I noticed this a few days back when it was already a suprisingly low £204, but I was expecting the price to go up, not down. It's quite a bit larger in dimensions than the ZBAITU module, but it would be notably cheaper if the time comes to actually get a laser.
2024 - Jan 04: Powder filled photopolymer for expanded material options
I've always thought that if the copper material worked, other materials that were in powder form could work too as long as the photopolymer sufficiently absorbed the laser power. I've just found out about The Virtual Foundry that sounds like they're doing that with PLA for FFF 3D printing, looking at this pdf about custom Filamet filament. The most notable part is that they recommend 45 micron particles:
I'm hoping that, during the printing process for L^3, shrinking predominantly happens vertically. To put another way, a 100um layer of photopolymer shrinks to 80um after being iradiated by the diode laser.
2023 - Dec 18: Orient omniwheels to long axis
This is so that the larger-diameter main wheel can go over bumps like the floor dividers in doorframes instead of the smaller wheel array on the omniwheel.
2023 - Nov 11: Send new print whilst current job is printing
The idea is to use the magnetic supports to build a scaffold for a designated amount of print area that is used if a user decides they want to print something whilst a multi-hour / multi-day print is already in progress.
Like, say you've got PartA that'll take 10 hours to print because it's multi-material, but you also think that you might finish designing a smaller/shorter/single-material PartB in 2 - 3 hours from now. The goal is to be able to start PartA, specifying to also stack scaffolds for a 50 x 50mm area. Then, when PartB is ready to be sent over, the Suspense starts printing it at its earliest possibility. Taking advantage that the area covered by the LCD will take the same amount of time to cure regardless, the hope is that the additional print would be negligible and it'll almost be like having multiple printers on demand.
2023 - Nov 11: Bed that only moves in Z
As a project targetted towards consumers, the amount of print space compared to the amount it takes up is an important metric. I looked at UK door widths, and the smallest was 27" / 686mm. I then looked at desk heights and the lowest was 28". Assuming that the thickness of the table is 1", it'll mean that there's 27" of space underneath it. From that, I'm thinking of going with a 52" x 26" x 26" (1320.8mm x 660.4mm x 660.4mm) maximum footprint area.
To maximise the print area, the plan is to have the LCD and material cartridges on a heavy duty gantry. Conveniently, this shouldn't be a printer that needs high accelerations to perform at a decent speed.
The hope is to get about 650mm x 490mm x 330mm of XYZ build volume (1cm more than the round sounding 64cm x 48cm x 32cm, like how the CR10 is advertised for 300mm but can usually do 310mm). Part of this large size is so that it meets / exceeds the XY bed area of the #SecSavr Sublime [gd0036], and part of it is because I beleive it's a very nice size to have for the expected price, but a part is so I can do reliability testing.
2023 - Nov 08: Enclosure pressure test for added safety
I'm thinking that, to test that the printer is airtight, the pressure is changed so that it's not 1 ATM and this pressure is electronically monitored. It doesn't need to be that much different, but enough to detect if there is a leak before or during the print. I'd imagine negative pressure is safer, as leaks will cause fresh air to move into the enclosure instead of pushing contaminated air out into the environment.
2023 - Sep 20: Moved from comment area
I've moved all the ideas from the comment section (called "Discussions") into the log itself so that it can be picked up by search engines. Think of these as nano-logs. The main header includes the general gist of the comment. Replies to the main coment will be shown under a smaller header.
I've also renamed this log from "Seemingly solid specification and quick comments".
2023 - Sep 19: Load cells
Considering using load cells on the bed to be able to detect pressure. Theoretically, this would allow the printer to make sure that the pressure against the LCD is constant across the printing area as well as detect if there's an unexpected amount of force being applied, stopping before LCD damage.
2023 - Aug 05: Shelving SecSavr
Currently shelving all SecSavr projects due to Tetent [gd0090] delays. This is due to manufacturing issues with Tetrinsic (https://hackaday.io/project/184180/log/221847), and I haven't even gotten to the programming stage yet.
I'm just going to have to hope that BCN3D and I are not the only ones designing a lower cost, higher viscosity compatible alternative to Polymer Jetting.
Because things like X * 1.2 * Zm grow tents and cheap 1.2 * Ym heavy duty shelving exists, I'm thinking of trying to get the footprint of the printer under 1.2m long so that it can fit in such store-bought solutions.
2023 - March 20
This seems not possible whilst still keeping the 652mm X axis. I'm only 10cm out though, so perhaps I can find a way when I start modelling.
2023 - Feb 15: Increase Placement Block X acceleration
I'm going to put a sping / damper between the PnP motors and everything else in the Placement Block to increase X axis acceleration.
I'm planning to use a self supported HGR15 rail (due to the 700mm+ span required now), so the Placement Block makes up less of a mass percentage when accelerating in the Y axis (the total mass = HGR rail + carriage + Placement Block). On the other hand, X mass = Placement Block + HGR cariage.
The syringe stuff is light so that can stay alongside the spindle (which needs the stiffness as a load will be applied against it) and laser (which is sensitive to ringing/ghosting oscillations, and high acceleration movement is a bigger factor of print time). The PnP shouldn't have any X axis loads applied to it and the 2 stepper motors likely have a significant enough mass % of the entire Placement Block such that mounting them like flying extruders in the FDM world will show noticable improvement in acceleration.
2023 - Jan 13: Meshed bed instead of solid
I'm thinking of initially trying to print on a mesh (similar to the print beds used in top-down SLA printers). I need the mesh anyway because of the laser cutter, and I can already see it now where I'm having difficulty cleaning off the first layer if I used a solid bed. Plus, I'd then have the option to fill the bottom of the build area with bolt heads for auto part eject similar to the SLAminator. I can imagine that now, and it looks sweet!
