That would be pretty magical, wouldn't it? :-)
I still can't find sources for local peak surface irradiances. All anyone cares about is total daily exposure, for green-stuff. Kills the SNR.
Cheers, James Arthur
Piling on, a chunk of meltable-wax in the box could smooth out temperatures quite a lot, too.
A heat-pipe to the dirt, and you've got a ground-sourced heat pump.
Another aspect would be to minimize surface area in sunlight, and maximize surface-to-volume ratio for max dissipation.
Another tactic might be to heat-pipe (or "copper") heat directly from heat-generating components to radiators on the enclosure's surface.
Cheers, James Arthur
Obliquity gets you a factor of cos(phi) (phi == zenith angle), and for reasonable zenith angles the atmospheric absorption goes as csc(phi), though this is a bit pessimistic when the sun is lower in the sky.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Here ya go, mounted in the drill press stand:
The chuck is "aftermarket", built by my grandpa about 70 years ago because the normal bits are cone-shaped and have a locking-blade at the end so they will never slip (in Germany called "Morsekegel"). This is why the machine has throw-out slits behind the front bearing. Woe to those who hold this machine and seize up one of those back-locked bits. That could mean a hospital trip.
On the other side there's grease reservoirs where, once in a while, you have to turn the caps and that squeezes some more grease into the bearings. When bottomed out one has to take these off and add a dollop of grease.
The home-made chuck allows the use of regular drill bits. Otherwise it takes this kind of bits:
-- Regards, Joerg http://www.analogconsultants.com/
Do you mind that being used on a wiki drill page?
NT
No problem. It is from Germany and could be an old Fein but there are no logos on it. Not even a label with power ratings or anything. Marketing wasn't a big thing in them days and electrical safety, well, I immediately replaced the 2-wire cloth cord with a medical grade safety cable.
Some day I'll have to find a good home for it, like I did with the old tube radios that went to a museum. We don't live forever but those machines have outlived a few generations by now.
-- Regards, Joerg http://www.analogconsultants.com/
Yes, those are taper shank drills, not to be confused with taper drills, the latter being just long drills. They are still widely used, although the taper is called mt1 and mt2 here, rather than mk1 and mk2. Guhring is my favorite brand of drill. I run a cnc lathe with a 5 hp servo motor on it. There are many drill holding systems out there. Your drill press will be working 500 years from now, if there is still a world then.
call this thing "durable."
ing it 10 years.
How are you defining the lifetime? If you don't have a mathematical definit ion, you don't have anything. And however you define it, it can't exceed th e MTBF of any single component. You need a 900,000 part to get 10 years 90% of the time, just for that component.
whole bunch of samples. Gorgeous stuff, a cut above the average domestic makers.
It will probably be illegal in less than 50 years the way we are going.
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Let's take an other approach (excluding any space vehicles).
If you are contractually required to deliver a service for 10 years (common in industrial applications), there are several options:
Of course all this will effect at what price you are going to be able to sell your product profitably.
For product life time costs, you really have to consider many more issues than the MTBF.
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The HSCO - cobalt drills from Guhring, GT100 are probably the best. In stainless, you can get up to 5000 parts before resharpening. j
Great, thank you. I like kit like that.
NT
That's what standards are for :-)
When they say that it's 10% then it is 10%. And that is not failed as in
*kablouie* but it means below the stated capacitance drop and/or above the stated ESR increase.
Nope.
-- Regards, Joerg http://www.analogconsultants.com/
Did he have some war stories, like people seizing up taper shank drill bits and stuff becoming airborne?
It probably already is. If I used it in a machine shop with employees the OSHA inspector would probably frown. Although, if trained well and operating it right there's nothing wrong.
-- Regards, Joerg http://www.analogconsultants.com/
I only design and never produce any actual hardware. There were opportunities but California is too business-hostile for that.
Yep, got to factor the warranty overhead into the financials. In the end the customers are paying for that one way or another.
Sure. I always do and I design rather conservatively when it comes to thermally stressing components.
-- Regards, Joerg http://www.analogconsultants.com/
War stories is an apt metaphor. Most of the guys that have actually seen this stuff don't really want to replay it in their heads or for others. It's usually human error these days. When people come up against metalworking machinery, the machine doesn't even slow down. Stuff shouldn't go flying if it's properly secured- but you could stall the drill or twist off the bit.
"Whip" is a good one. You are (say) parting off tubing or rod in a lathe so you run a long piece through the spindle hole and part the short bits off with the cross slide. Naturally you want high RPM for a good finish, especially if the part is small diameter. The longer pieces you use, the less often you have to reload it. There's a length beyond which the bit coming out of the spindle hole (to your left facing the lathe) will go unstable and start whipping around, potentially destroying stuff (including you if you get in way).
Here's a fatal accident report (no gore) involving a drill and extension:
Imagine some people (good citizens) are killed by a home-made weapon of some restricted type. The equation is that makers of such devices have to be registered. Lathes (say) can be used to make such weapons. Therefore all lathes must be registered (imagine the darkly lit videos of enormous indusrial equipment). The average person these days could not even identify a lathe (not even a dim memory of shop, since there isn't such a thing anymore in many places), so what would they care? Only those weirdos with dangerous stuff in their garages.. and they (we) don't have many votes.
Best regards, Spehro Pefhany
-- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Two things haven't been addressed yet: the actual time-at-temperature for hot operation isn't 'continuous...every day', but is episodic. You can get the weather reports from any airport weather station, I'd suspect the temperature of a thermometer in a shaded box is going to hit 70C very few hours a year. Check out Phoenix, AZ in June... The monthly maximum doesn't hit 45C. Non-extreme temperature ratings are good enough, if you emulate those weatherstation units (white slotted sunscreen around the case).
Second, a single component MAY fail, but if a capacitor can fail open, just plan on paralleling four units, and meet the filtering requirement when any two are fully functional. In case of failing short, consider a few fuses (or fusible resistors). You can tolerate failure with some planning. NASA does some interesting things in this regard.
You keep evading answering what you mean by "lifetime" which means you're just blowing smoke.
The manufacturers clearly spell out what they mean by lifetime and there are also standards for it. It is _not_ MTBF, has nothing to do with it.
First page, under "Endurance". Unless you now think that Nichicon is blowing smoke :-)
-- Regards, Joerg http://www.analogconsultants.com/
Slotted stuff would clog up over time. Most technical gear will simply sit in a rectangular box. Phoenix isn't so bad. It's when you get into Sahara-style climates where temps can hover around 55C for hours, day after day.
They would usually dry out. Capacitance goes down, ESR goes up, things like that. Of course one must design prudently and provide plenty of reserves.
-- Regards, Joerg http://www.analogconsultants.com/
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