WELsoft Website Notes

Note 10

Subject: The very first rapid move of the right hand tool to the right sometimes goes stoppy-starty

The scenario: you have just clicked "Start" to begin machining. On the screen, the chuck jaws close on to the billet. On the lathe and on the screen, the right hand tool begins to move rapidly and smoothly to the right, to the tool change position. Then, on the screen, the tool reaches the right hand edge of the screen. The chuck and billet scroll stoppy/starty to the left while, on the lathe, the tool continues to move to the right but in a stoppy/starty manner also.

Fear not! We did not want a lathe tool to ever disappear off the screen to the right. So, WELturn has been written so that, if necessary, the image of the chuck and billet can scroll to the left.

When scrolling is necessary, the PC has to do two jobs: keep redrawing the screen image and keep sending data to the WELturn lathe controlled box. An elderly PC may not be able to hop from one job to the other fast enough. The result is that the controller box runs out of data to process and the lathe tool stops moving for a moment.

There is a slight possibility that the tool could lose position when this happens. This is because the tool is going instantly from stationary to the rapid traverse rate and stepper motor steps could be missed because of motor inertia. Under normal conditions and acceleration control routine manages large speed changes and steps are not missed.

There are three possible solutions to the problem:

1. In WELturn - File - Settings ... decrease of the 'Rapid Traverse speed (mm/min)' from, say, 500mm/min to 400mm/min or lower;

2. In WELturn - File - Settings ... switch off 'Show real-time graphics' so that machining is not simulated on the screen;

3. Use a younger and faster PC!

April 2000

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