2023 - Jan 05: Another multi-material resin method found
I just realised that if I fully cure the first layer or layers under magnet stacks, won't the part the part be bonded too securely? Would the slicer need to print some kind of surface area reducing pattern?
2022 - Dec 10: Q5D 3D printer found
I saw this video and it's possible to laser sinter copper inks (with what looks to be a red (likely infrared) laser. Their machine can also lay copper wire or continuous fibres.
I'm trying to understand how they're doing it, but this company has been able to print from both the top and bottom of a build plane at the same time, essentially cutting the print speed in half and reducing the amount of supports required. They call it MAP(tm).
2022 - Oct 16: Tiles for enclosure
I'm likely going to use tiles for the outer enclousure. I've got maybe £60 of 50x60 and 55x60 tiles I bought for the SecSavr Soap that are now not doing much. Additionally, I'm looking for a rigid, cheap, opaque, non flamable, good looking sheet material, and tiles sure tick all those boxes. I'm somewhat concerned about weight, but I'm also going to be using galvanised steel tubes where I can for the frame, so it's probably not a metric I should use to consider usability.
This could merge 2 printer ideas I've wanted to do. First, the "original SecSavr" (which I renamed to the SecSavr Cylinder) was going to be a cube CoreXY printer that used tiles as an enclosure. The second was a printer built into a coffee table. At over 70cm tall and with no foot space, the Suspense would probably be more like a cupboard.
2022 - Oct 10: Increase X to 652mm
I'm tempted to increase the Suspense X from 614 to 652mm because 326x2 = 652 and the MGN9H is 40mm long. I'd like to stick to off-the-shelf rail lengths, and so a 650mm rail won't be long enough and I'd have to go to 700mm.
Additonally, I'm likely not going to build the SuspenseSmall mainly because the Suspense hypothetically CanDoTheTaskApp and an additional SuspenseSmall would only CanDoTheTaskBetter. If any component had to be (re)bought because expectations differed from reality, it'll cost 2x with 2 printers. To further add, the money would be better spent towards the materials R+D budget. I'd still have the SuspenseSmall in the BOM to confirm that a solution can cost under the arbritrary £999 with the Placement Block, but the real value meal deal in this lineup is the Suspense.
2022 - Oct 08: Laser edge smoothing
I just realised that, since I most likely would have to formulate the materials anyway, and the whole system blocks visible light getting in or out, I could have a photoinitiator for both 405nm and 450nm wavelengths. Then, the 450nm laser could be used to obtain SLA like surfaces. This would primarily be used on block-colour or transparent-coated surfaces to add a smoother or glossy surface.
The order would be: Coat film -> expose layer -> peel part -> laser edges -> clean excess -> cure all -> recoat film.
2022 - Sep 06: Increase X to 614mm
Now that the printer is planned to be fully enclosed and sealed (again), the requirements for the SleepCinema / CeilingSingle [gd0099] kinda just fell of a cliff, to the point where it would make much more sense to use a "heavy duty" shelf off ebay for cheap than cobble together the CeilingSingle. Therefore, I'm going to reclaim the 85+mm of space the 42.4mm vertical tubes would've taken up and increase the lengths of the Suspense + Slim to 614mm.
Can I think of a use for a 600mm long X axis? No, not really; there's more 500mm prints I've got in mind than 400mm ones, but the amount of prints drops off after 510mm. However, I expect the cost difference to be like <£30, the footprint to be about the same and FutureMe might have that one-off print and glad I made the decision. Additionally, the largest FDM in the hobbyist space is the TronXY X5SA 600 and I did ask "The best of resin with the best of filament; is such a 3D printer possible?" and this is an easy way to get even closer to "the best of filament" across all metrics.
2022 - Sep 10
Oh it makes the SecSavr Skyrise practically redundant. That printer has a >700mm Z height and I only cared for >600mm long prints.
2022 - Sep 04: Discovered Nevermore
I'm adding filtration back onto the list of features due to this article.
2022 - Sep 01: Silver paste in ceramic tracks
I'm thinking of trying to print the silver paste tracks in ceramic / ceramic-like resin in the hope that a near full sinter of the silver trace is possible with the laser.
2022 - Sep 01: Kickstarter 3D printers
Oh yeah. I forgot I heard about the NexD1 at the start of June. The Kickstarter got suspended because it was a complete scam apparently. I'd really like the Suspense to be the actually-working-version of the concept and have it not cost over 2300 euros (55% off super early bird, shockingly). Actually... I shoud probably keep a low profile until I've got prints because the project's deliverable now sounds like a massive overdeliver in comparison to anything else currently on the market, even though the science seems sound in my eyes. 🥺
There's also this little machine called Rubanmaster that can be turned upside down to switch from SLA mode to Laser cutter.
2022 - Aug 26: Overcuring and curing speeds
I'm currently reading a paper called Slurry Based Stereolithography and found out that "overcuring" refers to resin that would be in the layer under the one being exposed also being cured. I'm assuming that's the reason why UV blockers are added into the resin, and I suspect that these UV blockers are also responsible for clear resins being yellow-tinted. I don't have the information to confirm such a hypothesis, but I can conclude that UV blockers... block UV, the stuff that is supposed to be curing the material in the first place. This slows down the curing speed, so will not be added into DIY resin since I need curing speeds to go up and there *isn't* uncured resin under the exposed layer -- it's air or fully cured resin. This change would also add into the need for opaque doors to prevent premature curing from stray light.
Speaking of curing speeds, I'm reminded of this reddit post [https://www.reddit.com/r/resinprinting/comments/pcbvbv/diy_continuous_resin_printer/] where the vat is rotated to replenish the PDMS layer with oxygen. I don't know if this is going to be a bug or a feature, but the PET film for L^3 is cleaned and exposed to air after every exposure. Does this mean fast peeling of the part or trouble with cleaning up uncured resin?
