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  MKIII Drives
Posted by: LarryJ - 02-15-2019, 06:43 PM - Forum: LarryJ - Replies (5)

Been away for a while - haven't even touched the printer since before xmas.

Michael released his new drives and it started the itch back up again.

Here's the main frame in PLA - probably going to re-do it in PETG. It's pretty strong, but after I finished it I realized I did the last ones in PETG and they have held up great, why mess with a good thing. By offsetting the holes in the cross brackets, Michael made it real easy figuring out which parts go where.

   

Here are all the drive train pieces, these are all printed in PETG [6 shells (top/bottom/sides) - 30% fill]. The pieces on the left are printed axles - I'll most likely replace these with metal equivalents.

   

When installing the gears, install the middle one from inside the motor cage - and then move it left/right into position - fought with this one for a bit.

       

The rest is pretty straight forward.

               

I printed the tire with Ninjaflex Cheetah [ 3 shells - 20% infill ] - the lower infill gives the tire a little bit of flex. I lubed the edge of wheel with some Super Lube and positioned the tire on as far as I could by hand - a couple whacks with a rubber mallet and it popped right on - MUCH easier than V2.

   

Still waiting for some hardware and I still need to print the upper part of the assembly (ankle) before putting it together to test it out.

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  Hello from Ft. Lauderdale, FL
Posted by: Lowlight - 02-13-2019, 03:25 PM - Forum: New Members - Replies (2)

New to 3D printing, new to droid building.
But old timer when it comes to Star Wars.
Fan since first watching Empire Strikes Back in 1981.
Started using Fusion 360 but have years of experience in Autocadd.
Own a Creality3D CR-10 - basically stock, only mods - strain relieve bracket for the heated bed, leveling nobs, fan duct and dust cover for the extruder.
Will be printing Michael Baddeley R2-D2.
Started with the Dome.

By the way, Thanks Mr. Baddeley

Any members near Fort Lauderdale?

Regards

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  Big Printing
Posted by: Eebel - 02-12-2019, 04:14 PM - Forum: Eebel - Replies (9)

I have spent the last week or so learning big printing.  I have used three other smaller-scale printers for the last four years.  I thought I knew how to print stuff.  Well... almost.

So, a few days ago after tuning my Creality CR10S-500, I felt the printer was finally ready to print the experimental R2Dome1print.stl. So, I fired up Simplify3D and used the print profile I had used during my calibration tests.  This was .3mm layer height, 3000mm/min top speed,  default underspeeds for infills and perimeters, and three layers for top and bottom.  Simplify3D estimated about 67 hours of print time and it predicted just over 3Kg of filament.  Initially, the print looked fabulous!  I just had to switch out filament at some point. No problem since I have a filament run-out sensor.  Fast forward 36 hours...

This is when I noticed my print was in trouble.  At this point, nearly a full spool of filament had been printed and the print was getting quite tall.  On each layer the .gcode was putting three top and three bottom solid layers because the dome had curved enough for the slicer to interpret the inside of the dome wall as the bottom and the outside of the dome wall as the top.  The result was a continuous zigzag fill pattern that rattled the whole machine and the table the printer was sitting on.  This violent rattle lasted a couple of minutes on the inside of the print and then again on the outside.  This pattern happened each layer.  As the print grew the oscillations grew in intensity due to the print being taller.  Eventually, the printer vibrations became so bad that my Y-Axis shifted when the belt skipped during the vibrations and the print was ruined.  I tried in vain to realign the Y-Axis manually.  However, the experiment was over.  The print failed.

[Image: attachment.php?aid=1442]
[Image: attachment.php?aid=1443] 
So, back to the drawing board.  How could I fix this?  Mechanically, the Z-Axis was too wobbly.  The original owner of the printer had installed a single Z-Axis brace on the left rear of the printer.  It helped.  However, the right side fluttered quite remarkably.  So, I added two front side Z-axis braces. I may add a fourth rear brace. However, my drag chain mod is in the way and it would require additional rework of the mount. I figured I would try it without it and see how things worked (see IF it worked.. heheh).

[Image: attachment.php?aid=1444]

Additionally, I found that the Z-axis was not even square. Ugh.  Once that Z-axis was secured and actually perpendicular to the bed.  I set off to adjust my slicer settings to address the violent infill-induced vibrations.  

