Hey everyone,
I've decided to try and make my own frame for a quad. It's an H-X design for 5 inch props and 2204 motors (probable supports similar sized motors). It's more of an experiment than a proper frame, though I will try and fly with it, but I know it won't be amazing . I've attached a screenshot of my solid-works model so far for anyone that's interested. If anyone has any suggestions I'll definitely look at them (I'm still an FPV quad noob).
A quick explanation of the frame so far, FC on middle 4 holes (30.5mm) and camera mount is pretty obvious (i'm gonna just secure the camera with tape or similar to that bit), the slits are for velcro battery straps for battery underneath, and also for cable ties to attach the vtx at the back. I'm thinking of having a little raised platform above the vtx for the rx receiver to go on (which will again probably be cable tied to some slits in that platform). I'm also probably going to add some legs under the motors to stop the quad landing on the battery everytime.
It will probably end up being printed either PLA or ABS on 100% infill (we have 3D printers at school ), or if there are any other filaments that are better for this sort of thing but can be easily printed (they have ultimaker 2s and 3s) let me know

How thick is are the arms and other sections?

I would probably steer clear of using PLA because it is susceptible to breaking easily in an impact and is also affected by heat (becomes soft). People on here have printed frames in PLA only to have an arm snap off on the first crash.

IMO you might be better off printing the frame in either ABS or PETG. ABS is the strongest but it has poorer layer adhesion so could "de-laminate" in a crash, and it has less resistance to UV light which will weaken it over time. PETG is probably the best compromise as it's strong with a bit of flexibility, it has good UV resistance properties, and it can handle temperatures up to around 80°C without deforming.

Maybe you just need to print a frame in more than one type of material to see which one works best. Be aware though that all of them will have some flex in the arms which isn't really what you want on a quadcopter. This is why carbon fibre frames have become the standard material to build frames from...because they have high strength with minimal flexibility and are fairly lightweight at the same time.

dave_c has in general some toughtfull designs https://www.thingiverse.com/thing:3382398
some informations about how to print are probably written... somethings written about 100degrees on the printbed (i dont understand anything about printing settings)

the benefit would be, if it break, next day you take a new one out of the printer...
i saw a lot vertical framedesigns printed (edit: wrong its carbon design, i couldnt find a design on thingverse so far 4inch example https://www.thingiverse.com/thing:3836574 ), i guess this is a constructive intressting thing about stability, stiffness for printed frames. i guess - only a tought - the usual armdesign with carbon wont work, flat wide arms wouldnt work - a bele

a flat armdesinged frame https://www.thingiverse.com/thing:2686018
because sometimes good things are still good, i would explore otherframe designs first and start do combinate good improvements. this way will be more focused on a good result.

very nice you try this, keep is up to date about your design - and share it :-)
im ready to call my printbuddy and stresstest your design ;-)

Thanks for your guys support. Currently I've made the arms and while body 6mm thick though I can easily change that. I was thinking of making the arms detachable to its much easier to repair as I don't have to reprint everything. I can use ABS then if it's better. I'm gonna add some features like legs and a place for the receiver and a mount for the vtx anntena, and also a way to keep the vtx elevated so there is airflow on both sides of it.
Solidworks helpfully has a way to tell you the volume and as it was yesterday it is only 65g when printed in ABS assuming google has the right density of ABS (I took the median as I know it can vary depending on composition). The printers have a heated bed (which is pretty common) so that should help avoid warping and I'll ask the guy there for any other ways to help the print. Ill also ask him if they have any petg and if the printers can take it, so I might be able to use that.

