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Doc Brown
Doc Brown Dork
12/13/17 4:50 a.m.

In reply to lnlogauge :

I'm using PLA filament that came with the machine.  There doesn't appear to be a brand name on the package, just says "PLA filament".  

Anyway The print quality is set to HIGH in the Simplify3D splicer program.  I'll start posting the parameters of each part when I upload pictures.

So, what the heck are you making, is it a work thing or a fun thing?  

 

 

klipless
klipless Reader
12/13/17 12:02 p.m.

Although I haven't printed anything myself, I have done a bit of reading on the subject. And you know what they say about a little bit of knowledge...

One of the things I remember reading is that the slicer software can have a dramatic effect on the quality of the print. I've heard that switching to a quality on (like Simplify3D) can make a mediocre printer look awesome.

I've been meaning to try Fusion360 for a while, and when I do, I'll probably use this guy's tutorials to get me started. It's a paid class, but if you look in the description of his youtube videos, you can probably find a coupon code to bring the cost down to $40-50.

Doc Brown
Doc Brown Dork
12/16/17 12:20 p.m.

The printer is churning away making parts for the robot arm. I still don't trust the thing to leave unattended for long periods of time so I'm averaging 1 - 2 parts a night.

Lets look at some pictures....

All the cool kids are using blue painters tape on the bed. I'm not sure of the actual reason for using tape and glue, but with this printer the parts stick to the bare bed and need to be chiseled off.   At least for me, the tape and glue method makes it easy to withdraw the parts when the print is done.  

  

Glue!

 

the robot arm project calls for three smallish gears to be printed. I went ahead and loaded three models into Simplify3D and let the computer sort it out. On these gears, I changed the infill to 100% because they need to be strong like Ox.wink  

 

Zero efforts given......  

  

Ancient Chinese secret...... the main ingredient in this glue stick is CHEAP.... That's right, there is so much cheap in this little nugget that it actually works great. (didn't see that coming, did 'ya?) ... Anyway, short of setting out on a journey to the Far East to get more glue, I did the next best thing... went to the dollar store. Mind you, the dollar store this time of the year is filled with crabby old women and screaming kids..... but the alternative is far worse.laugh

The jury is still out, but this stick of Playschool glue seems to be full of cheap and its made in America.... perfect!  

Soon.....  

  

As you wind away with your Saturday afternoon, I'll leave you a short video on yet another 3D print.  

 

Stay tuned!

DrBoost
DrBoost MegaDork
12/16/17 3:43 p.m.

I print on a glass bed and use blue

glue stick. 

I have to let parts cool for a while or I REALLY have to work to get them off.  

Doc Brown
Doc Brown Dork
12/16/17 6:07 p.m.

In reply to DrBoost :

I'm having the exact opposite problem.  If I don't pull the parts while they are still hot then I have to use the spatula tool to get them off.    

Doc Brown
Doc Brown Dork
12/16/17 6:09 p.m.

In reply to klipless :

How does one get Fusion 360 if they are not a student?

klipless
klipless Reader
12/17/17 4:00 p.m.

In reply to Doc Brown :

Good question. I haven't done it myself. Some searching indicates that they want to keep it free for makers. 

I'd try going here. Notice that there's some text saying "Are you a startup or hobbyst?". If you hover over the info, it looks like you can sign up for a free trial, and then tell them that you're just doing this for fun and not for huge commercial reasons. It sounds like they should extend your free trial indefinitely...maybe...hopefully....

Good luck!

Doc Brown
Doc Brown Dork
12/17/17 4:35 p.m.

In reply to klipless :

Cool, I'll give it a shot!

Doc Brown
Doc Brown Dork
12/18/17 4:29 p.m.

Printing done!

 

Here are almost all the parts needed for the robot arm.  All the plastic parts are printed, just waiting on the proper hardware from McMasterCarr.

The Stepper motors were $24.00 on ebay with free shipping.  The Arduino and the CNC shield were $19.00 on Amazon.

Arm loosely assembled

The original design for the gripper calls for using a cut down servo horn to mate with the printed gear(left)... this was a bit sloppy so I had a go at redesigning the gear using TinkerCad. The new gear on the right fits the servo much better.laugh

TinkerCad to the rescue ! .... Awesome  

   

Close up shot of the gripper gear.

 

Stay Tuned!

Doc Brown
Doc Brown Dork
12/24/17 9:33 p.m.

This 3D printed robot arm uses communist base fasteners,  that's fine, except the fasteners are bookoo expensive through McMaster Carr.    To save some coin,  the nuts and bolts were converted over to freedom units.   The arm was assembled using 6-32 fasteners of various sizes and a hand full of metrics for the stepper motors.

