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Old 09-28-2010, 11:07 PM
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Carl@Semroc Carl@Semroc is offline
Junior ??? Rocketeer
Join Date: Mar 2005
Location: Knightdale, NC
Posts: 1,470

Originally Posted by CPMcGraw

I made some adjustments to the files based on text comments I made on the RS design. Attached below are both CDR 10 and 13 files (zipped).
Let me know how these alterations affect your setup.


I was going to cut a set, but it is going to take more work than I have time for right now.

The sheet size for the laser cutter is 11.811" x 8.268". If it is different from that, it cuts off some good stuff.

The lines to cut must not have any fill and must be hairline. The fill goes into slow raster mode and could take 10 or 15 minutes to try to burn an image. Black does a 30% power cut that burns names without going all the way through. Red cuts with 100% power. If it is hairline, the laser beam just follows the vector lines and cuts fast.

The other 14 basic colors are used for special power and speed levels for different canned settings for the Venus.

I use the Microgamma font because it shows up well on most balsa densities. The thinner fonts wash out.

The grain for balsa is left to right and plywood is (usually) up and down. Fiber has no "grain and can be cut in any orientation. We insert the sheets with the widest length from left to right.

We use balsa in widths of 8" (6 per sheet), 9.6" (5 per sheet) and 12" (4 per sheet) for different patterns. Plywwod is usually in 8" x 12" sheets and fiber is 8" x 10" sheets.

We use a .011" wide hold-in tab on 3/32" and 1/8". We sometimes use a .008" tab on 3/16" balsa, but it is preferable to just cut it into individual pieces since it is at the limit of the beams focus. 1/16" balsa is also .011" unless it is light, in which case we sometimes have to adjust the pieces to .013".

The colors (black and red) have to be set to RGB. If they are set to CYMK, they are selectively and sometimes arbitrarily ignored and nothing cuts in some areas.

We get the balsa sheets in 3" wide and 4" wide, but we try to avoid 4" wide since it costs almost twice as much.

Iknow it is minor, but I use 72 point for the title over the top of the page. This allows me to check the balsa size before I load the file by looking at the thumbnail. Saves a few seconds and it lets me manage many widths and lengths and thicknesses that are cut in a typical day.

Balsa is not always 3" or 4" so I try to keep the cutting area at least .10" from the top and bottom edges.

Whew!! That is about 5% of what you need to know to cut fins. Tomorrow's lesson will handle tab placement, smoothing, inter-object distance, optimizing order, grouping, cutting direction, object starting point, over-cut, handling raster scan early termination, and determining optimum balsa density and adjusting on the fly for different weights.

This is not nearly as boring as it sounds!
Carl McLawhorn
NAR#4717 L2
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