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nowinaminute

I got a Lunchbox double wishbone conversion 3d printed for cheap, let's see how it goes!

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I kept seeing the upgrade on thingiverse and wondering how good it was so I finally decided to get the prints done via 3dhubs.

Pic is not mine, just an example of how they look:G73cFL5.jpg

But then I discovered in the year since I last used them, they have stopped working with all the small partners who helped build their network and only do the printing in house, not very nice of them!

Then I found the site Treatstock which essentially offers the same service, you upload a design and spec the material and colour and you get a list of quotes from small businesses to do the printing. I found one that was cheap and had good feedback so I gave them a go.

I got some Lunchbox rear lower shock mounts done first because I needed some for a Nikko I'm working on and it seemed like a good way to test their quality. The parts turned up and I was very pleased, certainly good enough that it seems pointless to purchase and set up my own printer.

iou2yPC.jpg

Once I got these and decided the quality was more than acceptable, I sent the files for the double wisbhone conversion. I have no idea how well they will work but a couple of other people say they are pretty good. 

The best part is the price, I got 2 sets for the Lunchbox and 2 sets for the grasshopper/hornet, 2 transmission anti-slap braces, 4 suspension arms for one of my Nikko trucks, a set of narrow suspension arms for the Tamiya holiday buggy and some gearbox anti-rotation brackets for the Clod Buster just to try out.

All of the above in various different colours and infill settings and printed with ABS which should be a little less brittle and more robust than PLA.

Total price: £8.90 delivered!!

They should be with me within the next week. I can't wait to try it out. I'm sure they won't be on the level of Ampro stuff printed by shapeways but if they are even half decent then I will be more than happy, even if they break occasionally the cost to replace them would be trivial. I can experiment with the infill settings too to try and get the best compromise between tensile strength and flexibility.

Stay tuned!

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1 hour ago, ThunderDragonCy said:

Definitely going to try these guys out at that price! Thanks for the tip. 

Can't go wrong at that price! Worst case you lose a few £ but if they just broke occasionally but worked well I'd be more than happy, if you ordered a few copies it would cost you something silly like 50p to replace a part if they did break. The parts I've had so far seem decently strong though!

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I wish I had a clue about making the 3d files, I've tried a few times with different apps but it makes my brain hurt. Even if I could just edit existing files I would be happy but even stuff like tinkercad seem mysterious and bewildering to me.

If anyone out there is a dab hand at it and would be willing to help me by drawing up a few things I would be very grateful! There's a few trucks I own where I'd like ditch the stock suspension arms for ones that are longer and would also allow me to use tamiya hubs, all I need is for the arms to match the stock ones on the chassis end and be compatible with, say, TL-01B on the other end. It seems so simple but I usually end up with something like this:

SxZRETE.jpg
 

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Just ordered some enclosed Thunder Dragon battery holders I have had designed for a while, but were quoted at over 50 bucks a set on Shapeways. Just ordered them from Treatstock for under a tenner! Really hope the quality is good on these because at the prices I will be switching away from Shapeways if the Treatstock sourced parts are up to scratch.

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1 hour ago, ThunderDragonCy said:

Just ordered some enclosed Thunder Dragon battery holders I have had designed for a while, but were quoted at over 50 bucks a set on Shapeways. Just ordered them from Treatstock for under a tenner! Really hope the quality is good on these because at the prices I will be switching away from Shapeways if the Treatstock sourced parts are up to scratch.

I think a lot of it depends on the vendor, I just went with the cheapest one. The quality isn't on par with shapeways, especially the underside where it's been on the bed, shapeways stuff made with strong and flexible and with that slightly grainy finish just has a more consistent look to it. I'm not grumbling for the price though.

I got all my parts yesterday, there were a couple that had some warping so I contacted the vendor, they were going to replace them all free of charge.

I did a trail fitting with the Lunchbox, it all went together pretty nicely. I will need to add some washers where the uprights attach to the suspension arms but no biggy.

