Colibri Hummingbird Dynamic Sculpture - WIP

[Art K]

Kirk,
Its great to see this progress. I like the idea of the vacuum chuck, but I could picture myself going to deep, and watch the stuff fly.
Art

[kvom]

Art, it is a bit nerve wracking.  I set the tool Z0 to the surface of the plate and the target depth to .01".  Should be idiot proof, but they're always improving us idiots.

It's certainly possible to use the gaskets to form two separate vacuum areas as "insurance".

[kvom]

I cut the first two parts from some .375" aluminum stock today using the vacuum chuck.  Had some strange results but no disasters.

The machining involved two profiles and one pocket.  As the pocket is long and narrow (.439" wide) I did it as a ramped profile with a .25" endmill.  The target depth was .01" above the vacuum table.  No issues.  For the other profiles, I first programmed thenm as a trochoidal slot .375" wide using the same .25" endmill; this at .05" above the table with a .01" roughing clearance.  Doing this allows the chips to be cleared more easily than in a straight slot  Then to finish a finish profile at .01" above the table (.04" DOC).  This pass caused the material at the bottom to break off and in addition caused the bottom film to break, thus losing vacuum.  However, the vacuum table showed no machining marks, so it wasn't touched.  Luckily no damage to the parts resulted.

The only thing I can figure is that the endmill caused a vertical force on the bottom of the slot that was strong enough to break it off in places.  For future work I'll increase the table clearance to .015".

[10KPete]

Plate warp??

Pete

[kvom]

Here are the two parts mentioned in my previous post.



The long part is called the Cam Follower Tail, and the smaller is the Hummer Body Cam link.  The latter is shown assembled with the two spacers made in a previous post.  The screws are temporary as the right side of the body is attached to the opposite side from the spacers and the left side of the .body is attached to the spacers.

[kvom]

Having received the 1/8" acrylic sheet I ordered before New Years, I was able to cut out the 5 "forward" petals as well as the tail feather I was lacking.  The fit with the "rear" petals is quite firm, so perhaps they won't need glue.  Still not sure if the all red or the green-red combo looks best.



I think cut out the support frame from 1/4" aluminum.  This time I left a 0.015 flashing, but this proved really tough to remove with the deburring knife.  Plus a CAM error left an evident gouge that I stopped before it got too deep, but I'll need to run a face mill over the part if I can figure out how to hold it.

I'm hoping to get the main frame machined before needing to pack up for Cabin Fever.

[crueby]

The combination of the colored plastic sheet with the metal parts is going to look great.

 

[kvom]

Today was spent machining the frame, the most complicated part of the sculpture.  Started at 11:00am and finished the CNC about 5:00pm.  The most concerning part was drilling the 30 1/16" holes for the hypocycloid pins, since a broken drill bit in any one probably ruins the part.  I single stepped these spraying the bit with WD40 and cleaning it after each hole with a brush.  Here's the work at the end of the machining phase.



I had taken the cuts down to .01" above the table, so the flashing was quite a bit easier to remove.  Still there were a lot of edges to deburr.



I also had to drill the holes through the last .01" with a hand drill.  Not the 1/16" holes as the pins don't have to go through.

I still need to tape two holes 2-56 and loctite bushings in the gear axis holes, then place the pins.

[b.lindsey]

That is a very intricate part Kirk. I can see how the beburring could get tedious.

Bill

[crueby]

That is spectacular! How many more parts to make?

 

[Dave Otto]

Nice looking part Kirk!

Dave

[kvom]

Other than the wings, that's the last that needs the vacuum table.  But I'll probably use it for some of the larger parts left (e.g., 2 more cams).  There's about 20 parts left to machine, but about 50 various rods and bushings to cut to size.

No more before CF as I need to see if the other engines will run before I pack up on Wednesday.

[kvom]

Back from CF to find freezing temps and snow last night.  Good reason to stay in the shop most of the afternoon.  The first job was to cut the wings from the translucent acrylic sheet I bought at the show.  There was even enough room on the sheet to make another set of petals in case I like the color better.



As long as I was on the wings, I decided to do the drilling and tapping on the shoulder parts I made earlier.  As I needed to drill a very deep 1/8" home into parts with no flat edges, I cut out the actual size drawing and help it against the part in the vise for alignment.



More drilling and tapping for grub and mounting screws:



And here's how the shoulder and wing go together.



There will be a thin shoulder on the opposite side of the wing to clamp it.

[b.lindsey]

Glad to see you back on it after CF Kirk. Should be an amazing end result!!

Bill

[cheepo45]

Very nice!
Can't wait to see it in action.