When people ask why I exclusively watch TH-cam instead of other streaming services, videos like these are great examples of why. Very interesting project, instant sub
WOW! I saw some of your older videos about this project, but hadn't watched any since. I'm super impressed with how far it's come since then! Awesome work
@@Shrouded_reaper It's harder to make a gun with that than with existing tech: there's already 3D printed designs in plastic of guns that only requires a few, easy to source, metal parts to complete. Also, all of them require ammo which you can not 3D print.
@@DiThi Is it harder now? Yes, that's the point, because it won't be in the future. Is injection molding still easier to do at home than making a plastic object from a 3d printer? Plastic guns require metal components still and are not proper weapons capable of taking rifle cartridges and lack rifled barrels. Every one you see is a 9mm platform, not a threat to government goons in level 4 plate. And yes you can make your own ammo at home with a cheap press, very easily.
Have you tried pulsating the laser power? Like 70% half power, 30% max power? The idea is to heat up the material without melting it and when, locally, the material is hot enough to fuse with out sputtering you increase laser output to melt that spot and throttle it down fast so it can cool off. Sort of like tig welding.
If you have trouble with droplets at the start and end of tracks due to acceleration, why not separate the acceleration from the start of the track? As in: start moving, get up to speed, and only then turn on the laser. That would decrease the working surface, but might help.
@@gobble_gang Backlash is caused by the driven nut having play on the lead screw. There's way to minimise this, usually involving using two nuts, or by using a controller that takes backlash into account.
I can't elaborate because I am NDA'd out of my mind. however, love your project and determination. a suggestion and associated considerations. Try enclosing your machine/workspace, and pressurize it with helium. Why? Considerations. 1 - Typical commercial Laser powder bed fusion use argon atmosphere to reduce oxides and improve porosity etc. but 2 - the plume (thermal laser plasma, metal powder interaction) results in denudation in front and around melt pool - to reduce melt powder denudation as laser moves, a pressurized atmosphere is desired to mitigate/reduce plume size hence reducing powder denudation beside laser trace. 3 - argon at 5bar produces plasma due to fibre laser interaction with stainless build plate and plasma increases plume denudation because thermal increase and reflections, helium does not produce this plasma, yet reduces denudation due to increased surrounding pressure, at 5bar you will achieve 99% porosity
@@metalmatters that is true. The trick i have found is to pressurize the build area. But pressurized air has oxidation issues. Pressurized Argon has plasma/denudation issues. If the stars ever allign, give helium at 5bar a try. In the long run, this may be cheaper anyway since assuming you obtain 99% porosity, your control algorithm for z height control becomes manageable/predictable - this is crucial and is increasingly crucial for each additional layer. Either way, keep on keeping on! Love your work!
Might I ask u guys both where I could learn/read more about this stuff? Where I’m from nobody is working on this stuff and I really wanna learn more about it
@@ltpetsema876 Research papers mainly. Some are free, some are not. I've posted a few here: metalmatters.co/forumdisplay.php?fid=25 I'll post a few more up there soon.
When using helium, you may need to reduce laser power or increase travel speed as helium allows for greater energy efficiency. Also should be able to utilize mix of argon/helium. Not sure what ratio woul be best for this application but 75/25 argon/helium works very well for tig welding stainless while 25/75 works better for welding aluminum. Hope this helps. Cheers.
2:56 if the plastic swipe care still proves too stiff you might try car window wipers for the rain, think about how they just glide over ice not losing anything at all. and because they come from any where they should be cheap and easy to replace.
What an amazing project! This machine you have developed in incredibly impressive! I really hope you keep going with this project and keep developing it further 😁
Silly thought - would it possible to first run the laser out of focus over the printed region to partially sinter it to combat the powder being dragged in to the melt pool?
@@atari7001 Yes but those are electron beam melting machine, not laser melting machines, they have huge magnetic effect on the powder and thus needs this pre sintering. Denudation (removal of powder due to gas displacement) is inherent to this laser process. Process parameter have to be fine tune to minimise it, but it will always be here. I would suggest to go faster, limiting the heat applied to the melt pool and thus evaporation of material causing this powder suction
Hello, I am extremely impressed with your progress. I have done a lot of research and postulating on these systems so I Was thinking maybe I could help or clarify somethings. SLS Printers don't actually melt the material they sinter it. This is better because as you can see the pooling and controlling of the molten materials is quiet an issue. The SLS machine also have heated chambers. The reason for this is so that the exposure to the laser is incredibly short and cause the particles to bond to each other. So I think you have done phenomenal work but that might be the two areas that might be an issue. I really hope you come right :) Another thing, the scraper should be extremely flat material that cannot generate a static charge, perhaps like a gauge plate edge?
I agree....those look like kind of messy weld beads with spatter.Some sort of argon or other type of welding gas flow might smooth the depositions right out.
the thick spots at the start and end of metal tracks can be controlled by "skywriting" laser scan strategy in which laser start/stop emitting only when it achieves certain acceleration. However, the work you have done is still amazing and applicable, and truly speaking impossible for 1 man team.
8:39 Use a kitchen-blender, used for making smoothies and crushed ice. It makes powder so fine, that you have to keep its lid closed for a while when ready, or a cloud of fine dust will fill the room.
Nice work! In 2008 I met a material engineer who designed a metal 3d printer with pretty good results (at least the ones he showed publicly). He did the powder layer spreading method similar to yours, but then used an adhesive sprayed through a hacked inkjet printer cartridge... Once the print was done, he'd sinter the parts in a furnace.
Our physics professor told us about the laser-acceleration issue once. Aparently the trick is to accelerate first and then turn on the laser, then turn it off before decelerating. Maybe a toolpath for lasering a square could look like the weird hastag sign on an apple keyboard? Other than that, the work you do is absolutely amazing, you might very well become the one to make metal 3d printing available to normal people!
I nearly tried implementing a ramp but I think I will pursue an opto-mechanical switch instead. If I can run the laser at full power and modulate heat input that way, I think I will stand a better chance of preventing excess heat drawing in adjacent powder.