I was careful to drill out all the screw holes so they weren't too loose but also not too tight, although I chose the more flexible ABS, it's still going to be more brittle than the original plastic so I didn't want to end up breaking anything before I even had it all together.

I haven't driven it yet but it definitely does what it's supposed to! The suspension travel is limited of course by the rubber tube on the shock shafts, I could take it off but it's there to stop the wheels hitting the body after all. I might have more luck removing the internal spacers in the shocks to get more down stroke, there's potential for a fair bit more in the setup I think.

The quality is a little rough around the edges if you compare to something like shapeways but in isolation I think it looks fine for the price, you know how it is, the further away you stand, the better it looks! I still need to give it all a once over with a file and some wet and dry paper too.

There's a weird round yellow thing in the sky for the first time in about 2 months so I might try and get a quick bit of video later!

dl95igG.jpg

Wl9ZY8U.jpg

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Looks fine , any close up pics of the arms from underneath ? . I'm interested to see the finish of the arms .

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Well, that didn't last long :o 

It was ok for a while, doing little jumps etc but then after a bit of a wobble following a near grip roll, the A arm on one side gave up the ghost. It went in the most predictable places too. It wasn't an impact but the way the van wobbled about put some lateral force on the wheels which appeared to be too much for it!

There's still hope though, I ordered all these parts before I had a clue about infill etc so they were all done at 20% which is apparently recommended only for ornamental stuff and not structural :lol: 

As per the previous post, I had a few malformed parts arrive and they are replacing them for me. They are also going to use 100% infill which should see a massive increase in strength so hopefully this problem will go away. Failing that there are apparently more flexible materials like PETG that I could try. Vendor reckons the infill increase should make a fair bit of difference though.

I wish I could do 3d stuff, I'm sure that part could be beefed up, the arm could be made thicker so the eyelets were flush and I don't see why the shock mounts couldn't be thicker on the outsides instead of flaring out like that, you could make them the same thickness all the way and if you wanted to have a flare still you could just extend past the outside edge of the arm and have a bulge. If only I had a brain.

Before it broke, the handling did seem to be a bit better, there seemed to be less body roll and it seemed a bit more precise and tighter when turning or at least when the wheels were in contact with the ground! The uprights and centre mount seem to be fine at 20% infill but they are much denser parts in the first place.

So for obvious reasons, no video today but I should have the new stronger parts by the weekend so stay turned.

6f57288d9567c9e6a661d1186bb10aab_preview_featured.jpg

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Turns out there is already a beefed up version of the A arms on thingiverse, still not quite as beefed up as I would like to do if I had the ability but it can't hurt. 

The vendor is now doing my replacements with this new design AND 100% infill. fingers crossed.

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I'm just getting into 3d printing at the moment. I did a dual wishbone conversion for the Mad Bull. For me it failed along a layer boundary where the shock was screwed into the upright.  Point is that orientation of the print matters as much as the infill. I'm gonna get around to printing some more things out (for pennies 😀) and see if I can make them stronger 

 

Amazing technology though, has so much potential

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7 hours ago, KEV THE REV said:

Looks fine , any close up pics of the arms from underneath ? . I'm interested to see the finish of the arms .

Yeah here you go, this was the worst one. Not sure if it's because they had to add support structures underneath and then remove them?? 

jacfrZM.jpg

The top of the arm was much smoother in comparison:

NsNMuOr.jpg

The beefed up A arm design I found has the added benefit of not needing supports so will hopefully be a lot nicer on the bottom.



 

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I see what you mean . Top looks good , shame about the breakage though . Hopefully the next batch will do the trick

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9 hours ago, nowinaminute said:

Yeah here you go, this was the worst one. Not sure if it's because they had to add support structures underneath and then remove them?? 

jacfrZM.jpg

The top of the arm was much smoother in comparison:

NsNMuOr.jpg

The beefed up A arm design I found has the added benefit of not needing supports so will hopefully be a lot nicer on the bottom.



