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CarterTG

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About CarterTG

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    http://b9c.com/forum/viewtopic.php?f=22&t=371&start=20#p32950

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    3D design, modeling, sculpting and high resolution 3D printing via B9 Creator, Elegoo Mars and envisionTEC machines.

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  1. Kudos @Mad Ax on the insight to hone your suspicions toward layer-droop. As you gain more experience with resin printing, you'll immediately be able to identify areas that may be susceptible to this issue. In a mostly-text forum, it's a bit challenging to describe this without liberal image-posting allowances... let's see how far we can get.. There is never one single must-follow way of orienting a print on the Build Platform and I'm happy to hear that you're trying various methods. It's exactly these early prints that will give you the valuable experience seeing the results for yourself. Exercise 1: The Levitated Cube Take a cube, raise it up off the Build Platform, auto-generate supports. Expected end-result? That underside might look like a buttoned sofa cushion. The best way to see why this would be the case would require going back to the ChiTuBox slicer. This and almost all slicers out there reveal a feature that lets you step through the model slice-by-slice. This isn't just some fancy visual. It's a very important tool to illustrate exactly what will happen in the printing process. Step through the model. You can use the mouse on the slider, but I'd suggest using the keyboard arrow keys to tap through the layers. Tapping through the initial forest of supports from the Build Platform, you WILL reach that juncture where all those little dots of support columns suddenly explode into a huge square sheet. AT THIS VERY LAYER, keep in mind that what the printer is attempting to expose/cure is a sheet of resin that's 0.050mm thin -- roughly half the thickness of typical office copy paper. The Build Platform lifts this structure off the FEP film and as you should now imagine, the super-thin sheet is... sparsely supported here and there only cured enough (at 6 or 8 sec exposure) to maintain a fast model growth -- thus quite pliable as a 50-micron sheet weighed down (drooping) a bit from the uncured resin it has effectively ladled up away from the resin pool ...continuing our growing procedure, the Build Platform lowers this sheet layer down and intends on stopping 50 microns short, but in reality this sagging sheet has either drooped all the way down contacting FEP -or- it's netted FAR MORE than the intended 50-micron layer of resin against the FEP surface. 8 seconds of UV cures the cushion-shaped layer. Lift away. Lower. Expose. This is a plausible way the cushion surface manifests itself. Familiarize your mind's eye with this simulation and you'll quickly learn to detect it and account for it. Account how? Raise the flat cube up off the platform. Tilt the cube so that only a knife's edge of the cube gets a head start... the parallel length of that horizontal edge might still be susceptible to some bowing/sagging... so rid yourself of any parallelism to the build platform and have the layer assemble starting at one vertex corner. Visually stepping through these layers in ChiTuBox should show supported areas GENTLY growing -- none of the very-little-to-very-big explosions observed in the initial scenario. Exercise 2: Grow it directly on the Build Platform There are instances where it makes the most sense to rest an intended flat surface on the Build Platform and NOT raise it up via supports. Most obviously this removes the cushion effect. The main downside is that it SLIGHTLY compromises the Z-dimension accuracy. Factors that contribute to this may include how layer 0 is effectively thrown away due to how the Build Platform gets leveled. The other factor might be due to how the "bottom layers" get overcured. The resin jockeys that 3D model their own goods can certainly compensate for this by extending the side that makes contact with the Build Platform. Perhaps add anywhere from 0.05mm to 0.10mm of additional thickness to compensate for an expected loss in those initial "Bottom Layer" growth. And what of additional structures that jut out of the sides? Again, it will depend on those layer portions that explodes outward... Example? Go seek out my Driver Sculpt in the other thread. The intention was to grow this bust resting directly on the build platform. I immediately started worrying about whether the overhanging earlobes, nose, and chin would present a problem. Visually stepping through the layers in ChiTuBox, the critical areas in question was extending outward at a gradual-enough rate where I could possibly get away without supports -- and thankfully I did. However, if my ears were more like Yoda's and exploded outward at an alarming rate, I would absolutely play it safe and manually dot that bottom edge with as many supports as I could fit. If you are doing your own CAD work, it might even be prudent to build your own supports into the model. It's perfectly acceptable to do it this way for certain structures rather than be at the mercy of the auto-support algorithms. In this route, you are the one who ultimately knows which surfaces are "safe" to harbor support pock-marks and which surfaces need to be blemish-free. Designing in-situ like this also gives you the freedom to lay in some very imaginative support shapes. A support doesn't always HAVE to be strictly a column tipped with a cone pointer... A few examples can be found in this thread (posted before auto-generated supports came to the B9 printer)... https://forum.b9c.com/viewtopic.php?f=22&t=235&start=100#p5944 The "free" support-generating software still have a ways to go, IMO. I've played with a great deal of them (B9 Studio, ChiTuBox, Formlabs Preform) and for the most part, they ALL feature the same style of support. The ONLY