Forum Index > Projects > Egg-Bot
 Angle brackets not square.
 |  Printable Version
By: Anonymous: Adrian () on Tuesday, May 24 2011 @ 08:03 AM PDT (Read 2550 times)  
Anonymous: Adrian

Hi,

Just assembled my new Egg-Bot and tried it out. The results on a ping-pong ball are disappointing, so far. At this point, it seems impossibly optimistic that it will ever produce results like the ones posted by dnewman. But I'm reading through the "Improving Accuracy" page and hoping that will help. Will probably also try gluing the bushings in place, as per the assembly appendix.

Hardware question: When assembling, it seemed to me that the angle brackets are not bent to exactly 90 degrees (they seem over-bent so that the interior angle is slightly less than 90). The difference is slight but noticeable and I can watch the chassis panels bend every-so-slightly as I tighten the thumb screws. The question is whether this will be a significant problem w.r.t. plotting accuracy. Any thoughts?

Thanks





       
   
By: Windell (offline) on Tuesday, May 24 2011 @ 11:57 AM PDT  
Windell

Just assembled my new Egg-Bot and tried it out. The results on a ping-pong ball are disappointing, so far. At this point, it seems impossibly optimistic that it will ever produce results like the ones posted by dnewman. But I'm reading through the "Improving Accuracy" page and hoping that will help.


The Egg-Bot is somewhere on the spectrum between computer printer and artistic medium. The prints by dnewman are exceptional, reflecting not just mastery of the machine, but also careful selection of pen type and print media. You should allow yourself a little patience to learn the different adjustments and how they affect print quality.

The notes on the the "Improving Accuracy" page can help tremendously. In particular, make sure that the "egg" firmly registers to the egg motor-- otherwise you'll get slippage (precession, "camming out," or effective backlash), and that the pen faces exactly towards the centerline of the "egg" while printing. You can also achieve a tremendous improvement in effective resolution by moving to finer pens, or even a mechanical pencil.


Hardware question: When assembling, it seemed to me that the angle brackets are not bent to exactly 90 degrees (they seem over-bent so that the interior angle is slightly less than 90). The difference is slight but noticeable and I can watch the chassis panels bend every-so-slightly as I tighten the thumb screws. The question is whether this will be a significant problem w.r.t. plotting accuracy.


No, not really. The other factors are many times more important. What the angle brackets buy you (once everything is tightened down) is rigidity, the key to high quality plotting. The six angle brackets on each side are symmetrically balanced as far as how many face each way, so there shouldn't be any significant overall curvature once it is assembled. (You may also notice that the chassis sides are also not straight-- they only become reasonably straight when held under tension by the six angle brackets.) With all 12 thumbscrews tightened, the chassis should exhibit remarkable rigidity, and in particular, resistance to parallelogram-mode flexing.

What high squareness can provide is the need for less adjustment when you resize the machine for different sized objects. But, once it's set up correctly for (say) chicken eggs or ping-pong balls, the squareness won't affect print quality.


Windell H. Oskay
drwho(at)evilmadscientist.com
http://www.evilmadscientist.com/

Forum Evil Scientist
Evil Scientist

Status: offline

Registered: 06/15/06
Posts: 1932
Sunnyvale, CA

Profile Email Website  
   



 All times are PDT. The time is now 12:27 AM.
Normal Topic Normal Topic
Locked Topic Locked Topic
Sticky Topic Sticky Topic
New Post New Post
Sticky Topic W/ New Post Sticky Topic W/ New Post
Locked Topic W/ New Post Locked Topic W/ New Post
View Anonymous Posts 
Able to Post 
Filtered HTML Allowed 
Censored Content 

Evil Mad Scientist Forum Archives — Read only!

Please visit our new forums for new discussions.


DIY Hardware for Electronic Art


The Original Egg-Bot Kit


Octolively
Interactive LED kits


Meggy Jr RGB
LED matrix game
development kit.


Business-card sized
AVR target boards


Peggy 2
LED Pegboard kits

My Account






Lost your password?