View Full Version : math?

lucas kreft

12-07-2011, 10:41 PM

what is 52000mm/min @300dpi converted to sq.ft/hour

this is how fast the machine runs

300mm=12" so 300 passes will give me 12 square inches @300dpi

lucas kreft

12-07-2011, 10:45 PM

the answer is 34 square inches an hour @300dpi?

Rodne Gold

12-08-2011, 12:59 AM

408 sq inches per hr.

The laser will scan at 866mm/second or 34 inches per second. Barring anything like starting and slowing acceleration and the time it takes to jump to the next scan , it will do 300 passes of 34" s in 5 mins , So 34 sq inches in 5 mins , x12 = 408sq inches an hour or 1 sq ft in 21 minutes (2.8 sq ft per hr)

You can divide that by lets say 1.5 to get an ACTUAL and not theoretical time.

Richard Rumancik

12-08-2011, 9:22 AM

I question how reliable of an answer one can achieve with the limited data. I assume that the manufacturer's specifed maximum speed is being used. The size of the graphic will affect whether maximum speed can actually be achieved; as well, the overshoot (turn-around-time) will have a significant effect on the actual throughput.

If you just want a rough estimate I would suggest that the best way is to determine it experimentally. Just plot a long narrow rectangle, same width as the proposed graphic, and time it. You don't need the full height as you can extrapolate. For example, if the graphic is 6" wide, make a box 6" x .25" high and fill with black, no outline. Raster this, record the time. Multiply the time by 4 to get time per vertical inch of graphic/photo. You could also estimate time per square inch, but as I said before, be careful as throughput is width-dependent.

PhotoGrav has a time estimator for raster engraving built into the program; I'm not saying you should buy the program just to get time estimates but my manual (which is 10 years old) has some interesting discussion on the subject of estimating raster time. In order to have PhotoGrav do a proper estimate, you need to enter the turn-time for your machine. They describe the experimental procedure to determine this. But perhaps their information is more technical than what you need at the moment.

Also note that photos/bounded graphics will take more time to raster than say text, which has "white spaces" between lines which most lasers jump over, plus the laser will jump (accelerate) to the start of a text line rather than raster the full width. So in this kind of case you need a program that will do the estimate if you need more accurate estimates on an ongoing basis. But for photos, once you do a few trials, you can probably estimate without going to so much trouble.

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