#robotics Logs

Sep 02 2014

00:00 rue_shop3 I AM having a problem degassing the aluminum tho
00:00 armyofevilrobots Are you fluxing it?
00:00 rue_shop3 fluffywolf, after what rifraf was saying I have some ideas
00:00 mrdata is the mold pre-heated
00:01 fluffywolf ... duh.
00:01 fluffywolf grr, wrong window
00:01 rue_shop3 armyofevilrobots, flux and degass (borax and sodium free salt)
00:01 rue_shop3 I have not been preheating it
00:01 fluffywolf bbl, wolfy bedtime
00:01 rue_shop3 armyofevilrobots, I been adding brass too, which I understand is supposed to help,
00:02 mrdata if you preheat the mold, the aluminum will not have to do that work, and there will be longer for gases to bubble out
00:02 rue_shop3 and the problem is getting better, but its still got lots of little bubbles in it
00:02 rue_shop3 mrdata, OOoooo... hmm
00:02 rue_shop3 how do I preheat it without the sand falling apart?
00:02 mrdata idk
00:03 rue_shop3 it DOES seem to harden up around the poured in alum...
00:03 mrdata what binder do you have in your sand?
00:03 rue_shop3 bentonite clay
00:03 armyofevilrobots I heard that the salt was good for taking out the hydrogen. Never tried it.
00:03 rue_shop3 I been trying different amounts of it
00:03 rue_shop3 I think its helping a bit
00:03 mrdata does bentonite expand a lot when heated?
00:03 rue_shop3 not that I'v noticed
00:03 mrdata bentonite can suck up a lot of water, maybe it has moisture
00:04 rue_shop3 it does, thats the idea
00:04 mrdata ?
00:04 rue_shop3 my second pour was too wet, and I could tell
00:04 rue_shop3 even greensand relies on water
00:04 mrdata if water touches molten aluminum,
00:04 rue_shop3 not lots of water
00:04 mrdata it explodes?
00:04 rue_shop3 a little moisture
00:05 orlock When i did casting, we put the mould in the oven on high for several hours beforehand
00:05 mrdata the aluminum steals the oxygen away, releasing hydrogen
00:05 rue_shop3 just enough that the sand sticks togethor
00:05 rue_shop3 orlock, I dont have hours of patience
00:06 anonnumberanon i had a new idea for my senior design project, a robot that clears a path of it's non-heavy stones
00:06 rue_shop3 mrdata, by that logic, oil wouldn't be any better
00:06 rue_shop3 ;)
00:06 rue_shop3 tell ya what
00:06 mrdata oil is a hydrocarbon
00:06 mrdata no oxygen there
00:06 rue_shop3 anonnumberanon, make a search and rescue robot
00:07 rue_shop3 anonnumberanon, make a robot that goes out into a grassy field, finds all the ~1" yellow circles, picks them up, and brings them to home base
00:07 armyofevilrobots rue_shop3: Told Helen you had a foundry up, she is interested as well (art projects).
00:07 mrdata a good binder should not expand when heated, should not react with the molten metal, but should not crumble when heat-stressed
00:07 rue_shop3 mrdata, the aluminum absorbs hydrogen, not oxygen
00:08 rue_shop3 armyofevilrobots, if you (two) want to come over sometime I can give you a rundown so you know what were wroking with
00:08 anonnumberanon it will have feedback control for its claw to detect if the stone is too heavy
00:09 rue_shop3 mrdata, the water + bentonite hardens up around the molten aluminum
00:09 anonnumberanon if it's too heavy it will clear the other stones around it to keep trying to make a path
00:09 rue_shop3 anonnumberanon, the rescue robot is a viable commercial project
00:09 mrdata well, you will get a bit of hydrogen and slag as the aluminum reacts with the water
00:09 rue_shop3 lots of people have little yellow circles spring up in their yard in the spring that they want collected up
00:10 anonnumberanon you're asking me to make a bionic firefighter, completely out of touch with waht is possible...
00:10 rue_shop3 na
00:10 rue_shop3 its a green yard, its a 1" yellow circle
00:10 rue_shop3 just pick up the yellow circle and bring it back to base
00:11 rue_shop3 http://upload.wikimedia.org/wikipedia/commons/8/85/Top_view_of_a_dandelion.JPG
00:11 rue_shop3 JUST BRING THEM ALL BACK TO BASE
00:11 orlock and i think we may have even put it into a hot kiln afterwards
00:11 rue_shop3 every day
00:11 anonnumberanon dandelion.,.. https://gs1.wac.edgecastcdn.net/8019B6/data.tumblr.com/tumblr_lri4lplCmt1qg5q0x.png
00:11 rue_shop3 anonnumberanon, easy opencv
00:12 orlock hmm
00:12 rue_shop3 easier to pick up than rocks
00:12 rue_shop3 and millions of people will buy them
00:12 orlock i ended up in court because of that ring i cast
00:12 orlock also, i was using casting plaster
00:12 rue_shop3 thats the one with the long spike on it?
