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Published on 04-27-2012 04:50 PM
Updates have been made to some cross files to improve both engraving quality and runtime. This involves the use of a second laser color.
The improved quality comes about by running much slower with much less power for short laser passes. For crosses that lay sideways on the tray this corresponds to objects on the crossbar. This alternate setting prevents scorching while still giving a similar engraving depth.
The improved runtime comes about through some quirks of the laser's operation. Using two colors ensures that longer laser passes are used only where necessary (that is, the laser doesn't waste time running over blank portions where the laser is off anyway). For some files, this can translate to twenty minutes of saved time (forty minutes compared to one hour for ZPHC32B.gnh). Other files see little if any runtime improvement, but the above quality improvments still apply.
The actual setting numbers in use are 100% Power & 50% Speed for black (as before) and 25% Power & 20% Speed for green. Testing on a few machines produced very similar engraving depth between the black and green portions. You may be wondering, "How can running at 20% speed improve the runtime?" When running a narrow strip that uses short laser passes, the laser only runs so fast - the head can't accelerate to the requested run speed (e.g. 50%) before it has to slow down to turn around (it only ends up running 20-30% speed). The laser tries to compensate for this slower effective speed, but doesn't compensate enough, resulting in an overintense burn. By specifying the settings manually, we can actually get the exact burn intensity we want. So the laser head isn't really running much slower than before. The explanation above for improved runtime makes up for any minor slowdown caused by lowering the speed for the narrow/short pass elements.
If you make changes to a cross and forget to change the crossbar elements to green (that is, everything in black) you'll simply get results identical to what you've had in the past. If you change everything to green, your runtime can be much longer (1.25 to 1.75 times as long), BUT the cross will turn out just fine.
Not all cross files have been changed, only the following:
ZALC27.gnh
ZFTC01A.gnh
ZFTC01B.gnh
ZFTC32A.gnh
ZFTC32B.gnh
ZFTC32C.gnh
ZFTC32D.gnh
ZPHC01A.gnh
ZPHC01B.gnh
ZPHC32A.gnh
ZPHC32B.gnh
ZPLC03.gnh
ZPLC05.gnh
The artwork on ZFGN10 and the exact layout of ZALC26 do not lend themselves to needing this change. Also, alphabet crosses do not need changes as no engraving is placed on the crossbar (since the photo letters are already there).