@@metalmatters keeping the laser at a constant power sounds like the right thing to do, even if you COULD match the ramp to the acceleration of the motor you just showed that you cant compensate power by going slower. Im not 100% sure what you mean with modulating, are we talking a PWM approach?
Thanks for sharing. You want to accelerate before turning the laser on and turn the laser off before decelerating so that you are always moving at constant velocity while sintering. This should help with those blobs on the ends of the tracks.
Regarding the fiber end and how you noted the original connector was open ended, this is likely using an air gapped ferrule. This will mount a cleaved fiber so it has an optical face but will not have any epoxy near the end face. For any high power application this is usually preferred since it reduces the risk of epoxy related thermal damage/thermal runaway. Using a standard connectors thats polished with epoxy mounting the fiber in connector up to the end face runs higher risk of damage.
Very cool project! I am a qualified 3D print technician, I've worked on EOS printers before, primarily the EOS m290, its really cool to see how much you've overcome and implemented that is in line with existing high end metal printing techniques, I can suggest that you look at "skywriting", cold prossess 3d printing temp balances and nitrogen scrubbing for some potential improvements. Super cool project, I think what you've done with the recoter head is very cool!
I would add mass to the machine base. It appears you have a lot of gantry sway going on e which is going to effect your focal point. Another thing to consider is the machine may not be reaching your specified speeds. The distances travelled are shorter than the acceleration the machine is capable of. It would also be best to eliminate any sharp turns the machine has to make. Radii help prevent the machine having to stop and then accelerating on another access. The bigger the radius the longer the machine has time to accelerate the new axis motion up to speed.
you should try lowering the laser power near the end of the line travel to reduce heat build up and raised blobs. it would be similar to linear advance controlling filament pressure in a nozzle.
Part of the code could limit output of the laser to the *actual* speed, compensating for the acceleration issue. Additionally, the code could have a slight pause between telling the servos to move and telling the laser to turn on. That little buffer will allow the head to get up to speed or slow down. Downside is reducing the effective print area
@@sgullage I like this method more. Honestly, the closer you can get to actual temperature to target temp you can make it the better. It might even be worth it on larger builds to have passes being near more recent passes to compensate for residual heat.
Is this system using Marlin, Klipper or other open source movement controller? The code for Pressure Advance / Linear Advance in them is open source too, and could probably be used to control the laser intensity and speed/acceleration of the system based on a couple of variables.
I think a galvanometer scanner would be helpful to get rid of the gasket. Plus you can move and accelerate your beam way faster. Or would this destroy the point of the whole thing?
Likewise. Just a matter of cost really. $7-800 for large aperture galvos, $500+ for bespoke mirrors, plus the initial outlay for the diode pump/PSU. May as well go for a fiber laser at that point.
Nice project man, maybe activating the láser while machine is running or controlling initial power would help you eliminate the start and finish melt accumulation.
Just an FYI; I used to use the epoxy, shear and polish method for fiber throughout the 90s but unicam connectors have become the mainstay for fiber connections unless you're doing fusion connections on single mode.
Might I suggest looking at Hitachi CPM White #1 steel. It is an extremely pure steel with sulfur and phosphorus content at .25% or lower. It is just iron and carbon. It is in powder form. It could be one less variable for you to deal with in that the material is very chemically uniform and it could be simpler to calculate how it will respond to heat. Japanese master smiths use it to make blades that can take an edge like no other. I own several Japanese knives. The White #1 blade has an edge that will cut your name in two.
Sorry if this has been covered in another episode of this project, but I was really really wondering why you're not using a galvanometer solution instead of a large platform X/Y gantry set up which is inherently very sloppy when it moves? Is it a cost issue? As a galvanometer set up could be quite useful in this instance due to the fact that many of them are already permanently sealed against atmosphere. My apologies if this has been covered in a different episode. Excellent work my friend! Makes me wonder how this setup would run under vacuum with perhaps maybe the slightest amount of helium added. But most likely it lead to the formation of plasma which would be quite destructive when it comes to accurate and precise tracks. Perhaps maybe this would be better solved under find thin layer of some sort of liquid solution that has incredible heat tolerance? Who knows. Love your work man!
Hi Robert. Have a look on my shorts page. I have switched over to galvos, but yes, cost and complexity are significant factors. There are a number of papers dedicated to LPBF using a vacuum. Worth having a look if you are genuinely curious.
I think your slow switching times are due to your power supply. The actual laser junction should be able to turn on and off in micro-seconds and modulate in nano-seconds. (fastest turn on will happen if you idle the laser diode sub-threshold before applying full current) You'll want to get a cheap "test dummy" laser for testing, but you could get real gains in power controllability if you leave the bench supply on continuously, and use a custom circuit to regulate the laser current. The simplest and safest is probably a parallel shunt regulator to steal current from the laser when you want to reduce power output.
Can these diodes be modulated in power easily? If the power can be adjusted contnously then it shouldnt be too hard to take in to account the acceleration and start/end and make a function that calculates the power output to ensure the same laserpower gets dumped in every mm. Otherwise PWM? If you want to go ham it should be possible to make a program that takes 3D printer gcode and calculates laser output power for the whole file based on the movement speed at each moment. So you could use a normal slicer for a file then just run it through the described program and get metal laser gcode.
@@scifactorial5802 Don't need to do that much work. The 3D printing slicer already does all this. Just need a circuit to translate extruder steps to laser pulses.
This is awesome! I'd suggest writing to some companies that make metal powders if you haven't already, I'm sure you can find one that would want to sponsor the development of a diy sls printer, at least with some powder
Mainly to avoid headaches. The build plate is to be cooled (50C) so there is little chance of softening the base of the deck and I will reprint/line the arms if need be.
Wow that's a lot of work! Optics are a pain in the ass!!! Got a blue 80 watt laser array from a projector- been battling to focus it for my cnc ( tried 60×15 mm biconvex tried a 60×35mm convex but can't get it to cut 1mm steel... I can get it to melt the surface of a Stanley blade and make the whole blade red hot but I can't get it to cut. I have got a 5watt blue module which can cut 15mm wood and engrave steel-slowly(it has a .03mm focal point- apparently it has a FAC lens ) so I assume it would be possible to cut steel with 80w.