 

Not sure where it cracked but an obvious no no from a good design point of view on those is all the sharp inside corners. These cause big stress raisers. If you have the option on the new design some radii in the corners where the various sections meet each other will really improve the intrinsic strength of the design. 

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It cracked at the thinnest parts, the places I was most worried about really. 

hMopYmQ.jpg

Once I knew I was getting replacements I took an intact part and gave it a good squeezing. The shock mounts broke with no effort at all although the actual arm held up quite well, enough to leave a temporary indentation in my finger!

I see what you mean about the edges. With all respect to the original designer, it seems like he just tried to replicate the look of the stock parts without considering how to make them suitable for 3d printing. Unfortunately I lack the ability to alter the files, this 3d stuff has me stumped so far. 

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tbh i dont think i would go for 3d printed stuff for a basher as they dont seem to be up to the punishment that will be put onto them as you have showed on you 2 different ones so far. i would sooner stick to oem or go the alloy route. 

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4 hours ago, topforcein said:

tbh i dont think i would go for 3d printed stuff for a basher as they dont seem to be up to the punishment that will be put onto them as you have showed on you 2 different ones so far. i would sooner stick to oem or go the alloy route. 

Probably so, especially with this design I'm trying to use but I'll see how these new parts hold up. Failing that, there's a guy I dealed with about a year who has some nicer materials such as PetG so I can give that a try too.

If that doesn't work I'll probably call it a day. There are other materials like nylon and some with carbon fibre blended into it but for the amount it would cost I could just buy an FX10 conversion kit which although a bit more fiddly to fit, has a reputation for being pretty robust and able to absorb knocks, even the ones that have been cut about and modified.

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I can redesign the arms if you want. Do you have a link to the files? 

I've done a few printed parts for my RC's and you are right in that you want to make the design based on the process. A molded part and a printed part have pretty much opposite requirements. Moldings can't be too thick otherwise they have issues with sinkmarks and voids. This is why the lunchbox arm is the shape it is. A printed part however doesnt have that restriction but it weaker than molding and along the layers its much weaker so a better approach would be to make it more monocoque looking (like a manta ray Arm) But with really big beefed up areas around the pivots. 

I have dome some arms like this before on my F1 car (3Racing FGX) and they worked very well, but that lent itself to printing vertically as it didnt have the integrated hingpin.

If you had it printed front to back you would have broken in those areas, you would have definitely broken it at the hingepoints. 

If the printer can print in PETG that might solve the issue enough for you with this current design. PETG has much stronger interlayer bonding.

Anyhoo Attached is a piccy of the FGX arms and also the camber link mount (wanted a shorter upper link for better camber gain) The arms are printed front to back but the link is printed top to bottom and you can see how much more chunky it is compares to the molded parts around it. It was pretty durable though.

20190106_084155.jpg

Edited by marks
photo upload failed
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Just to update you, I received the replacement arms with 100% infill, significant improvement. I don't know how much they could take ultimately but they are definitely tougher, I've done about an hour of driving with them so far but I'm definitely being a little cautious.

The c hubs are still the original low infill and have become the weak link so I will get some more done with 100% infill.

The handling does indeed seem improved, I never found the Lunchbox as bad as it was made out to be anyway, at least with stock power. It didn't tip over as much as I expected although the crazy camber changes did make it pretty goofy.

With the new suspension, it seems more composed and stable and I could corner really hard, even on tarmac, with no tipping. It still has the same tendency to under-steer on the throttle and tighten up when you ease off but it just feels a little more predictable and clean. It still launches into the stratosphere when one of the rear wheels hits anything bigger than an ant though!

Sounds good, right?

But, believe it or not, that will soon seem boring!

A couple of the guys on here have offered to help find better solutions and I have to say I don't know what amazes me more, people's amazing skills or just the sheer generosity and community spirit of this place.

There's possibly 2 different ways of going about it in the pipeline and maybe a redesign of the original parts too, all I can say is that what I've seen so far is amazing. I wish I had 1/10 the ingenuity and skill of some of the people on here!