stand-out in this field is Materialise Magics. It is marketed with a plug-in they call Support Generation. It's claim to fame was the intelligent way it would analyze a model and lay down a repertoire of different support types that I've yet to see others offer. The downside? Only one. An insane $14,000 price tag. A bespoke version of Magics came bundled with envisionTEC printers. CAD jockeys should take a look at the various support types and be inspired to manually model them directly into the target print. Every time I see an impossibly dense forest of supports sprouted by ChiTuBox, I long for a future where they may be enlightened to switch to a wall/curtain type of support. Resin Vats and FEP The spare vat kit from Elegoo arrived last week. Two factory metal frames and four sheets of FEP. As a kit, none of this is pre-installed, but in following Elegoo's video, it's a very simple straightforward task that ought to take no more than 20 minutes. The bonus is that familiarization takes away the apprehension from future FEP changes and may even invite experimentation with the alternative "non FEP" film from EPAX. I've only had one occasion where a failed print required fishing from the bottom of the vat. With a gloved finger, I detected the fail and nudged it from the side and it offered little resistance in sliding off. I might suggest using an old credit card or business card to sweep the FEP. This temporarily squeegees away some resin to see if anything has stuck without scratching at the film. Sweep only, not a shoveling/scraping angle. The black plastic scraper should only be used to push objects cured onto the Build Platform. I'd never use it on the FEP. Soon enough, you'll dial-in the optimal exposure settings for your preferred resin and it should greatly extend the longevity of the FEP film. It's safe to leave the resin in the vat for back-to-back printing IF you know for absolute certain that your last object grew fully intact and that no unsupported islands left floating bits of cured resin in the vat. Jewelry and other simple curvilinear objects are easy to account for. Missing portions of a ring, or gear, or suspension arm are glaringly easy to detect at the end of a print. This can be a very different story for the figurine printing crowd. The new legion of noobs discovering resin printing for their detailed Dungeons & Dragons, Warhammer, and anime are over the moon at the new found detail, but I'd wager a large portion of them are not supporting every last detail or overhang that I'm seeing in many of the poses out there. Figurines that harbor unsupported islands only provide that many more opportunities for a chunk of resin to be cured... perhaps for a few layers.. and then left floating somewhere in the liquid resin. At the start of the next print session, the user initiates the start sequence where the clean Build Platform lowers into the "dirty" resin. If a sizable chunk of cured resin is in the way, that Platform is NOT going to care and continues to its ZERO Home Point effectively pressing a solid into the LCD Masking Screen. Destruction abound. This was not an issue with my previous Resin Printers as they used a true projector design leaving a required air-gap (and safety zone) in place. In this generation of cheap Resin Printers, the FEP film rides bareback directly on a super-delicate LCD masking screen. My suggestion for people printing a mixed variety of objects, strain the resin between prints to double-check for "floaters" until you've developed some measures to mitigate unsupported islands. THAT issue aside, there aren't further problems leaving resin in the vat. Just be sure to keep the Red (or Orange) acrylic dome over it. Its coloration DOES block the UV that reacts with the resin. I'm not certain the same can be said for Anycubic's use of BLUE acrylic windows on the Photon. Virtually all the other manufacturers use something in the Orange-Red color range. How long can it survive? I've left resin in my other printers for MONTHS in a room with shaded windows. No direct sunlight. Within a week, the resin's color pigment settles to the bottom, so before starting a print agitate, mix, and fold the resin in the vat using a business card -- again, a back and forth sweeping motion... no angled digging into the FEP. Resin is NOT like water... it doesn't evaporate or dry into a thicker viscosity... it is ONLY affected by strong exposure to 405nanometer wavelength UV (blue-ish). I've seen people post photos of a FDM-printed plate that fits over their vat while in the machine. Unless their machine lives in direct sunlight, I'll reiterate that it's perfectly OK under a Red/Orange translucent dome. The spare Elegoo vats do come with fitted covers furthering the possibility of leaving resins in there, but if storing outside the printer, just make sure the vat bottom is accounted for. This is my method for storing my spare vats: https://community.glowforge.com/t/elevated-elegoo/43655 During my B9 era, I would strain the resin every so often... or sometimes would empty the Vat contents into old resin bottles. I really don't recall ever throwing out resin for "going bad". I've always presumed I'll be treating the Elegoo resin in similar fashion. From the way you're describing your FEP film, I'd concur that you should get that spare kit. Of the four sheets of FEP, two will be designated to the Metal Vat Frames. One goes to rejuvenate the factory Vat leaving a single back-up sheet. When following the video instructions, do not be afraid of putting as much slack as possible (wedged sponge) during the sandwiching operation. This assembled frame (with loose FEP) is placed inside the bigger housing and when the large screws are installed, there's a great amount of drum-stretching that goes on. I'd also suggest that the screw-installation order be done the same way a REAL vehicle's wheel gets mounted... sequentially jump to the opposite-sided bolt from the last one fastened. I hope much of the above provides clarity. Let me know where elaboration is necessary.