[Image: attachment.php?aid=1446]

What I did was set up four print regions.  I changed several key aspects of the print as it got taller.
1.  Slow the top speed of the print as the print got taller.  3000, 3000, 2800, 2700 mm/min
2.  For region two, I eliminated tops and bottom infill.  This removed the massive zigzag infill vibrations.
3.  For regions three and four, I reapplied the top and bottom infills, but I lowered the infill underspeed from 80% to 20%.  Additionally, I set the bridging to 150% to accommodate for the lower overall top speed. I did this to hopefully get decent bridging around the top ring of the dome.  Additionally I reduced the bridging flow rate from 100 to 90 percent.  The theory is less plastic, less drooping during the bridge.
4.  For region three, I increased the infill to provide more strength.  Although thinking about it now, I should have added an additional perimeter or two instead 

The resulting predictions showed a 17-hour reduction in print time and 1KG less plastic used!  This is because I was not putting tops and bottoms on what was essentially walls.  Not only did this eliminate the violent rattle for most of the build, it eliminated nearly a kilogram of unnecessary plastic.

Here are the before and after screen shots of the of Zone 2.  Notice the green tight zigzag solid infill that caused the violent vibrations and was not need for the integrity of the model.  The after shot shows the three interior and exterior perimeters and a nice smooth infill.

BEFORE:

[Image: attachment.php?aid=1447]

AFTER:

[Image: attachment.php?aid=1445]
  

So, I tried to include my Simplify3D factory file to this post, However, this website won't let me as the file is 2.4 MB when compressed to a ZIP file.  If you have a CR10S-500 and want this file here is a link.

Simplify3d 1PrintDome FactoryFile




Hope this helps.

Eebel



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  Painting (Ironman)
Posted by: phul007 - 02-05-2019, 10:09 PM - Forum: phul007 - Replies (2)

I have been busy sanding and more sanding and now its paint time. 

Painted most of the parts some not shown as they are still hanging up and drying.

Only a few things left and then only the helmet and reactors to go before assembly time
[Image: attachment.php?aid=1430]
[Image: attachment.php?aid=1429]



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  Greetings from Baltimore!
Posted by: jcharlton - 02-01-2019, 08:59 PM - Forum: New Members - Replies (4)

Hi, my name is Jason and I'm a 3D printaholic. Smile 

After several months of research, lurking, and more research, I think I'm finally ready to start down the rabbit hole of droid building. Over the past year or so, I've been exposed to 3D printing at my work and have found a bias toward Star Wars-related projects. I have made a cool lightsaber hilt, a quarter-scale R2-D2, and even dabbled in Arduino for the first time in making a thermal detonator complete with lights and sound effects.

I'm still making some final decisions about how complex I want my droid to be, as well as how much will be printed in PLA vs PETG. In the meantime, I've got about half the dome printed and am looking forward to trying out some of the finishing techniques I've read about here and there.

So far, I'm really impressed with the sheer volume of information I've found both here and at the astromech forums, and the friendly, helpful nature of the community has me encouraged that it will help provide the motivation to keep this project moving forward.

I'm sure I'll be asking questions at some point in the future, if not here then over at astromech, so many thanks in advance for your help.

Cheers!

Jason

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  Greetings from NC!
Posted by: Solaren - 01-29-2019, 03:54 PM - Forum: New Members - Replies (1)

Hello everyone,

Been excited for this build since I met some members of the club and saw the awesome droids at Celebration Orlando. 

I finally got to invest in a 3D printer (Ender 3 Pro) and after working on some upgrades and other little pieces for a couple weeks I decided to get started on BB-8. 

Here is my progress from the first couple days:



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  Hello from Indiana!
Posted by: TheCheatOSX - 01-28-2019, 03:15 PM - Forum: New Members - Replies (4)

Hello all! I'm working on a ABS Dome and Styrene frame/skins. I'm 3D printing the greeblies and other items such as the panel hinges. I may switch to a 3D printed body. We shall see. I'm concentrating on the dome right now. And I have been eyeing printing out a BB-8.

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Smile Printing in Flexible Materials.
Posted by: Cyber_One - 01-21-2019, 02:35 AM - Forum: Cyber_One - Replies (1)

Hell Builders and Droid techs,

Been a while since I posted anything, so I thought I have better do an update.

Progress on my R2D2 has been slow of recent due to other family commitments, but recently I did manage to have R2 move around under his own power, albeit not very well.