Hi friend. You might to consider an laminar air flow across the powder bed. Looks like there is significant amount of spatter around ur scanned tracks. Metal vaporises under laser and condense when it hit the cold air. Those metal condensates attenuate your laser beam and by removing them with a laminar air flow, the melt will be much more consistent. The air flow ought to flow into a HEPA filter tho..
What if you passed a grinder over the surface after sintering, but before adding the next layer of powder? That would help to simplify the deposition and also improve the dimensional accuracy and keep one little screw-up from scrapping an entire print.
Brings back memories of the early days at Xact Metal. You appear to be working thru these issues similarly to how we did. Keep up the good work. Reach out if you have any questions.
Hey Matt. I sent you an email, although from my personal email due to problems with my mail provider. Just checking in case it has been marked as spam.
Continuous wave lasers make the welding process similar to existing welding processes. Pulse lasers open up a whole new can of worms when it comes to consistency of each vector in the raster pattern. There is a company called seurat technologies working on making the use of pulse lasers an advantage rather than a disadvantage. But again. There is a huge can of worms there to sort through.
Just wondering, but would doing this laser sintering under a noble atmosphere help at all? I only ask because the "spattering" around the sintered lines look reminiscent of a contaminated weld.
It's operating in an inert atmosphere, just not a very good one. I usually let get down to around 0.1 - 0.2% oxygen before running anything but shooting for a lower percentage results in an exponential consumption of argon.
Instead of controlling the power supply you could bypass the current by shorting the powersupply. Add a MOSFET in parallel to the laser and turn it on when you want the laser to be off. This way the current in the power supply is always flowing(should help with ramp up) and you can stop the laser very fast since a MOSFET turns on in nanoseconds.
Inductance/overshoot will kill the diode block if the rise/fall times are too short. At the moment it is slower than it could be, erring on the side of caution.
So glad to see the leaps and bounds youve made as far as progress goes on this project, as someone who has had an interest in this field for a while and now has a job in it i hope that i can help on the forum but every time you post and i try and register it gives me an error saying that multiple attempts to register have come from my IP and to try later...i will try again in a day or two. To echo off of what danny said below, chamber pressure is key to powder melt consistency and unfortunately that means either going lower or higher...which means a pressure vessel of some sort which isnt exactly feasable for diy...
@@metalmatters awesome! I just posted an article on vacuum in L-PBF, it does a good comparison of slight to moderate vacuum and slight overpressure of the chamber on the effects of both on powder denudation.
There are a few guys that have put together their own CMM using epoxy and sand/granite/special concrete for the base to reduce vibration. Cheap, just need molds. Might be worth establishing your machine and then fiddling with optics, speeds, etc
Just come across your channel, and boy has it been great going through your uploads. Thank you soo much for your incredible work and dedication toward such a fantastic project. Keep up the awesome work👍👍
What about microwave asisted sintering? i.e. if you have roughly equal powder sizes, you can use a microwave cavity to bring them to their (size dependent) critical temperature, then you don't need that much power in the laser, and you will not suffer from turbulent effects (i.e. domain wall will be less pronounced)
I really hope my other comment posted, unfortunately I seem to have lost it. I'm going to try and sum up what I said. I have experience in working with SLS and DMLS printers, specifically the EOS M290. For wipers, you can google "use cases of different re-coater configurations EOS" for a writeup that goes into detail about the re-coater blades in the EOS M290 DMLS machine. In short, they use a HSS parallelogram shaped blade which is ductile enough when coming in contact with the print, while in other cases a ceramic blade is used. More info on the writeup. For the build environment, we always pumped down the machine and filled it with argon. The build volume is also heated. As someone else mentioned below, you could pulsate the laser, which If I'm remembering correctly is something that is also done on the EOS M290. The EOS M290 also has a large filter cabinet which requires the filters to be replaced when switching materials or on occasion once the flow through them drops below a certain point. I believe the filters could have been capturing spatter which would have been blown into them by the flow of argon which traveled across the build surface. After printing on an EOS machine, the powder should be sieved as well, which I believe is done to remove anything in the stock powder which exceeds the size of the rest of the powder.
@@metalmatters I'll have to look back at my pictures to see if I have anything, or I'll ask around. If anything I could pop in and take a look as well. I'll let you know. Great work man.
I’m just wondering I noticed you’re saying too much heat causing the warping but I think it’s more the rapid cooling of the metal causing the stress and warping. From what I’ve been finding these need to be in a preheated enclosure to prevent these stresses. Were you using an inert gas? The normal atmosphere can cause contamination(moisture, oxidation, etc), even your skins oils can contaminate the powders. I’m curious to make my own so wanting to pick your brains if those are things you’ve tried?
I'm not too sure where I mentioned excessive heat leading to warping. I recall it was an issue when using overly thin substrates but other than that, I can't disagree about sudden temperature changes being the source of warping/internal stress. In spite of that though, as far as I'm aware, heated chambers *aren't* the de facto standard for SLM systems. Temperature regulated platforms are common, but can be bound to temperatures as low as 50C. I know it is common for SLS systems, but I don't believe it's the same for SLM. I know the PM100 by Phenix Systems is an example of such a machine though. Yes, atmosphere was inert. Always wear gloves and a respirator when handling metal powders.
@@metalmatters first of I wanted to say thank you for responding and I’m so sorry I think that was a previous video I was watching of yours. I hope this doesn’t come across as criticism or anything I want to learn as much as I can from you and bounce things back and forth. I am very much still in my infancy of learning all this. I seem to be on a different thought process, most of the slm/dmls machines I have seen have heated chambers, it’s allows for minimising thermal stresses, enhanced powder bed fusion, and a few other areas that help. I could also be completely wrong about this, that why I want to pick your brains as much as I can so I can learn! But also finding that even the powders need to be opened and handled in an inert atmosphere like argon or nitrogen to prevent contamination and oxidation. I haven’t seen the phoenix systems yet I’ll check them out! Thank you 😊
@@SurfyKirky Didn't catch this one! I have a feeling you might be referencing material related to mission critical applications e.g. medical and aerospace. Which machines have you been looking at? If you have a look at the TDS for brand name powders, some of them will mention build plate temperatures. e.g. www.eos.info/03_system-related-assets/material-related-contents/metal-materials-and-examples/metal-material-datasheet/aluminium/material_datasheet_eos_aluminium-alsi10mg_en_web.pdf Between this and a lot of systems using silicone/rubber recoating components, I'm under the impression that most systems don't rely on heated enclosures. Sustaining high temperatures for potentially days and the added build cost.. it's just easier/cheaper to deal with using mechanical supports and annealing. Btw, are you based in NZ?
