Antweight Kit

[daliad100]

Re: Antweight Kit

MG90s 360 mod Bottom of this thread

Use stiff glue (epoxy or super glue) so the neutral position won't drift or swap the potentiometer for 2x 2.2k resistors.

[Merkabah_PT]

Re: Antweight Kit

Thanks for the tutorial Jordan.
Does the main shat wooble with this method? The guy in the russian tutorial only cuts the rotation stop of the plastic piece, insted of fully removing it. He also bends the pot limiters for it to be able to fully rotate.
I might go with a mix of the two methods, but i will analyze that better when i get my servos.

Just found a cad of TGY-9018MG, the mg90s is exacly the same size and shape, so this cad will work for both. Just need to do myself the reciever and the battery pack.

[Merkabah_PT]

Re: Antweight Kit

So, this is a chassis i did today on SolidWorks. It's about 140x120x45mm.
I have tried some websites that say how much the printing will cost, and they say around 80€ and 170€.
A LOT of money for such a small and simple chassis.

Can someone that have used 3d printer/3d printing services tell me if the price is right?

I will only know prices of the company near my city in the end of the week, but i bet it will be more expensive than company in other countries...

If this prices are right, making the robot out of carbon fiber is much cheaper...

(I can send the SLT file if someone requires it to calculate prices.)

[harry hills]

Re: Antweight Kit

tried shapeways?

[Merkabah_PT]

Re: Antweight Kit

Yes i did.
Around 80€...

I used 4mm thick walls, maybe thats to much? I've never seen or grab any 3d printed parts... Maybe 3mm is enough?

I will make a version of my chassis with 3mm walls and try the cost simulator again.

Edit: Changed to 2.5mm outter walls and 2mm for the battery box, 45€ with wheel covers, 43€ without them. I will try and make some vents on the chassis in hope to reduce the cost even further.

Does someone knows if 2.5mm wall is to fagile? This chassis is not for competition, just to try to make kits for kids and teens to get in to this hobby, only play fights against other identical robots.

[duff]

Re: Antweight Kit

Yes, 4mm walls are definitely overkill. And printing solid walls will also cost you a fortune. Design a space frame chassis (not sure that's the correct terminology, I'm sure some proper engineering types can correct me). As it's charged by the volume of material you use, the less waste material, the more money you can save. Think of how a bike frame is designed, lots of beams to make a solid structure, not just one big lump of material. I'd say the most I've ever spent on a 3d printed chassis is 40 euros, and the least is under 10 euros.

[Merkabah_PT]

Re: Antweight Kit

Thanks for the info Duff, i didn't see your comment when i edit my last one.
Do you think 2.5mm outter walls is good just from playing around?
I will do some vents all around the chassis to reduce costs even further.

[Merkabah_PT]

Re: Antweight Kit

Chassis A:

Volume = 60616.52 cubic millimeters
45€

Chassis B (same but full of holes):

Volume = 46062.32 cubic millimeters
52€

About 4000 cubic millimeters less, but he price went up... Anyone knows why? Complexity?

Even at 45€ it's still to much, and that's without the flipper and wheels...

[duff]

Re: Antweight Kit

Sounds odd... Have you definitely selected the correct material? It should be white, strong and flexible. Other materials are more expensive.

[Merkabah_PT]

Re: Antweight Kit

Yes, i have selected the right material....

I even made this alternative version with no round parts:


Printscreen of my shapeways models:


Chassis2.2.3.2 - Volume = 60616.52 cubic millimeters
Chassis2.2.3.2current - Volume = 44754.50 cubic millimeters
Chassis2.2.3.2-test - Volume = 40133.38 cubic millimeters

It lost 2/6th from the 2.2.3.2 version to the test version, but the price is almost the same, this is very confusing... I better wait for Friday, when i will have my 3d printing workshop.

[duff]

Re: Antweight Kit

I know they give you a discount if your model is of a certain density, so I think its something to do with that.

From their website: We also offer a volume and density discount on Strong & Flexible materials. For models that are greater than 10% dense (material volume divided by bounding box volume), after the first 20cm3, the remaining volume is calculated with a 50% discount.

So it looks like your model is right on the boundaries of density.

[Merkabah_PT]

Re: Antweight Kit

Thanks once again for the info Duff!

I will wait for my workshop to learn more about 3d printing with professionals and know prices here.

3d printing still is expensive for what i had in mind... I will do some designs where the body is made out of carbon fiber sheet, it's very cheap on HobbyKing.

[daliad100]

Re: Antweight Kit

You could try getting some kit's laser cut. More assembly and design required but should be cheaper as you might be able to squeeze many robots on one sheet of material and set up costs should be less.

Also my servos were fine aside from some drift on the neutral position due to some flexible glue.

[Merkabah_PT]

Re: Antweight Kit

That's what i was thinking about Jordan, some laser cutted CF panels. They have a 135watts laser cutter on the lab.

I am changing my 3d printed design to be even smaller. It was a rectangle, so the front had many unnecessary space. For now it's with 2.5mm walls, and the battery/servo mount and wheel cover with 2mm. Should i keep the 2,5mm walls or make it all 2mm thick?

[mark_m]

Re: Antweight Kit

I don't know what algorithm Shapeways use, but I've found that some online, automated 3D printing price calculators will give you a different price depending upon the orientation of the part (it's generally to do with the z height of the print, as that's what takes the time and therefore dictates the cost).

I noticed your models are arranged such they are almost as tall as possible - maybe try lying them down flat.