Silicon carbide aggregate?


Results 1 to 20 of 20

Thread: Silicon carbide aggregate?

  1. #1
    Member Fungiblelaser's Avatar
    Join Date
    May 2023
    Posts
    2
    Downloads
    0
    Uploads
    0

    Default Silicon carbide aggregate?

    Have anyone tried using Silicon carbide (SiC) instead of (or mixed with) granite or quartz?

    SiC has a Youngs modulus of >400GPa, significantly higher than granite or quartz. Will this result in a higher modulus for the finished casting?

    SiC is available in 1200 to 8 mesh, roughly 5µm to 5mm. It's used for grinding stone and glass as well as for sandblasting so should not be hard to find in most places, except possibly the very fine and very course grades, but not as cheap as sand.

    It's extremely hard, which I think is mostly an advantage. But it may cause some problems such as abrasion of mold release and difficulty of processing after casting?

    Similar Threads:


  2. #2
    Member cncmakers001's Avatar
    Join Date
    Jul 2011
    Location
    China
    Posts
    463
    Downloads
    1
    Uploads
    3

    Default Re: Silicon carbide aggregate?

    Quote Originally Posted by Fungiblelaser View Post
    Have anyone tried using Silicon carbide (SiC) instead of (or mixed with) granite or quartz?

    SiC has a Youngs modulus of >400GPa, significantly higher than granite or quartz. Will this result in a higher modulus for the finished casting?

    SiC is available in 1200 to 8 mesh, roughly 5µm to 5mm. It's used for grinding stone and glass as well as for sandblasting so should not be hard to find in most places, except possibly the very fine and very course grades, but not as cheap as sand.

    It's extremely hard, which I think is mostly an advantage. But it may cause some problems such as abrasion of mold release and difficulty of processing after casting?
    Quite a new idea, you can try and share the experience.

    http://cncmakers.com/cnc/controllers/CNC_Controller_System/CNC_Retrofit_Package.html


  3. #3
    Member peteeng's Avatar
    Join Date
    Jul 2018
    Location
    dum dum
    Posts
    6248
    Downloads
    0
    Uploads
    0

    Default Re: Silicon carbide aggregate?

    Hi Fungi - Granted SiC has a high modulus but its expensive. I have made some coupons that are at a lab getting tested at the moment in ALOX which is 300GPa. One issue with any ceramic is that that they are crystalline and have different stiffness in different directions so although they have high E in one direction there will be a direction that has low E. So the average maybe not as good as you think. The other thing is that once you cast the stuff you have made a grinding wheel and need diamond tooling to even scratch it.

    My alox samples just slide like glass on files. So you have to cast in metal inserts or post-cast attach inserts. Last is that roundish particles do not strain transfer very well in a matrix, long fibres are better. So the efficiency of the composite will be down. My tests should be done in a week or two and I'll know more. I'm having aluminium grit, alox grit, steel fibres and some nano stuff tested. My current research is resulting in using UHPC, CSA grout or similiar. E=50GPa plus and I can buy it at the local hardware just add water. Epoxy has become very expensive and it does not like water. Moisture content in an aggregate is huge so bonding, hence strain transfer is questionable. I have vacuum cast many grits (metal and ceramic) in epoxy and the amount of water that comes out of the aggregate under vacuum before it dries is huge....If you just added epoxy to the aggregate I doubt it would be effectively coupled to it.

    I think the engineering grout path is the best path at the moment./ Chasing high modulus is not needed just make it a little thicker. eg for a machine base if you use 100mm thick aluminium as the benchmark you need 70mm of steel, 112mm of E=50GPa grout or 120mm of E=40GPa grout so just make a 120mm base and 40GPa grout is $1.80kg 1/10th the price of steel or aluminium.... I have been trying to make E70+ material for a couple of years and have given up, just use what's available much easier... Peter

    PS hardness is not an advantage unless you want something that does not wear or is part of a bearing system. Both do not apply for machine parts. ideally it needs to be able to be machined to correct size...



  4. #4
    Member Fungiblelaser's Avatar
    Join Date
    May 2023
    Posts
    2
    Downloads
    0
    Uploads
    0

    Default Re: Silicon carbide aggregate?

    Quote Originally Posted by cncmakers001 View Post
    Quite a new idea, you can try and share the experience.
    I will probably do that. I have some SiC and epoxy left over from other projects. Probably not the ideal particle size, mostly 80 grit, or the best epoxy, but should work for an initial test.



