Tag Archives: lasercutter

[notes] lasercutters and nyancat nails and such

Hrm, so apparently it is important to make money. Also, it’s important to be happy! πŸ™‚ Therefore I should investigate all the silly things on the internet.

Here are some notes to myself:
http://www.instructables.com/id/Thumbnail-portraits-Etch-an-epic-battle-between/?ALLSTEPS

image from the instructables

 Lasercutter interlocks~

But overall, it seems like a much better idea to not lasercut body parts directly πŸ˜›

Nyancat nails! Hattip to Jordan for sending me this via the facelols.

Fascinating, so it seems like there’s some paper which you deposit gunk on and then transfer it to your nails. Why does everything sound like 3d printing to me now?

Ah! It’s a stencil. Hrm. So the stencil can definitely be lasercut. The rubber stamp seems like it’d be easy to make as well.

Lasercut acrylic, bent into a bracelt:
http://www.instructables.com/id/Acrylic-bracelets/

image from instructables linked above

Hrm, can do a lot with that. I bet I could tuck a small working hexapod into such a bracelet… *plots*

screw-propelled vehicle prototype v1 — with soda cans

Yea so I did a CAD thing with a lot of procrastinating along the way.
Concluding thoughts: sleep. Also do more schoolwork / UA work and also apply to jobs. Good plan.
Oh, include more margin of error in general, in this case for the diameter of the can with cat5 cable included (you can see where I bandsawed the top platform just to see how it would do).

  • redo by making platform higher
  • oh and fix the snap fits
  • and make things a bit farther apart

Acrylic, it snaps.

the video is actually made still using this piece. actually maybe the extra degrees of freedom allow the vehicle to actually work.

Stockpile non-flathead style bolts (socket-headsss i want them), I hate using locknuts with non-flathead style ones

Some pictures

those count as bushings right
this is how you’re supposed to couple things to a soda can right
that’s what it looks like in solidworks

more pictures will be added to this album: https://picasaweb.google.com/113942194695013581888/ScrewPropelledVehicle

in which i rediscover the lasercutter: screw-propelled vehicles, making servo horns, and figurine+ruler keychains

i have been making a lot of things lately.
Never enough!
But yes, I rediscovered the lasercutter, and there happens to be one upstairs of MITERS now.*

* [I should really get a Real Laptop (that I can CAD on) and then I have no excuse to hang around upstairs when the MITERS computers are occupied. (or just set up another computer downstairs…) but in the meantime there are excellent computers are the third floor (which as a bonus are tucked away in corners. I have a special affinity for corners).]

My convoluted group loyalty issues aside, last week there was epic snowage, so much that MIT closed down. So then I decided to build a snowbot, or rather a screw-propelled vehicle.
http://en.wikipedia.org/wiki/Screw-propelled_vehicle

Turns out some excellent undergrad wrote a thesis on this topic, with pictures and build and equations!
http://www.wpi.edu/Pubs/E-project/Available/E-project-031411-150953/unrestricted/Ice_Inspection_Robot_MQP,_Final_Report.pdf

So he made his prototype out of PVC pipe. Specifically, giant!diameter!PVC pipe for the augur and 1/4” diameter pipe wound around the large pipe for the threads on the augur. His second revision was tube aluminum with specialty-ordered sheet steel threads (the two were held together with “Loctite E-20NS metal epoxy”. Wow. Heavy-duty epoxy).

Well! I wanted to complete snow-bot in a day so I decided to make it out of coke can + cat 5 cable hotglued onto it (with revision two to be 3d printed).

that is so totally a workable augur. right?

This err didn’t happen. I got distracted by other lasercut projects. But yea, the plan was to attach two continuous rotation servos to turn the coke cans and voila, I would have instant prototype.

note: for the sake of sleep this is going to be an overview post with more detailed / better formatted / all my files–posts to come, but in case I don’t get around to those:

My first step was to discover that I had SpringerRC continuous rotation servos, perfect for the job, but no servo horns. (First of all, note that servo horns are NOT all compatible). Oh noes! Well. Turns out, they are pretty easy to make, despite the total lack of help from this site which just says “lol they are easy to make”:

http://makeprojects.com/Wiki/Servos

A bit of googling and double-checking by counting by hand, I find out futaba-compatible horns have 25 “teeth.” And using calipers I determine the outer and estimate the inner diameter, for which I get roughly 0.02” which order-of-magnitude agrees with the super-accurate measurements made by this dude.

I also, via the internet (and later by trial-and-error) find 3mm acrylic-like plastic to have a kerf of about 0.005”.

