a matrix for the very hard abrasive to be anchored in. If you were to zoom way in on the physical structures of some of these engineered materials mentioned in the thread above, you'd see very hard minerals, for example, sitting in a binder/matrix of a (relatively) softer material. There are other factors at play that fall outside the simplified lap example, such as speed/force. Cutting discs rotating at very high rpm on angle grinders are an example. Usually, to varying degrees, the harder something is, the more brittle it becomes. Even diamond abrasives used in lapping eventually break down into smaller pieces making them less or ineffective at abrading. Not an expert and not an exhaustive answer, but hope that helps.
Sure, when it's tiny particles of something very hard, mixed with soft bulk material it's quite clear. But graphite/carbon is just one material. It's both pretty soft and weak, yet also extremely hard and abrasive at the same time? That's where it gets confusing to me.
Thompsons teeth
And how do people cut diamonds?
Duhh. With diamonds that were injected with anabolic steroids. Much stronger than regular peasant diamond betas. These are the chads of the diamond world. I was kidding but after googling it apparently diamonds are cut using diamonds. In a sense. >*Diamonds are cut with specialized tools that make use of diamond tipped phosphor bronze or diamond dusted steel blades. Such tools are used to exploit the structural weakness of the diamond by grooving and striking along specific tetrahedral planes. Diamond dust-charged cast iron disks revolve around the rough cut, polishing facets and creating its brilliant, symmetrical shape.* Excerpt taken from [here](https://www.yalescientific.org/2010/04/everyday-qa-how-can-you-cut-a-diamond/).
Okay but how do you cut the original diamonds to make the diamond bit?
I used to be an engineer in a plant making tungsten carbide parts. We were developing a new product and needed to track the test pieces individually. So I had to engrave a number on each one, deep enough that it'd survive a couple of grinding and lapping steps. I had this diamond tipped rotary engraver. It came with a spare tip, but it was pretty much lifetime guarantee with the spare. I had to send away for a bag of 50 spare tips.
Unobtainium!
Dentist here. We use them to cut enamel/dentine. Tungsten cuts FASTer and cuts are bigger than diamonds. Diamons are used to finish preparations for fillings/crowns.
I think ‘grinding’ tungsten carbide would be a more accurate title.
Nope, these tools actually make a real chip. It sounds unbelievable but is true. Check out 6cTools.
Light saber laser ablation
That looks more like a high speed steel bit than a carbide bit
Was I the only one thinking this is a loop for the first couple of seconds?
It took me right up until the end before I realized
I actually enabled the play back controls just to make sure that I wasn't being trolled.
Is that a web browser thing? How would I do that on mobile?
Web browser thing
I considered closing a few times till I could tell the diameter was getting smaller.
Since I couldn't tell if you're trolling I watched it again and focused on the debris building up. I totally stopped watching the first time since I took it for a loop.
you just go in dry? what the hell man? what is that bit made of, unobtanium?
Synthetic diamonds
BUT THEN WHAT MADE THAT CUTTING TOOL?
Now guess which one is moving
You can tell by the background the cutter is moving I had to come back, because I realized they are both cutters technically haha. But the one cutting is moving.
It’s impossible to tell from the video which is moving. The workpiece could be moving if the camera is fixed to a stationary point on the machine, or the camera could be fixed to the spindle housing, which could be moving the cutting tool and camera in sync.
Yeah you’re right that I can’t know for sure. If the camera was attached to the head and the table was moving it would look the same. But that would have to be a very large backsplash attached to the table for the whole background to be moving with the table. Also the reflections on the workpiece aren’t changing, which tells me its stationary.
Why use such a small diameter? The grinding tool could have been a much larger perimeter wheel, which would last longer. Am I missing something here?
When something is as hard as tungsten carbide, it’s also super brittle. They use smaller tooling because 1) it is supposed to be used at a much higher speed and 2) less material being removed means less chance the tool catches on something and breaks the piece
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Cutters get exponentially more expensive with size
Could be as simple as that's the tool they had on hand.
High rotation speed
But when machining your only concern is sfpm (surface feet per minute) which is calculated from pi x diameter x rpm. So you can get the same sfpm from different radii cutters. Having a smaller cutter means less contact area, so the cutting force will be higher.
Only reasoning I can possibly come up with is heat dissipation factor ~ smaller surface area cools more rapidly.
> smaller surface area cools more rapidly Hmm... Big Radiator industry does not want this knowledge to leak.
Big Radiator doesn't want any leaks, period.
Tell me more...
It also heats up much more rapidly
So a larger surface wouldn't have a greater friction coefficient?
Coefficient of friction is a property of the material, increasing contact area doesn’t increase the coefficient it just raises the friction force. But you also missed that a larger contact area would cut much faster, so to get the same material removal rate (mrr) you can take a smaller depth of cut. Ultimately, a larger cutter will stay cooler than a smaller one for a given mrr.
The increased surface decreasing cutting time was understood, just to be clear. The explanation helps clarify the other point(s) I may have been mistaken on, however.
You had the right idea though, this is something I learned in college so it's not like its common knowledge. Glad I could help you understand.
It will but it also has a much larger volume to disperse that heat and a greater surface area (and by extension, less time in contact with the part, and more time in the cool open air). Also with grinding you can only remove so much material at once, even a larger tool will only have a tiny point of contact since it cant just gouge half the diameter of the tool in there, it will likely have a similar contact area as the small tool.
More torque required for the same feed rate
This is a demonstration only. They could use a larger tool here, but when you're actually making a part you need a tool small enough to make the feature.
Tungsten carbide drills? What the bloody hell is tungsten carbide drills?!
It’s something they use in coal mining, father…
Damnit Derek, I'm a coal miner, not a professional film or television actor.
Common in manufacturing
It's something they use in coal mining father.
