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Honza

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Everything posted by Honza

  1. Yep, baterry would be dead, of it was connected. I didn't see the broken front damper tower. The replacement is part #51075, it's still possible to get a new one, for example from Tamico Here's manual for the chassis, it will help you with repairs and finding missing parts. I recommend to disassemble it, clean it, inspect and replace worn parts - it doesn't look like the previous owner took care of it.
  2. Looks like DF-02, but hard to say due to quality of photos. Electronics is there, so yeah, only battery is needed, of the electronics work. It looks quite gunked up, so I'd disassembly and clean it first.
  3. If you have too much buildup on the nozzle, you may need to dial back the extrusion multiplier a bit. PETG loves to stick to the nozzle and then pull something with the blob. Btw, silicone sock helps to keep the heater block clean. A little squish can help. The elephant foot can be compensated. You can also try to slow down. I need to check my notes, but I had batch of PETG filament that had similar issues.. but it was a while ago and I cannot remember how did I solve it.
  4. You can view G-code directly in the notepad - it's just a text file with readable commands. Since it's indicated in the viewer, there should be some extra gcode command, so it's weird it's not recognised. The 250° is the right temp for me as well, it seems that PETG is not as varied as PLA. I use satin sheet (I didn't want another sheet just for PETG and satin seems the most universal) and it works great, so I don't think you'll need to change anything, apart from Z-offset - petg can be quite sensitive to proper first layer. Stick glue can be quite tricky, for me, it was hit and miss - sometimes I needed to dissolve it to get the print off, other times, I couldn't get the print stick.
  5. That's weird, especially if it worked before and shows in the slicer.. Looks like some sort of bug, did the G-code changes write correctly into the file? You could make individual tests, but a single tower is faster and gives you direct comparison on the same object. I don't think that G-code tinkering falls I to rookie category 😁 it took me a while before I started with calibration models.
  6. Now I noticed I wrote bed adhesion instead of layer... Well, you got it 😃 What did you do for temp towers? I manually add M104 S(temp) in the slicer - it's a little tedious, but I can check the temperature change in slicer before printing.
  7. I realized that I didn't properly document the center diff. So I'll do it with the new version It's based on planetary gearbox. But instead of driving the pinion in stationary ring gear, the cage is driven and ring and pinion are outputs - that results in classic differential action, but thanks to difference in size, with different gear ratios to each output - in my case with roughly 2:1 split. This torque split is able to reduce wheelspin under acceleration, but still, some extra friction is needed - the original plan was to use one slipper pad to lock the front output to the spur. Unfortunately that was too much friction, so I threw the pad out and relied only on friction between the pinion and cage - which resulted in damage above. Also, the locking force was different due to gear ratio between front and rear. I wanted to make a new version, which would lock the outputs together for smoother operation, but never got to finish it... Until now. I found some information about Torsen typ C and noticed similarity with my design. The big difference is, that satellites don't turn on axles, but they are instead enclosed within cage, using friction against the cage to lock under load. Additional friction is created due to axial load from helical teeth. Today, I successfully finished the early proof of concept. Still a long road to the working part, but at least the gears run more smoothly than the previous attempt (I learned a lot about gear printing since then) and the locking action is already noticeable.
  8. Exactly, too low temperature will result in low layer adhesion. This can be also influenced by cooling. But printing too high also reduces quality, because the plastic will degrade. You need to hit the sweet spot in-between. Don't be afraid to break the tower. You already have results regarding quality, so now it's time for destructive tests. The little spike is meant for that, tenps with poor adhesion will break easily. Then you can try to break the larger portions and look for breaks that run accros the layers.
  9. The lower ambient temp increases warping of the print, if you start with bad adhesion, it makes the issue worse. It shouldn't have any effect on measurements, because the printer preheats the bed first. Yes, it's definitely too high on both prints. I'd guess around 0.1mm. There should be no visible gaps. The arm looks better thanks to long regular infill lines, but I'd say that the first layer is same as on Benchy. If you got more sheets with the printer, check the menu, if you got right preset for the smooth sheet. Then proceed with the first layer calibration , or check the first layer while it's printing and tune live-Z. I don't think you need to print another Benchy, you've already identified the issue. That is, unless your target is to have one completed 😃
  10. The prints shouldn't come off that easily. The smooth PEI sheet ha very good adhesion for PLA (and too good for most other materials), so there's some problem. Take a look at the bottom, check if you have nice, uniform layer. My guess is that the initial layer is set too high, which is visible on the bottom of the bow. Unlike newer printers, that tap the print sheet directly, MK3 is sensing the steel plate below, and the offset has to be set manually. Check this article https://help.prusa3d.com/article/live-adjust-z_112427 Also, here's manual for Benchy to evaluate your result: https://www.3dbenchy.com/wp-content/uploads/2015/04/3DBenchy_Broschure_3DBenchy.com_.pdf Also, if the nozzle is crashing to the print regularly, it's sign if over extrusion. Check some tutorials how to tune flow.
  11. Wow, it's been a while since I posted in this topic. Well, maybe because there are not many updates, the car just works. The only update were XV-02 shocks - I got them cheaply, so why not? But over the course of last season I noticed, that the center diff started to act weirdly - it needed significant effort to get it unstuck and rotate. Last week, I found out why. Well, turns out that it's not the best idea to use 3D printed parts as friction pads 😁 I reprinted the parts and added a teflon shim as a quick fix - but I'm aware that it needs a complete redesign - something I had in mind for a while. The new design requires helical gears, so I tried to do a little test of design and printing - it turned out great! They are just a little hairy because of wet filament. For reference, those gears are 9mm in diameter, module 0.8.
  12. Check the article I linked earlier. Without modifications, you can fit 35T/48p or 48T/64p. For larger pinions, you'd need to file part of the chassis.
