Hi Gang;
Yea, I know- pretty pretentious thread title, not to mention a bit eye-catching and intriguing to the laser crowd, but read on and make up your own mind. After four years of messing around with all kind of arrangements, including clamps, vacuum tables, double-sided tape, weights, nail tables,-you name it, I've tried it- I finally found the ideal solution for my type of laser engraving and cutting. I should mention that I do a lot of wood engraving and cutting-everything from 1/42" veneer up to 1/2" maple. I do not, however, do many jobs which have a lot of small pieces- that's a different kettle of fish and a topic for later discussions. Enough foreplay- here's the details as shown in the attached pics below:
The table frame is made of 1.5" x .75 " hard maple- any straight hardwood can be used or metal angle cobbed together since few of the dimensions are really critical. I used wood because I have a lot of it and metal warps because I'm a lousy welder. The profiles are cut on a router and the dimensions shown accomodate 1/2" x 1/2" aluminum grid stock- available from Mike Null on this forum. The routed stock is mitered and assembled with reinforced corners-mine is 24" x 18" to fit my laser bed. Note that the bottom of the stock is offset by 1/8" so when placed against the table rulers the inside edge of the frame is exactly on the zero-zero line or x-y axis for those geometrically competent. Note that the frame has a middle vertical support beam (3/4" high by whatever wide) and two diagonal cross braces to ensure strength and reduce any potential warping. The tops of these three pieces are covered with aluminum tape to eliminate laser burns. Note also that the frame material has a 1/4" square clamping strip glue to the top edge to accomodate spring clamps-more on that later. The bottom half of top member of the frame is cut away-except for a center post- to allow exhaust air to flow freely under the grid.
The grid is actually three separate pieces of grid material, arranged to accomodate my standard material sizes. Some of the grid has been cut away at places to allow spring clamps to be used for holding material flat- this is a personal preference option. The grid sections are lightly tacked to the frame with hot glue-allows changing or replacing sections depending upon job requirements (haven't needed to do that yet). Now the cool part:
Notice the small circular elements in the pics . These are Neobydium (sp) magnets- very thin, small but powerful magnets which come in various strengths and sizes. These are epoxied to 1/2" x 1/2" x3/8" wooden blocks which are dimensioned to snugly fit in the grid holes. The tops of the magnets, when installed, are level with the grid top. These are placed at various points on the grid and will hold down up to 1/8" material when a steel washer is placed on top- really works great with laminates and veneers, both of which have a tendency to warp. The magnet blocks can be moved around to accomodate various sizes of material but I found that 1/8" x1/2" steel bar stock of various lengths will let you accomodate a lot of material variations without moving the magnet blocks.
For heavier material, like 1/4" ply which I use a lot, I use the spring clamps which have been modified as shown to slip under the clamps bar or grid table and maintains a low profile to avoid impact with the focus probe.
That's about it-concept can be implemented with a lot of different materials and, obviously, many sizes. Care should be taken to make sure the basic frame is flat and not warped- or provide leveling feet or shims.
Enjoy
best regards
George
LaserArts.
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