2022 - Aug 27 (00:13)
I've been reading "Slurry Based Stereolithography" because it sounded like it could actually be a paper that inspired VLM; I still refuse to believe it's never been tried untill BCN3D. By the way BCN3D were talking about it, it sounded like it was one of those technologies that struggled to get out of the lab and they finally perfected the science/engineering.
Anyway, they're talking about ceramics and I was like "I've got a laser... could I sinter ceramics with it?", so I google search and see this image:
It's a diagram of a film based printer, where a projection comes in from the bottom, material is deposited onto the film from the right and pumped from the left, and it's a printer designed to print ceramics and metals!
I kinda thought this was possible (and that's one reason why I didn't initally want to use "liquid" in the technology's name), but I valued the rightside up print bed more than the mayyyyyybe that I could print ultra expensive metal powders that I'd still need to sinter. I believe that polymers + continuous fibre would meet the needs of most of the situations I'd want a metal part, which is stiffness without being brittle.
Anyway this is an animation of it printing [timestamp: 39s] and I can finally rest easy knowing that the 3D printing rule still stands: If you think of a cool 3D printing idea, someone else has probably done it already and usually at least 5 years ago. It seems that they are able to pump the liquid up and off the film. I was wondering if there was a solution that could make this kind of process gravity independent and this seems to fufill it.
2022 - Aug 27 (10:05)
I've found another instance of using a film, and this one is closer in line to what I'm doing. The researchers say that the printer is called the Onestage 6500, but Google doesn't find any relevant results.
There's also a study that uses an air jet to clean uncured resin off the part to allow for multi-material printing. It doesn't use a film but a moving glass plate.
2022 - Aug 26: CadQuery
I looked into CadQuery since I wanted to scan over my CAD options again before embarking on implementation modelling in Fusion360 and it was all seeming well until I read in the docs that tangent arcs haven't been implemented yet, which is kind of my "bread 'n' butter" after mutli-profile sketches.
2022 - Aug 28
I'm starting to suspect that Fusion360 is what's preventing me from project progress (in more than just this one) so I tried writing out a concept in Markdown.
2022 - Aug 26: Syringes
Found the syringe needles but it seems that 2x5ml is the max I can fit in the space provided instead of 4 x 10ml due to the lack of screw capped syringes under 100ml. There's a very nice looking steel 10ml on aliexpress, but they're 10x too expensive and I won't be able to use a light-based approach for detecting when the syringe is almost empty. For the latter, I may be able to detect a current difference on the pump.
I might be able to get 2x5ml + a 3ml syringe in there, so that UV curable resin, silver paste and solder paste can be used in a 3DPCB. I'd also be fine with 5ml + 2x3ml or 3x3ml.
2022 - Aug 25: Paste extruding via compressed air
On the search to make sure 400kPa (58psi) was good enough to despense things as viscous as solder paste, I found out about nScrypt's fabulous and fancy printer demonstrations:
Seeing this, it seems that it's possible to do away with the printed tracks, and instead: print PCB surface -> deposit tracks -> laser cure/sinter -> print next layer straight on top, filling in the gaps.
Additionally, I'm thinking of a 6 section rotating cam to use for enabling or disabling 4x10ml syringes + fibre nozzle. Ideally, I'd like to still be able to use pressurised air to extrude the paste, as then I can swap to 5 / 2 / 1ml syringes without much issue.
2022 - Aug 26
It's likely that the paste would spread out if it's not dispensed into a track. It might be something like 0.24mm min track width on substrate vs 0.16mm min into substrate. I'm going to aim for 0.16mm-into since a 30G syringe needle is 0.159mm.
2022 - Aug 25: Piezo probing
I'm thinking of going with piezo sensors instead of 3D Touch so that I can get Z offsets for all nozzles, as well as detecting if the entire head has hit something when the Z axis is raised (eg for laser cutting).
Thus, it makes sense to have a 5W laser in the Small. I was thinking of no laser since "Do I really need 2 laser cutters?"
2022 - Aug 25: Implementation research
Now I'm in "implementation research", which is the tedious process that can be simplified to something like "Should I use these bolts or those bolts?". I think it makes sense to write such research as comments to this log. The first one is going to be large because of the backlog before this idea.
So far:
Confirmed that the C80-EAIR + 12V slim PSU is the best option whilst keeping the upgrade price for laser under £200. The 12V has the same outer dimensions as the 24V, so at least I can make the wiring symmetrical.
Found out that off the shelf pick and place heads are really expensive.
Found out that silicone tubing is flexible enough to rotate +/- 180 degrees, avoiding a coupler that adds Z height and is apparently leaky.
Found the SY-020, which looks like the UV-U3 pump but it's rated for 50dB instead of 60dB and has a max pressure of 400kPa instead of 350kPa.
Found a current sensor (ACS712), which will be used on the pump to detect if a part has been picked up successfully.
Made a quick sketch in fusion to confirm that everything might be able to fit in 90x90mm XY, though it would be nicer if I could get 80x80mm.
Confirmed that basalt fibre is the best option currently available to me. I found out about UHMWPE fibres, but then I read a paragraph the basalt fibre seller sent me months ago that said basalt was better. UHMWPE also seems more expensive.
Decided to scrap the Desktop Metal way of placing continuous tow and will design for a 0.5mm thread. This is because raw carbon fibre and basalt tow doesn't seem to be all that stable at the tip end. I'll have to make a machine that takes the raw fibre and spindles it into nice, managable rolls. Additionally, this change to 0.5mm round thread means that I can get truly continous fibre and fit it in smaller cross sections. Very small and very large parts is what I expect would benefit most from reinforcement.
