3D Printing Parts

[gtrgeo]

So I have an Ender3 V2 I picked up last Christmas. I have been using it for smaller functional prints and am curious about making some replacement parts for RC cars. I have been learning to design parts on Tinkercad and have found some on Thingiverse which I can use as-is or as a starting point for others. My question is regarding orientation of parts in the printer for best strength. I can see where printing things like arms flat on the print bed would leave them weak around hinge points. While printing them upright on edge would likely make them weak along the width due to the layer lines. I am thinking they should be rotated to an angle with supports but am not sure how much to tilt. I am looking to find the optimal strength while minimizing the supports and print time. My initial thought is ~45deg as that provide better strength around the hinge pins but the print time doubles with all of the needed support. Additionally there seems to be nearly as much plastic in the supports as the part itself.

Another item I would like to make is gears. Tinkercad is weak in this area. What is the best (free) source for designing gears for a hobbiest?

I am just playing around with PETG at the moment but if this works out would like to try some of the CF or glass reinforced materials.

Thanks,
George

[Dadio]

Printing on a 45 degree angle is something I tried but never found enough benefit in strength around the mounts to make it worth while , designing parts with increased material at the weak points is the way to go if you can , check the cross section in the slicer to see where infill voids are and if you find them in critical areas then increase the wall thickness and top and bottom thickness , don't fall into thinking greater % infill will make it stronger , strength is always in wall thickness .
With the stock Ender 3 hot end you could try CF PETG or CF ABS , I've got some CF ABS and it seems fairly good , ultimately though the best idea would be to get an all metal hot end and go to CF Nylon as its actually up to the job for buggy parts .
Have fun and best of luck .

[gtrgeo]

Dadio,
Thanks for responding. I am fairly certain your posts on this section as well as your Yo-clone-oh project were what led me to this board when they came up on an internet search. Your work has inspired me to take on this venture and I appreciate your sharing of what you have learned along the way. Interesting find about the wall thickness rather than fill having a greater impact on strength. So far I have modeled a shock tower and bumper for my XXCR (Thingiverse - 4759199 and 4806199) as well as re-mixed some other parts found on Thingiverse. Most recently I modeled up front and rear arms for a Traxxas Bullet but have not attempted to print. May try them in PETG today to check for fit. It is a neat feeling to print out something you designed and have it fit and function. So far I have been limited to what I can do on Tinkercad. As I am becoming more interested in attempting to model some gears it sounds like Fusion 360 may be the next step.

Thanks again,
George

[Dadio]

Fusion 360 has a spur gear maker that in theory should be perfect , I'm sure with large pitch gears it's fine but with 0.8 modulus (common Tamiya pitch ) or 36 DP it takes some tweaking to get mesh right , different plastics contract differently as they cool so you have to see how they come out then scale up 1 or 2% if needed ,I also found that printing gears on a raft was most consistent with teeth coming out even . In short it's not so simple as it should be but very satisfying when it works , make notes to tell how you designed a gear and slicer settings so you have the recipe once you get it right !

[GoMachV]

I cheated. I went on SDP-SI and grabbed the gear models for some gears and pulleys they offer and I cored out the centers. Made a good base for making my own hubs on them while ensuring the geometry is perfect.

[gtrgeo]

I cheated. I went on SDP-SI and grabbed the gear models for some gears and pulleys they offer and I cored out the centers. Made a good base for making my own hubs on them while ensuring the geometry is perfect.

Thanks!! this is a great option I was not aware of. I found some online gear generators but they all cost money and are usually metric. I was just wanting to play around with them to explore possibilities before I invested anything beyond time and some filament.

Thanks,
George

[LoCoCNC]

Fusion 360 is free for makers and should suit your needs as long as you aren't a commercial user.