Thanks again for your comments.
I'm doing some serious web surfing at the moment and beginning to understand some of the issues regarding laser cutters. Previous CNC machine builds have been more for the sake of designing and building a machine than for a specific cutting purpose. With the laser idea, I have definite goals - I want to be able to cut light plastic, balsa and plywood up to 6mm for model building. I suppose I might do some engraving at some point in the future but this is not a pre-requisite.
I now believe that speed should be a major focus of any design and my thoughts are turning to belt drive on X and Y with a manual screw adjustment on the Z for focusing (I intend only to cut in 2D on flat material up to 6mm) this way I don't beleive that I will need a "raise and lower" type of work table. If I'm making sense so far, would I be correct to think that I would only need two mirrors if the laser was mounted parallel to the X axis - one to turn the beam onto the Y axis and one to turn the beam vertically down through the final focus lens? It is this lens that I would propose to arrange on a srew adjustment to accomodate different thicknesses of material.
The axis guides would probably be supported chrome plated or stainless round bar with open linear bearings on the X axis and twin round bar on the Y axis with closed linear bearings. I'm thinking the whole thing could be supported on a modified office type desk frame with the top removed. This could be a very cheap route for construction compared with ballscrews and THK type linear ways and carriages that I have used in the past. I am considering the use of the Epilog servo motors also as these appear to have been unscathed by the fire and need only new cabling.
As I think the design through, I see that a potential concern could be the acceleration and deceleration creating reactions on the table and causing vibration etc. My initial reaction is to limit speed of the axis and add weight to the table frame to dampen and reaction.
Everything is in my head at the moment as I am in the middle of a duty offshore but I will be returning home on leave shortly and will be keen to rummage around my parts collection for suitable components. Please keep the comments coming and any help in pointing to a build log of such a machine as the one I'm thinking about would be good.
If this thread turns into a build then I promise that I will take some pics and upload as I go along.
Cheers
Nick  |