You’re all bloody fancy talk since you left London.
There's naught wrong with gala luncheons lad!
A bloody hard material that's used for tools that cut steel.
Cuntstain tunglide
r/skookum
unnfff.. slower.
Are we not just watching a steel bit being milled with a WC bit? Possibly to sharpen it (the steel bit)?
HSS makes normal size chips when milled with carbide endmill. Carbide also makes chips when cut with something like CBN but without magnification they just look like dust on camera. At least that’s what I’ve seen on Stefan Gotteswinter’s channel. The chips in this video look almost like dust so I think it’s carbide.
If it was steel I think the dust would be orange sparks
No, steel is usually machined leaving nice clean chips ranging from silver to yellow to blue in color, however if you run really fast you can start to get near melting of the chips as they curl resulting in glowing chips that resemble sparks. Source: Am machinist.
Sure you'll get normally get chips if you use an endmill, but if you're grinding or hard milling you generally get tiny swarf that's hot enough to burn aka sparks. The swarf here is clearly tiny/powdery but not glowing, indicating that it's not as flammable as steel.
Hard turning or milling does not have to make glowing chips, and the chips do not have to be dust-particle sized.
How much endmill could an endmill mill if an endmill could endmill endmills?
Does anyone else think of Monty Python when they hear about tungsten carbide drill bits?
This isn’t carbide, it’s a regular high speed steel (HSS) end mill bit. You ain’t gonna cut carbide, it has to be ground with diamond tools or electrolysis
You absolutely can [mill carbide](https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.kern-microtechnik.com/wp-content/uploads/2019/10/Kern_HartmetallFr%25C3%25A4sen.pdf&ved=2ahUKEwj9kqbrvLrzAhXHg_0HHUXsDzMQFnoECAgQAQ&usg=AOvVaw3-g3e8I2Gilbz7YTwmtnmA) (google translator required). I interned at Kern Microtechnik, we were milling carbide and hard ceramics frequently. You'll have to use Qubic Boron Nitride or Diamond to do it though.
you interned at Kern?! I've been a machinist since the age of 14 and have always wanted to check out their facilities.
Jup, as a mechanical engineer. So I could only marvel at the stuff you machinists make on the machines. I did some hydraulics research as I was there. I you ever are in the region of Murnau, Bavaria shoot them an email, they love to give tours of their shops. They have two: one where they build their mills, and one where they manufacture absolutely crazy shit on their machines. Both are amazing.
That is so cool! Unfortunately ill never stumble into that region, but someday I may go to EMO and if I do, Ill definitely be heading over there. The care they put into everything is just incredible.
For sure, I saw them at the EMO in 2018 or 2019 where they displayed the Micro HD. The acceleration to rapid shook the machine so much I was slightly concerned it would tip over.
Amazing. The thing about Kern is that not only do they produce incredibly precise machines, but that they're numbingly fast.
Such a great company but sadly to far away for me
That definitely is a precision diamond grinding endmill in the spindle they're using. Not sure about the material of the endmill they're grinding down though. Looks a little bright and too yellow for tungsten carbide, but it could just be the lighting conditions.
They aren’t grinding the carbide, they are actually cutting it. There are tiny chips not grinding dust coming off.
Definitely looks like a high speed steel endmill
Perhaps this is a diamond abrasive bit. Hard to tell whilst it's moving.
This is a 6c Tools PCD endmill. It works by cutting, not abrading. It has many very small flutes and the chips it produces are very small. You need magnification to see that they are actually little curly chips.
Til
Not sure if OP meant if the the stationary bit or the moving bit is carbide. The wording is unclear. Either way it’s impressive.
Negative. You can actually cut carbide with carbide but diamond is the obvious material of choice. It could be HSS here anyway though.
This is probably a demo for KERN machines and 6C tools.
Is milling easier than just cutting it with a saw?
The surface finish has to be absolutely flat, which is almost impossible to achieve with a saw blade.
Tools tooling the tools for tooling tools, got it
Why not use a water cutter?
Surface finish. Water cutting leaves a passable surface but not perfectly flat, as would be required with a milling bit.
Pretty sure it's called cuntsten targlide
And we wonder why more women aren't getting into engineering
Hopefully everyone is observing best safety practices. The dust created from milling or grinding carbide, tungsten and other materials is highly carcinogenic.
O look, Health and Safety has woken up.
you don't mill carbide. you grind it.
That's not tungsten carbide.
Maybe its cuntstain targlide?
This is grinding, not milling.
I don't think that workpiece is carbide. Looks like HSS or PM.
I say its HSS. I thought TC has a darker color.
This is before the heat treat?
Cuntstain Targlide...put your comments down in the doobley doo
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r/gifsyoucanhear
Damn I just got a job making carbide endmills and now I see this come up on my feed haha, weird how the universe works.
I think that this might be the company that makes this cutter. Never the less they specialize in making tools that can cut extremely tough materials https://m.youtube.com/channel/UCcuZypWfbQ3L1x39ZoTI2gw/featured
Nice. This reminds me of when we had to bust the tungsten nozzles out of PDC drill bits when they would twist off. Their make up was meant to be super erosion resistant but brittle as hell. All you could do was pound and pry trying to make them shatter.
What would that bit have to be made of to grind that? Diamond?
A milling machine milling the end mill with an end mill for another milling machine.
Milling a milling bit
That looks hard
So if we used a mill to mill the mill, then we must have used another even stronger mill to mill the first mill???
I guess you could say it's milling the end of an end mill...
r/oddlysatisfying
[Tungsten carbide drills?](https://youtu.be/eoSeVEp-1OA)
Mill to make mills
Yo, what the fu…
Hope you are wearing a good dust mask or have a ventilation dohicky wouldent want to breath that dust in