Re: [CAD_CAM_EDM_DRO] Re: Re: Re: Electronic Lead Screw & Power Cross Feed | Poor Man''s CNC ?

Hi Henrik,

Read that from a few people.... Mach is doing all the counting out and in as far as I know. The axis will stall at almost 160 ipm, right where the voltage calculation-limitation of the drive dictated that it would. Don't have an explanation of how it can do this in regard to speed but, it does it. When first started using encoder counts to monitor position, the concern was timing constraints. Now they aren't given much attention after three machines have exceeded the 22.5k mark without any issues.

The Jet has those folding handcranks on it, in rapid they are a blur (700 rpm). Thanks for the compliment on the machine.

After using the interface, for close to a year now, I wouldn't want a machine without it. It has saved so many workpieces. Some big UHMW details (2X6X20) I was running on one of the Bridgeports a few weeks back. Very complex 3D surface and about 8 hours into the job, the X gib on the old Bridgeport got free of the adjusting screw and totally locked the X axis(fixed it). Normally Y and Z would have continued on and destroyed the part (80 ipm feed). The following error of .004" was exceeded and the interface stopped the machine. Saving the part.

Ron

Jon, Those are very impressive numbers. Thats a nice system you have.


Henrik Olsson <henrik-olsson@...> wrote:
Hi Ron,
Really? Impressive!
12800 * 140ipm / 60sec = 29866 encoder transitions per second. Even at 45kHz
it's impossible to detect more than 22500 and if I my memory serves me Art
said that number should be derated a bit too.
Then again, it's only theory ;-)

Or does your board handle the actual count and sends it back to Mach3
somehow? If so that would be another thing.

Thanks in advance!
/Henrik Olsson.

PS. Nice machine!!

----- Original Message -----
From: "R Rogers"
To:
Sent: Wednesday, December 07, 2005 6:37 AM
Subject: Re: [CAD_CAM_EDM_DRO] Re: Re: Re: Electronic Lead Screw & Power
Cross Feed | Poor Man''s CNC ?


>I keep reading what Mach3 wont do in regard to encoders in theory. It's a
>bit frustrating as I see everyday what it does.
>
> A machine I recently retrofitted with Mach3 and encoder feedback to the
> PC. Put Mach in "reset" and it has a screen with nothing but DRO's for
> manual operation.
>
> Here are the specs:
>
> X and Y axis are 12,800 steps per inch, max rapid rate is 140+ ipm on
> both 5 tpi ballscrews (.200" lead) (3.2:1 belt reduction)
>
> Z axis is 20,000 steps per inch. 10 screw revs per inch. .100"lead (4:1
> belt reduction) Z rapids at 60 ipm (driving the knee).
>
> All three axis's are monitored by their encoder in Mach, if position is
> lost the machine is halted.
>
> Mach in 45 khz mode, all three axis's can be rapid simultaneously and no
> lost steps are encountered. It will actually go faster.
>
> Do the math on the above for the true pulse/count rates.
>
> The machine can be seen here, the white JET 836: (disregard my dirty
> shop..thx)
> http://machsupport.com/forum/index.php?topic=2.0
>
> The board used is at:
>
> www.rogersmachine.net
>
> Ron



Addresses:
FAQ: http://www.ktmarketing.com/faq.html
FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com

Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@..., timg@...
Moderator: pentam@... indigo_red@... davemucha@... [Moderators]
URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO

OFF Topic POSTS: General Machining
If you wish to post on unlimited OT subjects goto: aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble.
http://www.metalworking.com/news_servers.html

http://groups.yahoo.com/group/jobshophomeshop I consider this to be a sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list.

NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
bill
List Mom
List Owner


Yahoo! Groups Links











[Non-text portions of this message have been removed]