  5. #5
    Member peteeng's Avatar
    Join Date
    Jul 2018
    Location
    dum dum
    Posts
    6248
    Downloads
    0
    Uploads
    0

    Default Re: Silicon carbide aggregate?

    Hi Fungi - Grit size does not matter, its the solid volume ratio that matters and P80 is about 0.2 to 0.3mm. I have used 400 mesh which is 0.037mm and it wet out and filled easily. I expect you will get 60-65% solid volume ratio... Peter

    edit - I use a very thin epoxy designed for infusion

    in image
    LHS is 400mesh aluminium
    middle is alox 2mm grit
    RHS is mashup of secret stuff I've just been told it will be june before I get test results back, bugger.

    I have seen one of my clients use SiC on leading edge & underneath of race car air dams to slow down wearing them out. Worked really well....

    Attached Thumbnails Attached Thumbnails Silicon carbide aggregate?-coupons-jpg  
    Last edited by peteeng; 05-16-2023 at 02:25 AM.


  6. #6
    Member
    Join Date
    Dec 2015
    Posts
    15
    Downloads
    0
    Uploads
    0

    Default Re: Silicon carbide aggregate?

    I'm not gonna call into question any of the well prepared numbers above, but I would like to point out perhaps a philosophical question.
    Is this a solution in search of a problem?
    I mean, if we had our preferences, what's wrong with cast iron? It worked for over a century and still does.
    Obviously, it's really hard to setup a foundry and do secondary milling and grinding on the castings like the factory does. But given a choice, wouldn't we all prefer a nice, fat, cast iron machine? I certainly do. I love my 2 cast iron machines.
    In exchange for all these inconveniences, we do various cast materials of our own. Cement. Epoxy Granite. These seem to be most popular. In similar form, we weld up extruded steel in whatever size we can afford.
    We don't build these because the final product is *better*, we do it because we *can*.

    While I applaud and cheer anyone that wants to go down the path less-traveled, it is indisputably less-traveled for a reason that may not be immediately apparent. While not always, it is often that it doesn't lead anywhere useful. I feel SiC is just such a path, though i may be wrong.

    When you're done, whattaya got? Is it significantly, or even measurably, superior to usual methods? As there's no shoulders to stand on, of pioneers gone by, will this just be a research project? Will the outcome be a result of luck? I'm not grilling you, i simply don't know.

    I suppose if I could get the sized SiC for free - or nearly so - it might be worth investigating. But downsides (like abrasion) are formidable. How do you drill into it? You WILL miss a mount or a hardware provision somewhere. You could bond on a plate/angle, I guess, but installing a threaded insert? In SiC? Good trick all by itself, really.

    An academic curiosity. Well worth the discussion. But it's not for me, FWIW.



  7. #7
    Member peteeng's Avatar
    Join Date
    Jul 2018
    Location
    dum dum
    Posts
    6248
    Downloads
    0
    Uploads
    0

    Default Re: Silicon carbide aggregate?

    Hi Wrat - I agree with many of your points. Especially about how do you attach something to the SiC part. This event will eventually happen & no doubt it will be a Makers nightmare issue. In my endeavors with new materials the ability to conventionally machine it has always been high on the "need" list. I don't think the SiC will achieve the stiffness that Fungi hopes for anyway. The only materials that have shown hope are fibreglass (E=35GPa) and std carbonfibre (E=75GPa). But these require good tooling and machinists will not put them on their machines. Steel and aluminium are easy to deal with, especially aluminium on routers so should become the go to material. So I'm building a mill just for composites. In my case I want to make many parts so casting is a good production process. For a bespoke build I'd use different materials maybe.

    I do disagree with the comment that CI has been good for 100 years so let's continue with it. Valves vs transistors (in my lifetime), steel racing bikes and cars vs aluminium (using giga presses) and carbon fibre, hot casting vs 3D printing, Technology moves on and times change. The major machine builders are already making 3D printed parts and making sophisticated 3D printing hybrid machines (additive and subtractive in same machine) cast iron will not be around in this area for much longer. Cast iron had its place but its slipping. Titanium and specialty steels and aluminium are easy to print so they will be the major players going forward for production machine builders. A production machines life is probably 10 years so the technology cycle in commercial world is long. But the machinists I work with are talking about 3D printing, robotic machining, high power laser welding and other stuff that is out there so I expect we are near the point where normal workshops will have these technologies very soon.

