All posts by nouyang

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abusing CNC mills for internet memes

It’s official. CNC mills are sexy. Even decades-old bridgeport model ones that take giant floppies.

So a while back I was all like “I’mma mill me some nyancat for my 2.008 paperweight.” (http://www.orangenarwhals.com/?p=187)
Oh yea, my partner for this lab is the awesome Cappie Pomeroy. He did all the lathe work o.o so don’t ask me about that.
So I got around to milling it.
look, nyancat got fatter so that you can fit a 1/16” end mill between it’s crevices!

(The way I did it is I did a Tools>Sketch Tools>Sketch Picture, then resized that reference nyancat picture until it looked appropriate. I then put a Tools>Options>Grid>Major Grid 0.07 / minor grid off. System Snaps>check Grid. Also, make sure Units>IPS, InchPoundSomething. Then just trace it with lines).

However, my resizing and retracing ended up not mattering, since I decided to engrave it. This was because we had to make a 15 minute version, and no matter how I tweaked Mastercam (using 0.02” depth instead of 0.1”, using a wide endmill to clear it and then remachining with the 1/16”), there was no way the full 3D paperweight was milling out in 15 minutes.

Yea so there are really dumb ways to make a path in Mastercam. 
See the X’d out paths to the left — I was tracing all the paths by hand, essentially. Then Pat, the shop instructor, came by and showed me the magic of the the “polygon” tool which will automatically apply a function (in this case, engraving) to everything within that polgyon. It created some weird paths, like you get on a lasercutter which doesn’t recognize your vector as one shape but as individual lines*, but it gets the job done. In other words, he finished in 10 minutes what was taking me hours to do… hah.
*aka it doesn’t trace them continuously but rather jumps back and forth between different lines in the drawing
See link below for g-code / mastercam / solidworks files.

The jig was made by the instructors for the class, along with the “offset” used in Mastercam to make sure the blank is positioned correctly.

gahhh technical difficulties. Yes, I used my phone to take a picture of picture on my camera.  You really don’t want to know.

Nyanweight documents:
https://docs.google.com/leaf?id=0B9r0HZeoMbmgZjgzMTkyOTEtOTU4OS00MDhjLWJlMmYtNTQzMjc2YmJlMzkx&hl=en_US
where “base/lab1” docs are for the CNC lathe and “engraving” docs are for the CNC mill.


Software used: solidworks (.sldprt, exported to .dwg), mastercam

Todo next: Mill out the actual thing.

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todo, DIY vending machine (countertop and oshw)

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Like this, but with arduinos. and caffeine. and breadboards. and 1/64” drill bits. and nyancat-etched poptarts. Oh, and open source. And constructable for less than $600.

(I get to the whole build-my-own vending machine thing further down the page. Got a bit ADD).

Well, in other news, my 2.008 group did not fall over themselves to build a PoV yoyo. This is okay. I will just make one or two PoV (persistence of vision) yoyo’s manually then. (you, dear reader, have just been saved from a pages-long rant as I sulked over the last few days :P)

In other news, in MAS.863, it’s waterjet and shopbot week! I’m super-excited.

<3 3-axis mill. Shopbot r awesome~

(look, someone made a giant scrabble set using the media lab shopbot:

http://mako.cc/copyrighteous/20110725-00

)
Mini projects this week:

[1] Shelving. make this (playatech’s plans — rec’d by fellow classmate novysan, who had fun with these at burning man. also rec’d “nomadic architecture” which sadly did not mean nomadic furniture like Walking Hexapod Racing Chair but rather furniture suited for nomadic humans)

http://www.playatech.com/index.php?deptName=03Bare%20Necessities&prodDesc=09Gear%20Gizmo

(aka shelving made from one sheet of $8 7/16” OSB plywood,

http://www.homedepot.com/h_d1/N-5yc1v/R-100091344/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053)

Artsy furniture (metal): http://dornob.com/open-source-free-flat-pack-plans-for-laser-cut-furniture/
Styrofoam furniture: http://dornob.com/laser-cut-styrofoam-seats-solid-3d-polystyrene-chair-design/

[2]  I have lots of marble leftover from our clock class, which some people took proper advantage of while I merely used lasercutter and acrylic:

classmate’s AWESOME marble koi fish clock

mmm, instant noodles. aww. I miss my old room.

