Dog Shifting Gearbox Feedback

[Knufire]

Originally Posted by BenGuy

Shashank, if we were to make this in the near future, you'd have to simplify the part, there is no way that this can be made on the bridge port, this would have to laser cut and we usually can't cash in on our sponsorship benefits from Superb until well into build season. Even if it will weigh a half a pound more, that's fine, just make an iteration that is feasible to make parts for on the mill if we are going to need it in the near future.

I've been looking into better optimizing parts for machine time over this off-season, especially gearbox plates like these which sucked up a ton of waterjet time for us. One thing I'm exploring is using unpocketed 1/8" plates with additional standoffs, after looking at 2826's robot.

[MichaelBick]

Originally Posted by Knufire

I've been looking into better optimizing parts for machine time over this off-season, especially gearbox plates like these which sucked up a ton of waterjet time for us. One thing I'm exploring is using unpocketed 1/8" plates with additional standoffs, after looking at 2826's robot.

That is totally viable, especially on anything that doesn't exit the frame perimeter.

[SerpentEagle]

Originally Posted by BenGuy

Shashank, if we were to make this in the near future, you'd have to simplify the part, there is no way that this can be made on the bridge port, this would have to laser cut and we usually can't cash in on our sponsorship benefits from Superb until well into build season. Even if it will weigh a half a pound more, that's fine, just make an iteration that is feasible to make parts for on the mill if we are going to need it in the near future.

Ben, did you forget that we are getting a CNC mill?

PCNC 1100 Education Package: http://www.tormach.com/store/index.php?app=ecom&ns=catshow&ref=PCNC1100_Package s_Ed1

Originally Posted by Knufire

I've been looking into better optimizing parts for machine time over this off-season, especially gearbox plates like these which sucked up a ton of waterjet time for us. One thing I'm exploring is using unpocketed 1/8" plates with additional standoffs, after looking at 2826's robot.

I'm pretty sure that 1114 has used 1/8 inch plates with bends for many of their drive boxes. I wouldn't think it would be a problem.

[Knufire]

Originally Posted by SerpentEagle

Ben, did you forget that we are getting a CNC mill?

PCNC 1100 Education Package: http://www.tormach.com/store/index.php?app=ecom&ns=catshow&ref=PCNC1100_Package s_Ed1



I'm pretty sure that 1114 has used 1/8 inch plates with bends for many of their drive boxes. I wouldn't think it would be a problem.

Yeah, I found plenty of examples of bent 1/8" gearbox plates but we don't have access to a decent brake.

[SerpentEagle]

Originally Posted by Knufire

Yeah, I found plenty of examples of bent 1/8" gearbox plates but we don't have access to a decent brake.

If you do some searching on harbor freight, you will find many hand brakes for under $80. They would do just fine for simple bends.

It looks like there's a shop right in your city: 1800 Fort Harrison Rd # 21, Terre Haute, IN 47804

EDIT: My bad, it seems that the only brakes online at harbor freight that can bend 1/8" aluminum cost over $200. I'm sure that if you guys use a strong grade of aluminum with frequent standoffs, you should be just fine.

[MichaelBick]

Originally Posted by SerpentEagle

EDIT: My bad, it seems that the only brakes online at harbor freight that can bend 1/8" aluminum cost over $200. I'm sure that if you guys use a strong grade of aluminum with frequent standoffs, you should be just fine.

There is a strength gain just by using 6061 alloy over the 5052 alloy, which is usually used in sheet metal fabrication for its ease of bending.

[SerpentEagle]

Originally Posted by Knufire

Yeah, I found plenty of examples of bent 1/8" gearbox plates but we don't have access to a decent brake.

Originally Posted by MichaelBick

There is a strength gain just by using 6061 alloy over the 5052 alloy, which is usually used in sheet metal fabrication for its ease of bending.

^This

On second thought, It would probably be much better to just use 6061-T6 plates in place of bent 5052 as it provides greater rigidity in comparison as Michael stated. Just don't use any pockets.

[AdamHeard]

Originally Posted by MichaelBick

There is a strength gain just by using 6061 alloy over the 5052 alloy, which is usually used in sheet metal fabrication for its ease of bending.

To elaborate more, there is a strength advantage but not a stiffness advantage. So there are many applications where people might think their plate is too "weak" where changing alloy won't help at all, as what they really want is stiffness.

[SerpentEagle]

Originally Posted by AdamHeard

To elaborate more, there is a strength advantage but not a stiffness advantage. So there are many applications where people might think their plate is too "weak" where changing alloy won't help at all, as what they really want is stiffness.

Wow, I didn't know this. I always thought that 6061-T6 is stiffer than 5052-H32 as it makes logical sense: 5052 bends and 6061 doesnt.

Originally Posted by Knufire

Yeah, I found plenty of examples of bent 1/8" gearbox plates but we don't have access to a decent brake.

Modulus of elasticity for 6061-T6: 10000 ksi

And for 5052-H32: 10200 ksi

As Adam said, 5052 is actually stiffer than 6061-T6. You would also need a laser cutter to make the plates with 5052 as it cant effectively be machined with a mill.

[Joe G.]

Originally Posted by SerpentEagle

As Adam said, 5052 is actually slightly stiffer than 6061-T6. You would also need a laser cutter to make the plates with 5052 as it cant effectively be machined with a mill.

I wouldn't say "can't." It doesn't machine as nicely as 6061, but it can certaintly be done effectively with care and the correct tools. We regulary perform secondary milling operations on 5052 bent parts with our mill.

Either way, unlightened, unbent plates as thin as .090 are definitely workable for gearboxes.

[SerpentEagle]

Originally Posted by Joe G.

Either way, unlightened, unbent plates as thin as .090 are definitely workable for gearboxes.

As low as .090? Would bearings stay put with that thin of a material?

[Joe G.]

Originally Posted by SerpentEagle

As low as .090? Would bearings stay put with that thin of a material?

We use positive bearing retention on all of our laser cut gearboxes rather than relying on press fits.

[R.C.]

Originally Posted by Joe G.

We use positive bearing retention on all of our laser cut gearboxes rather than relying on press fits.

Are you saying your relying on the geometry to keep your bearings in? Such as the shoulder of the shaft + the flange of the bearing?

[Joe G.]

Originally Posted by R.C.

Are you saying your relying on the geometry to keep your bearings in? Such as the shoulder of the shaft + the flange of the bearing?

No, should have clarified. Retention is almost always through rivets+washers clamping down on the bearing flange. We'll occasionally do it through other parts of the system, but never something as likely to be seperated from the gearbox during maintenance as a shaft.

[AdamHeard]

Originally Posted by SerpentEagle

Wow, I didn't know this. I always thought that 6061-T6 is stiffer than 5052-H32 as it makes logical sense: 5052 bends and 6061 doesnt.



Modulus of elasticity for 6061-T6: 10000 ksi

And for 5052-H32: 10200 ksi

As Adam said, 5052 is actually stiffer than 6061-T6. You would also need a laser cutter to make the plates with 5052 as it cant effectively be machined with a mill.

I was making the point that they are essentially the same stiffness.