Currently, I'm:
Reading about using compressed air to dispense pastes. Apparently, I thought anything that needed "compressed air" needed a massive air compressor. Turns out 20 - 40psi is only 137 - 235kpa, and uh... the SY-020 does 400. I'm looking for solutions different from the classic syringe plunger since Z height is limited. Now I'm wondering if I can actually use this air pressure to move the syringes up and down like a button press pen, as this would further reduce the amount if stuff that needs to be in the Placement Block whilst simultaneously increasing the amount of pastes and the volumes it can carry. I might actually be able to port the chocolate extruder from #SecSavr Sublime [gd0036], though I'd have to look into sub-ambient part cooling for actually decent results.
Things to do:
Briefly look into sub-ambient cooling.
Look into cheap + small cameras to use as syringe nozzle and cartridge application cams. Unlike gd0036, the movement would be slow enough to use 30fps cameras without it being a complete blur.
Look into the pressure required for the button press pen idea.
Things I'm not sure about:
Inclusion of a vinyl cutter. The blades used are dirt cheap, but that's an additonal tool I need to actuate.
It might be possible to use the laser to heat the silver and solder paste. Useless for BGAs, but might be required for localised heat curing the traces without having to expose the entire print to temperatures well over its Tg.
Things I might research further:
Flexures for the LCD screen. I found out whilst watching a video of a DIY scanning laser microscope that those dirt cheap steppers can be used for micron level movement. [see https://openflexure.org] Not sure why this hasn't been done, but if I can get 20 micrometres of movement, I might be able to get edges that even beat current 8K (28um) printers on the market.
Laser Direct Write. Researchers in 2017 were already making PCBs with it. See Timestamp 210s
2022 - Aug 25
Oh yeah and the rotational axis once used by the fibre tool is now being used for a second PnP nozzle.
2022 - Aug 21: Seemingly Solid Specification
With a description as confident-sounding as this, I think I can assume that I'm out of the bulk research stage and moving into the development stage. I can't think of anything now, but there's a low but not 0 probability of discovering a new innovative feature to implement whilst modelling the printers. Also, the Slim/Small is expected to change from 305mm -> 355mm in Y footprint for the Placement Block.
As I said in the previous log, unlike most cheap laser engravers and 3D printers with attachments, the Suspense has nearly everything for safe and effective laser cutting use. I'm not interested in engraving, and Klipper doesn't support it either, though at the time of writing, it sounds like it's in the pipeline.
I did a quick scan of modules, and since they were <= 40mm square by some Z height, I quickly thought of a solution that could fit in the Placement Block (the thing that houses things like the silver paste dispenser and fibre).
Still though, while it's technically an afterthought, I still have to treat it like a first rate citizen. I don't want some "Jack of all trades, master of none" review, but "It's just BetterTM". So I spent all of yesterday researching lasers, both for the SecSavr and so that I'm finally somewhat informed in this traditional manufacturing method.
The lifespan of the CO2 actually suprised me. I thought CO2 was a complete upgrade over the cheap diode laser modules, but allegedly, there's quite expensive recurring maintenance costs.
Cheap-ish diode lasers max out at around 5.5W of light power. The best efficiency I've seen is 27.5%, or 20W of input power. Unfortunately, the diode laser industry likes to advertise the input power. To get more light power, multple diodes go through optics to merge the beams.
The above is from Snapmaker's AliExpress listing. I saw it right at the start of the day and it's what got me thinking of lasers in the first place. It's >£400 at the time of writing and they advertised 10W, so I was wondering why. Other than getting the impression that Snapmaker is like the engineering version of Dyson, I eventually deduced that it was because of the optics and dual diodes. For the rest of the log, I'm just going to refer to lasers in their output power (unless talking about specific lasers on AliExpress).
Looking at options
The only 405nm laser I could find had 1W of output power; the vast majority are 450nm with some being 445nm. I couldn't seem to find any remotely affordable and high powered UV lasers either.
I found a black heatsink, 5.5W diode for £32 on the same listing as a 5W, gold heatsink diode for £80. Obviousy I'm confused, but it's because of optics again. As you can see from the snapmaker image above, Fast-Axis Collimating lenses decrease the laser dot, allowing for 100% faster cutting speeds. It's only when I went onto another listing that had this handy table that I found out.
Air assist, where pressurised air blows burnt debris away from the cutting area, is also an important feature to have:
Shortlisted Options
A few minutes later, I found the bottom two lasers:
I've been wondering why the 80W version is cheaper than the other 80W version on their same store, but while they look identical, only at this present moment that I'm writing this log that I see that the codenames are different so obviously there's got to be some change I don't know about. I just didn't want to pick a laser that was going to spontaneously bump in price, even if AliTools said that £132 is some of the highest seen in recent months.There are other "80W" lasers that have the same 10W output power, but the TwoTrees has a larger 69x157um dot, the gold one doesn't say and the orange one has a bold claim of 10um, though I suspect it's 100um.
Neither of these had air assist out of the box and TwoTrees was the only other laser to support 24V input. Additionally, the C40 is one of the cheapest modules with FAC lenses and the exact same outter dimensions as the C80. I would have to ask about 24V input since they only mention 24V once and 12V everywhere else.
Safety
I'm planning on putting a switch in an area of the door hinge that cannot be reached from outside (like a fridge light door switch) so that the laser only has power when both doors are closed.
An e-stop should be easy to add to the front of the machine, but I'd also need to have some way to mount it to the back of the machine if it's more favourable to use the machine in that way (closer access to the Placement Block, printer can be placed right next to a wall...).
The laser input power will be connected to one of the onboard mosfets.
Due to the toxic fumes of resin printing already, I'm planning on electronic locks on the doors that only unlocks when VOCs have returned to a safe level. These locks will also be on when the laser is in use.
Unfortunately, I don't think there'd be any suitable amount of space for fire suppression in the SuspenseSlim and SuspenseSmall. The expected laser cutting area is also not large, and the BOM suggests that the price between the Small and the Squared is going to be slim, so I'd recommend the Suspense and Suspense^2 if a laser is to be installed in the Placement Block. From my basic knowledge of fire, I assume that it would eventually run out of oxygen in an enclosed volume and self extinguish.
