Rough Fitting, Weigh In, and Improvements to Make On Honeycomb 2.0

Rough Fitting

All of the main structural components finished printing on Thursday evening and were available for pickup on Friday morning. In the final design we plan on switching out the bottom, top, and side plates for 6061 aluminium and increasing the infill for the mid and back plate to 100%.

We did a rough fitting, not screwing in all screws, but just checking to see if parts and electronics are lining up the way that they should be and to check the clearance's of the holes.

The electronics look messy, but we plan on cutting down and re-soldering all the wires to appropriate lengths to cut weight and free up some of the clustered space in the internals.

Below is a list of components used in the build

Component	Name
Drive Motors	720 RPM Planetary Gear Motors
Weapon Motor	Turnigy 2836 Brushless 450-Size Heli Motor 3700kv
Drive ESC	Scorpion Mini ESC
Weapon ESC	Hobbywing X-Rotor ESC - 40amp
Battery	Turnigy Graphene 1000mAh 3S 75C Battery Pack

Weigh In

For the weigh in we went into Autodesk inventor and found the volume of all the custom parts (excluding the drum and side armor), then calculated the mass of the parts based on material density and the volume. We also had a scale to weight out all of the components IRL to account for their weight plus the weight of wires and connectors. In total the weight came out 1170 grams, which leaves about 200 grams for drum and side armor which isn't enough. This weight account for the bearings, shaft, gears, and shaft collars that will be used on the weapon assembly leaving the weight for only the drum.

Places to cut weight from:

1. Midplate, instead of a 8 way cross hatch, cut it down to 6 way (diagonals and vertical only). Cut down the material between the holes to mount the top and bottom plate.
2. Sideplate, instead of a 6 way cross hatch, cut it down to 4 way (diagonals only). Maybe, add some holes behind the bearing mount to cut more weight.
3. Backplate, instead of a 8 way cross hatch, cut it down to 6 ways (diagonals and vertical only). Cut down the material between the holes to mount the top and bottom plate.
4. Bottomplate, maybe double the honeycomb design to the bottom plate may present structural issues for mounting ESCs, battery, and radio receiver.
5. Electronics, clean up wire lengths to whats needed. Currently a lot of extra wires present in the build can probably cut 30+ grams.

Out of all the places to consider cutting weight my most hesitant place to cut weight from is the bottomplate and sideplate behind the bearing mounts as this might negatively effect structural integrity. We think the most drastic weight cut will be from the plating since those will be the largest amount of material removal.

We will also weight out all of the potential hardware that will be needed to hold the bot together (screws, nuts, washers, etc.) This weight will probably be even with any weight we cut with electronic's clean up

Improvements/Changes

1. Increase hole size for all 6-32 screws to a .144" clearance holes.
2. Move the centers for the top and bottom plate holes and mounts on the plate to be 5/32" instead of 1/8", idk why I didn't do this to start since a 6-32 nylock nut is 5/16" not 1/8" wide
3. Increase hole size for weapon motor mount to m3 clearance holes
4. Increase hole size for weapon motor shaft to clearance hole for a 3.17mm shaft
5. Increase hole size for drive motor shaft to clearance hole for a 4mm shaft
6. Taper the connection between the plates by 1-2 degrees to allow for easier slotting.
7. Change the tolerance on the shaft connection for the drum so that it is a close slide fit, not a interference fit.
8. Change the tolerance on the bearing mount to be a soft interference fit.
9. Add slot for weapon motor wires to clear to allow flush fit.