[A][R][T] Seemingly solid specification and quick comments

A project log for SecSavr Suspense [gd0105]

The best of resin with the best of filament; is such a 3D printer possible?

kelvinAkelvinA 08/21/2022 at 16:1230 Comments
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.


kelvinA wrote 05/01/2023 at 14:55 point

Might be useful for fast + accurate bed probing using laser triangulation:

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kelvinA wrote 03/20/2023 at 16:16 point

Just read [] and realised that I'm aiming for 4-bit full colour, which is 1-bit per channel. 4 bits is for RGBA, where A stands for "alpha". It's the transparency channel.

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kelvinA wrote 03/04/2023 at 11:48 point

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.

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kelvinA wrote 03/20/2023 at 16:13 point

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.

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kelvinA wrote 02/15/2023 at 02:40 point

I'm going to put a sping / damper between the PnP motors and everything else in the Placement Block to increase uable X axis acceleration.

[PnP][Damper][Polishing Spindle + Laser + Syringes/Fibre Applicator]

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.

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kelvinA wrote 01/13/2023 at 18:11 point

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!

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kelvinA wrote 01/05/2023 at 23:11 point

Another multimaterial resin method found:

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kelvinA wrote 01/05/2023 at 15:19 point

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?

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kelvinA wrote 12/10/2022 at 13:25 point

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.

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kelvinA wrote 12/10/2022 at 13:22 point
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).

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kelvinA wrote 10/16/2022 at 11:00 point

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.

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kelvinA wrote 10/10/2022 at 14:49 point

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.

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kelvinA wrote 10/08/2022 at 17:33 point

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.

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kelvinA wrote 09/06/2022 at 10:56 point

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.

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kelvinA wrote 09/10/2022 at 19:42 point

Oh it makes the SecSavr Skyrise practically redundant. That printer has a >700mm Z height and I only cared for >600mm.

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kelvinA wrote 09/04/2022 at 13:45 point

I'm adding filtration back onto the list of features:

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kelvinA wrote 09/01/2022 at 22:07 point

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. 

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kelvinA wrote 09/01/2022 at 21:58 point

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.

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kelvinA wrote 08/26/2022 at 19:29 point

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 [] 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?

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kelvinA wrote 08/27/2022 at 00:13 point

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 from a company [] and it's 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 [] 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.

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kelvinA wrote 08/27/2022 at 10:05 point

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.

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kelvinA wrote 08/26/2022 at 16:27 point

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.

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kelvinA wrote 08/28/2022 at 01:41 point

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:

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kelvinA wrote 08/26/2022 at 15:00 point

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.

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kelvinA wrote 08/25/2022 at 23:24 point

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.

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kelvinA wrote 08/26/2022 at 10:51 point

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.

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