I think I've finished the design now...
It's comprised of a middle base plate, 4 arms, 4 legs and 4 "standoffs" which are like legs for the top so if it lands upside down everything else shouldn't hit the ground.
Features of it:
6mm thick body and arms, with 100% infill
An H-X frame with the motors in a perfect X (took some maths )
30 degree camera mount
30.5mm FC holes
Slits for battery strap
Little bumps for VTX to sit on so airflow is both sides to keep it cool, and slits either side for cable ties
A platform above the VTX for the RX receiver to be mounted, again with slits for cable ties
The arms are detachable with 4 M3 screws to hold them on
Legs are attached to arms with more M3 screws
"Standoffs" are in 4 corners of main plate with M3 screws

I've attached screenshots of each part.
I'll try and get it printing tomorrow (out of ABS most likely) so I'll be able to see the thing printed on Tuesday.

Edit: I could maybe make a Solidworks assembly if that's easier for you to visualize, also modified my camera mount to be slightly higher so if it looks like the camera would hit the frame in the picture, don't worry , and if it all works when it's printed I'll chuck it on thingiverse incase anyone wants it (hugnosed_bat's friend )

Edit 2: Using Solidworks to get the volumes, and lowering a couple because infill, it comes to around 90 cm^3, which is 96g in ABS (1.07g/cm^3), though I might be able to lower this by not having 100% infill on the frame, arms and standoffs, and even lower infills (like 40%) on the RX mount and legs, which don't take that much impact if I crash

I was thinking of making myself a little whoop frame as well (not definite though), I'm very much doubting that I would be able to reuse my motors (DYS MR2202 2750KV) with smaller, 2 inch props? I'm assuming I can reuse my FC, VTX, RX, cam etc. (not battery) or would I have to replace any of that.
Anyone got any suggestions for inexpensive motors for 2 inch props (and the props), I'm aware it won't be amazing as my FC, VTX, etc would be fairly heavy, it's all just a thought for when those rainy winter days kick in.
Edit: Just did some maths on the weight, and it would be around 150g including battery, which I know it quuiite a lot for a 2 inch quad, is it at all possible to get motors and 2 inch props that can generate upwards of 100g of thrust each? As that would give me a 2.6:1 thrust to weight ratio, which still isnt amazing
Edit 2: After more googling and theoretical weight saving, it could get down to 86g, giving a 4.6:1 power to weight ratio.

I'm no design expert but I would probably rethink the way you have designed the frame where the arms attach to the base. The current design is going to be a particular weak point and one that will take a lot of strain during a crash. Very likely the "thin" part that protrudes from the base will just snap off. I would at least try to ensure that the same thickness of material is present on both the frame and the arm where they connect together. By this I mean that rather than use a "sandwich" type fixing, use an overlapping joint like in the picture below.



Also, if you take a look at other quad designs you will see that some of them use bracing brackets across the leg mounting points for added strength, so just something else to keep in mind.

(14-Oct-2019, 02:14 PM)SnowLeopardFPV Wrote: I'm no design expert but I would probably rethink the way you have designed the frame where the arms attach to the base. The current design is going to be a particular weak point and one that will take a lot of strain during a crash. Very likely the "thin" part that protrudes from the base will just snap off. I would at least try to ensure that the same thickness of material is present on both the frame and the arm where they connect together. By this I mean that rather than use a "sandwich" type fixing, use an overlapping joint like in the picture below.



Also, if you take a look at other quad designs you will see that some of them use bracing brackets across the leg mounting points for added strength, so just something else to keep in mind.

Yeah that might help, I'm probably gonna use that instead of a sandwich and also attach the arms "underneath" the main body so it can have much more contact area. Also means I can make the arms not flat to give better resistance when bent vertically. My first design is currently printing out of PLA (he couldn't be bothered to change filament if it wasn't deffo my final design) so tomorrow I can give that a test manually and probably also in the air if my new FC arrives in time. I'm thinking of making the main frame thinner aswell (probably to 4mm) though maybe thicker around where the arms join, also might do the arms as 3 separate thinner beams as opposed to 1 thicker one, I'll see.
V1 is also on thingiverse incase anyone cares (https://www.thingiverse.com/thing:3914223)

