bluemattersoda Posted October 5, 2014 Author Share Posted October 5, 2014 Ugh, the wait for my parts is excruciating! Shapeways are reprinting two of my jobs at the moment, but - as with the first time - there has been a delay in the manufacturing process with one. The second job is has been languishing at a New York post office for a week according to the post tracker! This is the first time that Shapeways America has done my prints and I must say their Dutch counterparts are much more reliable! I've never had a delay with the Dutch; and US Postal Service are...reeeeally slow. So I still haven't been able to evaluate the success or failure of my 3D printed mechanics! In the meantime, I've been working on my next project - N Scale TGV Duplex - more info on that to come. Been thinking about starting a blog to document my projects. Any recommendations for blogging sites? I'm looking at something that would be able to host images over slabs of text. Cheers, Alan Link to post Share on other sites More sharing options...
Multiple identity account Posted October 5, 2014 Share Posted October 5, 2014 I'm at a loss for words....... Amazing work. Link to post Share on other sites More sharing options...
mikeharvey22 Posted October 6, 2014 Share Posted October 6, 2014 On the TGV Duplex - do you have something you don't like about the Kato one? Link to post Share on other sites More sharing options...
bluemattersoda Posted October 7, 2014 Author Share Posted October 7, 2014 On the TGV Duplex - do you have something you don't like about the Kato one? Hi mike, The kato one looks great but I can't get my hands on one. The ones that are available eBay sellers other retailers are really scalping them for well over what they're worth so I figured I'd make my own and possibly sell them on Shapeways. Link to post Share on other sites More sharing options...
mikeharvey22 Posted October 8, 2014 Share Posted October 8, 2014 Could you run up one of these for me while you are about it, please? Link to post Share on other sites More sharing options...
bluemattersoda Posted October 10, 2014 Author Share Posted October 10, 2014 Could you run up one of these for me while you are about it, please? haha, i was thinking about doing a corail print - don't feel like paying AUD60 a carriage off ebay! We'll see after the duplex! Link to post Share on other sites More sharing options...
mikeharvey22 Posted October 10, 2014 Share Posted October 10, 2014 I have some drawings for the driving trailer, and I did start a Sketchup drawing once............ I envisaged a brass wrap-over providing the sides and main roof, over a 3D printed body carcass with detailed 3D printed cab/bodysides back to the sliding plug door. On the Corail coaches I have already produced a load of brass sides to convert the Roco Eurofima coaches into the Vu Compartment stock. Covered almost the whole range except I did not get round to the driving trailers or the latest wheelchair coach. But 17 variants was a good start. But I digress from your beautiful V'locity. Well done. Link to post Share on other sites More sharing options...
bluemattersoda Posted October 15, 2014 Author Share Posted October 15, 2014 Thanks Mike, I will post up any work on the corails when i get to them! Progress update on the chassis: Not good. I have finally received the final parts and I have assembled the motorised chassis. However, the friction between all the parts in contact seem to jam the motor - touching the wheels will stop the entire thing so I doubt there is enough torque to actually propel the train. As yet I have no idea where the friction is coming from as there aren't that many gears involved. I can only guess it has something to do with the coarseness of the WSF material from Shapeways. For now, I'm baffled. Link to post Share on other sites More sharing options...
RMweb Gold Revolution Ben Posted October 15, 2014 RMweb Gold Share Posted October 15, 2014 Hi there, It may be worth locating the areas of friction by elimination - assembling parts in turn and testing them by pushing along the track without a motor installed to "get a feel" for any friction in the drivetrain. Have you oiled the gears - most "regular" models require that, though I would test the oil on a small piece of WSF beforehand to check there are no degradation issues.... I know that regular models can jam with the tiniest bit of grit in the gears - is the WSF finish smooth enough to function as a gear train? Might more sanding or finishing help? Or perhaps get certain key components printed in FUD? cheers Ben A. Link to post Share on other sites More sharing options...