So using coreldraw (or inkscape), there is a polygon/star tool, and I enter 25 pointed star. I then eye-ball the “sharpness” parameter, which you have a bit of slack on (the horn teeth just needs to fit between the servo teeth). I also initially set the x-y width to be 0.235”, the exact outer-diameter I measured. When cut out, this servo horn a bit loose but slides onto the servo and turns the servo when it is turned.

yes. my camera has a permanent dust speck somewhere inside it…

Then I iterate. You can see I drew a green and yellow rectangle, for 0.02” + 0.005” kerf, to get the “sharpness” (pointiness of the star) setting right (if you draw it out, to account for kerf, the OD of the star should be smaller by 1/2 kerf and possibly the star’s inner corners should go 1/2 kerf deeper, hence why 16 sharpness with the inner corner somewhere between the length of the green and yellow rectangles. I’m not 100% how sharpness is interconnected with the diameter of the star so it’s hard to say what the exact adjustment should be).

f* yea MS Paint

The laser settings I used for a 120W epilog laser:

Of course, I don’t finish over the weekend and Monday I walk into 2.007 lab (which I am undergrad assisting with, UAing, this term) and there are a gazillion springerRC servos and servo horns. But that’s beside the point.

I also realized that part of my search criteria for LIFE aka a career included “access to lasercutter,” but maybe I am supposed to look for a job that pays well so that I can buy my own lasercutter. Hrm.

Hrm…

Anyway, what else happened? Oh right, Jordan‘s birthday came up. Because she is awesome, I decided I should make her a birthday gift. Inspired by Kat Struckmann’s cruftmas (putz hall secret santa tradition where gift has to be entirely made of cruft, aka free stuff. Oh right, I made a sheet steel bookstand for my secret santa and learned the importance of product design, because the gal I gave it to was like “wtf is this, a shelf?” ^^; #toblogabout) gift to Sterling Harper, aka by the Archer TV show:

image courtesy of jordan.

Oh gosh. I had to use so many programs to make this, I don’t even. No. Anyway, the general idea is to use various selection tools (oh robutts don’t use the polygon tool by itself, it’s so easy to accidentally hit escape and erase all your work with the selection, make sure to use quick-mask model with shift-Q — everything this is orange is not in the selection and everything that is white is) in GIMP on the original image (see: her blog), export selection to path, save path as an SVG, import that into inkscape, use various path tools (difference, something like that) to merge the Person outline with the rectangle outline that I want to cut out to create a stencil-like effect, realize that coreldraw hates inkscape SVGs for whatever reason, save inkscape file as PDF and import and clean up import in coreldraw, still recreate a lot of the work in coreldraw because I am more familiar with sending coreldraw files to the lasercutter, find flowers on openclipart, and then spend a few hours playing around with the DPI / whatever settings because I want to get a raster image of the photograph etched onto the outline. This… doesn’t go so well. Somewhere along the way I decide to add a ruler to the thing, because really, useless keychains may as well have rulers on them. I discover the magical coreldraw “blend” tool, where I can just draw two lines at the beginning and end and then specify how many copies I want to use to blend between them (since the end and beginning lines are the same, all the intermediates are the same as well).

so many rejects. luckily this is all from small bits of scrap other people would probably just throw right out.

Then there were other lasercutter shenanigans, but that’s for another time. Briefly…

Oh gosh that is a topic in and of itself. Inkscape has a gear generator, but then I tried to x-y scale that, so the pitch becomes something strange, and then I import that dxf into solidworks to make a 3d model and also to measure the pitch and other things, and later export it as a dxf from solidworks to coreldraw … … apparently solidworks has a gear generator in its toolbox. I should use that next time.
Oh, food-wise:

Oh also this excellent post on designing sninges, aka how to make acrylic bend:

http://blog.makezine.com/2011/12/08/designing-sninges-in-laser-cut-acrylic/

Guys I should just go do lasercut etsy things. Forget scaling and engineering, and go be a craftsperson >__>;; and sell things at cons or something.
Oh and speaking of bending acrylic, 
Hrm this is rich with possibilities. I CAN EMBED SO MUCH ELECTRONICS IN HERE with this 3d possibility.
Heck I could like embed a mini hexapod in there probably. With a button. So I can hit the button and pop out a small hexapod army from brace/ankle-lets.

HRM. 
Hexapod armies.

*reminds self to talk about microcenter and finding hexy, the kickstarter project funded just seven months ago, on the shelves there….* #toblogabout

Okay, when my blog posts get to the topic of hexapod armies it’s a definite sign that I am procrastinating. Time to get back to CADing snowbot. (CADing a spontaneous robot? wtf? MIT, what have you done to me, that I would prefer to CAD and lasercut something instead of putting things together by hand until it works…)

==
additional resource: list of screws, in case you lose those screws for the horns:
http://www.rcgroups.com/forums/showthread.php?t=914983

I made a video about hexapods.