Hi, @MetalMatter great video. What effects would you expect if you were able to change pressure as a parameter? For example, if this system were located in a pressure chamber, then how would varying pressure affect the expected outcome? Also, since it's a finely packed powder you could use the tip of a syringe mounted on the head to carve a canal into the powder's surface that will be filled in once the powder on either side of the canal melts pouring itself back inside the canal. In essence, the canal creates a greater surface area, which alters the dynamics of the reaction. Alternatively, maybe using a different gas in the atmopshere of the melting. My naive guess is that the liquid turn to vapor and causes the bubble to pop and splatter the metal.
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Really cool project hope you get the results your looking for
As someone who understood very little about the creation of your printer.. I found it fascintsting.. As someone who does specialty welding, needing to change gas percentages, voltage/ amperage, or alloying properties, I found it really interesting. Just not sure how all of that translates into lasers.. looking at it you need more heat input in a wider area for the amount of filler metal you are using.. or you have a compatibility, contamination issue with the base metal.
does the steel disk get lower and lower in its housing each layer or are the layers raising on the z axis? if you had a base that slid lower and lower down a tube and add material on top you might be able to simplify some stuff.
Not sure if you tried this (you talk too fast 😅): About the droplets at the starts and ends of tracks: Did you try to first accelerate to desired speed and only then switch the Laser on? Or block/mirror away the Laser light if switching is not reliable enough? Same for stopping. Keep speed and Laser ON until end of track and only then switch the Laser OFF and decelerate afterwards? I know some CNC CAM software is capable of creating milling paths where the speed during metal cutting is always as intended and acceleration/deceleration is outside of the current steel cutting surface. So for a 90 degree corner the CNC machine makes a loop at the end of side one to change direction and accelerate in the new direction before milling the side two.
I can supply you with an optical diamond window to protect your optics if you think it’ll help. It’s what’s used in commercial systems rated for many kW. Diamond is used due to extremely high thermal conductivity and durability. Overkill for your application but it’s the best you can use
When people ask why I exclusively watch TH-cam instead of other streaming services, videos like these are great examples of why. Very interesting project, instant sub
Same, glad that I'm not the only one 👍
Same. I subbed as well xD
Only TH-cam videos? No other certain sites that are a ‘hub’ of videos
@@jabatheshort660 He said exclusively, not only YT 😅
I feel this very hard
This is clearly a very excruciating project with all of the debugging and failures. I commend you for sticking with it.
Wow. Open source is a divine gift to humanity. You know why. Thank you. Can't wait.
Five years from now we'll be buying an Elegoo or Creality version on Amazon for $169 on Black Friday, lads. All thanks to this clever fellow.
That would be awesome. Be able to make custom brackets, fixtures, and other devices that are hard to acquire will be game changing.
You're pioneering the metal 3D printing movement dude. You might be the next Josef Prusa.
Uh
So glad you have kept going with this mate. Well done.
This is the coolest project i've ever seen. A homemade metal 3d printer... Incredible
WOW! I saw some of your older videos about this project, but hadn't watched any since. I'm super impressed with how far it's come since then! Awesome work
Thanks!
I thought about pursuing a home brew metal printer a few years ago. It's awesome to have found someone that actually did.
This project is so cool , the prospect of consumer metal printing in the future is unbelievable
Consumer metal printing is never going to be a thing because the government will step in.
@@Shrouded_reaper Why?
You think they will let the populace have access to technology that let's them print a machine gun in their house?....
@@Shrouded_reaper It's harder to make a gun with that than with existing tech: there's already 3D printed designs in plastic of guns that only requires a few, easy to source, metal parts to complete. Also, all of them require ammo which you can not 3D print.
@@DiThi Is it harder now? Yes, that's the point, because it won't be in the future. Is injection molding still easier to do at home than making a plastic object from a 3d printer? Plastic guns require metal components still and are not proper weapons capable of taking rifle cartridges and lack rifled barrels. Every one you see is a 9mm platform, not a threat to government goons in level 4 plate. And yes you can make your own ammo at home with a cheap press, very easily.
I just know that you will nail this bad boy at some point... love this project !!
Have you tried pulsating the laser power? Like 70% half power, 30% max power? The idea is to heat up the material without melting it and when, locally, the material is hot enough to fuse with out sputtering you increase laser output to melt that spot and throttle it down fast so it can cool off. Sort of like tig welding.
Great point, if I'm remembering correctly, EOS uses a similar technique, as well as a heated build chamber.
@johnjagger jack
I have pulsed laser . Gets similar results. But trying to get better results.
@@additivealex4566 Yea it's true .Do you use Eos ?
@@manthanpatel45 yeah I have some experience using two different EOS machines.
@@additivealex4566 Do you own machine or operating machine?
If you have trouble with droplets at the start and end of tracks due to acceleration, why not separate the acceleration from the start of the track? As in: start moving, get up to speed, and only then turn on the laser. That would decrease the working surface, but might help.
Sounds like a good solution. A more permanent solution that might work would be controlling laser power based on velocity
I was just thinking you could just design the gantry to have counterweights on both sides to eliminate backlash.
@@gobble_gang Backlash is caused by the driven nut having play on the lead screw. There's way to minimise this, usually involving using two nuts, or by using a controller that takes backlash into account.