Considering there's not much safety precausions for 1mW laser pointers, I'm assuming that the laser power has to be reduced to this level when talking about safetly glass. The OD rating has the formula ResultantP
ResultantPower = LaserPower * 10 ^ (-1 * OD)
So an OD rating of => 4 is needed to reduce a 10W laser to 1mW. For glasses, that's straightforward to obtain. For an A3 sized window... no. Therefore, a dark and heavily frosted material is required instead of the dark grey lexan window. The laser focus is fixed, a 3DTouch will be included on the Placement Block and there's a scanner inside, so there shouldn't be any requirement to see the dot of the laser. Heavily frosted is preferred over opaque as light from the laser or the start of a fire can still be visible from outside, but I cannot confirm if the laser dot will be diffused enough to be safe. Considering that the 108W UV LED is now being used to cure the 3d printed part, it's likely that I'd opt for an opaque door regardless.
Comparisons with other budget laser cutters on the market
The first thing I was concerned about is the cutting area. The "Ender3 of the laser cutting world" K40 CO2 laser cutter only comes in at 300x200mm, and the Suspense is expected to be 360x320mm without replacing the bed for a larger one that doesn't move in Y. If this bed is replaced, the area becomes an expected 360x480mm.
Watching this video (timestamped), it's probably fine to have any airflow at all. Actually scratch that as I just found this writeup and a 24V fan actually looks worse than no air at all, but the compressor that looks very similar to the one I just found is where the good cuts start (and it seems that David, the author of the writeup, also questioned adding a laser to his project). I found the pump on Amazon for £28 and most of the reviewers use it on laser engravers fine, though a PC fan on the heatsink would help with keeping the compressor cool.
Other than CO2 lasers, I can't seem to find lasers with enclosures. The most similar I've seen is this:
It has a 370x370 work area.It seems that the market for both buy and DIY is:
Large, cheap and open laser cutters, which may be part of a cheap CNC mill or 3D printer,
The ultra rare DIY diode build with an enclosure and filtration,
The K40's for £400,
DIY enclosures for the open laser cutters, and
The >£1,000 CO2, enclosed-diode and fibre laser machines.
Thus, it seems that a laser in the Suspense would fufill a gap in the market.
You may be wondering why it sounds like I'm once again considering increasing this SecSavr Suspense lineup when I haven't even got a working prototype, but it shouldn't be that much of a design alteration since the idea is just to put a Y axis stage on the bed.
I've been considering this for >2 weeks I believe, and it stems from reading a post in one of the online spaces for DIY resin printers about someone wanting to make a 24" SLA printer. I've also seen instances of 15.6". The latter in an X only design can be done with an 8.9" LCD, but the 24" would be somewhat expensive, requiring 13" screens iirc. Uniformily coating the PET becomes more questionable the longer the Y axis, and there likely wouldn't even be an off the shelf scanner long to verify it. I've also been imagining some perfect, idealistic future where the printer is so good that I can print custom LED matricies for #T^2 Tiles [gd0095], but the PnP wouldn't be able to cover the entire area of the PCB.
The main drawback is that printing in 2 Y zones would take 2x the time. For things like the 260*260 mm LED matrix cover of the #T^2 Tiles [gd0095] where [ Z in current build volume] >> 2 * [ Z in Sizeable build volume], it makes 100% sense. I also worry that there'd be new things I want to print that would exceed the current build volume. Just like the goal of the #SecSavr Sublime [gd0036], I'd rather not have to design another printer further out in the future. There's also things like #Teti [gd0022] and #TetInventory [gd0039] that use the entire Z height for half the print anyway, so I just get the possibility to save on assembly time or being around to send another print job.
With the plummeting probability that I'd actually make the Sublime because of the Suspense, and the fact that I'd need to build the biggest printer to make sure it scales issue-free, I'm thinking of this as the new strategy:
SuspenseSizeable -> Suspense [build this]
Suspense -> SuspenseSlim [design only]
Suspense^2 (SuspenseSquared) [design only]
SuspenseSmall [build this]
Some othe quick things to mention:
I might need a (thick) layer of insulating material on the surface of the print bed so that the aluminium doesn't affect the static pulling force of the Charge plate on the first few layers. The issue is that electrons from the surface of the aluminium would be repelled away, causing a positive charge on the plate. Polar molecules are attracted to all charges, so the resultant force on the resin would be reduced.
The new Suspense and Suspense^2 can theoretically scan A4's now. The Suspense might even be able to stitch together an A3 scan. Wait, it could actually print those optimally now too! Hey, speaking of A4's and A3's, I could now have a build volume to compete with Ainsoprint's A3 Composer.
This new lineup reminds me of the iPhone Pro Max / Pro / [Standard] / Mini.
[11:55] I don't have much interest for laser cutting (and Klipper doesn't really support it), but the printer looks like a good candidate for safe laser use. It just needs a protective window material instead of the grey lexan, since things like locked doors, airtight-ness and ventilation are already things needed for safe resin use.
[11:55] The MGN9H is rated for 1.9kgf-m in the Y moment axis, and according to Fusion360, the mass of the new Suspense bed is 2.7kg for a 517 x 325mm bed for a Y axis of 320mm. (327.x mm is the max, so I could stretch for 325mm on a 330mm long bed.) At the extremes, the bed's centre of gravity would be 75.5mm from the rails, creating a moment of 0.2039 kgf-m which is well under the static force. I'm planning to use a thrust bearing between the star bolts and the printed bed holder so that the moment isn't transfered to the bolt and loosens it over time.
Me, a single person designing the SuspenseSmall in a smaller volume than 125L:A mix of "heh" and "uhh... how big is this project again?"
It seems that this was written in 2015, so there's a good 7 years in which innovation could've taken place.