    Hobby builders will stay with steel and aluminium, some will go the cast UHPC (grout) grout is 1/10th the cost of metal and you can make the shape you want in your garage and pour the grout into the mould. Holes can be post drilled using concrete drills. I think this is the way forward for hobbyists who want to do something cheaper or different. The usual problem with welded steel is that it requires thermal stress relief to make straight parts. SR is a common hiccup in the forum. The hobby CNC world is moving slowly, the 3D printing world is moving at a spectacular rate.

    I'd prefer a full carbon fibre CNC mill vs a CI one and that's what I have been working towards.... But my machinists have CI machines and they are great as well.... NASA have recently made a concrete mill. When they set up on the moon they won't be able to take CI machines with them, they will have to make concrete from moon dirt to make machines....Keep at it Peter

    Perhaps in the future we will never repair or modify anything. We will put that part in the recycler and print a new part with the extra hole in it. Thats whats happening in the 3D printer world...



  8. #8
    Member
    Join Date
    Nov 2013
    Posts
    4280
    Downloads
    0
    Uploads
    0

    Default Re: Silicon carbide aggregate?

    Hi,

    I do disagree with the comment that CI has been good for 100 years so let's continue with it. Valves vs transistors (in my lifetime), steel racing bikes and cars vs aluminium (using giga presses) and carbon fibre, hot casting vs 3D printing, Technology moves on and times change. The major machine builders are already making 3D printed parts and making sophisticated 3D printing hybrid machines (additive and subtractive in same machine) cast iron will not be around in this area for much longer. Cast iron had its place but its slipping.
    I call this rubbish. See that attached, the worldwide market for cast iron in 2021 was 101 Billion USD and is forecast to grow at 6% PA until at least 2030. Does that sound like a material in decline?

    The second pic is from the same source. Close to one third of the worlds cast iron is used for machines and tools, does that sound like a material in decline?

    3D metal printing will never be cost competitive to casting in iron until multi kilowatt lasers come down to the cost of a domestic refrigerator, ie not any time soon.

    Craig

    Attached Thumbnails Attached Thumbnails Silicon carbide aggregate?-castironuse-png   Silicon carbide aggregate?-castironconsumption-png  
    Last edited by joeavaerage; 05-16-2023 at 07:20 PM.


  9. #9
    Member
    Join Date
    Nov 2013
    Posts
    4280
    Downloads
    0
    Uploads
    0

    Default Re: Silicon carbide aggregate?

    Hi,
    and what's more Australia is a huge exporter and relies on steel and iron demand.

    Last year Australia exported 37% of the worlds iron ore to the tune of 130billion AUD. They also export some 30% of the worlds coal, largely destined for steel and iron making.
    Cant find a reliable value off-hand, but the two commodities are the backbone of the Aussie economy.

    Indeed peteeng has many times posted of the work he has done on mining equipment (made out of steel and iron no doubt) and presumably to support iron and coal mining.
    Does your livelihood still depend on the mining industry? Even if peteeng has moved on from that economic dependency many many Aussies are still reliant on the industry.

    If indeed there is a downturn in the steel and iron demands it will hurt Australia badly, and yet the demand figures for both steel and iron are positive and exceeds the rate of growth
    of global economic output and has done for many years.

    Craig



  10. #10
    Member peteeng's Avatar
    Join Date
    Jul 2018
    Location
    dum dum
    Posts
    6248
    Downloads
    0
    Uploads
    0

    Default Re: Silicon carbide aggregate?

    "I think there is a world market for maybe five computers."
    Thomas Watson, president of IBM, 1943

    Mr Watson regretted his words I'm sure...

    The Kodak people missed the bus as well, also RCA Inc. Can't sell a steel racing bike these days, 30 years ago I was struggling to sell aluminium ones, now Reynolds 531 a famous tube for decades went many years ago... steel and iron will continue, but in production machines maybe not... Tesla has revolutionised making cars with giga presses. Maybe thats how we will build production machines... Lets look back in 2033 and see how this is going....
    Peter

    The mining industry stuff I do is looking for a change as well. The payload ratio of vehicles has to be lifted and steel can't get there so aluminium is the next consideration. CI has its place and I do not advocate for any particular material. I do advocate for the "best" material for the job or the material the person is interested in. Home builders generally can't afford patterns and hot casting and all the secondary things that are associated with that process. However they can make plywood moulds and pour in concrete and make a very good machine. Making machines is always hard no matter what path you take.... Peter


    Last edited by peteeng; 05-16-2023 at 11:21 PM.


  11. #11
    Member
    Join Date
    Nov 2013
    Posts
    4280
    Downloads
    0
    Uploads
    0

    Default Re: Silicon carbide aggregate?