What a crazy video that took a lot of effort
I can't elaborate because I am NDA'd out of my mind. however, love your project and determination. a suggestion and associated considerations. Try enclosing your machine/workspace, and pressurize it with helium. Why? Considerations. 1 - Typical commercial Laser powder bed fusion use argon atmosphere to reduce oxides and improve porosity etc. but 2 - the plume (thermal laser plasma, metal powder interaction) results in denudation in front and around melt pool - to reduce melt powder denudation as laser moves, a pressurized atmosphere is desired to mitigate/reduce plume size hence reducing powder denudation beside laser trace. 3 - argon at 5bar produces plasma due to fibre laser interaction with stainless build plate and plasma increases plume denudation because thermal increase and reflections, helium does not produce this plasma, yet reduces denudation due to increased surrounding pressure, at 5bar you will achieve 99% porosity
Thanks for the feedback. Helium isn't getting any cheaper though :/
@@metalmatters that is true. The trick i have found is to pressurize the build area. But pressurized air has oxidation issues. Pressurized Argon has plasma/denudation issues. If the stars ever allign, give helium at 5bar a try.
In the long run, this may be cheaper anyway since assuming you obtain 99% porosity, your control algorithm for z height control becomes manageable/predictable - this is crucial and is increasingly crucial for each additional layer. Either way, keep on keeping on! Love your work!
Might I ask u guys both where I could learn/read more about this stuff? Where I’m from nobody is working on this stuff and I really wanna learn more about it
@@ltpetsema876 Research papers mainly. Some are free, some are not. I've posted a few here: metalmatters.co/forumdisplay.php?fid=25 I'll post a few more up there soon.
When using helium, you may need to reduce laser power or increase travel speed as helium allows for greater energy efficiency. Also should be able to utilize mix of argon/helium. Not sure what ratio woul be best for this application but 75/25 argon/helium works very well for tig welding stainless while 25/75 works better for welding aluminum. Hope this helps. Cheers.
this will be the next revolution in 3d printing because the parts will have real strength
Fantastic work!!! To get thin layers, galvos with mirrors are used for speed at lower power and an inert gas argon chamber preferably under vacuum
Looking forward to that closed loop control!! This is improving at a wild pace man
2:56 if the plastic swipe care still proves too stiff you might try car window wipers for the rain, think about how they just glide over ice not losing anything at all. and because they come from any where they should be cheap and easy to replace.
Car window wipers may have too soft rubber/silicon which scoops too much of the powder. The material is pretty strong otherwise.
Excellent results so far! Many variables to control and tune.
this guy is amazing,
I like that you don't simplify the information and explain things well
love it
great progress! 👏😎 wonderful job!
What an amazing project! This machine you have developed in incredibly impressive! I really hope you keep going with this project and keep developing it further 😁
Silly thought - would it possible to first run the laser out of focus over the printed region to partially sinter it to combat the powder being dragged in to the melt pool?
I second this thought. General Electric uses this strategy with their metal printers…
@@atari7001 Yes but those are electron beam melting machine, not laser melting machines, they have huge magnetic effect on the powder and thus needs this pre sintering. Denudation (removal of powder due to gas displacement) is inherent to this laser process. Process parameter have to be fine tune to minimise it, but it will always be here. I would suggest to go faster, limiting the heat applied to the melt pool and thus evaporation of material causing this powder suction
Hello, I am extremely impressed with your progress. I have done a lot of research and postulating on these systems so I Was thinking maybe I could help or clarify somethings. SLS Printers don't actually melt the material they sinter it. This is better because as you can see the pooling and controlling of the molten materials is quiet an issue. The SLS machine also have heated chambers. The reason for this is so that the exposure to the laser is incredibly short and cause the particles to bond to each other. So I think you have done phenomenal work but that might be the two areas that might be an issue. I really hope you come right :) Another thing, the scraper should be extremely flat material that cannot generate a static charge, perhaps like a gauge plate edge?
how about doing this in a vacuum environment? I think it may help get rid of molten metal getting spit everywhere caused by thermal expansion of air.
I imagine that would cause issues with heat dissipation.
I agree....those look like kind of messy weld beads with spatter.Some sort of argon or other type of welding gas flow might smooth the depositions right out.
the thick spots at the start and end of metal tracks can be controlled by "skywriting" laser scan strategy in which laser start/stop emitting only when it achieves certain acceleration. However, the work you have done is still amazing and applicable, and truly speaking impossible for 1 man team.
8:39 Use a kitchen-blender, used for making smoothies and crushed ice. It makes powder so fine, that you have to keep its lid closed for a while when ready, or a cloud of fine dust will fill the room.
Nice work! In 2008 I met a material engineer who designed a metal 3d printer with pretty good results (at least the ones he showed publicly). He did the powder layer spreading method similar to yours, but then used an adhesive sprayed through a hacked inkjet printer cartridge... Once the print was done, he'd sinter the parts in a furnace.
Kind of a Holy Grail Project !
...Fusion, and Metal 3DP...
Whenever I complain about TS'g my own Tech Pipeline I'll think of You !!! ~Very Inspired !
The card recoater is GENIUS!!!!!!!!!!
I've just found this and I've gotta say that it is fascinating! I'm definitely going to be following this project closely.
I love following your project, thanks for posting
Our physics professor told us about the laser-acceleration issue once. Aparently the trick is to accelerate first and then turn on the laser, then turn it off before decelerating. Maybe a toolpath for lasering a square could look like the weird hastag sign on an apple keyboard?
Other than that, the work you do is absolutely amazing, you might very well become the one to make metal 3d printing available to normal people!
I nearly tried implementing a ramp but I think I will pursue an opto-mechanical switch instead. If I can run the laser at full power and modulate heat input that way, I think I will stand a better chance of preventing excess heat drawing in adjacent powder.
@@metalmatters keeping the laser at a constant power sounds like the right thing to do, even if you COULD match the ramp to the acceleration of the motor you just showed that you cant compensate power by going slower.
Im not 100% sure what you mean with modulating, are we talking a PWM approach?