Wait! This is the hackaday commentor?! Well in this page's comment section, there's someone that sounds like they started FirePick.Wait. It's been 7 years since the comment. How is it not even in beta?Woah that's actually a lot of stuff.Last seen 7 years ago. Oh.
Anyway, I've realised that I don't need to limit the Z height of the paste/fibre head to the same height as the roller, since as long as it's under around 65mm in Y, it can be fully moved out of the way. Thus, I'm researching PnP grabbers to see if I can fit it in the head and eliminate the arm entirely. I was worried about having to have multiple nozzle for different sized components, but as you can see from that hackaday commentor's experiment above, it's likely a non issue.
Researching silver paste
I also need to decide how heat would be applied to the components and silver paste. I might have to find a room/low temperature silver paste. Doing some light research suggests that the question of solder paste vs silver paste adhesive has been asked before.
This gives the impression that it's possible to not need the former and that the components would stay on the substrate well enough to be moved into a curing oven (in my case, probably a food dryer or a heated 3D printer bed with a bowl on it).
Oh. It's that easy. Wow! But doing more looking, it seems that AliExpress sellers don't just sell the same generic noname paste like I originally thought so I should look around.Hold up it's only £6 delivery for 10ml @ £2 each. That's like £3.12/ml after tax -- way under the £4.50 I estimated the PCB cost with. The description also has a wealth of information:So this one has a potlife limitation and apparently can't be extruded through a 250um nozzle. I wonder what ECA the researchers used as they were able to get track widths of 134um, so I was aiming for a 100um nozzle for 120um traces.The multimeter is on the 200 ohm setting, so I believe they missed a "." in the caption. Still, 5.5 ohms for a track of that width seems kind of high. Nice to see that it'll work fine on flexible PCBs.This answers the question I had earlier up in the log.
Back to the research paper, they used a 250um nozzle and I didn't see the "and height" part of the below sentence:
EJ4110 has <=20um particles while EJ2189 has <=45um, so I was like "yeah that makes sense how the line width of one is slightly over 2x the other. Any line widths over 200um is a no-go-zone, so I'm thinking of going with a 150um nozzle and finding a less viscous silver paste so that I can hopefully get 160um line widths and 40um layer heights.Left:EJ2189, right:EJ4110
https://unimtech.com/pastes-for-printed-circuit-boards/ has pastes that can go as low as 50um line width and >150mm/s print speeds with a viscosities of <350 cP and particle sizes of <8um. The issue is the high cure temperatures and no indication of price, so it's probably £££.
Concluding thoughts
It seems that implementation complexity is something that I'd have to visit at a later date, since I'd need equipment to conduct my own tests. For now, I've got a general idea of the system, so I can make a concept placeholder for the design. Due to favouring probability-of-success and wire management over saving a £ here or there, I'm going back to the M8P + Monster8V2.
Due to the fact that this printer is targetting the consumer and light prosumer, I'm expecting that most components won't be bought in enough quantities to come on a reel. The PnP would pick the components from trays similar in size to the PnP wheel.
This means that I can use the negative ion generator modules I found across Ebay and AliExpress.
I wanted to calculate how much electromotive force (aka voltage) I'd need to wrip-n-tear excess resin (aka finding the force exerted on a molecule of resin and seeing if it's greater than the surface tension) but it's seems that it gets really mathematically intense really quickly. Thus I've just gone for the -2 - -6KV version over the -0.5 - -3.5KV generator. The other potential problem is that the LCD is within a few centimetres away from the charged plate, so I'd rather not have a higher voltage than necessary. Speaking of the charged plate, I'm wondering if turning it on whilst the resin is laminated onto the film would increase uniformity as if by negative gravity.
https://patents.google.com/patent/CN101659785A/en Now this sounds like a patent for me. Wow, environmentally friendly, nontoxic, based on water and alcohol (aka ethanol most likely) so this run could actually work.
At the modelling rate I'm going at, and with other projects I still have to tend to, it's not looking like I'd be able to receive parts and start building until the second half of September, so I'm slightly sadly scrolling through Youtube, seeing what could be printable with the Suspense. I actually wanted to have a design ready and start ordering parts on Aug 1, so I'm at least 3 weeks behind that goal.
I'm noticing that there's a few things that could use some integrated conductive traces.
With the supreme conductivity of silver paste and my research suggesting that its use would be affordable, I'm thinking that coils could be back on the menu.
With things like the PnP wheel (video below), and the fact that products from Voltera and Nano Dimension exist without PnP functionality, it seems that 0 to being able to 3D print PCBs is a more valuable jump than 3DPCB's to auto populated 3DPCBs.
The roller assembly is no longer needed, but that really just leaves a void of space that could be better utilised with the silver paste extruder. I'm also thinking that it would be possible to fit the fibre applicator on there too instead of on a scara-like arm.
The first benefit is that conductive and fibre paths can be placed in the print up to around the build height back when I was using a roller. The second one is that I'm much more likely to be able to pull of 120 or even 80um silver tracks with a cartesian motion system as no angles are involved in positioning.
Then there's the fact that it's more space efficient, meaning that the SecSavr SuspenseSmall could have this installed. Additionally, moving the fibre tool onto the gantry would increase the amount of space for the PnP tool if it ever comes to fruition.
Speaking of which, it should still be possible to implement my magnet stacking reusable supports with the degaussing electromagnets I was going to use in #SecSavr Sublime [gd0036], and I'd like to see if it's possible to implement placing SMD resistors and capacitors since they're symmetrical in 2 spacial planes. It would use the same motor as the fibre tool.
The kinematics to be used is CoreXY. Hopefully I can fit all that and the unsupported MGN9 rail in a 60x102mm footprint, but it's probably going to be twice as long. Oh and I might add a screen on the front for some visual flair. I'm thinking that this is going to add around £50+ back onto the BOM, but I think it's well worth it.
