How do you design these days?
in [Design]
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From: Baron on 5 Jan 2010 15:39 krw Inscribed thus: > On Mon, 04 Jan 2010 16:52:09 +0000, Baron > <baron.nospam(a)linuxmaniac.nospam.net> wrote: > >>Spehro Pefhany Inscribed thus: >>> >>> With the spindle Morse taper Loctited in so that the side forces >>> don't loosen it up! >>> >>> Best regards, >>> Spehro Pefhany >> >>I've never had a Morse taper fitting loosen due to side forces or had >>to use Locktite on one. > > You haven't put any side pressure on one, then. This is a very common > occurrence for woodworkers using their drill press as a drum sander; > not a good thing to do. Agreed ! Very definitely not. I would suspect debris in the taper could cause that, even an oil film might. Wood dust would be difficult to clean out completely. The Morse tapers have to be kept scrupulously clean. A draw bar would eliminate the problem at the risk of loosing concentricity due to any trapped debris. -- Best Regards: Baron.
From: JosephKK on 6 Jan 2010 01:15 On Wed, 30 Dec 2009 22:15:46 -0800, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Wed, 30 Dec 2009 20:02:02 -0800, D from BC ><myrealaddress(a)comic.com> wrote: > >>On Wed, 30 Dec 2009 20:01:39 -0600, "RogerN" <regor(a)midwest.net> >>wrote: >> >>> >>>When I was in school components fit on solderless breadboards and we made >>>circuits using breadboards, power supplies, meters and oscilloscopes. Many >>>of today's components don't appear to be breadboard friendly, so how is it >>>done today? >>> >>>Is circuit design software and simulation good enough to go straight to a PC >>>board? Or do you use surface mount to breadboard adapters? Do you still >>>use a soldering Iron to solder or paste solder and an oven? >>> >>>I'm wanting to tinker with some circuits but some chips I'm interested in >>>only comes in MSOP or other packages that look intimidating to attempt to >>>solder. >>> >>>Thanks! >>> >>>RogerN >>> >> >>My motto: >>If it works on a breadboard, it's not worth producing. >> >>On my current project, I have to feed the simulator pcb parasitics and >>component parasistics to get accurate simulations. >>I've had to bench test to get some parasitics. Once parasitics are >>included, scope results and simulation results get close. >> >>If all looks good on sim, I make a pcb, etch it and bench test it. > >One problem is that device models often aren't available for fast >parts, or all you get are S-params when you need large-signal >time-domain stuff. So sometimes you can learn a lot by hacking some >FR4 and testing parts. > >I never breadboard entire products, or even complex circuits... just >enough to characterize parts or simple subcircuits. > >This is an EL07 driving a PHEMT... > >ftp://jjlarkin.lmi.net/BB_fast.JPG > >which made decent 5-volt, 1 GHz square waves. > >John Is that 0.085 or 0.141 semirigid.