I made a video about hexapods! yay. I’d estimate it was a full 4 or 5 days working on it, learning final cut pro along the way. It basically covers my journey through 2.007 two years ago, and is meant to be a resource for students in the class.

Note to self: shortcuts: < > ctrl-= alt-w

Meanwhile, I think an instructable a week sounds like an excellent plan for Spring semester senior year.

Spring making, round one + glass etching on lasercutter

round bottle did better than I expected, I guesstimated size with ruler and tried to get it roughly straight with respect to the bed. no “lathe”-like turning tool, but I etched a fairly small area — approximately straight then, good enough for laser to focus on.

lasercutter: etching glass — went very quickly. I suspect the anodized aluminum setting may be overkill and can go much faster (perhaps they’re settings for straight up etching metal?).

What was this?
last minute crvftmas (everything you give must be “crufted” aka freely obtained, our hall’s version of secret santa) gift: laseretch lab glass bottles (clean autoclaved) I got off of reuse a while back

I meant it when I said 50 lbs of lab glassware. 4 boxes. I only took about half from the reuse post too…
pre-etch

Had issues due to irregular shape of bottle with placement and getting it straight :/ oh well (you can’t really tell from the photos)

I ended up doing putzputz, winning MASLAB robot, (this year’s hall tshirt design, MASLAB team composed of 4 putzen including dfourie), on the back

Also, thicker bottle could not use due to limit of how deep z wise the bed can move o.o

BTW lasercutter settings for 100kw epilog co2 with gas assist:

200 ppi, 40-60% power, 60 speed.

and more pics on picasaweb as always.
https://picasaweb.google.com/113942194695013581888/LasercutterFun#

Spring making round one — I am still going to investigate manufacturers. but diy:
http://www.instructables.com/id/Make-your-own-springs-in-seconds/
Someone legitimized it in a comment:

β€œMany years ago I used to make springs this way on a lathe. We used commercially available untempered spring wire and after we finished we heated up the spring to red hot and dropped it into fish oil to temper it.Some times we would make special custom springs by soft annealing standard off the shelf springs and straightening them to salvage the wire. Then we would rewind them to suit the job at hand and re-temper.”

my Emergency!Labduein60minutes!results:

comparison between real vending machine coil off of ebay and my hand-wound in 2 minutes one
I compensated for non-spring steel (unlike Real Coil) by getting thicker diameter (plain steel) wire.

Material acquisition trip to TAGS (right off of porter square T stop in cambridge, MA, next to shaws and radioshack)

hi, receipt for techfair grant. also if you click for larger pic you can see what I bought
everything I could find at MITERS and that I bought, includes some thin spring steel.
Also, ~2” OD pvc pipe I wanted to wrap my spring around
First, safety equipment check:

Well, find out pvc pipe does not fit inside chuck (compare to hole) and is just too small to be gripped by OD jaws.

Definitely too big for drill. I’d considered making an adaptor — smaller pipe that fits in drill with two keys slotted through it, or turned plastic that more closely fits pipe and then has a “handle” that the drill grips — similar to larger sized drill bits. but then weekend passed and emergency!lab dictated I do simpler thing.

Learned about “flipping” jaws, or in this lathe’s case swapping out OD jaws for ID gripping jaws. Thanks shane colton and matthew hon

step one, take jaws out by backing it out all the way with chuck key
they’re numbered 1-3 (or 4) and must be engaged by scroll (spiral thing that turns when you turn the chuck key) in that order to have an even grip

Well I can’t find the right sized ones,

they’re curved. top one’s threads are “inner diameter” gripping, but too small for  the chuck currently on the lathe

so I gave up and used the smaller diameter aluminum rod stock seen above.

starting it was difficult. There was a preexisting throughhole in the (hollow) rod that I stuck the end of the rod through
So, then I twisted it upward and pressed it to the rod with the glove. This was awkward to do. I immediately applied the square steel stock but you can see I had issues getting it pressed against the stock and creating a uniform spacing, since I only had one hand (spinning the lathe with the other). Surprisingly easy and fast.

yea, very uneven result, will need to do more trials (there went $5 of weldable steel rod, ⅛’’). went very quickly, even by hand.
you can see starting out I didn’t get it to follow the rod closely like in the vid, though I am using thicker diam rod

end result again

probably still need use light sensor detect when item vended, safer b/c of uneven nature of coils (can’t dead reckon with degrees of rotation)
==== todo: order light-up buttons, rfid reader, more servos (or hijack from hexadancingpod :/)

(tangentially, this is a ref for designing springs, linked off of makehttp://home.earthlink.net/~bazillion/intro.html)
look how they do it automagically / industrially: http://home.earthlink.net/~bazillion/Trusprings/index.html and sexy video: http://www.youtube.com/watch?v=Ix4-UUelDc4