90 ton 1/14 metal excavator scratch build w/embedded PC

[SteinHDan]

Thanks, Kevin, Jim and Reg! :-)

Originally Posted by RCP57

On a different note. How did you post your video(embed) like that on this site? I didn't think we could do that here. I'm glad we can!

I don't think this site support video embedding. What I did above is just to add a screenshot of the embedding in a link to YouTube. I did that because I was afraid that the video would drown in all the (boring) programming code I was pasting in the previous posts. and so I wanted it to stand out and look like a video.

How I did it:
1. Upload the video to YouTube
2. Copy the embed code from YouTube
3. Paste the embed code into "TryIt Editor" - http://www.w3schools.com/html/tryit....=tryhtml_basic
4. Take a screenshot
5. Crop the screenshot to only include the image of the embedded player
6. Upload the player screenshot to my image server
7. Add the image to the forum post
8. Add a link to the video on YouTube around the image (e.g. [ url= ..] [ img=.. [ /img ] [ /url ] ) so that the image becomes clickable.


Quite a few steps. Not sure if I'm going to do it again. :-)


Best regards,
Stein :-)

[fhhhstix]

This is awsome, I really enjoy seing the all electric builds and this one is top shelf.

Travis

[SteinHDan]

Moving some snow:





https://youtu.be/3Uzl0L9bS7g

[Lil Giants]

<- This smiley pretty much sums up my ability to fully comprehend your elaborate programming code to make this beasty of a model function.

It's looking pretty good so far... it'll be even more interesting to see you get it dialed in for digging dirt.

What's a rough calculation of the total investment so far with this innovative creation?

[Jolipe]

Your job is complete, thanks for links, and the instructions, etc.
Awesome!

[Machfab]

Very impressive craftsmanship!

[logger/dirtman]

nice build and the links are very helpful

[Machfab]

Question....
Will the gamepad/pc controller give you proportional control of the gearmotors or just on/off control?
Nice build!

[SteinHDan]

Hi Machfab!

> Will the gamepad/pc controller give you proportional control of the gearmotors or just on/off control?

The gamepad gives full proportional control for all the gear motors, including the track motors. I'm using the front analog triggers for the track motors, and I use the two front buttons to reverse the track directions. The swing, boom, stick and bucket controls are on the two joysticks and equal to running a normal excavator (ISO-mode).



This particular gamepad (the Logitech F710) doesn't stand back in sensitivity or accuracy in control from any of my normal RC transmitters. But most cheaper gamepads have less accurate analog control and also a larger deadspace in the middle / neutral position.

I would say the pros and cons VS a normal RC transmitter:
- Pros: Smaller, cheaper, 2 analog joysticks, 2 analog triggers, 1 digital four-directional pad and 10 digital buttons
- Cons: Short range (10m), no telemetry


Machfab, are you by any chance affiliated with http://machfabengineering.co.uk/ ? I just asking, because it would be interesting to get a quote on how much it would cost to get all the aluminum parts cut at a professional shop. I'd buy a set myself if someone could make it (depending on the price of course).


Best regards,
Stein :-)

[SteinHDan]

Hi Lil Giants!

Originally Posted by Lil Giants

What's a rough calculation of the total investment so far with this innovative creation?

I think it's very roughly around $1000 at the moment, but I'll set up a full bill of materials when I get it a bit more finished.


Best regards,
Stein :-)

[SteinHDan]

Hi all!

Thanks for all the comments! I've not posted many updates lately because I've started working on the finish that will go over the skeleton and make the excavator look more like the CAT 390F that is the basis for this model. Here is a sneak peak at my current design:







Best regards,
Stein :-)

[Machfab]

Originally Posted by SteinHDan

Hi Machfab!

> Will the gamepad/pc controller give you proportional control of the gearmotors or just on/off control?

The gamepad gives full proportional control for all the gear motors, including the track motors. I'm using the front analog triggers for the track motors, and I use the two front buttons to reverse the track directions. The swing, boom, stick and bucket controls are on the two joysticks and equal to running a normal excavator (ISO-mode).



This particular gamepad (the Logitech F710) doesn't stand back in sensitivity or accuracy in control from any of my normal RC transmitters. But most cheaper gamepads have less accurate analog control and also a larger deadspace in the middle / neutral position.