  2. The more the merrier in this resin jacuzzi, Yogi! Elegoo and Anycubic are brothers from another mother. If time allows, the next post might cover dialing-in resin settings with calibration prints.
  3. Congrats Mad Ax As a fledgling TamiyaClub usergroup of two, this thread can certainly be open to discussing the minutiae of tips and tricks in the name of producing great Tamiya-compatible parts. Since the last post, I’ve explored the r/ElegooMars Reddit forum and attempted to add to the conversation with a few helpful posts only to get a response like “...it’s such a wall of text..” Apparently, one should not post more than 280-characters in a forum dealing with the nuances of resin printing. The rest of the reply also demonstrated a massive failure at reading comprehension. Not currently feeling the urge to go back and correct them. Best to just laugh it off and back away from that dumpster fire. Makes me appreciate the posts in here all the more.. On the resin hazard issue... as you’ve surmised, the hysteria and fear drummed up mostly by newcomers has been overblown to viral proportions. I and numerous pros have 3D printed with envisinTEC and B9 resins continuously for the past SEVEN years. According to some YouTubers, I should have died instantly from handling the uncured resin with my bare hands all this time. Not dead from the odor. My skin isn’t a cauldron of blisters. And I’ve no intentions to ingest nor vape 3D resins. Are there folks who may have skin sensitivity to resin? Probably. I’ll report that in all those years immersed in the B9 Forum exchanging ideas with fellow owners, I can’t remember anyone bringing up skin irritation issues... and the only time folks mentioned any sort of ‘stink’ was when they tried one of the few third-party resins available back then. The smell that comes from using Elegoo, B9, and EnvisionTEC resins is approximately equal to detecting someone unrolling a newly-printed vinyl banner from the graphics shop. Detectable, certainly not a gas-chamber scenario, and easily mitigated by flipping on the house fan or opening a window. OK, onto successful Tamiya wheel printing... One of the first things to understand is how this and almost all other resin printers want to work. The general concepts of SLA (stereolithography) can likely be found across some YouTube infographics. The pertinent point I want to make is how crucial the first layers are. It’s imperative to overexpose the first layer to ensure it’s tenaciously cured to the Build Platform. ChiTuBox’s settings refer to these as ‘bottom layers’. Default settings might be 60 seconds for each of the initial 5-8 layers. Thereafter, the rest of the model layers might be exposed for 6-thru-9 seconds. IF that initial crucial first layer isn’t sufficiently bonded to the Build Platform, the successive pulling of this growing model from the FEP membrane (throughout 1000+ layers) might eventually cause layer 1 to detach prematurely where the model stays planted at the bottom of the Resin Vat and no further growing occurs. Is there any penalty to cranking ‘bottom layer’ exposure to the sky? Aside from just the time penalty, not really. If you are getting detachment failures, don’t be shy about cranking the exposure to 120 seconds. In older resin printers that used a PDMS release in its vat, nailing an area with 2 minutes of exposure repeatedly is guaranteed to cause clouding on that PDMS material and thus cause premature degradation. No such worries or problems with the FEP film used in the Elegoo & Anycubic vats. Whether 5 seconds or 3 minutes of UV light exposure, cured resin on that film will still peel away at a consistent given force — so all that remains to ensure is that the OTHER side of that cured resin layer (attached to Platform) has seen enough exposure time to out-grip the FEP side. The Platform and layered object lifts up, more resin flows in, the object is lowered just shy of the FEP film (leaving a 50 micron ‘underwater’ gap) and next layer’s exposure commences. Next opportunity for failure is demonstrated by my very first wheel attempt (not shown or detailed above). My initial wheel was 3D modeled years ago. It was faithfully detailed to the point where the BACKSIDE of the rim lip had a delicate rolled profile to it. The problem with positioning this wheel flat on the Build Platform (in ChiTuBox) was that the rolled lip was BARELY presenting enough surface area to the Platform at layer 1. It became apparent that I was effectively trying to grow a pyramid where layer 1 is the top vertex point and all the subsequent layers got larger and larger pulling with successively greater force on that initial weak anchor point. Imminent failure regardless of how much curing exposure it got. As this backside wasn’t visible to the audience, I had to compromise and rework the 3D model to have a flatter profile. Where the initial contact point was maybe 0.25mm wide, the revision planted a full millimeter to the Platform surface. One additional reason for that failure was that