    Hi peteeng,

    Home builders generally can't afford patterns and hot casting and all the secondary things that are associated with that process.
    That is the general perception but I'm far from convinced it reflects the truth, it certainly isn't cheap but its not prohibitively expensive either.

    You may recall some time ago I posted that I had 'made to budget' welded steel extension from the saddle of the Z axis to the spindle mount. Despite
    being 100 x 100 x 9 RHS its still a 'little wobbly' when the pressure comes on. It was what I could afford at the time, but I'm now thinking of revisiting it and building
    a new one.

    This would be a perfect case for two or more different fabrication/manufacturing strategies to be compared along side each other. The part has a 275mm x275mm base
    to a 200mm x 150mm nose and about 350mm between base and nose. It would not be a hugely expensive part to make.

    I will give it a little more thought and do some rough sketches. You and others might like to chime in and contribute. If I do so I'll start a thread and see where it leads.
    Might be a good time to compare cast iron, epoxy granite, some sort of concrete mix, welded steel and maybe even glass or carbon fiber when talking about a fairly simple
    and managable part of modest dimensions.

    Craig



  12. #12
    Member peteeng's Avatar
    Join Date
    Jul 2018
    Location
    dum dum
    Posts
    6248
    Downloads
    0
    Uploads
    0

    Default Re: Silicon carbide aggregate?

    Hi Craig - Happy to contribute. An aside - In the mining industry with costing very heavy equipment and all the equipment is sort of close in performance and weight, a rule of thumb has developed to cost new equipment based on $$$/tonne. So if a machine weighs 200T it costs about 200$$$ whatever that is. I was in a meeting and this came up when I suggested we try to make a 300T trailer at 200T. The bean counters and sellers said no can't do that because the buyers will expect to pay 200$$$ not the same price ie 300$$$. So currently there needs to be a paradigm shift in expressing $$$ values to drive weights down not stay static. In the truck and aero industry they talk about $$$/10,000 hrs or $$$/million miles. This is better because it does not matter what the thing is made of or what it smells like the operator will know it saves money to use thing A vs thing B as its lifetime or cycle time cost is lower, irrespective of the up front cost. This is the same with production mills. If it can do twice the work in the same time yet is 50% dearer then its a sale. Thats where lighter stiffer structures come into it. Operators are demanding more speed. They can't double the size of their factory, they can't double the size of their staff but they can get faster machines... Peter



  13. #13
    Member
    Join Date
    Jan 2008
    Location
    Australia
    Posts
    1523
    Downloads
    2
    Uploads
    0

    Default Re: Silicon carbide aggregate?

    Quote Originally Posted by joeavaerage View Post
    Hi peteeng,



    That is the general perception but I'm far from convinced it reflects the truth, it certainly isn't cheap but its not prohibitively expensive either.

    You may recall some time ago I posted that I had 'made to budget' welded steel extension from the saddle of the Z axis to the spindle mount. Despite
    being 100 x 100 x 9 RHS its still a 'little wobbly' when the pressure comes on. It was what I could afford at the time, but I'm now thinking of revisiting it and building
    a new one.

    This would be a perfect case for two or more different fabrication/manufacturing strategies to be compared along side each other. The part has a 275mm x275mm base
    to a 200mm x 150mm nose and about 350mm between base and nose. It would not be a hugely expensive part to make.

    I will give it a little more thought and do some rough sketches. You and others might like to chime in and contribute. If I do so I'll start a thread and see where it leads.
    Might be a good time to compare cast iron, epoxy granite, some sort of concrete mix, welded steel and maybe even glass or carbon fiber when talking about a fairly simple
    and managable part of modest dimensions.

    Craig
    Craig,
    Your "headstock" is definitely the weak area for your machine. It looks comical (meant in a nice way) compared to the rest of your machine.

    A good area for laser cut steel weldment. And consider filling with a vibration damping material.



  14. #14
    Member
    Join Date
    Nov 2013
    Posts
    4280
    Downloads
    0
    Uploads
    0

    Default Re: Silicon carbide aggregate?

    Hi,
    yes it is a weak spot, but that was what I could afford at the time. Its OK with the little 800W spindle but with a bigger spindle it is just not good enough.

    I'm still leaning to get it cast in grey iron or maybe SG iron.

    I'm thinking that there might be a number of options including as you say welded laser cut plates, and/or epoxy granite etc.

    Might b an opportunity to compare the different approaches with respect to performance and price.