  13. Great that he listed through the manual. Now I know that the rear gearboxes are a separate U-parts tree. I wonder what's the length of swing shaft. Unfortunately it's not covered in the video and the resolution is too low to make up the PN from the manual.. I'm disappointed with tires though.. I hoped they'd at least make softer compound - that really changed standard rally blocks from unusable to great. Otherwise, it really is just smaller XV-02 😃
  14. I don't have experience with these, since I haven't work with materials that are moisture sensitive, I just throw a roll into the drier once in a while and it will do for a few weeks. From what I've read, if you start with dry filament, the storage boxes should keep it dry, but some, especially cheap, material is wet even new and dessicant might not be enough to absorb all moisture.
  15. Right choice, PLA+ can be used for functional prototypes, it's not as brittle as the regular one. PETG is better for final parts, but it can be sticky, which might be an issue on finer details. But with right settings, it can be printed with almost uniform strength even in Z-axis. One notice: never print PETG directly on the stock smooth PEI sheet. It can ruin it fairly quickly. There are companies that collect waste filament and recycle it. There are even ways to build your own extruder for recycled filament, if you want to invest into that. One another part to add to your list - filament drier. PLA becomes brittle while it absorbs moisture, PETG becomes much more stringy when printed and very wet filament will cause voids during printing. If you don't want to invest into specialised filament drier, a cheap food dehydrator with temp setting will do. Enjoy your new toy! 😁
  16. It's size of teeth (and 68T, marked on TT-02's spur means number of teeth). Tamiya uses metric 0.6mm profile on TT-02, 48p is equivalent of 0.53mm - the lower number means finer teeth. A 48p equivalent of TT-02's m0.6 68T gear will have around 77 teeth.
  17. That also requires adjustable motor mount to set-up proper mesh Although 48p can work with the original mount, the adjustable mount provides more options and precision.
  18. I'd be happy with a re-release of TB-03 with gear differentials and TRF420 suspension 😃
  19. Not exactly specific, but I'd like to build another mini rally and this chassis opens numerous possibilities: - the separate rear gearbox, if it's easily available, could be used to make a custom composite chassis for XV-02/XM-01 - XM-01 suspension, which is compatible with XV-02 mounts, could be also used to make a mini XV-01 - uprights compatible with M-07/8 would make them even more capable as rally chassis
  20. All I need to know at this point is, if the rear diff case is available as a separate part and if the uprights are compatible with M-07/8 😁
  21. TB-series were great for that. Combination of fully enclosed transmission with fully adjustable suspension and good materials. Unfortunately they are not made anymore. It's been replaced by other three shaft-driven models, neither of which fully replaces it. TT-02 lacks the quality materials, TC-01 is too complex and heavy (though, its suspension apparently provides enough travel to run as a rally car) and XV-02 has higher CG and rally-optimised suspension, which isn't the best choice for high traction runs.
  22. MB-01 and BT-01 have an extra differential gearcase within the bulkhead for this exact reason - to easily swap direction. The whole chassis is rotated when swapping between front and rear motor position. That means, there's no space to put a second motor. Unless you somehow Frankenstein two "motor" chassis halves together.
  23. Only thing I can think of is cooling improvement by using the motor mount and a strut base to mount the transmission assembly to the bumper plate - something similar to XV-01/M-06. But that would mean a major redesign.
  24. Dusty workshop is not ideal, but the bigger issue is temperature - open printers tend to be quite sensitive to low temperature and temperature changes. If you'll print only pla/petg, it's safe to leave them inside (although It's advisable to keep it in an unnocupied room).
  25. MK3 became obsolete more in terms of electronics, than mechanics, which are very similar to MK4 and solid. Unlike cheap Enders and similar entry models, there are not really upgrades needed to make it print reliably. The biggest disadvantage is its driver board that runs on 8-bit MCU, which limits its speed, connectivity and its UI is ugly. It's biggest disadvantage for your use case is lack of enclosure, which is needed for materials that require higher temps. But those are common on printers around price point of a new MK4. That was main appeal of Prusa. Instead of going through community forums to get firmware and slicer profiles that actually work, or even making your own (I owned an Ender before and it's been like that), Prusa continuously worked on everything to make their printers work seamlessly (although sometimes a while after they sent long delayed printers to customers cough cough XL). Others have caught up recently, but Prusa still generally does great job, with MK3 receiving updates relatively recently. Of course, that doesn't mean that it will just print anything that you throw at it. There are some things you need to thing about during design to make it print faster, with less supports and with right orientation. But generally, RC parts already have right shape for printing. You can still tinker with your printer if you want - there are things that can be upgraded - but you don't have to. Tamiya uses ABS, polycarbonate, nylon - those are available, even in fiber reinforced variants. But those are the exact materials that need enclosure and even then, PA and PC is not trivial to print. I use PETG, which is easy to print material strong enough to make a working model, but it's also quite brittle. There's also PCTG, which promises mechanical properties of ABS with printability of PETG. But I still didn't get to unpack my roll and test it. The biggest issue of FDM is Z-axis strenght. Some materials are better than others, but generally, bond between layers is much weaker that other directions. That's something that must be thought out during design. I'm not a type of person would would spend time printing various figures. I see it as waste of print time and material. Even then, my printer runs very often even if I don't work on any project, doing just that - various flexy animals are very popular among kids and even adults, and 3D printed figure stil has unique feel, so it's great little gift. There are opportunities for various functional prints, too - holder here, cover there, replacement for some obscure part that disintegrated due to crap material... And suddenly you printer has days of print time in a matter of weeks, even if you think it barely runs. So in the end, if you have good deal on a printer, get it. You won't regret it. It's a really useful tool.
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