I was trying to grow a cylinder on the Build Platform. In order to understand why this is generally frowned on, analyze what’s going on at each layer... a circle shape is ‘projected’. This is supposed to cure as a ring layer. In the seconds that this occurs, it’s possible that there may be a difference of some type inside that ring versus outside (pressure? suction?) If this difference causes trapped resin to unexpectedly flow, exposure curing might fail and the layer is compromised. All the subsequent layers building on this compromised layer might not fare well either. This is why experienced users will suggest positioning the wheel at a 45-degree angle (with generated supports). The initial layer profiles avoid the ring shape. (Moreso crescent shapes) As we travel up the layer stack and profiles do present rings, it’s not an issue as the established initial layers have provided open breathing spaces and avoids the trapped resin scenario. The test Rook prints successfully because it as a large surface area base to establish that crucial initial anchor.... and although it appears as a cylinder, the ‘windows’ provide relief of trapped resins. If users can internalize these fundamental things, it’ll go a long way towards not just troubleshooting failures but successful planning and layout of models. Cheers and congrats again
  4. A deeper 2¢ dive into how I evaluated the field based on my professional use of resin SLA machines... The current generation of super-inexpensive resin printers caught my eye around June. The first one I saw getting buzz was the MonoPrice MP Mini at the $200 mark. The buzz was solely based on the price. I immediately spotted design problems like the dual-rod z-axis rail (linear bearings are a MUST for me), build platform attached by magnets (MAGNETS for a high-stress, absolutely-musn’t-shift region?? Seriously??), and electrical-actuated auto build-platform leveling (already sounds like a needlessly over complicated feature begging to break). These “features” almost caused me to paint the entire generation as bottom-barrel scraping cheap sludge. Majority of folk generating the buzz ended up returning theirs for one or more of the reasons I pointed out. This only served to testify the gospel that if you buy crap, you’ll always buy twice. Hard pass on the MonoPrice MP Mini. The Anycubic Photon showed up on my YouTube feed, but as a $499 Printer, I batted it away. At that kind of price point, I’ll continue to operate my previous resin printers. The Elegoo Mars at first glance looked like a clone of the Anycubic and in many ways it is, but yet in many good ways it’s not. Identical resin vat dimensions, identical LCD masking screen, identical z-axis mechanism. To be HALF the Anycubic’s price, it HAS to be cheaply constructed right?? I couldn’t find any consistent voices to shore-up this accusation... in fact, many Amazon and YouTube reviews were showering the build quality and materials with praise. For their supposed July-only sale at $250, I was willing to give it a shot. If the buzz were based on price alone without build reviews, I would’ve given it a cautious dismissal. I fully expected Elegoo to follow the razor-blade or inkjet business model. Doesn’t seem to be the case here. A litre of their black resin is now only $39 and they just announced a bundled set of FOUR (disposable?) resin vats will be dropping September for only $30! ~ $7.50 each vat! That’s cheaper and way more convenient than replacing the FEP film! My $500 stretched-film resin vat on the $15,000 Printer has been in service for the past 7 years. If I get six-months off a $7.50 vat, that’ll be a colossal win in so many, many ways. Meanwhile, the Anycubic ecosystem had third-party replacement resin vats at $60-$80 (for each) listed on Amazon. With a bullet to their head, Anycubic finally relented and lowered the Photon’s $499 price to $299. These forced reactionary moves certainly doesn’t endear me to Anycubic. Because of the cloned dimensions, Anycubic users will fully be able to use Elegoo’s resin vats. The $200 Sparkmaker is another race-to-the-bottom sludge-scraper that had me hammering the NOPE button with a mallet. No screen of any kind to report the print progress, 26 watt light engine (vs everyone’s 40 watt) for extra-slow printing, and a SINGLE button/knob to handle some very important controls. The dumbest feature design? It will only recognize a single specific “PRINT.WOW” file name for 3D printing. Oh, the fun of having to maintain a sub folder library of PRINT.WOW files. Who’s the genius that thought this up? The 673 cubic cm build volume is also half that of the Anycubic and Elegoo’s 1224 cu cm. Any two of the above deficiencies would negate the $50 difference for me. All this activity leaves Anycubic and Elegoo as standouts that has garnered an impressive critical-mass of users. This ensures availability of formulated resins, FEP film, resin vats, and spare parts will be available for a much longer span than anyone else. Between the two, Elegoo has