RE: [CAD_CAM_EDM_DRO] Static electricity - WOW

Bill:
 
You are correct about how the Drip feeding worked.  True NC machines had very little memory and were operated by punched tape, usually paper and you used what is basically a teletype console to create the punched tape.  Some of the first NC machines had no memory to speak of and you had to run the punched tape every time you wanted to make a part. 
 
Later tape decks were introduced and you could drip feed the data to the machine.  You are also correct in that all you needed to create the programs in a computer for transferring onto the tape (or in some cases directly to the CNC controller) was a simple ASCII editor such as notepad or, in the case of DOS based computers which is what most of the computers back then had, you could use PCWrite.  Of course central mainframes, and a little later just servers, would use something like a UNIX operating system, pretty much the same thing as Linux is now.
 
In most cases the carriage return was both the end of the line and a linefeed command.  Depending upon the controller used, there might need to be some control characters and/or a string of NULs at the beginning and/or end of the program.  These characters served to tell the controller where the beginning of the program file started and then where the end of the program file or EOF was.  When the controller saw the EOF character(s) it would cease communicating with the tape deck or computer.
 
Do you know the make of the controller on the machine you are considering?
 
If you want to discuss things further just contact me at my E-mail address below so we can go into more detail.
 
God Bless,

Randy Abernathy
CNC and Industrial Machinery
service, repair, installation and
design

4626 Old Stilesboro Rd NW
Acworth, GA 30101
Fax: 770-974-5295
Phone: 678-982-0235
E-mail:
randyabernathy@...

--- On Sun, 2/28/10, William Thomas <wthomas@...> wrote:


From: William Thomas <wthomas@...>
Subject: RE: [CAD_CAM_EDM_DRO] Static electricity - WOW
To: CAD_CAM_EDM_DRO@yahoogroups.com
Date: Sunday, February 28, 2010, 10:26 PM


 



Hi Randy and all:
     This the reason many of small grain mills have been closed in Michigan is because of the fire hazard cause by the dust.
     I notice you you said you have been working in industry for 26 years so you may remember some of the first conversions from NC to DNC or now CNC by what was often called drip feeding.  This is where the RS232 signal was sent to the tape reader control to a connection just behind the tape reader.  What it does is use a signal the same as the tape reader put out but, it gets it from the computer.  What I have forgotten in the last 17 years since I helped do it on a Bridgeport Mill is how the signal was generated on the computer.  As close as I can remember is we used note pad to generate the text needed for each block of G or M code with all the proper dividers.The carriage return was the end of block if I remember right. 
    My question is do you any more about the setup as I am looking as a NC lathe in GOOD condition that I would attach this type of computer control.  Thanks in advance for your time and answers.
                                                         GOD'S BLESSINGS
                                                                   Bill