I'm going to refine this, but this is what I came up with.
Originally, when I thought about using servos, I planned to use 2 -- one for each arm. However, once I got to thinking about the torque requirements for keeping the LCD down and problematic powered-from-off states the arms could be in, resulting in component damage, I wanted to revisit the idea of using 1 motor for both.
The idea I had going into it was some kind of incomplete gear solution.
I was worried about the modelling complexity (and that's the reason why I had the servo idea instead of using a stepper), and I didn't like the idea of relying on magnets to keep the panels up when the drive gear wasn't in contact with the driven gear of said panel. Additionally, I may need a high torque motor to prevent the LCD panel being pushed back up.
Whilst scrolling though all 507 mechanical movements on the site, I had the idea to use a groove track, like:I'm not sure how much friction these kinds of things have, so I've just used a 5x14x5 bearing in the design for now. It is very most likely going to be replaced by an 8mm smooth rod/steel dowel.
Movement explained
The track has 2mm long horizontal sections after a movement for lower tolerance requirements of the servo. Additonally, I'm thinking of moving the servo somewhat slowly (180 degrees per second) to cut on noise.
This configuration starts with the LCD panel all the way down on the surface of the film and the Charge panel at 45 degrees. As you can see from the Charge panel will almost completely cover the expected light path of the UV lamp.
Leftwards movement of the groove track from 0 - 10.18mm will slowly move the Charge panel until it is parallel with the expected light path and thus completely out of the way. The LCD panel hasn't moved. This is to control how much of the screen is exposed to UV light in an effort to increase longevity when only part of the screen is needed to expose a part of the layer.
The next 9.62mm of movement will (relatively quickly) move the LCD panel so that it is also parallel to the expected light path on the other side. Now the configuration is in a position to cure the layer.
Moving the track another 12.8mm will move the Charge panel down against the film. As you can see by the horizontal move in this part of the track, any force that attempts to push the panel up will be counteracted by the force exerted on the bearing pushing on the side of the track. This is the same for the LCD panel, thus the holding force of the panels are not dependent on the torque of the motor.
I've typed up all the tasks I could remember from the computation to get me from my current point in Fusion 360 to the modelling finish line, but not in order:
The last time I did this was the #SecSavr Skyrise [gd0092] and I had a full Fusion 360 model in 3 days. I don't know if I'd be able to do the Suspense in the same kind of time, but it means that I'm at a point where I've got confidence in what I need to model.
This to-do list hasn't dealt with the specific implementation of the fibre applier or PnP head.
I've also been cleaning the BOM file, and I'm at 26 motors total. A few weeks ago, I was expecting 26 motors for the Suspense alone, but now it's 26 for both systems. The current incomplete BOM price is looking pretty favourable now.
£649 for the SuspenseSmall looks to be in the cards, and I might have a shot at £599.
The only issue I know about is that BTT has said that their CB1 can only do 4096x2160px instead of the 4096x2560px the screen has. I can't find anything saying that the CM4 can do any better. HDMI 2.0 is on both, and places like wikipedia say that it should be possible for 5K@30fps, so I'm just going to buy it and try it. I only need something like 10Hz refresh. Since I get the full Y axis length of pixels, the solution would just be less efficient when limited to 84.3% of the LCD, and the X axis may be reduced by 16mm.
A compute that has failed has been the desire to have a resin cartridge that can be sealed-like-a-bottle. This is because it wouldn't be possible to pump in collected resin into the cartridge tank without a way for the air to escape. I think I have a solution which would also eliminate the application pump--
My mental compute as I'm writing this log:
The compute... fails, due to the following confliction:
- The X axis will not move a sufficient amount (>3mm) to
be able to change the state of the proposed spring
loaded seal
A new compute is being processed...
A compute... succeeds.
Ok, as I was saying. I have a solution which eliminates the application pump, resulting in the reclaimation pump doing everything. This reduces the moving parts on the cartridges and the amount of motors needed. I'll explain again once I have a concept modelled, but for now I'm going to have to describe it via text.
Instead of my original idea to have both the reclaimation -> tank and tank -> application ports on the bottom of the tank, the reclaimation -> tank silicone tube port will be at the top of the tank and trickle in as seen on the self filling vats that are appearing on printers these days. This is to prevent noise and bubbles.
Source: Elegoo
The silicone tube length between the application silicone tube port and the new application minivat (explained further below) will be long enough that the volume in the tube exceeds the volume pumped into the tank when the layer is reclaimed from the film. This is so that the resin can be retracted to milimetres before the application port before reclaimation (the air would exit through the reclaimation port) and by the time all the resin has been reclaimed, the resin in the application tube would be pushed to the application minivat.
There are two "minivat's" in the design. The first one serves as a buffer for the reclaimed resin to reduce the amount of air that is pumped into the cartridge tank. The second one I've thought of now is the application minivat, which is something more like a waterfall tap.
Source: Appliance DirectThe minivat is integrated with the application knife and is sloped such that gravity pulls unapplied resin back into the minivat instead of sitting ontop of the knife. Here's a quick doodle of the before on the left and after on the right.These changes reduce the amount of steppers to 9, but since that's just 1 more than the M8P and the X axis strategy I'm doing prevents me from applying from one side while reclaiming from the other, I'm replacing the £10 EXP MOT + cables with a £2.70 2 channel relay that connects to the 2 pump motors. These motors are actually the only ones that won't need constant power, so is the most fit for this purpose.
I've been meaning to find out how much conductive silver paste is actually needed for a PCB. I used an old gerber file for a #T^2 Tiles [gd0095] board I never got made. Long story short, Fusion 360 kept crashing when using the svg (converted to dxf), so I just went with a simplified dxf.