Once everything was assembled it was time to deal with the electrical.   Just for giggles I went over to Thingaverse.com and did a search for a printable enclosure and to my surprise there were quite a few of them. laugh

Let's take a peek at some photos...

    

To my amazement, a printable enclosure was available exactly engineered for the Arduino UNO with a CNC shield.    

Ain't buying more metric fasteners ... Nope,  zip ties work just as good.  I certainly appreciate somebody went through all the trouble designing this enclosure, but WTF is the deal  with using  two inch long 3mm screws?

 

This robot arm runs on G-CODE...   The Arduino is configured as a slave to the laptop and a Java based universal G-Code sender is used to send the instructions to the arm.  Everything is open source and is free... but a serious pain in the a%% to set up.  I could go on a rant about this but in the end, what remains constant is the stuff was all free... you get what you pay for.

 

Movie time!

 

Stay tuned!

bgkast
bgkast UberDork
12/26/17 12:08 a.m.

Pretty freaking cool!

paranoid_android
paranoid_android UltraDork
12/26/17 7:43 a.m.

Awesome job Doc!  I’m glad you were able to put tinkercad good use.

Any plans for a human interface instead of g-code control?

RossD
RossD MegaDork
12/26/17 10:18 a.m.

Neat. So other than moving a sewing bobbin around, what are you going to do with it? Can you use your camera following robot thingy to grab a rolling ball across your green screen?

Doc Brown
Doc Brown Dork
12/27/17 3:55 p.m.

In reply to paranoid_android :

TinkerCAD is awesome!  thanks for the heads up!  Right now I don't have any plans for a sophisticated human interface, however I am designing a remote for the arm. 

 

Doc Brown
Doc Brown Dork
12/27/17 3:57 p.m.
RossD said:

Neat. So other than moving a sewing bobbin around, what are you going to do with it? Can you use your camera following robot thingy to grab a rolling ball across your green screen?

Hmmm, I might just dig up the cambot and see what happens,

AngryCorvair
AngryCorvair UltimaDork
12/27/17 10:14 p.m.

FREEDOM UNITS haven't lost a World War yet!

Doc Brown
Doc Brown Dork
12/31/17 12:15 p.m.

would be lying if I said I wasn't disappointed in how the robot arm came out. Overall the arm works, but the motion is sloppy and given the amount of high tech in the motors and controls I expect more precision. so... back to thingaverse and after a brief search I was able to locate a very nicely engineered arm. Even though the arm was free, its going to cost a few bucks to put it together.

is a pretty cool robotic arm I believe it was engineered to showcase the special stepper motors that it uses. As I understand it, the arm uses 'ustepper' motors (pronounced micro stepper) The ustepper motors are conventional stepper motors that have a built in driver. The ustepper is awesome motor by all accounts, however for this project I'll go ahead and use the conventional stepper motors that I already have in stock.

One annoying drawback of this robot arm is it is all metric... Now according to my calculations, this metric system is never going to catch on and is a complete waste of time.... however this time around I'll go ahead and build it with the recommended fasteners.

Anyway the printer has been running non stop for a few days and here are all the parts. As you'll notice, this time around I used white PLA. This white PLA was a bit troublesome to work with at first and required a bit of experimentation to get it to print right.

The engineers/designers of this arm have provided a well written and very detailed instruction manual on how to assemble the arm. The STL files along with the manual are here ustepper robot arm

 

Soon.....

...because I can't wait....

The motor on the right produces 30% more torque.  This mod theoretically will increase the payload of the arm... we'll see.

herringbone gears...... NICE!

 

 As I mentioned earlier, one of the annoying aspects of the project is that it is all metric. The fasteners can be expensive and luckily I was able to source everything from Amazon for less than $20.00. This project also calls for aluminum tubing to connect the various 3D printed parts. Metric tubing caused much aggravation to source and is literally imposable to get at an affordable price in the USA. Affordable tubing is available overseas with a two or three-week lead time but anything stateside is unobtainium through conventional sources. Carbon fiber tubing is slightly more common than aluminum tubing and I was able to source the required 6mm and 15mm tubing through Amazon and Ebay. Carbon fiber also looks cool, so in the end I'm not too upset.

Nearly all the parts for this arm printed as designed with the exception of the large rod ends. These parts just wouldn't print right and were quite a challenge to make. I guess sometimes you have to make some effort to get what you want. The pictures do a better job explaining..

The large rod ends are printed in two halves and the assembler is expected to glue them together. problem is I could never print the two halves good enough to match and glue.