00:13 rue_shop3 armyofevilrobots, I'm gonna build a larger cope/drag, not there yet
00:13 anonnumberanon rue_house, millions will buy a dandelion-picking robot?
00:13 rue_shop3 yes
00:13 mrdata i am told the mold will not crumble if you preheat it slowly
00:14 orlock http://i0.wp.com/www.retroist.com/wp-content/uploads/2014/05/claw-rings.jpg?resize=616%2C381
00:14 mrdata but i havent done it myself
00:14 orlock kind of like that
00:14 orlock i made one cast and one out of sheet
00:14 rue_shop3 I have to go to bed!
00:14 rue_shop3 armyofevilrobots, I look forward to ideas!
00:18 mrdata if you dont preheat the mold, the heat-shock can cause crumbling afaik
00:18 mrdata when you cast
00:19 rue_more not a problem so far
00:19 rue_more all the crubmling has been because of soft spots I touched up by hand
00:19 armyofevilrobots I also bed.
00:19 rue_more goodnight();
00:20 rue_more http://www.intermodalics.eu/sites/www.intermodalics.eu/files/images/ur10-white-bg.intext400.jpg
00:20 rue_more I really have to work one out liek that sometime
00:20 rue_more I hope I have lots of packages from china tommorow
00:32 mrdata soft spots touched up by hand could be about moisture remaining
00:32 mrdata maybe try a test, condition the mold before you use it, by slowly heating to bisque temperatures
00:33 mrdata http://www.ceramicartdaily.net/PMI/KilnFiringChart.pdf
00:34 rue_more I cant, I dont ahve anything to do that in
00:35 mrdata even 500C might be high enough
00:36 rue_more I dont ahve anything
00:36 rue_more and I'v seen this done without baking the mold
00:37 mrdata how are you melting your aluminum?
00:38 rue_house smelter, diesel fired
00:38 rue_house nothing a wood cope and drag can withstand
00:38 mrdata i got 600C on my kitchen stove
00:39 rue_house not into putting that stuff into the stove
00:39 rue_house and gingery didn't have to
00:40 mrdata sure; well, a small portable electric burner isnt expensive. i used a 6" dia steel coffee tin, set inside a 7" dia paint can, set inside a 8" dia mesh with aluminum foil outside it
00:41 rue_house mine has a ~6L pot
00:41 mrdata mhm
00:41 rue_house ...
00:42 rue_house two mins..
00:43 rue_house http://ruemohr.org/~ircjunk/projects/smelter/p1040233.jpg
00:44 orlock nice
00:44 orlock that a little air blower?
00:44 rue_house wow, that lining is 5 years old!?
00:44 rue_house nowonder its comming apart
00:45 rue_house that is the burner from a diesel (oil) furnace
00:45 rue_house http://ruemohr.org/~ircjunk/projects/smelter/p1040232.jpg
00:46 rue_house http://ruemohr.org/~ircjunk/projects/smelter/p1020016.jpg <-- early lost foam, with plaster mold
00:46 rue_house http://ruemohr.org/~ircjunk/projects/smelter/p1020010.jpg
00:47 rue_house almost impossable to dry properly, and the plaster reacts with the aluminum
00:47 rue_house http://ruemohr.org/~ircjunk/projects/smelter/p1020001.jpg
00:47 rue_house that insulation has become much, much thinner since I origionally did it
00:48 rue_house the outside used to stay cold to the touch, now its a little hotter than you can keep your hand on
00:49 rue_house 2010, huh
20:47 rue_shop3 http://www.ebay.com/itm/Kuka-KR200-Robot-W-KRC1-Controller-Pendent-Complete-ABB-Fanuc-Motoman-Nachi-/121265466480?pt=LH_DefaultDomain_0&hash=item1c3bfc2c70
20:47 rue_shop3 !! someone laid off lots of robots!
21:30 Tom_itx sure that's not a pic of your shop?
21:30 rue_shop3 not yet
21:38 Tom_itx i bet those things would run up your electric bill
22:23 fluffywolf rue_house: feel free to send me a couple of those
22:51 fluffywolf I don't know what I'd do with them, or where I'd put them, but that doesn't mean I can't want them!
22:51 uffywolf waits for GargantuaSauce to suggest different end effec
22:54 rue_shop3 I have 3 small working arms
22:54 rue_shop3 *so far*
22:54 rue_shop3 next I'm working on a control arm, just pots, no motors
22:54 rue_shop3 pendant arm?
22:55 fluffywolf there's a name for those... you also use them for tracing 3d objects. I don't remember what that name is, however.
22:55 rue_shop3 you cant google waldo, so its a word I dontuse for it, esp around you :)
22:56 fluffywolf ?
22:56 rue_shop3 hmm time for some food!
22:57 rue_shop3 armyofevilrobots, would you be into comming over on thurs and checking out the casting stuff?
22:58 rue_shop3 hmm this joint I made came out pretty goood...
22:58 rue_shop3 I'll have to think of a use for it sometime
23:00 fluffywolf I wish I could remember the nick of the other guy doing robot arms, and what channel he was in... I'm thinking it must have been somewhere on dalnet now.