I've redesigned the whole frame (though it's still similar). It's now slightly larger, though is 4mm thick, not 6mm. Except around the arm joins where it is 7mm, giving 3.5mm minimum thickness around the join. I haven't yet figured out how I'm gonna mount the camera (might do something like this (https://www.thingiverse.com/thing:1345133)), and haven't designed the standoff parts yet as I can do them last minute quickly (the front 2 have holes ready and the back 2 go on top of the rx mount).
It is updated on the thingiverse page (https://www.thingiverse.com/thing:3914223).
Sadly, I can't print it at the moment, and won't have it done until around Wednesday after this next week (so quite a while). So I can't let you know what it's like until then.

I've been thinking (wow :0 ) and realised that my frame out of ABS will never compete will a proper frame, I knew it would never be as good but now doubting it more, probably will still print the version above but for the time being just gonna get a TBS source 2 as my current frame snapped this morning.

However, I was thinking of designing and printing a different frame to any I've seen, and this may be for a good reason, but one where the components are mounted below the motor height allowing the props to be very close, giving the quad a significantly smaller wheelbase. Is there any reason something like this would fail dramatically, just thought it might be fun to do something quite different.
Only thing I can think of is air getting blocked from the props by the rectangle main bit in the middle but don't think that that would be a major issue.

I'm not sure if you are still pursuing your ambitions of a 3D printing frame, but have a watch of JB's views on 3D printed frames from his live stream on Sunday HERE.

Unsurprising take by JB, sounds very similar to when he did a video about how HD video wasn't possible. I felt the same until just last week when I was at a long time customer of mine who has been doing advanced CNC work for years. He had a variety of 3D printed stuff on his display case that was the cleanest, stiffest, and lightest prints I've ever seen. When I asked him about it I was expecting he had some kind of very expensive printer but he had done them on an 800 dollar Prusa i3 MK3, all from nothing special PLA. I could not bend or discern any flex in some of the parts he had printed. Those prints have me interested in picking up a machine and trying it myself. Might be awhile as I have a lot on my plate right now but he has me thinking its possible.

Other people on this forum have done 3D printed frames in the past and they have usually been destroyed on the first or second crash. The type of forces that get exerted on a frame in a crash can be quite extreme, even in what seems like a relatively minor crash. The problem is that there will always be a weakness between filament layers (especially with PLA which is one of the weakest filaments), and even if you use 100% infill, the layers that run along the length of the arms will just split apart and break off in any type of crash where one of the motors hits the ground. Maybe the people who are successfully using 3D printed frames (if there are any) are good enough pilots that they never crash.

It would be great to see some proper crash test data from 3D printed frames, but it seems that even Andy Shen has already tried and failed to create a 3D printed frame that is strong enough.

the benefit is for crash pilots, get a new frame over night x-)
in a printed frame all konstruktive mistakes will cause more problems. with time and pioneers they will be better, the filaments will go better - carbon is still available to print... not as good, but i beleive this will change over time.
yes - a propre crashtest would be awesome nice..

as for micros, there are still a lot good frame designs available, still a sort of competitive... in my eyes

After really quite a while, I've finally printed and assembled my 3D printed quad, with a different design to above. However, when I take off it wobbles / vibrates a significant amount, haven't tried actually flying it yet. In my hands the frame feels pretty rigid, though currently the top plate is 3mm MDF and only attached to 3 of the standoffs, which I'm guessing affects rigidity, but I don't know how much. To avoid getting my screws in my motors I used 1 rubber spacer on each screw, between the frame and motor, should I move this to between the frame and feet  / screw head, though it is really quite compressed / tightened.
Basically what can cause vibrations / wobbling, I might have a motor slightly angled or some other issue I haven't mentioned. Just chuck every issue at me and I'll check if it's a problem on my quad.

Cheers

P.S. My design is here: https://www.thingiverse.com/thing:4128124