Using the Laser Cutter and AutoCAD Template

Transcription

1 1 Using the Laser Cutter and AutoCAD Template This tutorial outlines the best way to cut and etch using the laser cutter. Your project is important to you, and you want to finish it efficiently. Using this tutorial will increase your efficiency and decrease your material cost and time. If you can quickly use the laser cutter with few mistakes, then you will spend less time working and more people can use the laser cutter. If you do not know how to use AutoCAD, Rhino, or some other program that produces vector line work, ask another student, professor, or refer to the AutoCAD Command Help document found on the woodshop website for help. The laser cutter technician can help you cut materials, but will not teach AutoCAD or appropriate file layout. Scaling your Drawing Before you set up your drawing, you will need to scale your drawing. Use the scale command in AutoCAD and then select a reference point on your drawing. Then you will type in scale factor. Below are some common scale factors. If you have questions about how to scale please refer to the AutoCAD Command Help Document, ask another student, or professor. Imperial Scale Factors Scale Scale Factor 1-0 = 1 1/ = 3/4 1/ = 1/2 1/ = 1/4 1/ = 1/8 1/ = 1/16 1/192

2 2 Using the AutoCAD Template This tutorial includes an AutoCAD template as a guide to formatting your files. The template has preset layers, associated colors, and line widths. Copy the objects you wish to cut and/or etch into the template. The image below shows how to set up layers in AutoCAD. GREEN LINES ARE The template has multiple cutting and etching layers. Use blue for the primary cut color and use yellow for the primary etch color. The image below shows which colors the laser cutter associates with each action. All of these layers are set up on the Template file.

3 3 Allowing for Margins and Boundaries Before cutting: Make sure you have a ¼ margin around your material Place etching on a separate layer Format so you can cut details and holes before cutting the final object Your layout can dramatically improve the efficiency of laser cutting. You need to layout your files before you try to cut. Because technicians cannot help you format your file you will have to leave to reformat it. The following images and descriptions will help you determine how to create an efficient layout that will use the least material and make the fewest cuts. The laser cutter has a 32 x 18 bed and a margin of ¼ around all margins. Just like printing with paper include the ¼ margin in your file. THE LASER CUTTER TABLE 1/4 MARGIN If you want to cut material that does not completely fill the laser cutter bed create a boundary to represent the size of the available material. Put this boundary on the 02Material Outline Layer (GREEN). With material like 24 x 4 Balsa and Basswood strips remember not to place your objects to the extreme edges. Leave a ¼ margin.

4 4 How you layout the object will make a difference in how much material you use and the time it takes to cut. In many cases, you can reduce the number of cuts by almost half if you lay things out correctly. The images below show how to do this. If you have overlapping or double lines, the laser cutter will cut each line; cutting a line twice may result in burning the material. To delete overlapping or double line, you can use the overkill command in AutoCAD, but some versions of AutoCAD do not know this command. Be careful and thoughtful to decrease your number of overlapping lines. If you determine that you will need to cut multiple sheets or you have multiple materials, please do not have a separate file for each sheet or each material. Use the following instruction to find out how much material you will need. We recommend bringing extra material in case of mistakes. 1. Use one of the boundaries that represent the laser cutter table (There are four on the template file just in case you need more than one.) 2. Fill it with objects to cut or etch 3. Repeat until you have accommodated all objects.

5 5 Changing Etch and Cut Order The template uses multiple cutting and etching layers, and the laser cutter uses a color based hierarchy to decide what to cut first. Use the color codes to make sure you cut your objects in the correct order. The code allows you to cut holes or smaller portions before you cut out the main object. Put the object on the last cut layer. The laser cutter does not automatically cut in a logical order. If you cut the main piece first the force of the exhaust fan may shift the entire project and place the next cuts in the wrong place. The image below shows how to set you cut layers to cut smaller holes before the main object. If you need to etch lines with different depths then you would need to put each etch depth on a different layer. If you only have one cut or etch use blue for the cut layer and yellow for the etch layer. The image below shows the color hierarchy used by laser cutters, and the order that it process lines and curves. Black goes first and orange last. Do not use black as a cutting, etching, or raster layer.

6 6 Choosing Appropriate Materials Paper and Card Stock Pros: Cuts very quickly with minimal burning Cons: High risk of catching fire if cutting details and exhaust fans can suck up small projects Matte board, museum board, chip board, and cardboard Pros: Cuts fairly quickly, allows for fine details, minimal burning, and excellent etching quality Cons: May need to tape over surface to reduce burning, may catch fire if cutting details Note: If using cardboard pay attention to its orientation when cutting thin objects. If you cut along the corrugation the pieces will fall apart, cut skinny object perpendicular to the orientation of the corrugation. Foam Core Pros: Cuts fairly quickly with minimal burning. Cons: The inner foam core melts inwards making it difficult to glue the edges to other things, and will create an inconsistent surface if stacking. Cutting very thin objects may result in the inner foam completely melting. Basswood, Balsa wood, and any hardwood up to 3/16 thick Pros: Cuts quickly with minimal burning, high level of detail possible and excellent etching quality. Cons: Densely packed details prone to catching fire or burning. Bottom side surface burning with top side residue may occur with thicker stock. Note: The thicker the material the slower the laser cutter will cut the material. Fabrics Pros: Higher quality cuts possible than with scissors and fraying reduced by melting edges Cons: May shift during cutting due to exhaust fan. Not all fabrics will cut some melt, catch fire, or blow around.

7 7 Plastics Pros: Most plastics result in nice edges with very little burning. We recommend acrylic. Cons: Avoid PVC, Polycarbonate, Polypropylene, plastics with a thin, clear protective film, and similar plastics because they tend to warp, catch fire, and melt. Avoid using PVC because it produces toxic fumes during cutting. PVS has a slight bluish edge color and when bent the crease turn white and does not snap. Polycarbonate and Acrylic would snap. Polycarbonate does not cut cleanly and the cutting process creates charring and red or yellow residue. Plywood and Masonite Pros: For materials up to 1/8 thick, you can achieve high detail and etch quality. Cons: Slow cutting process, significant charring occurs on edges, and top and bottom surfaces may burn. Masonite has an inconsistent density and rarely cuts all the way through. Note: If you are only cutting rectangles out of ¼ stock, do not use the laser cutter. Use the tables saw because it will cut faster without burning the edges and surfaces.