Just received my 3D printed frame back from Shapeways, and I thought I'd post up some picture in my Blog. But, it's been taking a while for the moderators to update my blog. So, here are some pictures, and an update.
Here's how the parts come, right off the presses(AA battery for size comparison):
Just to show how TREX 450 (12mm) tail booms will fit:
The frame weight with screws and nuts, work out to just 69.3g. But the 16 screws and nuts, weigh 26.2g. So the frame itself actually weigh only 44.1g!
Here's the assembled frame in + configuration. It was pretty quick build with the integrated arms. Unfortunately, the 4" props are too small to lift it. With the motors, and 1500mah battery, and some screws, it works out to just under 400 grams.
I've reconfigured it for X configuration, using 6" props. Now I'm waiting on more props, and a new lighter, higher capacity battery from Hobbyking. Also ordered some 3-blade props, which will smaller for the surface area it takes up.
My assessment so far are the following:
1- Really happy with the print quality.
2- The Strong White and Flexible material is definitely strong enough for a frame.
3- These little propellers really need extra attention in balancing or else they cause crazy vibrations.
4- The APM/Oilpan combination is to big an heavy and bulky for a decent miniquad building. The APM 2.0 should be a great for miniquads. I'll probably be getting one, when then become mainstream, after ny bugs have been worked out of it.
Actually, 20g is not that bad. But like I mentioned, would be better with the APM 2.0. The main issue is to be able to use a prop with a larger surface area. Size is the main issue. You want the craft small, but you also want bigger props. The motors I used would generate 130g of thrust each with 7" props, but that's out of the question. The max size for 2 blades is 6". However, I'm hoping the 3 blade will be better.
Also my battery is too heavy, so I'm getting a 950mah nanotech battery from HK, that's supposed to weigh in under 50g.
And, if I really wanted to cut down on weight more, I can use more nylon standoffs, instead of brass where structure is not needed. Also, I'd cut some of those power wires shorter, once I'm at the final build stage, and hard solder the motors to escs eventually.
I'm new here so my knowledge of weight vs power of motors is very small. How is the weight of the printed parts compare to the carbon fiber?
Also, if you need any more printed parts I know I can do a cheaper price than Shapeways. How much did they charge you for those parts?
My print resolution wouldn't be quite as fine but I can still easily do 0.25mm layers, possibly 0.1mm if I push it.
Hi Steven, I don't think that this plastic will be less dense than CF.
For example here's a picture of the arm:
It weighs 5.4g, and the volume according to Shapeways, is 5.71 cm³. So by my math that's 0.94 g/cm³. I don't know what the density of CF is for a comparison. Maybe someone else, who knows can weigh in. (pun intended)
I know, that a plastic extrusion 3D printer might be cheaper in terms of material cost, although at a start up cost of about $1300, before shipping and taxes, you'd have to print quite a few parts to recover that. I'm not even sure someone can keep such a printer working long enough to be able to get that much utility out of it. Right now I can print the entire frame at Shapeways for under $100. That means, if I get one of those plastic extrusion printers, I'd have to be able to print 13 of the frames, before breaking even. This is discounting the question of whether they are capable of printing the arms and base sufficiently straight to result in a squared frame.
Also from a technical point of view, I think the plastic from Shapeways' SLA printer is more suited for the frame, because it has a slight flex to it. On the other hand ABS is stronger, but more prone to cracking on impact.
Ultimately, I want to put a version of the frame on sale on Shapeways, so I'm trying to validate the design, and business case relative to Shapeways.
Thank you for the reply. I figured it would be a bit heavier than the CF, but was just wondering by how much. I'll have to do some research to see what the weight differences are. I have a feeling the plastic parts would be light enough and not make a huge difference as many of the copters I've seen here on the forums are coming in over 1.4kg.
BTW, I didn't mean to try to sell you a printer. I meant I could print test parts for you, for a cheaper price than Shapeways. Also, I'm not sure what plastic Shapeways uses, but if it is plastic, chances are it is ABS. But it could be HDPE.
Well, I'll be diving into making my first copter shortly. I'll be creating a printable design my self also. I'll make a post when I get to printing the parts. My printer is busy right now printing parts for other printers.
Steve, the material that I printed the frame in is called Strong White and Flexible (SWF). According to Shapeways, it's nylon-12. It's would be less dense than abs.
My opinion of using CD for frames is that unless used properly, it's not really going to be an advantage. CF is strong, and great when you design the parts so as to replace solid parts with parts of the same shape, but hollow. Due to it's strength hollow CF is stronger and lighter. However, the way I see it being used in the centre hubs, is usually as flat sheets. In that case it's not going to be much different than plastic or fibreglass. Some people use CF tubes for arms, but I feel that aluminium is stiffer, straighter, and has less flex.
I'd love to see the design for your quad. Keep me and the community posted.