demonstrated their willingness to cut pricing deeper without sacrificing material quality. I also greatly prefer how the lid completely lifts away giving me easy access from all angles to the vat (for mid-print refilling or checking progress) versus Anycubic’s hatched access. Disassembly into the guts of the machine also goes to Elegoo. Either way, these two gets my thumbs-up compared to the rest in this field. Not sure how it is elsewhere around the globe, but the US Amazon page for the Elegoo Mars is almost comical to observe. Refreshing at least twice a day, they seem to restock on average every three days. It sells out as fast as it restocks. Within an hour, you’ll see the page trigger it’s “only 5 left in stock” warning. I hope they can find reason to maintain their $250 pricing but would fully expect them to sell briskly even if bumped to Anycubic’s $299 price for the Christmas harvest. Back to your normally-scheduled Tamiya-talk...
  5. Just doing some exploring for on-road touring car wheel designs I'd make for the TA04... Integrated cross-drilled racing rotors. We all know by now that the resin printer should have no problems keeping the holes intact. In the traditional injection-molding process, the space between the spokes and rotors would be a nightmare. 3D printers will breeze through these layers like a champ. I'll save these for printing in grey resin.
  6. Another day, another skillset to tackle... Where wheels and suspension arms and gears are best created with CAD software, the other end of the 3D spectrum is represented by digital sculpting programs for those who want to create organic, non-mechanical subjects using an artistic approach. The choice for those committed to sculpting is ZBrush. Are there ways of using scanning tech to acquire 3D data? Yes, but specifically for capturing living subjects, the choices become very narrow and harder to come by as explained here. Capturing/scanning 3D data without ANY sculpting knowledge means being locked into that one pose until more $$$$ gets ponied up for additional scans. Using some reference photos and coaching from "likeness sculpting" YouTube videos, a self-portrait sculpt gets finished in ZBrush... Sculpt is exported as an STL mesh and brought into the ChiTuBox slicing software (Free download & bundled with the $250 Elegoo Mars 3D printer). For this particular model, there weren't any egregious overhangs that warranted generating supports. YMMV. The model is double-checked to print at a target 1:10th scale. If it wasn't already done in ZBrush, ChiTuBox v1.5.0 offers another opportunity to hollow out the model by specifying the wall thickness. The CBDDLP file generated by ChiTuBox contains all the sliced image data along with resin exposure time info. All that's left is to feed this into the Elegoo Mars via USB thumb drive and tap the touchscreen Print button. This printer's touchscreen makes a Pause button available where it'll even raise the platform out of the resin to visually confirm and double-check the progress. Tap the screen and the printer continues back on the same spot it left off. Nice touch not found on my previous resin printers. All of 24 cents worth of resin used, the high resolution print finishes in three and a half hours. Remove it from the platform, quick rinse in an isopropyl tub, and it's off to the UV tanning bed for 10 minutes. As stated in another thread, I've devoted this resin vat to holding black resin. Once additional vats are available, I'll use those extras to hold Elegoo's grey, clear, and skin-colored formulations. For figurines, painting on black resin should make the colors pop more. The Elegoo Mars shares the exact same resin vat dimensions with the Anycubic Photon. This will allow users from both sides to jump brands or even find this market large enough where third-parties start offering replacements (eBay has vats listed for ~$35) Note how the eyeglasses printed perfectly. 'Nuff detail for ya? The main downside to a fresh black resin print is the difficulty in capturing the sculpted details despite using a macro lens and a light tent. Earlier red resin prints from years back posed in the driver's seat of the M-04L. Future iterations might involve tweaking the sculpt to evoke the sense of being reclined in a seat with arms reaching toward a steering wheel. This was not possible on the red resin printer as it was configured for a super-tight build envelope. On the Elegoo Mars? Plenty of build platform space to include the driver's seat headrest, steering wheel and even the instrument cluster - all in a single printed object. Still plenty more additional tasks to finish in this vein... sculpt a helmeted version for the F1 F201 chassis... review a bunch of YouTube videos on painting/airbrushing techniques with acrylic... Exercise that sculpting muscle and the world opens up to sooo many possibilities -- take your own creation and alter it at your whim... road-raging Xenomorph Wild-Willy substitute behind the wheel flipping the bird? Do it. Do it NOW!
