Re: [CAD_CAM_EDM_DRO] Digest Number 2321

Hello list,
I thought I would pass on a tip from the old days. I you mount heat sinks
to the power fets, transistors with nylon screws it makes troubleshooting
easier. When the smoke comes out the part gets hot. A melted mounting
screw is a sure sign of over heating.
Paul

----- Original Message -----
From: <CAD_CAM_EDM_DRO@yahoogroups.com>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Saturday, May 18, 2002 9:41 AM
Subject: [CAD_CAM_EDM_DRO] Digest Number 2321


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> ------------------------------------------------------------------------
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> There are 3 messages in this issue.
>
> Topics in this digest:
>
> 1. Re: Digest Number 2320
> From: Ray Henry <rehenry@...>
> 2. Re: CNC robotic welding arms
> From: "rainnea" <rab@...>
> 3. Software for sale on the list Slight change in Prcedure.
> From: wanliker@...
>
>
> ________________________________________________________________________
> ________________________________________________________________________
>
> Message: 1
> Date: Sat, 18 May 2002 08:18:54 -0500
> From: Ray Henry <rehenry@...>
> Subject: Re: Digest Number 2320
>
>
> Jon, Babar
>
> I disagree but not violently. The names of all five files can be changed
and
> still make a working system. As Jon points out you change the ini file
name
> in the run file. The others are changed in the ini file. What Jon may be
> thinking of is trying to change a file name while the EMC is running.
> Several of us have fallen into that trap at one time or another.
>
> By way of example, I want to use a custom .nml file if I plan to run or
view
> machine progress over a network. When I do several different small lot
parts
> I save .tbl files and name them along with the part program file. I also
use
> the var file to save parameters and variables from one run to the next.
For
> one project here I engrave serial numbers and keep the last one as a
variable
> in a specific ini. In general, I keep a separate specific personality for
> the EMC under each major project. This includes all five of these files.
>
> HTH
>
> Ray
>
> > From: Jon Elson <elson@...>
> > Subject: Re: How to setup STG-II?
> <s>
> > But, the other files, (xxx.var, xxx.nml, xxx.tbl) should have the names
> > emc.var, emc.nml, emc.tbl to be used by emc. (In general, you shouldn't
> > need to modify these files outside of EMC anyway, so using the standard
> > names shouldn't cause much of a problem.) My understanding, unless
> > things have been changed (possible, since I still use an old version of
> > EMC) is that these files are always used as emc.var, emc.nml, and
emc.tbl
>
>
> ________________________________________________________________________
> ________________________________________________________________________
>
> Message: 2
> Date: Sat, 18 May 2002 13:49:50 -0000
> From: "rainnea" <rab@...>
> Subject: Re: CNC robotic welding arms
>
> Thanks for the info on the EMC files.
> As I understand it, EMC can handle all these calculations and would
> be the ideal method in theory, but has some rotational velocity
> issues in practice ?
> I'd imagine that it may just be easier and provide more flexibility
> to use a 3D animation program designed and perfected to handle very
> complex kinematics (and able to visualise them) to work out all of
> the joint / axis movements and then from there, output the
> coordinates that each axis has to move to in order for the toolpoint
> for follow a subdivided toolpath.
> >From this, the CNC controller would be able to handle the translation
> of these axis movement coordinates into step and direction signals
> while being totally unaware of the configuration of the machine if
> (and this is the problem) it could determine how fast each axis
> should travel for each move.
>
> One method that kind of works is to set a maximum feedrate per axis,
> for example, when using a 3-axis controller to do rotary machining
> where the Y-axis controls the rotation of the part and the controller
> doesn't know how far the toolpoint is really moving but calculates
> the feedrate based on the maximum feedrate set for the Y-axis as if
> it were a linear axis. This at least gives smooth and predictable
> movement but the axis feedrates would be the same whether the tool
> was cutting near the centre or at the outer radius of a rotary part,
> giving very different toolpoint velocities.
>
> Another method, not without its disadvantages, but that may be very
> effective is tagging the distance that the tool tip is actually
> moving relative to the material onto each line of G-Code containing
> the axis movements (as opposed to the tool movement). The distance
> value would be used to calculate feedrate or it could even be
> replaced with a feedrate or time value. Would this be enough for the
> controller to generate proper constant velocity movement at the
> toolpoint?
>
> For example, take a hexapod machining over a cusp or sharp point of a
> surface where the tool is changing angle rapidly but the toolpoint is
> actually moving very little in relation to the material. Using the
> above method would mean a series of six-axis coordinates for the six
> hexapod struts to move to, along with corresponding values that
> correspond to the distance that the toolpoint is actually moving. The
> controller would move the hexapod struts, coordinating their
> acceleration / deceleration, target and max velocity not knowing or
> caring about the physical arrangement of the machine, but just how
> long these axis movements should take. The same should hold true for
> other 4 and 5 axis arrangements.
> Could / should this method work ?
>
> Rab
>
>
>
>
> ________________________________________________________________________
> ________________________________________________________________________
>
> Message: 3
> Date: Sat, 18 May 2002 11:09:45 EDT
> From: wanliker@...
> Subject: Software for sale on the list Slight change in Prcedure.
>
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