On Tue, 23 Feb 2010 13:01:15 -0800 (PST), RANDY ABERNATHY wrote
>  
>
> Jeff:
>  
> If you paid close attention to my post you will see I recommend first a ground line back to the distrubution box and THEN for a backup, mainly to help prevent interference with the electronics, a ground rod near the machine.
>  
> As far as wood dust exploding being an uban legend, you must not have looked hard enough.  It is not a common everyday occurance but it does occur.  And yes it does occur sometimes from static electricity.  I have been to 2 factories over the 26 years or so I have been in this industry where they were totally destroyed by explosion of wood dust.  One of these, it was determined by the investigators, was caused by a maintenance man repairing a section of the dust collector pipe with PVC.  That section caused a big static buildup and ultimately caused a spark inside the pipe, which melted and the fire spread.
>  
> You are correct about proper dust collection helping to prevent this type of thing, the key is PROPER dust collection and I am afraid there are a lot of people out there that either don't know how to do this or just don't want to spend the money or time.
>  
> Stay safe.
>
> Randy Abernathy
> CNC and Industrial Machinery
> service, repair, installation and
> design
>
> 4626 Old Stilesboro Rd NW
> Acworth, GA 30101
> Fax: 770-974-5295
> Phone: 678-982-0235
> E-mail:
> randyabernathy@ bellsouth. net
>
> --- On Mon, 2/22/10, Jeffrey T. Birt <birt_j@soigeneris. com> wrote:
>
> From: Jeffrey T. Birt <birt_j@soigeneris. com>
> Subject: RE: [CAD_CAM_EDM_ DRO] Static electricity - WOW
> To: CAD_CAM_EDM_ DRO@yahoogroups. com
> Date: Monday, February 22, 2010, 7:01 PM
>
>  
>
> >On large industrial machines we often ran a separate ground wire from the machine chassis directly to a grounding rod driven into the ground >thru a hole drilled in the concrete floor of the factory or shop.
>
> Hopefully your bonding this to the main supply ground? Most earth ground driven inside of a factory are next to useless as the ground is too dry to provide a good ground at all.
>
> >Many of the fires in woodworking factories start in the dust collection system from static sparks because of improper grounding or using PVC or >other polymer material in the dust collection tubing.
>
> Urban legend as far as I have ever been able to find out. I have found no documented cases of the cause of a fire at a wood working plant being caused by a static discharge (but I would love to see it.). A grain mill would be much more likely and then it is from having just the right combination of flour dust to air, controlling the dust takes care of most of the problem.
>
> Jeff Birt
>
> Check out [UTF-8?]– [UTF-8?]Soigeneris. com…
>
> From: CAD_CAM_EDM_ DRO@yahoogroups. com [mailto:CAD_ CAM_EDM_ DRO@yahoogroups. com] On Behalf Of RANDY ABERNATHY
> Sent: Monday, February 22, 2010 5:23 PM
> To: CAD_CAM_EDM_ DRO@yahoogroups. com
> Subject: Re: [CAD_CAM_EDM_ DRO] Static electricity - WOW
>
> YES, the machine should have a ground run with the power line which is also connected to the machine chassis. On large industrial machines we often ran a separate ground wire from the machine chassis directly to a grounding rod driven into the ground thru a hole drilled in the concrete floor of the factory or shop.
>
> Are you using PVC by any chance anywhere between your dust collector unit and the machine? If so, get rid of it and put metal pipe instead. If you are using a small portable dust collector or a shop vacuum with plastic head on it, you probably should ground the hose going to your machine.
>
> One other thing you need to know is that wood dust can ignite and explode from even a small spark. Many of the fires in woodworking factories start in the dust collection system from static sparks because of improper grounding or using PVC or other polymer material in the dust collection tubing.
>
> Hope this helps out.
>
> Randy Abernathy
> CNC and Industrial Machinery
> service, repair, installation and
> design
>
> 4626 Old Stilesboro Rd NW
> Acworth, GA 30101
> Fax: 770-974-5295
> Phone: 678-982-0235
> E-mail:
> randyabernathy@ bellsouth. net <mailto:randyaberna thy%40bellsouth. net>
>
> --- On Mon, 2/22/10, Jack <freshwatermodels@ yahoo.com <mailto:freshwaterm odels%40yahoo. com> > wrote:
>
> From: Jack <freshwatermodels@ yahoo.com <mailto:freshwaterm odels%40yahoo. com> >
> Subject: [CAD_CAM_EDM_ DRO] Static electricity - WOW
> To: CAD_CAM_EDM_ DRO@yahoogroups. com <mailto:CAD_ CAM_EDM_DRO% 40yahoogroups. com>
> Date: Monday, February 22, 2010, 2:32 PM
>
> I guess I have a static electricity problem. While cutting a model boat
> stand on my router I was using a dust collector . I was holding the
> hose by hand. Something touched something else and both I and my
> computer got a jolt of static electricity. Has anyone else run into
> this? Cures???
>
> I am assuming I need to ground the router which is aluminum on a wood
> stand. Do I need to somehow ground the plastic hose on the dust
> collector?
>
> Any suggestions, insight, etc. appreciated! !!!!!!!!! !
>
> jack
>
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>
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>
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>

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