  7. I'm not sure how to decipher Elegoo's shrinkage number above... possibly as a measure of the volume when it transitions from liquid to a cured solid layer? It certainly isn't related to the finished dimensional difference of the physical print versus STL model. My custom wheel was 3D modeled in Rhino following measurements of the typical Tamiya on-road wheel; 52mm rim diameter and 26mm depth. I think the end results compare favorably. If I needed more stringency, I'd simply have the ChiTuBox software bump up the scale by a fraction of a percent -- no need to go alllll the way back to the CAD software. In resin printing, changing the layer exposure time can also help dial-in the accuracy. Going from a 6-second exposure to 8 or 9 seconds might be enough to bring that finished print to the target 52mm.
  8. I wouldn’t have pursued this if the initial attempt with the $3500 2nd Printer didn’t show promise with the black resin I was using back then. As stated above, I don’t have any hesitations if they served as moderately stressed components...and real-world tests might likely show it’ll go the distance. I’ll leave it up to the professional engineers in the crowd to extrapolate Elegoo’s cured resin properties from their Amazon page: Hardness: 84 D; Shrinkage: 7.1 % Solid Density: 1.195 g/cm³F Flexure Strength: 59-70 MpaE Extension Strength: 36-53 MpaE Elongation at Break: 14.2 %C Some figures for extruded ABS based on a quick Googling: Hardness: 68-113 Solid Density: 1.01-1.20 g/cm³S Flexural Yield Strength: 69.2 MPa Tensile Strength: 40.5 MpaE Elongation at Break: 34.2 %C To this layman, the two seem to be in reasonable ballpark for it’s given RC hobby use. Add the equipment value proposition to this mix and it should be a no-brainer for those craving superfine, detailed parts.
  9. There are legions of YouTubers showing how their resin prints get painted. Some use a wax-based buffing method... Others airbrush with lacquer based paint... And still others who 3D print miniatures (Dungeons & Dragons, Warhammer, etc) like using acrylic-based paints I suppose paint’s steadfastness to 3D resin might be about the same as painting an ABS or nylon plastic rim and expecting it to withstand daily bashing. This is why I’d rather re-print my wheels in grey resin before committing a set of rubber tires to them. For shelf display though, the lacquer Alclad metallic range might be in order.
  10. Completion of this project has been almost a decade in the making... Commercial-level high-rez resin 3D printers had been sitting beyond $200,000 for all of the nineties and even when smaller desktop units dropped below $20k by 2011, their build envelope was only large enough to cram 5 or 6 custom ring designs into... IOW, not terribly applicable for 1:10th scale modeling. Jewelry casting resin was $175 a liter. Disruptors came on the scene with their $2500 resin printers. In 2012, this was a downright bargain compared to my first printer at $15k. Resin was "less" costly at $100/liter. Reasonable expense for paying clients, but remains extravagant for hobby tinkering -- and the build envelope stayed minuscule at 5.7 x 3.2 cm. The only way to fit a standard on-road 26mm wheel into this space is to orient it upright. I attempted this very exercise around 2014 but the end-result wasn't worth posting here. Problem? Vertical print position pooled and caused a resin imbalance. The build-envelope constraint permitted no other alternative attempts. The wildly off-balance wheel was only good for shelf display. 2019 is the next watershed year where resin 3D printers have started tickling the $200 milestone. How'd they achieve this? By utilizing super-inexpensive components from the cellphone industry -- deploying a relatively cheap 2k-resolution smartphone screen rather than building a 3D printer around a $1000 theatre projector makes all the difference in final cost. All the buzz became loud enough to take notice. At $200, there are indeed some cheap resin printers cost-wise but also cheap in quality; questionable design features abound. Experience proved invaluable in identifying features to avoid. The standout winner worthy of a spot in the stable is the Elegoo Mars at $250. Jaw-dropping price point no matter how you cut it. Tons to like: Stretched-film release design similar to my $15k printer suggesting low-maintenance workhorse reliability/repeatability. Superb Z-axis rigidity using a linear-rail like design. A wobbly Z-axis arm can cause disastrous banding in the print. User-replaceable critical components as demonstrated by their own instructional YouTube videos. Crack the masking screen? $40-ish replacement makes things right. Considerable leap in the build envelope. The Elegoo is able to print what fits within 11.9cm x 6.8cm (x 15.5cm height) and still maintains a 50-micron resolution. Color touch-screen control. Files read off a thumb drive. Prior resin printers mandated tethering to a dedicated computer to drive the projector. (itself limited to a bulb lifespan) After running a few calibration tests (largely unnecessary and for my own satisfaction), it was time to address my long awaited project. 26mm width BMW Style 35 wheel fitted to a Tamiya hex hub. Elegoo Mars 3D printer. Quickly Glowforged a pedestal storage box for it and made sure there was resin on-hand. One liter of their resin is just $45. Third-party resins can be used as long as they're formulated for these kinds of masked-SLA printers. Laser SLA like Formlabs and Moai require different resin formulations. Still, not many are gonna beat $45/liter! The free support & slicing ChiTuBox software has quite a bit of nice features coming from this veteran resin jockey. The ways to identify & edit supports for undercuts or floating islands is praiseworthy. One nit is that there's no apparent publicly centralized data pot for exposure times for Elegoo resins. Possibly walled off in their Facebook page. The product box only provides a range -- thus my initial tests. Small-object test prints suggested that my settings for Elegoo Black Resin be 60 seconds for the first 5-6 layers and all subsequent layers can be at 6-seconds exposure. As shown here, the represented build platform has plenty of space to accommodate an on-road wheel. For reasons outside the scope of this hobby forum, a flat lay-down positioning of the wheel isn't necessarily the most recommended, but I've printed using two alternate ways and got away with successful prints. ChiTuBox goes as far as asking how much I paid for this batch of resin and can calculate the projected volume of resin used and total cost of parts put on the build platform. Let me do the math for you.. a liter of resin ought to yield around 66 Tamiya wheels. Toss the sliced file onto a USB thumb drive and feed it to the printer. Here's the angled & supported version... What kind of detail does 50-micron yield? Hex heads on the lug bolts resolved with a faithfully reproduced dimple at the center of every one! Here 'tis mounted to the M-04L chassis... spins just as nicely as the Tamiya-made wheels. No off-balance issues. Giving the back part of the rim a squeeze shows that it takes nearly DOUBLE the effort over Tamiya's ABS plastic to start deforming. At roughly 1mm resin wall thickness, the toughness observed so far suggests it would fare no worse than manufactured wheels. Once I get my hands on more resin vats, I'll dedicate each one to their own resin making for super-quick printing material changes... black, grey, white, translucent, etc Now all the things that normally get scuffed up (side mirrors, body posts) can be easily and affordably re-grown on the high-res 3D printer. Onto the possibilities of fabricating all the details I only dreamt of decades ago... windshield wipers, light buckets, suspension arms, action cam mount...
  11. Bravo BW! Cog is quite photogenic in the photos, but it wasn’t until watching the video that I realized you have created a bonafide CHARACTER. As a viewer, I WANT to see episodic content of Cog getting into adventures. A small servo near the throat could be the hinge point to hold a lower jaw so that Cog would have a way of holding/grabbing things to assist in his hijinx. You’ve got the star, you clearly have the video ability, find collaborators who can flesh out stories. Get at least a few episodes “in the can” before pushing it online. ...and don’t forget us little people here at TamiyaClub when you’re at a million subscribers pulling in $15k/month! Bravo again!
  12. A well-done video of ‘im romping around pushed up onto YouTube should get a few thousand viewers wailing on Tamiya’s door for their own.