In commercial scanners a run in an out path is provided to let the galvo’'s get up to speed
Thanks for sharing. You want to accelerate before turning the laser on and turn the laser off before decelerating so that you are always moving at constant velocity while sintering. This should help with those blobs on the ends of the tracks.
wow. Truly amazed how much you know about all of this. Looking forward to your next vid...
This is very very impressive.
Seriously. You have some skills to be proud of.
Regarding the fiber end and how you noted the original connector was open ended, this is likely using an air gapped ferrule. This will mount a cleaved fiber so it has an optical face but will not have any epoxy near the end face. For any high power application this is usually preferred since it reduces the risk of epoxy related thermal damage/thermal runaway. Using a standard connectors thats polished with epoxy mounting the fiber in connector up to the end face runs higher risk of damage.
Nice work, I admire your focus and determination.
Very cool project! I am a qualified 3D print technician, I've worked on EOS printers before, primarily the EOS m290, its really cool to see how much you've overcome and implemented that is in line with existing high end metal printing techniques, I can suggest that you look at "skywriting", cold prossess 3d printing temp balances and nitrogen scrubbing for some potential improvements. Super cool project, I think what you've done with the recoter head is very cool!
Thanks Jason. Can I ask, what is the typical build chamber pressure of the machines you work on?
@@metalmatters in most cases a light positive presure of 0.3 bar, strangely in the case of aluminum a negative presure of 0.5 bar
Great, easy to follow video. Your video-making skills has come a long way!
I would add mass to the machine base. It appears you have a lot of gantry sway going on e which is going to effect your focal point. Another thing to consider is the machine may not be reaching your specified speeds. The distances travelled are shorter than the acceleration the machine is capable of. It would also be best to eliminate any sharp turns the machine has to make. Radii help prevent the machine having to stop and then accelerating on another access. The bigger the radius the longer the machine has time to accelerate the new axis motion up to speed.
you should try lowering the laser power near the end of the line travel to reduce heat build up and raised blobs.
it would be similar to linear advance controlling filament pressure in a nozzle.
Part of the code could limit output of the laser to the *actual* speed, compensating for the acceleration issue. Additionally, the code could have a slight pause between telling the servos to move and telling the laser to turn on. That little buffer will allow the head to get up to speed or slow down. Downside is reducing the effective print area
@@sgullage I like this method more. Honestly, the closer you can get to actual temperature to target temp you can make it the better. It might even be worth it on larger builds to have passes being near more recent passes to compensate for residual heat.
Is this system using Marlin, Klipper or other open source movement controller? The code for Pressure Advance / Linear Advance in them is open source too, and could probably be used to control the laser intensity and speed/acceleration of the system based on a couple of variables.
I think a galvanometer scanner would be helpful to get rid of the gasket. Plus you can move and accelerate your beam way faster. Or would this destroy the point of the whole thing?
Likewise. Just a matter of cost really. $7-800 for large aperture galvos, $500+ for bespoke mirrors, plus the initial outlay for the diode pump/PSU. May as well go for a fiber laser at that point.
Bro, amazingly thorough and thoughtful. Well done and keep up the good work!
Nice project man, maybe activating the láser while machine is running or controlling initial power would help you eliminate the start and finish melt accumulation.
Just an FYI; I used to use the epoxy, shear and polish method for fiber throughout the 90s but unicam connectors have become the mainstay for fiber connections unless you're doing fusion connections on single mode.
Great Video...... more of this please❗ The topic of DIY Metal 3D printing is becoming more and more important❗👍
Might I suggest looking at Hitachi CPM White #1 steel. It is an extremely pure steel with sulfur and phosphorus content at .25% or lower. It is just iron and carbon. It is in powder form. It could be one less variable for you to deal with in that the material is very chemically uniform and it could be simpler to calculate how it will respond to heat. Japanese master smiths use it to make blades that can take an edge like no other. I own several Japanese knives. The White #1 blade has an edge that will cut your name in two.
Sorry if this has been covered in another episode of this project, but I was really really wondering why you're not using a galvanometer solution instead of a large platform X/Y gantry set up which is inherently very sloppy when it moves? Is it a cost issue? As a galvanometer set up could be quite useful in this instance due to the fact that many of them are already permanently sealed against atmosphere. My apologies if this has been covered in a different episode. Excellent work my friend!
Makes me wonder how this setup would run under vacuum with perhaps maybe the slightest amount of helium added. But most likely it lead to the formation of plasma which would be quite destructive when it comes to accurate and precise tracks. Perhaps maybe this would be better solved under find thin layer of some sort of liquid solution that has incredible heat tolerance? Who knows. Love your work man!
Hi Robert. Have a look on my shorts page. I have switched over to galvos, but yes, cost and complexity are significant factors.
There are a number of papers dedicated to LPBF using a vacuum. Worth having a look if you are genuinely curious.
I think your slow switching times are due to your power supply. The actual laser junction should be able to turn on and off in micro-seconds and modulate in nano-seconds. (fastest turn on will happen if you idle the laser diode sub-threshold before applying full current) You'll want to get a cheap "test dummy" laser for testing, but you could get real gains in power controllability if you leave the bench supply on continuously, and use a custom circuit to regulate the laser current. The simplest and safest is probably a parallel shunt regulator to steal current from the laser when you want to reduce power output.
Can these diodes be modulated in power easily?
If the power can be adjusted contnously then it shouldnt be too hard to take in to account the acceleration and start/end and make a function that calculates the power output to ensure the same laserpower gets dumped in every mm. Otherwise PWM?
If you want to go ham it should be possible to make a program that takes 3D printer gcode and calculates laser output power for the whole file based on the movement speed at each moment. So you could use a normal slicer for a file then just run it through the described program and get metal laser gcode.
@@scifactorial5802 Don't need to do that much work. The 3D printing slicer already does all this. Just need a circuit to translate extruder steps to laser pulses.
@@martylawson1638 Very good point, I don't know how I missed that.
This is awesome!
I'd suggest writing to some companies that make metal powders if you haven't already, I'm sure you can find one that would want to sponsor the development of a diy sls printer, at least with some powder
Unlikely. Most of the SLS methods used for that are patented still.