I'll update when I know more but it's definitely interesting to be able to try different things out. The basic upgrade from thingiverse seems to now work fairly well as long as you use 100% infill which is already awesome but there could be much better things in the pipeline.

Until then, I'll see if I can get a little video of it running the thingiverse parts tomorrow :)

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On 1/2/2019 at 3:40 PM, topforcein said:

tbh i dont think i would go for 3d printed stuff for a basher as they dont seem to be up to the punishment that will be put onto them as you have showed on you 2 different ones so far. i would sooner stick to oem or go the alloy route. 

You should check out the orb racing ff210. 

3d printed (done right) is plenty strong enough for structural parts. It just takes some care in design (ie don't just copy moulded parts) 

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I couldn't get video today, folks. I was in work and the carpark out the front was never empty enough at any point. And because of the time of year it was dark before and after work! 

I will try and get some video Sunday.

I noticed the tyres rub less with this suspension so I took the rubber tubing off the shock shafts, much more articulation!

jYDjGSp.jpg
LVNoxTx.jpg
lC1LOuW.jpg

It still rubs a little at full lock and full shock compression but that's not really something that happens all the time so it was worth doing I think.

 

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So the reason these keep breaking with PLA and ABS (not to say that SLS is perfect by any means) is that the guy that pilfered my design tried to "modify" it by molding in the lower shock mount. This is not how they were supposed to work.  When I designed this suspension set, the structural analysis showed a stress concentration at the shock mount that I was able to mitigate by using the stock metal Tamiya lower mount. On top of that, this design was intended for SLS nylon, and not ABS or PLA. The design will change depending on the material used. Now I print these in the new HP material and they are pretty solid. Really, these needed to be molded in a soft ABS like the stock arms are made of. The tires are way to big for these arms to be so rigid but that is where we are right now. I also designed a metal reinforced version (that I disagreed with heavily but people wanted it) but I still run my original nylon ones on my Pumpkin. Here it is at the track, annoying everyone around me. 

 

You can see the original prototype set up:

26120244073_ae5ed25c1c_b.jpg

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6 hours ago, Pintopower said:

. I also designed a metal reinforced version (that I disagreed with heavily but people wanted it) 

Where is that? Shapeways?

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10 hours ago, Pintopower said:

So the reason these keep breaking with PLA and ABS (not to say that SLS is perfect by any means) is that the guy that pilfered my design tried to "modify" it by molding in the lower shock mount.

I didn't realize it was a copy of your design, it seemed to be all angular and lacking reinforcements where the c hub attaches whereas yours is curved and has support in that area. The guy put up sets for the Grasshopper and DT-01 too. It wasn't me, honest! Please don't sue!

It did occur to me that reusing the stock bracket would be a much better idea and several other people have mentioned it too, I was tempted to just take the mounts off entirely and do exactly that.

I know the design is totally unsuited to the material, I don't know how to use the 3d software though, not sure I have the necessary grey matter to be honest :lol: seems like the person who came up with the file on thingiverse missed an opportunity to tailor the design more towards the intended print process, it could have been bulked up in certain places to at least give it more of a chance. It seems needlessly delicate.

I think a couple of guys on here are looking into maybe making a more suitable design for the arm. And there's also a couple of different directions I will be trying soon, with help from fellow members.

Saying that, the replacement parts I got with 100% infill are at least an improvement. With the breakages I had, a lot of those trouble areas were essentially hollow so not only a weak design but a poor execution too! The solid parts are at least holding up to casual use. I'm sure a better design would be beneficial though and even then, unlikely to be as tough as a sintered nylon.

 

10 hours ago, Pintopower said:

I also designed a metal reinforced version (that I disagreed with heavily but people wanted it)

Why did you disagree? Because you believe the part should stay flexible?

By the way, I sent you an email regarding Nikko F10 buggy parts in regards to your youtube video, not sure if you got it or not? 
 

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