Project Logs

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• [R] Ease Of Use

  kelvinA • 09/02/2022 at 12:23 • 0 comments

  This log is just a collection of articles that I agree with.

  • https://www.fabbaloo.com/news/do-3d-printers-make-you-cry
    • The issue I agree with is that hobbyist 3D printer manufacturers (except Prusa) aren't tackling ways to make the process less problematic. Unfortunately, there's only so much you can do with FDM, but SLA requires even more work from the user, leading on to the next article. 
    • With (soluable) support material and reusable supports, as well as isotropic properties of resin without having to worry about enclosed voids, the process should become much simpler in both hardware and software for L^3 printing. 
  • https://www.fabbaloo.com/news/the-trouble-with-many-asian-desktop-3d-printers
    
    • On the software side (#SecSavr Sol^2 [gd0045]), I'm thinking of a feature that is a merge between the Windows 8/10 UWP print dialog and the online shopping experience of AliExpress and Amazon. It's not "at the press of a button" simple, but hopefully something like "print now" and "add to queue" instead of "buy now" and "add to basket".
    • I also would like to make in-software tutorials similar to the reason I write these logs in the first place: to be able to direct those interested to concentrated source of my research and information.
  • https://www.fabbaloo.com/news/resin-3d-print-times-longer-than-you-think
    • Because of Suspense and Sol^2, I should be in a position to eliminate most of the steps described in a typical day resin 3d printing. There'd be new ones though, such as putting back the reusable support blocks, but the most important seconds to save are the ones that I have to be doing something.
    • There's actually a step even larger -- way larger -- than any on the list he talked about: creating the model itself. 
      • Specifically for parametric + history based modelling, I've still got the opinion that I want to develop #enSweepen [gd0096]. Reading https://develop3d.com/cad/the-future-of-cad/, it seems that the big players in the industry also acknowledge that sketching needs some work, but they all seemingly going to use machine learning and AI to predict or inspire the user. Obviously, I don't have that kind of training data, and looking at all the stuff that I've modelled gives me the impression that each new modelling project has to be conceptualised differently enough to mean that an actually useful system is years away. I personally think that the way of creating sketches needs to be less linear and more explorative since, especially in 3D printing, requirements and specifications are usually going to change. 
      • For human-to-computer interfacing, I'm working on #Tetent [gd0090]. I see this as the most important project of mine currently since this will speed up near everything I do when I'm awake. While the Suspense project is smaller in scope than #SecSavr Sublime [gd0036], I still need to make sure I have enough confidence and energy to go through all the required steps, and my classical keyboard and mouse isn't going to allow for that.
  • https://www.fabbaloo.com/news/seven-hardware-features-that-should-be-on-resin-3d-printers
    • I also believe that as many surfaces inside the printer should be wipe-able and I'd like to get some sort of cartridge fill level sensor. Additionally, I think implementing a wizard into Sol^2 is a needed feature, especially since the material side of this project's equation is a big question mark. The other 3 features are not needed for this printer as the problems they address no longer exist.

• [A] Seemingly solid specification

  kelvinA • 08/21/2022 at 16:12 • 17 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.

• [R] Laser Cutting

  kelvinA • 08/21/2022 at 11:35 • 2 comments

  [Published 21 Aug, 16:16]

  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.

  Laser Types

  This page from XTool helped a lot in my research. The TLDR is that:

  • Fibre lasers have max watts, max lifespan
  • Diode lasers have min watts, medium lifespan
  • CO2 lasers have good watts, min lifespan.

  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...

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• [E1][T] SuspenseSizeable and Suspense^2

  kelvinA • 08/19/2022 at 23:33 • 0 comments

  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:

  1. 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.
  2. 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.
  3. This new lineup reminds me of the iPhone Pro Max / Pro / [Standard] / Mini.
  4. [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.

• [R] Pick and Place (and silver paste)

  kelvinA • 08/18/2022 at 21:46 • 0 comments

  [Published 19th Aug, 15:43 ]

  Reason for starting research PnP

  Watches that PnP dial video embedded in a previous log

  Me: Hmm that seems kind of long... I wonder if I could at least automate the rotations of the disk.

  Somewhat related hackaday article:

  Me: I don't have that kind of time!

  The comments:

  Me: Hmm...

  Looks at the link in the hackaday article
  

  The person who made the pump:

  Me, designing the SuspenseSmall with 2 >50cm dimensions but a smaller volume:

  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.

  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...

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• [R] Polar molecules

  kelvinA • 08/18/2022 at 12:52 • 0 comments

  Before I get ahead of myself, I just wanted to quickly confirm what molecules are polar and if they can be part of the chemical mixture of resin. 

  Water and ethanol sound like likely candidates.

  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.

  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. 

  This research sounds good enough for my science. I just don't want a #Filament Furnace [gd0042] situation.

• [T] Replace cleaning roller with silverpaste extruder

  kelvinA • 08/17/2022 at 22:18 • 0 comments

  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.

• [M] Starting the LCD/Charged panel switcher

  kelvinA • 08/17/2022 at 12:40 • 0 comments

  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.

  1. 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.
  2. 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.
  3. 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.
  4. 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.

• [A] A solution has been mentally computed.

  kelvinA • 08/15/2022 at 20:27 • 2 comments

  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.

• [T] Cartridge solution

  kelvinA • 08/15/2022 at 16:46 • 0 comments

  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.

  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.

  The 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.

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