23:00 rue_shop3 hmm
23:02 rue_shop3 I need to port my IR remote reciever code to a mega32
23:02 fluffywolf plappy, perhaps? I hate having a worthless memory.
23:07 rue_more I been thinking of making up a protocol for serial comms, sort of like usb
23:07 rue_more usb over serial?
23:07 rue_more something that will identify what a device is and how to talk to it
23:07 Tom_itx BISS
23:07 fluffywolf kinda like, say, rs485?
23:08 rue_more so I can plug in an array of serial robots and know which is which and how they work
23:08 rue_more no 1:1 serial to robot
23:09 rue_more but when I have ttyusb0 ttyusb1 ttyusb2 ttyusb3 ttyusb4 I can know which is arm4, arm7, arm8, conveyor, etc
23:09 Tom_itx http://www.biss-interface.com/
23:13 rue_more oh I thought it was an acronym for soemthing else
23:14 anonnumberanon Should I take VLSI design as one of my electives for electrical and computer engineering?
23:15 rue_more yea, aim for fpgas
23:20 anonnumberanon ah okay you are saying knowing how to play with fpgas is useful?
23:22 rue_more yea
23:23 rue_more then you can make me a glitch free 32 channel, serial access, hobby servo controller
23:23 anonnumberanon kk
23:24 anonnumberanon so thousands of hours of research for me so that you can use a $40 part?
23:24 anonnumberanon ;)
23:24 rue_more $40!?!
23:24 anonnumberanon how much?
23:24 rue_more I'm sure you can design it around an fpga I already have
23:24 rue_more :)
23:24 rue_more something like...
23:24 anonnumberanon send it in we'll see what we can do
23:26 rue_more the xilinix xcv300
23:26 rue_more that shoudl be able to do serial and a few pwm channels
23:29 anonnumberanon gosh the datasheet for it is monstruoushttp://www.xilinx.com/support/documentation/data_sheets/ds003.pdf
23:29 anonnumberanon closing
23:29 anonnumberanon im also FatPanda
23:30 rue_more yea, prolly, all fgpa seem to have evil datasheets
23:31 rue_more I'd have programmed one by now if tom could help me cough up a programmer
23:32 rue_more Tom_itx, hey wait, you ditching your fpga stuff?
23:35 rue_more oh! new pic!
23:35 rue_more http://ruemohr.org/~ircjunk/projects/smelter/p1060669.jpg
23:35 rue_more I cast a lump of aluminum!
23:35 rue_more (the little bar is a vent)
23:35 fluffywolf now you need to dye it green, and hold it.
23:36 rue_more ...?
23:36 rue_more green isn't cool, if your gonna anodize soemthing go blue...
23:36 fluffywolf I see you haven't watched blackadder. let me google it for you.
23:36 rue_more as you can see, the casting sand hardens up around the peice
23:37 rue_more (you can see the split stick I used as a mold at the back left)
23:37 fluffywolf https://www.youtube.com/watch?v=TkZFuKHXa7w should be it, maybe. (it'll take a very long time to download here)
23:37 rue_more stupid ads!
23:40 rue_more heh
23:40 rue_more anyhow, as you can see, its prettymuch just liek the stick is was cast of
23:41 fluffywolf looks like it needs much machining now.
23:41 FatPanda do you make bullits as well rue?
23:42 rue_more FatPanda, muffins
23:42 FatPanda no lead?
23:42 rue_more not that I'm aware of
23:42 rue_more lead or lead?
23:43 FatPanda bullet lead
23:43 rue_more I'm not good at working out the paths in and out yet
23:43 rue_more no lead no
23:43 FatPanda so you arent a shootist? how sad
23:43 FatPanda ;)
23:44 orlock FatPanda: even the shooters i know that do hand loading dont case bullets
23:44 rue_more whats wrong with aluminum projectiles?
23:44 orlock not heavy enough
23:44 rue_more I dount know hwo they manage to pour the lead onto the gunpowder without it going off ;)
23:44 orlock uhh, cast, not case
23:46 FatPanda hahahaha
23:46 FatPanda the lead bullet is pressed into the cartridge once it had a chance to cool off
23:47 FatPanda i meant pressed into the case/casing
23:47 fluffywolf FatPanda: he knows this
23:48 FatPanda ah okay
23:49 uffywolf labels FatPanda as "unfamiliar with hum
23:49 rue_more :)
23:53 FatPanda and I though i was getting ready to discuss powder weights for Magnum loads, etc. oh well I haven't touched the stuff for a few years anyway.
23:58 fluffywolf I'd be much more interested in die casting than sand casting...
23:58 rue_more yea, you guys have me interested in that too
23:59 rue_more I was thinking of a log die mould
23:59 rue_more I got 1000 resistors for $5, I'm happy
23:59 FatPanda i have a log mould
23:59 rue_more 7.5k, a value I was apparently out of
23:59 fluffywolf log?
23:59 rue_more yea, sylinder
23:59 rue_more cylinder
23:59 tPanda is tr