 

both halves were imported in TinkerCAD and assembled in cyberspace (talk about lazy), anyway, I downloaded the 3D model and printed it sideways on the print platform. Nope, The tolerances were a bit sloppy but overall the part looked good'ish... Meh, lete's try again....

 

Sideways printed part sort of came out ok,....  it would work but we can do better.

 

After a bit of fooling around I managed to come up with a printable part. The Simplify3D software has a utility to help print difficult parts. The technique is called rafting and it basically includes a platform or raft appendage on the part to help stabilize the part during the print. While the raft technique is probably a good solution, it didn't work for me. The rod end broke away from the raft during the print. I'm sure some fiddling in the settings would have solved this but I went ahead and took the nuclear option and added a platform to the part with TinkerCAD. The draw back to my solution is I'll have to use genuine tools to cut the platform off, but I think I can handle that.

 

New part printed standing up on a platform.  Printing the part standing up solves a bunch of issues but also creates some issues.....Fortunately  the tradeoff is worth it.

finished part ... well almost. This part is sized to fit the inside diameter of an aluminum tube that the project originally called for. Since I have upgraded to a Carbon fiber tube I'll have to wait until the CF tube arrives to get a measurement of the ID.

One more trip to TinkerCAD is certainly in the future.

Some may wonder why I'm putting in a lot of effort in to making what is basically a big toy. Whelp, this is the learning process and most of the problem solving can be applied to future projects. Its bitterly cold outside and I really should be putting a clutch in the Miata but this is far more interesting...

 

Speaking about the Miata.... stay tuned... Miata parts have been printed, I 'm just not ready to do the write up yet...

 

paranoid_android
paranoid_android UltraDork
12/31/17 1:32 p.m.
Doc Brown said:

In reply to paranoid_android :

TinkerCAD is awesome!  thanks for the heads up!  Right now I don't have any plans for a sophisticated human interface, however I am designing a remote for the arm. 

 

It’s no problem!  I’m glad it’s been useful to you.

your prints are looking awesome.

Atomictaco
Atomictaco New Reader
12/31/17 2:15 p.m.

wOw! I really like the use of the carbon fiber tubes. Gives the project a high(er) tech vibe!

Doc Brown
Doc Brown Dork
12/31/17 4:10 p.m.

In reply to Atomictaco :

Yeah, it should look great!  Its amazing that semi exotic carbon fiber is more common than aluminum tubing.  The 6mm carbon fiber tubing that I sourced was  originally intended for use on a RC helicopter tail boom.  The 15mm tube is part of some camera rigging equipment that was being offered cheap.  Anyway, the tubing should show up in a few days. 

Atomictaco
Atomictaco New Reader
12/31/17 5:40 p.m.

Remember when we were industrial junk store hopping and we saw the titanium tubes? The carbon fiber is going to be way cooler!

Vicariously living through you,

Doh!

RevRico
RevRico UltraDork
1/3/18 4:47 p.m.

So if Simplify3D has "rafting", I'm assuming it has other settings like skirt or brim.

What I have found especially for small parts and vertical tubes, is that I have to run a brim. Mine in Cura is set to 8mm, which is a bit large honestly, but it gives a larger attachment point and snaps right off what I'm done. 

At least with cura, a raft will print a platform for the part, a skirt will print an outline, and a brim is a single layer border of specified size.

Maybe poking around in your settings will find these. 

Another thing I've learned about printing tubes is always print them vertical, especially if it's the only thing you're printing at the time. I've noticed a much tighter, stronger, rounder tube doing it vertically instead of flat on the heat bed. 

Those robot arms look great though, I'm kind of curious to see your printer in dual extrusion mode. I'm thinking about making that upgrade for mine, but it looks to kick the difficulty up a bit with my kit printer.

Doc Brown
Doc Brown Dork
1/4/18 4:38 p.m.

In reply to RevRico :

Cool, I'll give the brim feature a shot on the next print.  

I had an epic failure on the plastic bed sheet that came with the printer and had to remove it.  Im watching how your PEI sheet is working out and I need to get something like that in the near future.

 

Keith Tanner
Keith Tanner MegaDork
1/4/18 5:19 p.m.

About metric - since China is outside the US, more and more metric stuff is available at HF. I've got one of these, comes in handy quite a bit for little stuff: Box o' metric bits

This is fun stuff, thanks for sharing. And really, you shouldn't have to justify why you're building a robot arm. That's fairly obvious.

Doc Brown
Doc Brown Dork
1/5/18 3:58 a.m.

In reply to Keith Tanner :

I cant believe I totally forgot about HF as a source for metrics, that's an awesome lead!   Thanks!.   .  

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