Oh right, where was I?

Arduino vending machines. That’s right. Make a DIY “open-source hardware” vending machine. Not interested in the electronics of accepting money and such (although that’s what everybody leaps to help with that, despite me explicitly stating I’m more interested in the vending mechanism).

Research:
http://en.wikipedia.org/wiki/Vending_machine#Mechanism
www.discapa.com/eng/download/manualt/MTMacSpiralE — coin mechanism and spiral set? not sure what it vended
http://www.vending.com/vending_machines/combination_vending_machines/combo/manual/
So they’re called “augers.”

from: http://www.vending.com/vending_machines/combination_vending_machines/combo/manual/

Found! mcmaster-carr “Dry goods screw conveyors”

http://www.mcmaster.com/#auger-conveyors/=ecttus

 ?!?!?! $677 is the cheapest one?! holy shiznatz that is out of the question.

Smexy pdf images: http://www.screwconveyors.com/profile2006x.pdf
mmm online worksheet AND considerations pdf:  http://www.kwsmfg.com/products/Screw-Conveyors.htm, http://www.kwsmfg.com/pdf/KWS-0709PBE.pdf . So I want “shaftless screw conveyor”
Ewww, this just ‘cos it has a pic of a screw conveyor used in a slaughterhouse: http://drycake.com/equipment/screening/downloads/Screening_Catalogue.pdf
Making Things Talk mentions it briefly… I wonder where I get a “big screw” (via libproxy.mit.edu): http://proquest.safaribooksonline.com/book/hobbies/9780596510510/chapter-9dot-identification/301?reader=pf&readerfullscreen=&readerleftmenu=1

Interesting tidbits about vending machine locks: http://books.google.com/books?id=6tRcZtGADBcC&lpg=PA142&ots=KBqWOPS2Jk&dq=vending%20machine%20screw%20mechanism&pg=PA143#v=onepage&q=vending%20machine%20screw%20mechanism&f=false

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NyanCAD: Correct motivation for learning CAD

I’m embarrassed to say how many hours I’ve wasted CADing nyancat paperweight for 2.008 now.
Off to go spend even more time producing CNC mill G-code using Mastercam for a machining appointment at 8am o__o

10/1/11 Edit:
Aha, so I realized (thanks to Steve, shop instructor extraordinaire) that there are many things wrong with my CAD. Sadly, I chose 5 mils spacing for the grid I used to trace nyancat. Turns out our smallest drill bit is 1/16” ( over 6 mils). Eheh. Also, I was planning on going 0.3” deep, which would take forever to mill out using 1/16”, as it can only go ~0.02” down per z-axis pass.

yea, milling fail.
that, dear friends, is the look of a lot of milling time.

I was halfway through the infuriating MASTERCAM too. Lesson learned: avoid branching as much as possible. See that right-most sprinkle that touches the cat’s head? Caused me no end of trouble!

Next step? Infinite Mastercam’ing. Instead of being a nice cavity with extruded nyancat, it’ll probably end up being closer to pedestal with a nyancat on top done in thin layers. I’ll also use a larger diameter tool to pocket out each shape and then contour with the 1/16”. So, first up, redo solidworks using 0.7” grid spacing (resize reference picture accordingly — btw, found under insert > sketch tools > sketch picture).

I’ll stick the files up on github sometime soon.

=====
Todo this weekend:
Saturday: Get ISP and PoV working, 6.131 lab writeup, MITERS misc. (project grants / safety / update website), PoV with partner 10am, Theater scene practice 2pm. Apply to summer jobs.
Sunday: 6.131 lab (1pm to midnight), 2.008 group meeting 7pm, watch a play (3 pm), go visit Sprout? (2pm)
Monday morning: lasercut cookies, document cookies and ISP.
Oh yea, speaking of ISP programmers, this week’s assignment was to mill ISPs using these desktop Roland Modela 3d mills:
So someone made an even tinier one that doesn’t need a USB connector (fits right into the slot): http://bardagjy.com/?p=628
Then someone riffed off of that and made one that has a break-off part for bootloading the chip:
http://fab.cba.mit.edu/classes/MAS.863/people/valentin.heun/2.htm