Very cool, but curious why you didn't use ASA for all FFF polymer parts. Green and silver looks like PLA to me.
Mainly to avoid headaches. The build plate is to be cooled (50C) so there is little chance of softening the base of the deck and I will reprint/line the arms if need be.
Is it possible to cool the printing surface? Perhaps with a bunch of TEC modules placed below the print chamber?
TECs are pretty inefficient. Watercooling would be the way to go I think.
Im pretty sure you need an argon atmosphere inside the printer to improve spatter and weld quality?
Wow that's a lot of work! Optics are a pain in the ass!!! Got a blue 80 watt laser array from a projector- been battling to focus it for my cnc ( tried 60×15 mm biconvex tried a 60×35mm convex but can't get it to cut 1mm steel... I can get it to melt the surface of a Stanley blade and make the whole blade red hot but I can't get it to cut. I have got a 5watt blue module which can cut 15mm wood and engrave steel-slowly(it has a .03mm focal point- apparently it has a FAC lens ) so I assume it would be possible to cut steel with 80w.
First time watching your work, and I'm impressed!!
We need more people like you with this level of creativity..keep up the good work big guy! 🤟🏽
Do you keep the powder heated in the machine during the lasering process? Would there be any benefit to doing this within a vacuum?
link.springer.com/article/10.1007/s00170-020-06071-6
Hi friend. You might to consider an laminar air flow across the powder bed. Looks like there is significant amount of spatter around ur scanned tracks. Metal vaporises under laser and condense when it hit the cold air. Those metal condensates attenuate your laser beam and by removing them with a laminar air flow, the melt will be much more consistent. The air flow ought to flow into a HEPA filter tho..
Fascinating! Thank you for posting this video.
What if you passed a grinder over the surface after sintering, but before adding the next layer of powder? That would help to simplify the deposition and also improve the dimensional accuracy and keep one little screw-up from scrapping an entire print.
Insitu? Keeping the powder clean and stopping powder from being blown around would be quite challenging.
Wow fantastic prototyping
Can you adjust the focus/distance of the laser during acceleration, I don't know how this would work in practise but it may be worth exploring.
Amazing job👍
As someone who has trouble finishing projects, I am impressed.
Brings back memories of the early days at Xact Metal. You appear to be working thru these issues similarly to how we did. Keep up the good work. Reach out if you have any questions.
Hey Matt. I sent you an email, although from my personal email due to problems with my mail provider. Just checking in case it has been marked as spam.
@@metalmatters Got it! In the process of replying 👍
Does the laser need to be CW or can you use a q-switched pulse laser? Just thinking of styropyro's tattoo removal laser.
Continuous wave lasers make the welding process similar to existing welding processes. Pulse lasers open up a whole new can of worms when it comes to consistency of each vector in the raster pattern. There is a company called seurat technologies working on making the use of pulse lasers an advantage rather than a disadvantage. But again. There is a huge can of worms there to sort through.
I think you could eliminate a lot of issues with a galvo scanner 😊
You and I both
Just wondering, but would doing this laser sintering under a noble atmosphere help at all? I only ask because the "spattering" around the sintered lines look reminiscent of a contaminated weld.
It's operating in an inert atmosphere, just not a very good one. I usually let get down to around 0.1 - 0.2% oxygen before running anything but shooting for a lower percentage results in an exponential consumption of argon.
Fantastic work. You're an early pioneer.
Instead of controlling the power supply you could bypass the current by shorting the powersupply. Add a MOSFET in parallel to the laser and turn it on when you want the laser to be off. This way the current in the power supply is always flowing(should help with ramp up) and you can stop the laser very fast since a MOSFET turns on in nanoseconds.
Inductance/overshoot will kill the diode block if the rise/fall times are too short. At the moment it is slower than it could be, erring on the side of caution.
So glad to see the leaps and bounds youve made as far as progress goes on this project, as someone who has had an interest in this field for a while and now has a job in it i hope that i can help on the forum but every time you post and i try and register it gives me an error saying that multiple attempts to register have come from my IP and to try later...i will try again in a day or two. To echo off of what danny said below, chamber pressure is key to powder melt consistency and unfortunately that means either going lower or higher...which means a pressure vessel of some sort which isnt exactly feasable for diy...
Hey Rob. Approved your account, should be OK now. I think both you and Danny are right. I'll figure something out.
@@metalmatters awesome! I just posted an article on vacuum in L-PBF, it does a good comparison of slight to moderate vacuum and slight overpressure of the chamber on the effects of both on powder denudation.
amazing work! Just found this channel and definitely subscribed to follow this build!
There are a few guys that have put together their own CMM using epoxy and sand/granite/special concrete for the base to reduce vibration. Cheap, just need molds. Might be worth establishing your machine and then fiddling with optics, speeds, etc
Massively impressive, man.
Just come across your channel, and boy has it been great going through your uploads.
Thank you soo much for your incredible work and dedication toward such a fantastic project.
Keep up the awesome work👍👍
What about microwave asisted sintering? i.e. if you have roughly equal powder sizes, you can use a microwave cavity to bring them to their (size dependent) critical temperature, then you don't need that much power in the laser, and you will not suffer from turbulent effects (i.e. domain wall will be less pronounced)
Not sure I'm game enough to add a microwave into the mix. Preheating via defocused scanning might be a solution though
I really hope my other comment posted, unfortunately I seem to have lost it. I'm going to try and sum up what I said.
I have experience in working with SLS and DMLS printers, specifically the EOS M290.
For wipers, you can google "use cases of different re-coater configurations EOS" for a writeup that goes into detail about the re-coater blades in the EOS M290 DMLS machine. In short, they use a HSS parallelogram shaped blade which is ductile enough when coming in contact with the print, while in other cases a ceramic blade is used. More info on the writeup.
For the build environment, we always pumped down the machine and filled it with argon. The build volume is also heated.
As someone else mentioned below, you could pulsate the laser, which If I'm remembering correctly is something that is also done on the EOS M290.
The EOS M290 also has a large filter cabinet which requires the filters to be replaced when switching materials or on occasion once the flow through them drops below a certain point. I believe the filters could have been capturing spatter which would have been blown into them by the flow of argon which traveled across the build surface.