The 2 Razor 100W 12V motors were very much under powered using the single belt drive. 
I have a DC-Clamp meter so was able to get current readings of the power going to the motors while R2D2 was driving.


So first a little bit of basic motor 1O1.
A 100 Watt motor running at 12 Volts will draw around 8.33 Amps at full rated load.
Watts Law is given with the formula P = E x I
When a motor first starts, it is overloaded, until it reaches its designed speed, normally, this is only a few seconds and isn't too detrimental to the motors.
If the power is available the short overload can be as high as 5 times the rated load of the motor.
Once up to speed the current feeding the motor will drop off to a current that matches the current load on the motor.
If your motor is under loaded, then the current drawn will be less than the full rated load of the motor. (Marvellous creation the electric motor.)

There are a number of factors that can reduce the current drawn by an electric motor, these include:

  • Motor Controllers
  • Wiring resistance
  • Battery internal resistance
  • Faulty connections

On my first attempt to drive R2D2, I had a current draw of 18 Amps, and R2D2 did not move.
The motor did not turn.
If I gave the droid a push, if would move and continue to move, but the current did not drop.
Based on my experience I was experience I was expecting a locked rotor current of somewhere in the order of 41 - 42 Amps.
So now I was looking for a resistance that could drop the voltage to the motor and therefore the current to the motor.
My speed controller is a IBT-2 PWM controller (not very smart but can handle big currents at a low cost) 
The controller is rated to 43 Amps with internal load limiting, the 18 Amps was no where near the load limit of the controller.
Being the electrician that I am, I did slightly oversize the wires. The larger the diameter the wire, the lower the resistance and so the less voltage drop in the wiring.
All the connections tested as OK and the thermal imager did not show any heat buildup where it wasn't expecting it.
That leaves only the Battery.
In my case a 12V 5 Ah SLA.  The internal resistance was too high to supply that kind of current...  Sad
I should have known better, and now I have done the maths, do know better.
The quick and dirty solution was to add a second battery in parallel to double the current capacity, in truth, I think I could use 4 batteries instead of 2.
First test run saw R2D2 make it half way across the kitchen before pulling a hard left.
Each main motor in my build has its own fuse. The 20 Amp fuse for the left motor had blown.

I replaced the fuse, added the DC-Clamp meter and tried again.
Now R2D2 was drawing 28 Amps for each motor, or at least is did until the right motor fuse blew.
Well, the wiring would handle it for a while (Remember I did oversize the wires Big Grin  )
I replace the two 20 Amp fuses with 30 Amp fuses and gave it another try.
It's still way under powered but I could get it to drive around, and I had to dome turning as well with no problems at all. (10 Amp fuse there)

I installed an MP3 player module and installed the MicroSD card with all the downloaded sound effects.
My R2D2 is currently being controlled by an Arduino Mega 2560 withe FlySky FS-IA6B RX unit connected to it via Serial 2.
This allows me to send 10 channels of control from the transmitter to the Arduino.
Using this I can select a random sound file to be played from one of three groups that I can select with the transmitter.

While R2D2 is far from complete or functional enough for any sort of get together, it was enough to impress my Nice and Nephew  Smile

Back to the problem at hand and the overloading drive motors. 
I really need to change the gear ratio and I think I have too much resistance to rolling in the front Omni wheel assembly.
Its was about then, Michael Baddeley uploaded an Alpha version of his new MkIII geared drive system.
So now I'm back to printing.
Most of this has now been printed out and a dry fit (Still have the new omni-wheels print, but that's just a mater of time.)
I had bearings on hand for the main wheel and as it happens the middle gear.
The Middle gear is difficult to fit (This is an Alpha Version so bug are to be expected)
And the order of assembly is critical. 
Mount the wheel on its shaft first then the middle gear, not easy but can be done.

I needed another tyre printed for this wheel, the last tyres I printed weren't the best so decided to print a new one. (Next Headache)
The roll of flexiable filament I had is labeled as TPE with a print temp of 190-240 C
I have a modified Cocoon Create Touch.
  • I replaced the extruder a while back with a Flexion extruder.
  • Moved the part cooling fan to the back using a duct.
  • mounted a BLtouch Bed leveling sensor to the front
  • I replaced the bed with an Anycubic Ultrabase glass bed. (this has a pourus like surface in the top of the glass)
  • Replaced the firmware with ADVi3++ (https://www.patreon.com/andrivet/overview)

My first attempt to print the tyre resulted in it coming loose from the bed.
I tried a number of other configuration before finally finding one that worked.
All the information I found online talked about the extruder and how flexible filaments tend to find the path of least resistance out the side of the extruder. I didn't have any of those problems, The Flexion extruder solved that for me.  My problem was the print would let go of the bed around 15 layers in of the 136 print.

