Let's Make Robots!

Valkyrie No.4 - Closer to useful ;)

Engraving PCB's for now
p1110900.jpg3.15 MB

Hi again!

She is back up, almost useful now.

Now with video ... =>










And the result of the video:













(yes the dark stripes are palm/finger prints on the cooper)

Update 10 - Nov - 2010: Gears?! Yes sir!

Quick gear test, probably can be further optimized ...















I like polystyrene, Valkyrie loves it!



Update 13 - Dec - 2010:  Isn't that nice? But it is WROOONG!!

Well I fixed the table, fixed a driver going smoky. Still no PCB milling going on :(
The problem is still structural, while the Z-Y assembly looks almost arty, the material is simply too flexible resulting in Z axis play again .... so no cutting tough stuff.
So I guess another upgrade is needed to replace the Z-Y assembly, i.e the whole arty top part .... yes ... 


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Looking good, dude, looking good. See how all the wires are neat, looking good :)

Hi TinHead,

in your orientation, Z is up and down - cutting depth, correct?

can you visually see the problem of it flexing, or is it only visible in the result of running a job?    your not getting good enough control over the depth of cut?    how about a closeup pic or 2 of the part that holds and controls Z.

what kind of cutting tool are you using?  presumably something that comes to a point, and perhaps an up-spiral.    I have a client that manufactures a wide variety of CNC cutting tools, and it is very important to match the cutting tool to the application.   otherwise, without the right cutting tool, even the best machine will not do a good job.

tell me what kinds of materials you want to cut, and tolerances you expect, and I'll research the proper tools.

Yup Z is up-down, Y left-right, X forwards-backwards.

It flexes visually, and it is also visible on the job. I cannot accurately control the cutting depth because of that, I got play in all directions at the cutting tool level.

I was actually expecting that, it's the nature of the laminate I used to build the assembly- pretty strong but flexible. I hoped it would not mater that much for what I wanted to achieve - turns out it is much worse.

The end mill is indeed an issue for me, I cannot find any real small (read =< 0.5 mm in diameter) end mill so I'm experimenting with bits I have sharpened in different ways. Some do work some not but until I get the play out of the axis I can't really blame the tool.

I'm looking to be able to engrave PCB's at SMD size, and cutting various materials such as wood, plastic maybe aluminium ... with under millimetric precision.

The resolution OK now, I just need to fix the accuracy part. 

Bottom line is that until I finally get the mechanics fixed, a thing I kept running away from, I cannot rely on getting any usable output. So I will not invest in cutting tools because I would break them anyway as it is now, but if you can get a good deal let me know.  

flexing in all directions at the cutting tool?    thats called deflection.  

how about adding some 1/8" thick, long, right-angle steel (or aluminum) to the edges of all the critical longer pieces to keep it from flexing.  similar to the roller rails mounted to the table.

.5mm end mills.   I'll see if they have any of those.  I know they have some endmills that are so small, its hard to see and are sometime actually lost on the table or ground when dropped.  all the tools are solid carbide, or high speed steel.  that SC stuff is expensive.

the materials you want to cut, I would not consider hard to mill.

if you slow down the feed rate, is the problem reduced?

can you see the flexing even when your not cutting anything - just running the tool in mid-air?

are you able to wiggle the rotary chuck with your hand?   (too much play in the worm gears?)


.. 1.5 to 2 mm by gripping the end mill ... that's what I call flexing.

There is no problem with the tool itself it's a Proxxon IB/E no play there, the play comes from the mount. 

I will simply redo the thing "The Right Way" ™ this time ....

Congratulation TinHead !  I'm so happy for you and your new born. He looks like a sharp little guy, perfect in every aspect, and soooo cute.  Was he a little rough at first or was he perfect coming out?  How long was Valkyrie in labor?

Richard came out pretty much as it looks, I only had to clean shrapnel off of it. 

The labor lasted a few minutes or so, I was too excited to really notice :) 

Wow dude!

How do you cut it so nice in plexy? I mean what speeds do you use? How many depth steps?

Your machine is getting closer to be able to make aluminum brackets... I bet that with slow advance speeds and small depth increments you can do it. I will try for sure when I'll have some time.


... plexy is expensive. 

The material is a kind of transparent polystyrene sold around here under the name of HobbyGlass (Hornbach has it), not sure how it compares to plexy it feels much more elastic. 

I used 0.5 mm steps to cut the gear with a feed rate of 150 mm/min, the endmill is a two flute fishtail 1 mm.  

Aluminium is probably something to try but for now this material is my favorite :D

congratulations, your first robot part!