After printing on an EOS machine, the powder should be sieved as well, which I believe is done to remove anything in the stock powder which exceeds the size of the rest of the powder.
Didn't see your previous comment. Thanks for your insights Alex. Do you recall what sort of pressure the build chamber is held at?
@@metalmatters I'll have to look back at my pictures to see if I have anything, or I'll ask around. If anything I could pop in and take a look as well. I'll let you know. Great work man.
I’m just wondering I noticed you’re saying too much heat causing the warping but I think it’s more the rapid cooling of the metal causing the stress and warping. From what I’ve been finding these need to be in a preheated enclosure to prevent these stresses.
Were you using an inert gas? The normal atmosphere can cause contamination(moisture, oxidation, etc), even your skins oils can contaminate the powders.
I’m curious to make my own so wanting to pick your brains if those are things you’ve tried?
I'm not too sure where I mentioned excessive heat leading to warping. I recall it was an issue when using overly thin substrates but other than that, I can't disagree about sudden temperature changes being the source of warping/internal stress. In spite of that though, as far as I'm aware, heated chambers *aren't* the de facto standard for SLM systems. Temperature regulated platforms are common, but can be bound to temperatures as low as 50C. I know it is common for SLS systems, but I don't believe it's the same for SLM. I know the PM100 by Phenix Systems is an example of such a machine though.
Yes, atmosphere was inert. Always wear gloves and a respirator when handling metal powders.
@@metalmatters first of I wanted to say thank you for responding and I’m so sorry I think that was a previous video I was watching of yours. I hope this doesn’t come across as criticism or anything I want to learn as much as I can from you and bounce things back and forth. I am very much still in my infancy of learning all this.
I seem to be on a different thought process, most of the slm/dmls machines I have seen have heated chambers, it’s allows for minimising thermal stresses, enhanced powder bed fusion, and a few other areas that help.
I could also be completely wrong about this, that why I want to pick your brains as much as I can so I can learn!
But also finding that even the powders need to be opened and handled in an inert atmosphere like argon or nitrogen to prevent contamination and oxidation.
I haven’t seen the phoenix systems yet I’ll check them out! Thank you 😊
@@SurfyKirky Didn't catch this one! I have a feeling you might be referencing material related to mission critical applications e.g. medical and aerospace. Which machines have you been looking at?
If you have a look at the TDS for brand name powders, some of them will mention build plate temperatures. e.g. www.eos.info/03_system-related-assets/material-related-contents/metal-materials-and-examples/metal-material-datasheet/aluminium/material_datasheet_eos_aluminium-alsi10mg_en_web.pdf Between this and a lot of systems using silicone/rubber recoating components, I'm under the impression that most systems don't rely on heated enclosures. Sustaining high temperatures for potentially days and the added build cost.. it's just easier/cheaper to deal with using mechanical supports and annealing.
Btw, are you based in NZ?
Hi, @MetalMatter great video. What effects would you expect if you were able to change pressure as a parameter? For example, if this system were located in a pressure chamber, then how would varying pressure affect the expected outcome? Also, since it's a finely packed powder you could use the tip of a syringe mounted on the head to carve a canal into the powder's surface that will be filled in once the powder on either side of the canal melts pouring itself back inside the canal. In essence, the canal creates a greater surface area, which alters the dynamics of the reaction. Alternatively, maybe using a different gas in the atmopshere of the melting. My naive guess is that the liquid turn to vapor and causes the bubble to pop and splatter the metal.
Really cool project hope you get the results your looking for
are you preheating your powder? have you considered using a galvo mirror for the laser motion?
I'm not preheating the powder. Yes, too expensive with the current config.
Keep going man your work is impressive. This must have taken a ton of effort.
To reduce or possibly eliminate the build up at the end of the run, ramp down power a few mm before end.
Tnx for this new video.
Good progress!
As someone who understood very little about the creation of your printer.. I found it fascintsting.. As someone who does specialty welding, needing to change gas percentages, voltage/ amperage, or alloying properties, I found it really interesting. Just not sure how all of that translates into lasers.. looking at it you need more heat input in a wider area for the amount of filler metal you are using.. or you have a compatibility, contamination issue with the base metal.
Glad to see you not giving up. 👍
As one famously said: Metal matters! ;-)
Less than 1min in to your video and I love your humourous presentations style!! Slapped that sub button hard
I've watched this way more than 3 times.
This is all well and good, but what we all want to see is a benchy!!
does the steel disk get lower and lower in its housing each layer or are the layers raising on the z axis? if you had a base that slid lower and lower down a tube and add material on top you might be able to simplify some stuff.
Not sure if you tried this (you talk too fast 😅):
About the droplets at the starts and ends of tracks: Did you try to first accelerate to desired speed and only then switch the Laser on? Or block/mirror away the Laser light if switching is not reliable enough? Same for stopping. Keep speed and Laser ON until end of track and only then switch the Laser OFF and decelerate afterwards?
I know some CNC CAM software is capable of creating milling paths where the speed during metal cutting is always as intended and acceleration/deceleration is outside of the current steel cutting surface. So for a 90 degree corner the CNC machine makes a loop at the end of side one to change direction and accelerate in the new direction before milling the side two.
Unbelievable! Fantastic work!
I can supply you with an optical diamond window to protect your optics if you think it’ll help. It’s what’s used in commercial systems rated for many kW. Diamond is used due to extremely high thermal conductivity and durability. Overkill for your application but it’s the best you can use
Appreciate that. I'm not sure that is quite the answer to my problems but will keep that in mind.
Excellent project, just subscribed
I’m wondering if an inert gas in the build chamber might have any impact on quality
🤔
Fantastic! Hopefully one day we can build one ourselves.
Sorry for my word but holy shit this is amazing
Awesome progress!
Happy to see the progress!
Is this likely to be viable for aluminum printing as well?
I know it has a very narrow working/melt range.
I won't be pursuing it. I think you'll need a substantially higher power density to offset the lower absorption.
aluminium is much much harder to work with compared to steel.