    Craig



  15. #15
    Member
    Join Date
    May 2013
    Location
    washington
    Posts
    480
    Downloads
    0
    Uploads
    0

    Default

    In my opinion the best way to test a new material for a rigidity multiplied by dampening coefficient divided by density experiment is to make a boring bar and test against other boring bars under identical conditions.

    Given that the core of a boring bar doesnt matter much, all you have to do is cast a 25mm core 250mm long with a 5mm hole through the middle, grind both ends flush and them bolt your business end through the bar.

    See how far you can extend it before it chatters, compared to your other epoxy granite mixtures, cast iron, steel, lead, etc.



  16. #16
    Member peteeng's Avatar
    Join Date
    Jul 2018
    Location
    dum dum
    Posts
    6248
    Downloads
    0
    Uploads
    0

    Default Re: Silicon carbide aggregate?

    Hi Eldon - If you made a boring bar of SiC epoxy, Alox epoxy or UHPC it would snap as it entered the material. Those materials are fine for large low stressed components but not good for high stressed components such as you describe. I made a sample of alox/epoxy once and dropped it onto a timber floor it shattered easily. Peter



  17. #17
    Member
    Join Date
    May 2013
    Location
    washington
    Posts
    480
    Downloads
    0
    Uploads
    0

    Default

    Quote Originally Posted by peteeng View Post
    Hi Eldon - If you made a boring bar of SiC epoxy, Alox epoxy or UHPC it would snap as it entered the material. Those materials are fine for large low stressed components but not good for high stressed components such as you describe. I made a sample of alox/epoxy once and dropped it onto a timber floor it shattered easily. Peter
    Thats what the bolt hole through the center is for, to keep the composite under compression, and so you can compare two or more tubes with the same cutting tool.



  18. #18
    Member Mr-MaW's Avatar
    Join Date
    Jun 2023
    Posts
    136
    Downloads
    0
    Uploads
    0

    Default Re: Silicon carbide aggregate?

    Hello everyone, Peter / Craig / pippin88 /

    I enjoyed the discussion very much, and thankfully, I am a practitioner of mineral castings.

    I have experienced all the problems with production technology.
    Silicon carbide and ceramics, I chose ceramics, there is no shortage of ceramics in China.
    Ceramics have many advantages as filler materials.
    But on this forum I haven't learned to upload photos,
    If you need mineral castings.You can contact me,I'm from China,My company has produced a lot of products, small can reach 100KG. large can do 46 tons.
    Because the drawings are confidential, I will share some photos for everyone to see.
    https://grabcad.com/library/ma-miner...inear-motors-1



  19. #19
    Member peteeng's Avatar
    Join Date
    Jul 2018
    Location
    dum dum
    Posts
    6248
    Downloads
    0
    Uploads
    0

    Default Re: Silicon carbide aggregate?

    Hi Fungi - Tests are back and disappointing. The ALOX sample got E=18GPa. This was hard packed alox and epoxy. So even though the alox is E=300GPa it did not translate into a stiff product. I think this is because the particles are roughly spherical and do not transfer strain well. At 60% pack it should get 300x0.6x0.5=90GPa but no. So I'm going with UHPC seems to be much stiffer, at least 40GPa Or I shall use fibreglass which I have had tested at 30GPa or carbon fibre at 80GPa. Peter

    for reference the steel fibre sample tested at 7GPa and the aluminium powder tested at 12Gpa so nothing brilliant there either. Interesting thought. The efficiency of the alox is 18/300=6% yet the aluminium was 12/70=23% both have the same packing factor from tests (60-65% solid) so seems uneven in modulus translation... more research to do.

    Mr-MaW do you test your materials for modulus and if so what is it?



  20. #20
    Member Mr-MaW's Avatar
    Join Date
    Jun 2023
    Posts
    136
    Downloads
    0
    Uploads
    0

    Default Re: Silicon carbide aggregate?

    Hi

    Modulus of elasticity and density?We pay more attention to the ratio of these two parameters.
    (Elastic modulus/density).

    Our lab has tested a lot of materials,But we ended up choosing granite.I don't know if I'm saying it accurately because English is not good.

    Elastic modulus:40Gpa-60Gpa
    The elastic modulus fluctuates relatively large and is affected by various factors.Therefore, the process flow of construction is very critical, temperature, humidity, structure, size and so on.

    This is a complex problem, so you cannot pursue the modulus of elasticity alone.



Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


About CNCzone.com

    We are the largest and most active discussion forum for manufacturing industry. The site is 100% free to join and use, so join today!

Follow us on


Our Brands

Silicon carbide aggregate?

Silicon carbide aggregate?