I've used water to get the volume, which would be 0.18ml. Multiply this by 2, and it's 0.36ml for a 2 layer board with conductive planes. For the resin minus the 80 microns for the conductive layers, the volume is 7.05ml.
Looking across the internet, it seems that the going rate is £4/ml and up (incl 20% tax).
Then, even with this first-seen-in-industry, as-non-toxic-as-PLA-in-liquid-form resin I found out about yesterday that costs £78 after tax for 500ml, I'm only looking at £1.0998 in material. I'd like to believe that some high temp resin or "digital soldermask" resin would cost less than this.
Assuming the conductive paste is £4.50/ml, the final price is £1.10 + £1.62 = £2.72 for a 122x42mm (5124mm^2) board, which is actually in my league budget. The square area is 51% the size of the 100x100mm boards for $2 at JLCPCB. I had a second revision, 3993mm^2 board fabricated (which was 110mm on the long side so couldn't get the offer), and the minimum order quantity (MOQ) of 5 cost £8.70 with ultraslow shipping, coming in at £1.74/pcb. Extrapolating the above, a print of this size would cost £2.12 and should arrive wayyyyyy faster than 4 weeks. Likely even faster than next day delivery.
These conductive paste's required quanities and prices per ml mean that it's also not favourable to use the L^3 method. I imaginee that the lowest end minimum fill level for even a silicone-tube-only (no tank, but collector pump straight to application pump) cartridge would be >15ml.
kelvinA
I'm hoping that, during the printing process for L^3, shrinking predominantly happens vertically. To put another way, a 100um layer of photopolymer shrinks to 80um after being iradiated by the diode laser.
With a description as confident-sounding as this, I think I can assume that I'm out of the bulk research stage and moving into the development stage. I can't think of anything now, but there's a low but not 0 probability of discovering a new innovative feature to implement whilst modelling the printers. Also, the Slim/Small is expected to change from 305mm -> 355mm in Y footprint for the Placement Block.
The above is from Snapmaker's AliExpress listing. I saw it right at the start of the day and it's what got me thinking of lasers in the first place. It's >£400 at the time of writing and they advertised 10W, so I was wondering why. Other than getting the impression that Snapmaker is like the engineering version of Dyson, I eventually deduced that it was because of the optics and dual diodes. For the rest of the log, I'm just going to refer to lasers in their output power (unless talking about specific lasers on AliExpress).
I've been wondering why the 80W version is cheaper than the other 80W version on their same store, but while they look identical, only at this present moment that I'm writing this log that I see that the codenames are different so obviously there's got to be some change I don't know about. I just didn't want to pick a laser that was going to spontaneously bump in price, even if AliTools said that £132 is some of the highest seen in recent months.
There are other "80W" lasers that have the same 10W output power, but the TwoTrees has a larger 69x157um dot, the gold one doesn't say and the orange one has a bold claim of 10um, though I suspect it's 100um.
Due to the toxic fumes of resin printing already, I'm planning on electronic locks on the doors that only unlocks when VOCs have returned to a safe level. These locks will also be on when the laser is in use. 
Me, a single person designing the SuspenseSmall in a smaller volume than 125L:
Wait! This is the hackaday commentor?! Well in this page's comment section, there's someone that sounds like they started FirePick.
Wait. It's been 7 years since the comment. How is it not even in beta?
Woah that's actually a lot of stuff.
Last seen 7 years ago. Oh.
So this one has a potlife limitation and apparently can't be extruded through a 250um nozzle. I wonder what ECA 
The multimeter is on the 200 ohm setting, so I believe they missed a "." in the caption. Still, 5.5 ohms for a track of that width seems kind of high. Nice to see that it'll work fine on flexible PCBs.
This answers the question I had earlier up in the log.
EJ4110 has <=20um particles while EJ2189 has <=45um, so I was like "yeah that makes sense how the line width of one is slightly over 2x the other. Any line widths over 200um is a no-go-zone, so I'm thinking of going with a 150um nozzle and finding a less viscous silver paste so that I can hopefully get 160um line widths and 40um layer heights.
I wanted to calculate how much electromotive force (aka voltage) I'd need to wrip-n-tear excess resin (aka finding the force exerted on a molecule of resin and seeing if it's greater than the surface tension) but it's seems that it gets really mathematically intense really quickly. Thus I've just gone for the -2 - -6KV version over the -0.5 - -3.5KV generator. The other potential problem is that the LCD is within a few centimetres away from the charged plate, so I'd rather not have a higher voltage than necessary. Speaking of the charged plate, I'm wondering if turning it on whilst the resin is laminated onto the film would increase uniformity as if by negative gravity.
With the supreme conductivity of silver paste and my research suggesting that its use would be affordable, I'm thinking that coils could be back on the menu. 
I'm going to refine this, but this is what I came up with. 
I was worried about the modelling complexity (and that's the reason why I had the servo idea instead of using a stepper), and I didn't like the idea of relying on magnets to keep the panels up when the drive gear wasn't in contact with the driven gear of said panel. Additionally, I may need a high torque motor to prevent the LCD panel being pushed back up.
I'm not sure how much friction these kinds of things have, so I've just used a 5x14x5 bearing in the design for now. It is very most likely going to be replaced by an 8mm smooth rod/steel dowel.
The last time I did this was the 
£649 for the SuspenseSmall looks to be in the cards, and I might have a shot at £599.
These changes reduce the amount of steppers to 9, but since that's just 1 more than the M8P and the X axis strategy I'm doing prevents me from applying from one side while reclaiming from the other, I'm replacing the £10 EXP MOT + cables with a £2.70 2 channel relay that connects to the 2 pump motors. These motors are actually the only ones that won't need constant power, so is the most fit for this purpose.
I've used water to get the volume, which would be 0.18ml. Multiply this by 2, and it's 0.36ml for a 2 layer board with conductive planes. For the resin minus the 80 microns for the conductive layers, the volume is 7.05ml.
