Jeffrey, I didn't really address the "pulses per inch" issue in my other post. I can understand if you are confused about the "ppi" issue. In fact, a lot of us are . . . and it is partly because different machine vendors use different terminology.
I suggested that you search the forum but unfortunately you can't search on PPI or DPI as the search algorithm ignores short terms. Here is a thread from 2007. I hope it does not confuse you even more . . . but you will see that
it is a difficult topic to get a handle on.
http://www.sawmillcreek.org/showthre...fect&highlight=
I would like to tell you that PPI (pulses per inch) is a cutting parameter, as Rodne said in the 2007 thread. I think it is true for my GCC laser. But when I read the Trotec info, I can understand why there is so much confusion between users, as it seems PPI means something a bit different in the Trotec world.
Also, I don't understand what they are saying in several places. The highlights are mine.
Here is a excerpt from a Trotec manual:PPI/Hz (Basic, Advanced, Expert)
PPI = pulses per inch (laser pulses per inch). Only for the Engraving process.
This setting determines the number of laser pulses per inch emitted by the laser.
This occurs depending on the position, e.g. the pulses are always emitted at the
same interval irrespective the speed.
Adjustment range: 100 - 1000 PPI
The higher the selected PPI value is, the better is the quality of the engraving. To obtain a good result, the PPI value should be usually larger than or at least the same as the dpi setting of the printer driver (Process options – Resolution), e.g. a minimum value of 500 PPI should be selected for a resolution of 500 dpi. A low PPI value is only useful when processing some types of rubber or in cases where the contour is only to be perforated but not cut through. Unlike the resolution in dpi, increase in PPI does not have an effect on the engraving time.
Hz
Frequency of laser pulses during cutting. This setting determines the number of laser pulses per second emitted by the laser. Unlike engraving, with cutting it is not necessary to create fine contours by means of resolution. In this case, the position sensitive control used with the PPI can therefore be replaced by a set frequency.
Adjustment range: 1000 - 10000 Hz for CO2 systems,
10000 – 150000 Hz for YAG systems
Additionally YAG systems can use frequency mode for engraving.
Resolution
Selection of the required resolution in dpi (dots per inch). Equivalent to the lines to be engraved per inch (25.4 mm). A higher value improves the engraving quality, but results in increased engraving depth and longer engraving time using otherwise identical parameters as the laser has to process accordingly more lines.
Setting range: 125, 250, 333, 500, 600, or 1000 dpi
The setting for standard engraving should be 500 dpi. The resolution to be selected largely depends on the material used as well as on the focal length of the lens.
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Ok, they say for Trotec, PPI is "only for the engraving process" . Then they go on to say : "A low PPI value is only useful when processing some types of rubber or in cases where the contour is only to be perforated but not cut through." This doesn't sound like engraving to me . . . so the statement is contradictory.
Under HZ they say:"Unlike engraving, with cutting it is not necessary to create fine contours by means of resolution. In this case, the position sensitive control used with the PPI can therefore be replaced by a set frequency."
I have no idea what this means. I always thought that for cutting you wanted to keep the pulse distance constant (as the vector speed can change on contours or corners.) So, does Trotec PPI parameter apply to cutting or doesn't it?
Under Resolution: they say " . . . dpi. Equivalent to the lines to be engraved per inch". "Lines" is a vertical measurement - so it makes me think that they are using the ULS terminology where the vertical direction (Y) is measured in DPI and the horizontal direction (X) is measured in PPI. That is an odd way of doing things to me. Most people think of dpi as the measurement unit in both axes.
The point is, until you can understand what terminology Trotec is using, and clarify what I see as inconsistencies in the above info, it will be hard to gain a thorough understanding of your machine and how to set the parameters. What I (or someone else) tells you might be inconsistent with Trotec terminology.
Maybe some of the Trotec users can help on this point, or else I suggest you challenge your Trotec rep to explain the information in the manual.