  13. CAD YouTube has a healthy selection of gear tutorials for nearly every CAD program ever offered... some are sketched out manually and others deploy a plug-in (wizard) that merely asks for the parameters before instantly spitting out the 3D model. Onshape for its first few years had been free to use, now apparently has done away with their free tier. Grandfathered free users can only continue use by making all works publicly accessible to the community. Autodesk Fusion360 remains as one of the last free-to-hobbyists CAD program that has a decent amount of polish to it. My own CAD tool of choice is McNeel's Rhino 3D and according to a few forum threads, seems to have at least two plug-ins devoted to gears. Then, there's a stand-alone webpage that creates a 2D gear profile from just entering parameters: http://hessmer.org/gears/InvoluteSpurGearBuilder.html The resulting 2D DXF file (while originally an AutoDesk format) is easily ingested by almost any CAD program out there. Once imported, have that CAD program to extrude the 2D profile to the desired 3D depth. Boolean-subtract a shaft-hole in the middle and that's probably one of the fastest ways to make a spur gear. PRODUCTION 3D printers that squirt its layers from a nozzle (FDM Fused Deposition Model) would be the worst application for producing a finished product. As Speedy indicates, 0.2mm nozzle width still results in a coarse surface where layer lines are easily visible. Stereolithography resin printers (SLA) will do the trick. They typically print at resolutions of 0.050mm and layer heights of 0.025mm! My B9 Printer is configured for a 0.030mm resolution (XY flat direction). In this thread, I 3D printed a custom-modeled Tamiya wheel in B9's Black Prototyping Resin: https://forum.b9c.com/viewtopic.php?f=22&t=371&start=20#p32950 Another post to show that it takes a Stereo Zoom Microscope to detect layer lines in SLA 3D printing: https://forum.b9c.com/viewtopic.php?f=22&t=235&start=120#p32491 Properties for all the different types of resins used in all types of SLA printers vary across a huge spectrum. Where the original Tamiya ABS plastic wheels can deform when squished by fingers, the B9 Black Resin is at least an order of magnitude more resistant. Not sure about its abrasion properties (constantly rubbed against another resin gear) but I do know that it only gets scuffed when I break out the coarse sandpaper or hand file. Formlabs has around 11 types of resins for their SLA printers and I would expect at least one of them approaches the toughness I've seen in B9 Black. Then there are all the aftermarket resin makers that offer their mix of formulations. So far, all of this is going with the intent of directly using the 3D printed part as the working object. The SLA printer can be loaded with a castable resin. This is what jewelers use. Look up "investment casting" on YouTube to dive down that rabbit hole, but the point is that a castable resin model can be used to cast a brass gear. The other non-printer possibility would be to just hand that CAD file to a service bureau that offers CNC Milling. From here, the custom gear can be cut out of aluminum, brass, or steel. In capable hands, this would offer the sharpest detail, uniformity, and smoothness. I believe Shapeways is the place to investigate. They quite a large range of materials that their motley crew of machines churn out.
  14. "Wong Kwok" is a close phoenetic equivalent, but it won't help audionutter find it. All the subway (MTR, tube) signs, all the free airport tourist maps, the Centamap.com website, and pretty much everyone else spells the infamous shopping district on the Kowloon peninsula as Mong Kok. [] If I recall, the first half of the following thread has info on how to reach the hobby nirvana of the district: http://forums.radiocontrolzone.com/showthread.php?t=116875 ...failing that, go to the www.centamap.com site, switch to their english language page, zoom into the Kowloon peninsula, find the Mong Kok district toward the center. At the southeast fringes of the district north of the Kwong Wah hospital is where you want to be. There's another lone-standing Tamiya-laiden shop south of the Hospital named Waigo that should be worth visiting if they're still around.
  15. The motor isn't mounted high like that on the Tamiya Frog. The M-04's motor is directly in front and inside of the driver's side rear tire. The motor's CoG isn't all that far off on the chassis. If this were truly a critical issue, you wouldn't see Tamiya repeating an off-center motor design in the TB0x, TT01, and TA05 chassis. The M-04 chassis has in inherently low-profile design. There are hardly any chassis components that rise higher than top edge of the tires. As for understeering, the primary cause of THAT on this chassis are the staggered compound kit tires - overly hard fronts (no grip), soft rears. Once I changed mine to a consistent set of aftermarkets, the car exhibited oversteer as it should with more weight located in the back half (think real-world rear-engined 911s). All that traction caused the car to roll when steering was too abrupt. To lower the overall CoG even more, I relocated the top-mounted speed control and receiver to the chassis sides directly in front of the battery pack. Kit tree A, part #2 creates a basket on the driver's side to hold the reciever. use your own ingenuity to hold the ESC on the other side. This alone will TREMENDOUSLY minimize the car's tendency to roll. The stock all-plastic servo saver is the culprit of steering slop. I upgraded mine to the Tamiya High-Torque Servo Saver (#50473) as a tip from playing with the TA04 chassis. With some strategic use of washer shims at the suspension arm, the M-04's steering is remarkably slop-free.
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