The solution was: 
set the part cooling fan off
Set the hot end to 240 C
Set the bed temp to 90 C
Retraction I set to off  but have since set it to 3 mm and no Z hop
and the speed is set to 15 mm/s
layer height of 0.25 mm

The results were quite good.
[Image: attachment.php?aid=1425]

So while I had the TPE loaded, I have also printed out a few other parts so i can get the doors working as well  Smile

Parts for the new feet printed so far
[Image: attachment.php?aid=1426]


A closer view of the Middle Gear
[Image: attachment.php?aid=1427]


As can be seen, this is just a dry fit, so no screws yet installed, but already I can see a number of improvements.
The other major change, is all the axle pins are printed.  Will be interesting to see how that holds up over time.
This was printed in PLA.

More updates to come....



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  Body - Wiring
Posted by: cobra troy - 01-16-2019, 04:52 AM - Forum: cobra troy - Replies (10)

I'm getting close to having the main body wired. Final hookups for the servos and a few smaller wires to power the 5v systems to go. I also need to figure out the wiring system for the 2-3-2. 

Since my eyes aren't getting younger, I installed four strips to LED lights and wiring them to the 12v bus. They can be turned on by a small toggle switch inside the right frame.



[Image: 46034350934_c34dc63527_c.jpg]


Here are the shoulders and motors for Martyman's 2-3-2 system. Only half of the shoulder parts are in this image. The other half is mounted to the center supports.

[Image: 31817647317_d3f7576cde_c.jpg]



I redesigned my dome and utility arm servo mounts. I also needed to redesign the gripper and data arm servo locations due to interference issues with the 2-3-2 system. This wiring is still rough...

[Image: 31817646937_cf33f545de_c.jpg]


[Image: 31817646667_82dc27c3d0_c.jpg]


This is my removable electronic board. The four LED displays monitor the power levels of the different power buses. One is for the 12v system and one is for the 5v system. The other two monitor the power levels of the two 6s Lipo battery packs and will sound an alarm so I don't discharge the lipo packs to far. (The servo leads in this image are temporarily attached and will connect to the back of this board)

[Image: 46034348584_52ae57683b_c.jpg]


The electronics board also swings open so you can access the back and work on the 2-3-2 system.

[Image: 31817645937_199da96ebe_c.jpg]

The back of the electronic board. I'm still adding wires...

[Image: 46034347394_bf37342d37_c.jpg]

The challenge of wiring for a 2-3-2 system is keeping the wiring out of the way of the center leg lift. The XT-60 connectors in the upper right of this image connect to the main drive motors.

[Image: 31817645287_4a4386e807_c.jpg]

This is a battery tray I designed to hold my two 6s lipo batteries. The balance plugs are wired to the battery monitors on the main board. The switches are there so I can power down the monitors without unplugging the batteries.

[Image: 46034346304_d3dce1b95a_c.jpg]

Batteries installed. Simple cap head bolt with a printed knob holds it all in place, plus the back cover.

[Image: 31817644867_b4954bacc1_c.jpg]


More images...


[Image: 46034345244_96a210858d_c.jpg]


[Image: 46034344884_f0a4dda0c1_c.jpg]

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  Hello from the UK
Posted by: rozzy - 01-14-2019, 12:00 PM - Forum: New Members - Replies (5)

Hi everyone! I'm Ryan and I'm from Bedford, UK.

I've wanted to build an R2 unit for some time now and have been lurking on the astromech forums reading build logs. I've finally decided to take the plunge and start a build of my own. I have three 3D printers (AM8, CR-10 & CR-10S) and sub-par woodworking skills, so printing my R2 seems the best way to go.

I do however have a few of questions:

1. Are there any recommended settings for printing the parts (layer height, shells, top/bottom layers, infill % and pattern)?

2. Is the mk3 body just for 500mm printers? If so I assume that means I should print the mk2 body since I don't have a large printer?

3. Will the 2-3-2 upgrade work with both the mk2 and mk3 bodies?

Sent from my SM-G955F using Tapatalk

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