I would say the pros and cons VS a normal RC transmitter:
- Pros: Smaller, cheaper, 2 analog joysticks, 2 analog triggers, 1 digital four-directional pad and 10 digital buttons
- Cons: Short range (10m), no telemetry


Machfab, are you by any chance affiliated with http://machfabengineering.co.uk/ ? I just asking, because it would be interesting to get a quote on how much it would cost to get all the aluminum parts cut at a professional shop. I'd buy a set myself if someone could make it (depending on the price of course).


Best regards,
Stein :-)

No, not them. Just own a machine shop here in the US.
Also a user of Fusion360
Plan to do this build. Very nice! Thanks

[SteinHDan]

I've added some bronze self-lubricating bearings to the bucket linkage. I don't think they were really required, and it goes against one of the goals of this project, to keep it simple, but it just pains me to know that there is a load-bearing joint without any form of bearing in it. So it had to be done! :-)













The parts:
- Clips: HSP 02053 Body Clip
- Bearings: 8 x 10 x 12 oilless bronze bearing

[SteinHDan]

3D printed the ABS plastic parts that go in between the aluminum sides in the boom and stick sandwiches. I also re-did the boom sides in 3mm aluminum, as by mistake I made them 6mm thick the first time, which made me have to add 3mm spacers in many other places.

The ABS parts are printed with 16% infill, except the mounts for the stick and bucket cylinders, which are printed with 25% infill.

The filament used is this one:
- eSUN ABS 1.75mm Gold

This filament's color isn't really that close to the Caterpillar yellow, but it's the closest that I've found. I know there are companies that do custom colors, like www.plastic2print.com, but those are quite expensive and have order quantity minimums.

So if anyone of you guys know of a yellow ABS filament that is a closer match to the Caterpillar yellow, I'd very much like to hear about that.

[RobotArms24]

Can you explain a bit about infill on 3d parts please. Is it something you put in the model, or something the printer settings control? What does it look inside when its partially filled in? Is it honeycomb or some other pattern? How would the strength of say 25% infill compare to 100% infill?

Thanks

[SteinHDan]

Hi RobotArms24!


The infill is set in the printer settings (not in the model) and it's typically only used for FFM-machines (the typical home desktop 3D printers). Shapeways will always make a solid model, I believe.

I usually print with something called "fast honeycomb". There are lots of alternatives, but I feel that fast honeycomb is a good combination of strength, speed, weight and also the zig-zagging gives less pull on the edges and less warping of ABS prints.

I use a software called Simplify3D. They have a lot of good information on their web site. This is a video on infill:
- https://www.youtube.com/watch?v=BMWTK2ZgJCM

And they also have and this very helpful 3D-printing troubleshooter:
- https://www.simplify3d.com/support/p...oubleshooting/

I don't know exactly the strength of different infill percentages, but to the hand it feels linear, i.e. 20% feels twice as strong as 10%.


Best regards,
Stein :-)

[SteinHDan]

Starting to paint the metal parts on the boom, stick and bucket linkage. Need a couple more layers on the stick parts.
The paint color is the closest match I could find to the ABS filament color in the previous step. It's this one:
- Dupli-Color 577789 AC 3-0600
Sanded (120 sand paper) and primed with aluminum etch primer first.

It's a shame, really, to cover shiny metal in this way ;-)

[SteinHDan]

Mounted the counterweight to the base plate. After testing with 4, 6 and 8 kg ballast, it seemed 6 kg (13 lbs) gives the best balance.

I bought 2 kg (4lbs) lead plates from a local scuba-diving shop:
- http://dykk.no/main.aspx?page=article&artno=MTDA-1

I don't like exposed lead because of the health hazards, so I covered it in liquid plastic and added a shrink wrap tube on top of that. Probably overkill and you can probably use whatever to cover the lead, but I had these things at hand.
- Polytek EasyFlo 60 Liquid Plastic
- PVC Plastic Heat Shrink Tube F/W:95mm

Then I printed a 3D clamp (ABS, 30% infill) that has two very long M6 110mm hex bolts going through it.
- M6 110mm stainless steel hex bolt

Finally adding some common furniture anti-skid rubber pads to both the clamp and the lead to avoid the lead sliding in the clamp.

[bigford]

looking great I cant wait to see it dig dirt!!

[SteinHDan]

Thanks, Bigford! The snow has melted away here now, so as soon as I have it assembled again I'll make a video of it digging dirt. :-)