From: JosephKK on 6 Jan 2010 01:37 On Thu, 31 Dec 2009 14:01:44 -0000, "markp" <map.nospam(a)f2s.com> wrote: > >"RogerN" <regor(a)midwest.net> wrote in message >news:ROudnXLvg9-Tm6HWnZ2dnUVZ_oidnZ2d(a)earthlink.com... >> >> When I was in school components fit on solderless breadboards and we made >> circuits using breadboards, power supplies, meters and oscilloscopes. >> Many of today's components don't appear to be breadboard friendly, so how >> is it done today? >> >> Is circuit design software and simulation good enough to go straight to a >> PC board? Or do you use surface mount to breadboard adapters? Do you >> still use a soldering Iron to solder or paste solder and an oven? >> >> I'm wanting to tinker with some circuits but some chips I'm interested in >> only comes in MSOP or other packages that look intimidating to attempt to >> solder. >> >> Thanks! >> >> RogerN >> >> > >I tend to design a PCB with CAD software then have prototype PCBs made. >There are several companies out there who do 'pooling', i.e. they amalgamate >many designs onto one PCB, that way you end up only paying a small fraction >of the tooling cost of the PCB. Some companies can handle 6 layer boards >with this process. Example in the UK is PCB Snap from Spirit Circuits >(www.spiritcircuits.com). > >This can be quite cost effectve for producing protptypes that are as close >to the final product as practicable. > >Another way is to design with CAD but make your own PCBs. One way that works >reasonably well is to produce gerbers and print them in mirrored form on a >laser printer with high contrast (i.e. lines are as black as possible) onto >glossy paper, then use an clothes iron to transfer the image directly to a >sheet of copper laminate, and then etch. The reason this works is the ink is >somewhat resistant to the etching chemicals. Carbon and black dye laden polyethylene is rather resistant to ferric chloride and ammonium persulphate. Not so much BF3. But BF3 is NOT suitable for casual use. Not to mention the process pretty well tops out for two sided boards. >There is a product that is >specifically designed for this (can't remember its name, it uses blue paper >to ease the transfer process), do some Googling for homemade PCBs. The transfer process is the limiting factor, closely followed my multipass printing registration issue (very especially for any attempt at fine pitch). > >As for soldering, with a fine tip soldering iron and a little practice it's >not that difficult to solder a MSOP or TQFP to a PCB. Get yourself a good >magnifying glass on a stand, lots of no-clean flux, some silver laden >solder, and the most important part small thin solder braid for tidying up >the inevitable shorts between pins and your away. > >Mark. > And the total process is called a Gootee board named after Tom. He has been seen in this NG recently.
From: Charlie E. on 6 Jan 2010 01:52 On Fri, 01 Jan 2010 07:20:41 -0800, Fred Abse <excretatauris(a)invalid.invalid> wrote: >On Thu, 31 Dec 2009 15:52:38 -0800, Joerg wrote: > >> Not at all, but I use thin copper-enameled wires and run them in orderly >> fashion :-) > >I tend to use wire-wrapping wire. But, where do you find it! RS no longer carries it, and I couldn't even find it at Fry's this week! Had to buy just some 26AWG to do some prototyping... Charlie
From: JosephKK on 6 Jan 2010 02:46
On Mon, 04 Jan 2010 21:09:49 -0800, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Mon, 4 Jan 2010 20:22:14 -0800, "Joel Koltner" ><zapwireDASHgroups(a)yahoo.com> wrote: > >>"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message >>news:hfa5k51hc8fad9u8b0dpqbae43p4lekho8(a)4ax.com... >>> You haven't worked with The Brat. >> >>I've never even worked with a layout woman. Heck, not even any female >>hardware designers... although a few female programmers. (And one claimed to >>have done digital hardware design at a PPOE...) > > >The best two layout-ers I've worked with pre-Brat were women. > >I've never worked with a full-time female circuit designer, or even >met one to my knowledge. I have worked with lots of female >programmers, scientists, and managers. > >I know one physical chemist who got pregnant and didn't want to be >around chemicals and magnets for the duration. She wandered the halls, >saw some guys designing FPGAs, and decided to do that. So she did, >very well. But she can do anything. She was the R&D manager last time >I checked. > >> >>> I'm not working on the checklist... The Brat is! >> >>Would you be willing to post it when she's done for the benefit of the rest of >>us plebes? :-) Arguably we can possibly even add value, recounting our own >>foibles. > >Sure, will do when it's presentable. Additions are welcome. > This may be done best when it is not really presentable but something like organized, and repeated when it is halfway or better in shape. >> >>> The first page of our schematics is the block diagram and table of >>> contents. >> >>Do you create those within PADS itself or use, e.g., Visio and then copy & >>paste? Do you use hierachical design on the schematic itself? > >We draw it with PADS Logic, which isn't a bad drawing program. I don't >like hierachical schematics, so all of mine are flat, over 30 B-size >pages some time. > >ftp://jjlarkin.lmi.net/22SS346A.pdf > >John |