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

[egronvold]

I think we all apreciate the detailed descriptions, and the link to the parts used. Keep up the good work!

[SteinHDan]

Thanks, Emil! I'm loving your videos BTW. :-)

Maybe I can come over and run the excavator in your quarry some day, when it has been completed?


Best regards,
Stein :-)

[SteinHDan]

The lid lock mechanism is just another thumb screw and another nut glued into the body:

[egronvold]

Originally Posted by SteinHDan

Thanks, Emil! I'm loving your videos BTW. :-)

Maybe I can come over and run the excavator in your quarry some day, when it has been completed?


Best regards,
Stein :-)

Det kan vi nok få til

[SteinHDan]

Originally Posted by egronvold

Det kan vi nok få til

Kult! Det blir nok ikke helt med det første, ganske mye som gjenstår. Men kanskje på denne siden av nyttår. :-)

[SteinHDan]

Got started on the CAD work for the cab and the cab interior:

[Hofabooz]

Hi Stein

This is amazing work you are much further down the path I intend to follow developing my 3D drawing and printing skills.
Thank you so much for sharing as Joe on this forum says "Sharing knowledge is one thing that defies basic arithmetic logic --- the more you share, the more you get!"
This is true thanks again.

[Ben1272]

Excellent craftsmanship! I have always been partial to the hydraulic builds, but this electric build has opened my eyes to new possibilities!

Sorry if you reported earlier and I missed it, but waht 3d printer are you using? And what mill do you use to cut your aluminum parts?

Thanks!

-Ben

[SteinHDan]

Thanks Mark and Ben! :-)

This electric version even exceeded my expectations. I was planning on testing the electric motors and then converting to hydraulic if it didn't work out. And I didn't actually think it would work, because the arm is so long and the leverage it puts on the motor axle is enormous. But it did work quite well and it can dig normal dirt, which was the goal.

it even dug that gravel you see on the video. That's pretty tough stuff to dig.

I also got rid of that gear backlash I discussed with Joe previously. It was by most part caused by a machine key inside the gear motor that wore down and not by the gears themselves. To combat this I welded the gear motor's final gear to the axle. The weld looks so bad that I don't think I can show it here.. but it works and removed the backlash. I've only done it on the stick motor, though, and I'm planning to do it on all the motors.

The gear motors are so strong (320kg/cm) that they will rip themselves apart if not limited in some way. That's why I added the current limiting and the position sensors.
I've set the current limiting to match the scale force of the original full-size machine. For example, I've set the current limiting for the boom so that it can lift 12kgs. Multiplied by the scale (1/14)^3 (three dimensions), we get 12kgs * 2744 = 32928 kg which is around 33 metric tons. That value is close to what the real machine lifts with the same arm configuration and arm position.

So, the machine doesn't need to be any stronger to be a scale replica of the real CAT 390. I still don't feel too well about the leverage the arm has on the motor axle, though, so I've been thinking of maybe adding an external final gear that bolts directly to the arm and not feed the force from a 1m long arm through a 10mm axle. That also would remove the need to weld inside the gear motor.

I guess the things I like best about it being electric is that it's very quiet and there's no oil anywhere.


Stein :-)

[SteinHDan]

The 3D printer I have is this one:
- Makerbot Replicator 2X

I like it a lot, and I even have two of them.. But it's quite an old 3D printer. I think these days, you can get better offers. The only important thing is that you can print ABS, because it's so much tougher than PLA (less brittle). And you need a heated build plate for ABS printing. Maybe one of these could do the job:
- Ultimaker 2
- Zortrax M200 Pro
- FlashForge Creator Pro

I've not tried any of them, but I've heard some good things about them and the specs look ok. There's probably lots of reviews on youtube.



My mill is a K2CNC KT-2415S with a Bosch 1617EVS 1400W spindle.

The one I have is no longer sold, but I think there are some good quite cheap alternatives, like this one:
- CNC 6040Z 3-axis, 1500W VFD spindle, 110V/220V



I've not tried it, but the spec looks ok. 1500w spindle is good for milling aluminum. Ball screws are good.

There are lots of reviews on YouTube. I saw these two:
- Review: https://youtu.be/DeRuMZKCiy8
- Cutting aluminum: https://youtu.be/kTIYiZFGcRE


Best regards,
Stein :-)

[SteinHDan]

Now I'll get on to get the build finished! I'm working on the cab, windows, lights and webcam inside the cab at the moment.

Stein :-)

[Hofabooz]

Hi Stein

Happy New Year

Any update of your build to share with us yet as I cannot wait

Thanks for sharing with us all.

[SteinHDan]

Hi Hofabooz!


Progress is very slow these days. Too much to do at work.


But, I have an updated CAD file here, in case anyone is interested:
- http://d1t2tbzmskak12.cloudfront.net...age_4+v300.f3d

A screenshot:




Best regards,
Stein :-)

[NebraskaTrevor]

I downloaded your fusion 360 model and I have been marveling at it. As a fairly new fusion user I have no idea how you accomplished this but it sure is impressive to look at! I am working on a little bruder conversion at the moment but who knows I may print a few pieces of this for fun. Thanks for sharing!

[Mumin]

Hi,
can You also exported model in step file.
Thank you in advance!

[SteinHDan]

Hi Mumin!


Sure, here it is:
- http://d1t2tbzmskak12.cloudfront.net...ge_4+v301.step


Best regards,
Stein :-)

[skeeter]

I so very much want one of these. I think next year, rather then do several small(ish/er) projects, I'll save that monies, & buy a decent milling machine at the end of the work season.

[SteinHDan]

I found a use for it at my workplace doing promo work and I just finished it enough for that. Now it has been at my work for the past two years and I'm thinking about retiring it and taking it home to do the final pieces of work (add lights etc).

Here are two recent pictures of it in it's current shape:






Stein :-)

[SteinHDan]

One of the things I have to fix, is the left track motor. After a truck transport from the other side of Norway, the back platform had been broken off on both sides and the track motor did not run. I think maybe it was attempted lifted in the plastic, it broke and the whole thing crashed to the ground. But I don't know exactly since I wasn't there. Anyways, it has to be fixed.

Heavy as it is and with all that force on the track tensioner, I actually had to make a little plan on how to go about it, almost like on a real machine. I put it on it's side and got to work. Luckily I had a replacement motor lying around:



















Finally back in shape!


Stein :-)

[Riley XX-L]

Nice job those tracks should be plenty strong with that chain