Rabs Posted October 15, 2014 Share Posted October 15, 2014 My money's on the worm to worm-wheel interface. I'd definitely look into polishing both of these. You could also try a PTFE spray coating - that might help reduce the friction. Link to post Share on other sites More sharing options...
Multiple identity account Posted October 16, 2014 Share Posted October 16, 2014 I too am pretty sure it's the worm to worm-wheel interface. Judging from you're pics it does look way too rough for that scale. May I suggest using something smoother?- Shapeways' Polished WSF- Shapeways' FUD- i.materialise's Prime GreyEven the bogies lost some detail coz of the WSF...... Link to post Share on other sites More sharing options...
bluemattersoda Posted October 16, 2014 Author Share Posted October 16, 2014 Thanks guys. I suspect it has something to do with the material, so I've commissioned another print in FUD on shapeways. Stayed tuned! Another avenue of investigation is the torque on the motor. I've noticed that after removing the bogies, the corkscrews can be stopped with a finger. Granted, that should be expected but I wonder what the expected torque should be on a model train motor? The NWSL motor I've used has a torque of 0.47 oz/in (0.003Nm). I'm also aware that there is some friction on the corkscrew shaft due to the curvature of the shaft which is a manufacturing issue. I've partially ameliorated that with the joint. Link to post Share on other sites More sharing options...
Multiple identity account Posted October 16, 2014 Share Posted October 16, 2014 Thanks guys. I suspect it has something to do with the material, so I've commissioned another print in FUD on shapeways. Stayed tuned! Another avenue of investigation is the torque on the motor. I've noticed that after removing the bogies, the corkscrews can be stopped with a finger. Granted, that should be expected but I wonder what the expected torque should be on a model train motor? The NWSL motor I've used has a torque of 0.47 oz/in (0.003Nm). I'm also aware that there is some friction on the corkscrew shaft due to the curvature of the shaft which is a manufacturing issue. I've partially ameliorated that with the joint. He, Forgot to mention that I love you're work and haven't seen someone got to such lengths to design everything. If it's of any help the very same NWSL actually do Bo-Bo motorized mogies. http://shop.osorail.com/category.sc?categoryId=110 It may lower the cost also (though not sure) but assures you of performance. Cheers! Link to post Share on other sites More sharing options...
bluemattersoda Posted October 16, 2014 Author Share Posted October 16, 2014 Thanks Jeffrey, it's an interesting idea but it looks like they only do HO scale. I'll see how the new prints work out otherwise I will be going back to Tomytec chassis. Link to post Share on other sites More sharing options...
bluemattersoda Posted November 29, 2014 Author Share Posted November 29, 2014 I've received my new prints, and have some news to report. Starting off with the bad news - it's still not working. For some reason the overall friction in the system is enough to stop the motor. The good news is I worked out where the friction is occurring - it's not the interface between worm wheel and worm gear (which works fine when tested) but rather in the worm wheel to driving wheel. It looks like the teeth can get caught in the gap between the driving gear teeth. This stops the gears, which feeds all the way up to the motor. I've circled the problem in red. Any thoughts? Link to post Share on other sites More sharing options...
Marbelup Posted November 29, 2014 Share Posted November 29, 2014 If you rotate the gears on your CAD drawing can you see the point at which they bind? It looks to me that pitch of the teeth on the large gear is greater than on the small ones, but they may be an optical illusion. I am not an expert on gear design but the pitch should be uniform measured at the "pitch diameter". Did you base the gear profile on a known standard or design it from scratch? Link to post Share on other sites More sharing options...
bluemattersoda Posted November 29, 2014 Author Share Posted November 29, 2014 Hi Richard, The gears spin reasonably well up until it gets snagged so I don't think the point at which the mesh is the issue. I believe the snag occurs due to a 'pushing' action which causes the large gear to push into the smaller gap in the smaller gear, causing the snag. Good point regarding the uniform pitches - because my gears do not have a uniform pitch! (which I think is the fundamental problem) I designed the gears myself but used a gear generator to cut and paste the tooth profile so the teeth are all the same size. Thanks Richard! Link to post Share on other sites More sharing options...
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