I want to make a very small (open profile, about 80 mm2) aluminium profile by extrusion, but need some calculations.\n\nThanks for help!
128649
I think you need to use a special cnc machine\n any way herein below some under considration useful sites\n\n•http://www.8bestsites.com/aluminum-extrusion/6/\n\n•http://www.maytecinc.com/\n\n•http://www.extrusions.com/005issue/htmls/ExtrusionAdvantages.htm\n\n•http://unisource-tech.com/Products_-_Unisource_Technolog/Aluminum_Extrusion_front_panel/aluminum_extrusion_front_panel.html\n\n•http://www.aeroext.com/\n\n•http://www.pennaluminum.com/extproc.asp\n\n•http://www.sati.com.tw/
215514
There is a HUGE amount of infomation on metallurgy out there, but if you want an interesting search, try searching out why the HUBBLE Space Telescope failed - there was some deformed metal and the reason the optics tests passed before launch is an interesting story about materials, optics and people.\n\nI'm a metallurgist, and of all the exotic materials it turns out steel has the greatest range of properties (from annealed iron all the way up to ball bearing steel and stainless).  Titanium is interesting stuff (good for corrosion and medium temps (500°F-1000°F), but aluminum can have the highest density-to-strength ratio.  Research on how tungsten filaments are made is interesting too.  \n\nMark Twain said that a metallurgy student would learn more making his own pocket knife by digging the ore out of the ground, refining it into steel, and fabricating the knife than he would by book learning - do you have a passion you're particularly interesting in?  Learning about something you're interested in is effortless.\n\nAnother optics subject of interest is what is currently going on in semiconductor photolithography - they are reaching the limits of what can be done with light and refractive materials (CaF lenses) and immersion lithography (see link below).
406178
Try the Sheetmetal Contractors Association  its somthing like SMACA .\n\nFabrication is not the hard part.   Laying out the various fittings may be more than you want to do.\n\nThere are software packages available that will do the layout work for you but all I've seen are pretty expensive.
117013
that's a real vague question, try to be more specific or at least say what king of structure do u want? (steel, conc, ..?)\nanyways this is an exremely simple example.\n\nlets' say u want to design a tension member -carrying tension force = 100 tons, -between 2 supports and this member is a steel member of yield stress= 1.4\nso to get the area u need :\n100/1.4= 71.43 cm square let's say again u want it to be I-shaped steel then u'll need  I number 400 i.e IPE 400
673
I haven't tried it, but check out MatPy (linked below).  Another possibility is Numerical Python (also linked below).
567176
I have no idea how legitimate this source is but it does deal with molding plastic. Good Luck!\nhttp://www.epsilonindustries.com/
15961
you can find a very good tutorial at the link.\n\nNo need to write whats already writtenm =)
619708
you could porb try an internet site like howstufworks.com
619311
You'll have to give us a better idea of what you're trying to do.  An angular error of 1 second of arc corresponds to a deflection of 5 microns over a length of one metre.  It's difficult just making things smooth to 5 microns in a workshop, so any angle you measure will probably have an error in excess of 1 second anyway.\n\nI doubt any solution we can provide would fall under most definitions of "cheap".
525167
this looks like the closest thing that I could find that looks like how my old technical manual shows on drawing threads:\n\nhttp://honolulu.hawaii.edu/distance/aec80/threads/20c-ctl.htm\n\nI'll look for more tommorrow\n\naddon\nif you want a 3d thread look around here:\nhttp://discussion.autodesk.com/search.jspa?numResults=25&source=forumlist%7C39&q=3d+thread+spring&inputEntered=true&objID=c39\n\n3d springs are easy to do in 2007 there is a helix command that lets you make a 3d helix that you can use for the path of an extrusion
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Make a 3d model and print it out using anim8or @ anim8or.com\n\nIf that is not in option, try using a styrafoam block and carve it.
610834
Umm, you aren't really going to be dipping your micropipetts into acids and bases, are you?  \n\nWhat you want to worry about are how well they fit the tips you like, or how much the tips required will cost, how ergonomic they are, and if they cover the range of volumes you want (for instance, it's really hard right now to find a multi-channel that will do < 1 uL).
350412
Surefire's are amazing.  The entry level is worth every penny ($33) the others I am not so sure about.  I have seen SF mounts with light for $250 and I know I could fabricate something for much less.    Do you have a rail that you can mount to?  If not, you need to solve that first.  The second problem should be elementary, finding or fabricating a mount with an appropriately sized opening for the light should be pretty easy.
402771
yes it can be done. The 203 x 133 are I hope in millimetres.This would be 8 inch x 5 1/4 inch if you measure the beam it should be somewhere close.The weight of 30kg would depend upon the thickness of the metal in the different parts of the beam.A steel stockist could give you the thickness of the different weights per metre so you could compare the millimetre thickness given to the inch measure. To convert millimetre to inch  divide the number of millimetres by 25.4 if you know any engineers they should be able to assist.Not being at work I do not have the information to hand.If your local library has "KEMPS"  year book in its reference section that could help.Kellys directory would give you steel stockists, if you cannot find one locally.The info is probably on the internet somewhere.Can investigate further for you if you cannot resolve.
582724
The radiation length for Al is 24 cm, for Pb 0.56 cm. To reduce the beam to 10% we need 2.3 radiation lengths, 55 cm of Al or 1.3 cm of Pb. \n\nNo idea how your  attenuation coefficients relate to my radiation lengths. A radiation length is the length of material needed to attenuate the beam by 1/e, that is to 0.368 of the original intensity.\n\nGood luck!
127889
Why not take a page from Archimedes' Eureka! moment?\n\nMeasure the density, then ask a jeweler.
213359
a good radar reflective surface has to be hard and flat, just like a ball bouncing back off a wall, you want the radar reflection to bounce back to the receiver with most of the strength that was sent out so you can get a good 'reflection'\nthe balloon is round so not a good reflective target, the aluminium is a metal so a good reflective material, it all depends on the line of sight as well. If the balloon was right in the middle of the radar beam width it might give of a weak sig? depends on the size of the balloon as well. A huge blimp of that material would give a better reflection than a normal size balloon. Hope this was a help.