LASER CUTTING ESSENTIALS
HERE'S THE THEORY
Laser Cutters are not difficult to use, but they do require some preparation in advance of using the machine, and they are potentially hazardous. Before we allow anyone to use the machines for themselves, you need to know:
1. What you can and cannot use the machines for, what the main hazards are, and how you can reduce the risk of incidents occurring.
2. How to prepare digital files for our machines using Rhino.
3. How to use the Template file.
4. How to prepare your files for our '7s Challenge' Essentials task.
You must follow all four parts of the online guide, prepare your file for cutting, and check your file and programming with a Lab Staff and they will then book the Practical part for you.
You should only need about 5 minutes to go through the points, and 5 minutes to complete the quiz.
What do laser cutters do.
Laser cutters use an extremely fine beam of light at a very high temperature to burn through material. This fine beam allows you to cut at a very high level of precision and detail. Using your line drawings in CAD the laser follows those lines, cutting as it goes. However, laser cutters do not only cut through material, they can also engrave into it. Text or patterns, or even Jpegs; think of it as a monochrome printer.
With the ability to use the laser cutter you will quickly be able to incorporate a level of precision and detail into your work that you would not be able to achieve by hand alone. But before you can do this you must first complete the Essentials.
What laser cutters do we have.
We have five Trotec laser cutters, they are named Kahn, Corb, Mies, Zaha and Liz. They have important differences:
Kahn has a 30W laser and can cut material up to 2mm but no MDF. It has a bed size of 720mm x 430mm Mies and Corb are both 60W and can cut everything we stock within a bed size of 720mm x 430mm
Zaha and Liz are a 100w and they are also bigger than the other three, their bed size is 1000mm x 610mm. Their only limitation is that she does not cut MDF.
It is important that you remember the differences between each machine.
What Materials can you use on the laser cutter.
Due to the risks involved in laser cutter, the potential for fire or for toxic fumes to be created you can only use the materials that we stock and provide. However this is an extensive selection. From paper and card to acrylic and wood. There is a wide price range so that all your model making needs are supported. From quick sketch models made in card to more polished final models made from finer materials.
What are the hazards.
The hazards involved with laser cutting can be great if proper safety measures are not followed. The rules that we have set out for you to use the laser cutters have been put in place to minimise these hazards, so for these hazards not to occur you must all take responsibility for following them at all times.
As the laser cutters use heat to cut the material, the possibility of fire is always present. This hazard is minimised by constant vigilance of the laser when cutting. At no point should you be unable to observe the machine.
A by-product of laser cutting is the fumes from the burning material. We have extraction systems fitted that insure all the fumes are extracted and filtered safely. However, if you lift the lid to quickly you may be exposed to a small level. To avoid this after the laser has finished always count to 10 and then lift the lid.
Although you can use any CAD software to draw your your work to be cut. you will need to import it into a custom made template in Rhino. So it is best that you familiarise yourself with Rhino before you begin. A good place to start are these tutorials on youtube: An introduction to rhino. Once you have grasped the basics of rhino you can download the template file. Always download a new template every time you use the laser cutter.
Once you have opened the template you are ready to either import your CAD drawing or you can start draw- ing in rhino. The most important part to understand within the template is the different layers. The layers are activated by the light bulb next to each layer. Activate the laser cutter layer and expand it to show the sub layers.
- Your drawings here:-Your drawing must appear in the following layers:
- Etch - (black) this is what you use to engrave. Think of it like a chisel (rather than the other three layers that a more like a knife. If you want to etch a line you must give it a thickness in the line weight option in properties.
- Score - (red) Is like cutting but only goes half way. It is used for folding and is also very useful for marking out lines.
- Internal cut - (blue) This will cut first, it is important to maintain accuracy, so all internal parts should be cut first so that they do not move.
- Perimeter cut - (green) This is the last part of the drawing to cut.
- Materials - It is very important that when laying out your drawing to be cut, you have the material you will use selected as all materials are different sizes and all are smaller than the laser bed itself. They must always remain locked.
• Guide - this contains all the information you will need, including how to use the machine, material prices and the do’s and don’ts of laying your drawing out.
Nesting.
When you arrange your drawing in the template ready to cut, this is called nesting. You want to arrange the drawing in such away that it wastes as little material as possible and cuts in the fastest time. The screen shot below shows a right and a wrong way to arrange.
- Your drawing should be up against the dashed line
- You can share a line, so instead of separating objects out you have them share a single line. HOWEVER, DO NOT SIMPLY PUT ONE LINE ON TOP OF ANOTHER. YOU MUST ONLY HAVE THE ONE LINE.WRONG - A waste of material RIGHT - Saves time, money and material
• You do not need to send everything all at once, if you have a lot of small pieces or a lot to etch it is quicker to send them one section at a time using the ‘hide’ and ‘show’ commands.
Our Laser Cutters have been setup to run directly from Rhino. This makes them easy to use and more likely to produce good, predictable results. You must however use the Rhino Laser Cutter template for any use of the machines. They won't work with any other file type.
The Template file is extremely rich and includes a host of information in the 'Guide' layers. It also represents the sizes of the beds on our different machines and the size that we supply materials. We recommend that you:
- Always work from the latest Template file, which you can download below
- Do not change the file, apart from adding your own drawing into the appropriate layers
- Do your drafting in a separate Rhino file or whatever other software you like, and then copy/import what you want to cut into the Rhino Template
- If at any time your Rhino file becomes corrupted or confused, just download a fresh, up-to-date copy and start again.
- If you have any questions or want your file checking before using up your booked time, come in advance and ask a Lab Staff for help.
Essential drawing - the ‘7’s challenge’
For your Essentials you will need to draw a plaque to a very specific criteria. The outer perimeter need to be 77mm square. Inset within the perimeter are four internal squares measuring 7mm square, they are to be set in 7mm from the perimeter. You must have your name, group and date within the plaque. You can be as creative as you like.
Essential drawing - the ‘7’s challenge’
For your Essentials you will need to draw a plaque to a very specific criteria. The outer perimeter need to be 77mm square. Inset within the perimeter are four internal squares measuring 7mm square, they are to be set in 7mm from the perimeter. You must have your name, group and date within the plaque. You can be as creative as you like.
If you think you need to, go back and review these 5 stages and 15 points. If you are sure you've taken them all in, then please now proceed to the Quiz to see if you've got it!
If you want to progress further please register or login first!
Book a Slot
If you are not able to book a slot (greyed out button) and you have completed your Laser Essentials last term or earlier, please come to the Lab to get your record updated.
FABRICATION LAB
University of Westminster
College of Design, Creative and Digital Industries
35 Marylebone Road, London NW1 5LS
