Design guidelines for Metal Laser Cutting Service

Posted By Sculpteo on Mar 29, 2017 | 0 comments

We recently launched our new metal laser cutting offer. Online metal laser cutting is an easy, fast, and high-quality way to create your mechanical and aesthetic parts, but, to make the most of it, it is important to apply some essential design rules. Today, we share with you those design rules, as well as some information about how metal laser cutting works, that will help you understand the reasons behind the design rules.

What is our online metal laser cutting service?

Laser Cutting is a type of digital manufacturing technique which is known as “subtractive” that uses a large amount of energy generated by a laser. This laser concentrated on very small area in order to cut or engrave the material and enables to cut until 20 mm thickness of material depending on the types of laser.

On our online laser cutting service, you can laser cut your parts extremely easily, by simply uploading your 2D file on our platform, choosing your material, and ordering.

To learn more about laser cutting, you can read our “History of laser cutting: from MASERS to CO2 Lasers”, and our free ebook: The Ultimate Guide to Laser Cutting.

We have a wide range of materials, but in this article we’ll focus on our three metals: steel, stainless steel and aluminum. We offer laser cutting and engraving, but engraving is not recommended for metal, since the engraving is very light and sometimes is not very visible.

To learn more about all our laser cutting materials, read: “Which laser cutting material for which application”

The particularity of metal laser cutting compared to other materials: laser initiation

For Metal Laser Cutting, the laser initiates before cutting or engraving. This initiation will naturally leave a mark on the material. This has several consequences in the design rules for metal laser cutting:

1. Your details can’t be smaller than the metal sheet’s thickness.

For metal laser cutting, because of this initiation, you can’t include in your design details that are smaller than the material’s thickness. It goes for holes (their diameter needs to be bigger than the thickness), and any other kind of detail. The thickness of the materials available for all metal laser cutting in Sculpteo are: 1 mm, 2mm or 3mm.

If this first design rule isn’t respected, laser cutting can leave marks on the part. To ensure the best quality standard, we won’t accept a design that doesn’t respect this design rule.

Scratches on the surface of an Aluminium laser cut part

2. A minimum distance must be respected between two lines.

This is true for laser cutting in any material, but needs to be respected most particularly for metal laser cutting. The minimum distance between two lines are: 2 mm, 2 mm and 3 mm, respectively for the material thicknesses of 1 mm, 2mm and 3mm. As for the previous design rule, we won’t accept a file that doesn’t abide by this constraint, as if we did we wouldn’t be able to guarantee the best quality standards.

3. Laser cutting multiple objects: be careful of the inside and outside!

The third rule you need to keep in mind specially for metal laser cutting is that you won’t receive the off-cuts, only the finished objects. I’ll explain: for all our other laser cutting materials, you will receive the “order frame” with the object: a rectangle that contains your laser cut objects and the matter that is between the different objects. This allows you to create multiple objects without having to think, when you’re designing, of what’s the part you’ll keep and what’s the off-cut.

For metal laser cutting, it is different: the offcut is used for the initiating of the laser, and will therefore be scarred. This is why you won’t receive it, you’ll only receive the parts themselves, without the order frame.

How to take this into account in your design? You need to only create closed objects (the lines can’t intersect and they need to be continuous). And you need to be careful of what’s the inside of your object and what’s the outside.  

We’ll take the image below as an example. If you submit a file which only contains yellow and blue drawings without the outer black square, then the inside of the objects is the inside of the blue and yellow lines. You will receive a square, stars, rectangles and disks. But if you upload a file that contains the black square and the blue and yellow drawings, then the inside of the object is the inside of the black square, minus the inside of the blue and yellow lines. You will receive the black square with holes in it, in the shape of the rectangles, discs, and stars.

Classical laser cutting design guidelines applied to our metals.

On top of those 3 very important specific design guidelines, metal laser cutting has to respect the classical laser cutting design guidelines, just like our other laser cutting materials. Those guidelines are:

1. Maximum and minimum laser cutting size.

The dimensions of the machine’s cutting table determine the size of your design which has to be, at most, 1000mm x 1000mm. Above this measure, it cannot be cut by our machine. You also need to respect the minimum dimensions of 15mm x 15mm because if the objects are too small, it could be lost under the cutting table grid.

You can refer to our material pages for aluminum, raw steel and stainless steel for more precision and guidance.

2. Laser Cutting and Laser Engraving your Texts.

If you need to cut or engrave text, the process is quite simple. Your file needs to be vectorized and upload to our platform just like the other materials. For full letters (A, D, O, B, G…) it is better to create a link to separate the inside and the outside of the letter (see the example below) so that the center does not get detached from the rest of the letter and to keep the outer parts of the cut or ‘stencil’. This link makes your text look better and organized. For consistency, you can even use this link on the letters that don’t need it. Read more about preparing texts for laser cutting and engraving on our laser cutting tutorials.

Keep in mind that with metal laser engraving, the result isn’t very aesthetic, and is not always very visible. It is recommended to use it for serial numbers and post-processing marks, but not for readability or decoration. We sometimes can’t avoid scratches on the surface of our metal laser cut parts.

What materials do we offer for metal laser cutting?

Aluminum

We offer the aluminum called AIMg3 which is manufactured using a continuous casting method. Its durability and ease of use make Aluminum convenient for many uses. Its benefits range from high corrosion resistance to high strength compared to its weight. Aluminum has a smooth surface even after the cutting process. This material also does not need a rustproofing treatment, the surface is relatively shiny which offers possibilities for aesthetic objects and many applications for industries such as automotive, aerospace or energy.

Aluminum can be folded with the appropriate equipment or by including specific designs in your part to make it foldable by hand.

As for all metal laser cutting, scratches are inevitables in aluminum material. In order to avoid scratches on the surface, it is recommended to avoid sharp edges and hard friction on the material surface. We advise you to use a clear lacquer or light oil in the surface to protect it. The back of the sheets can have scratches easily however it is easy to remove with a light abrasive.  

Stainless Steel

Our Stainless Steel material is known as 304L which contains 10%of nickel and 18% of chromium. The material has a brushed surface which is covered by a plastic film during the cutting process. This brushed finish is called GR220: the number 220 refers to the fact that the abrasive used to brush the material contains 220 grains per cm². The same as the other metal materials, stainless steel can be folded using appropriate equipment or design.

Stainless steel contains large amounts of chromium which makes the material highly corrosion-resistant. It has an excellent solidity, weather resistance and is suitable for many applications, including to be used outside.

Steel

Steel is darker than the two other metal materials and it is the roughest and solid one. Steel has excellent mechanical properties in terms of its strength, toughness, ductility, weldability and durability. This material can be applicated in the construction industry, automotive and energy sector as steel is widely used as a structural material. However, the raw steel is not as resistant to high corrosion as Stainless Steel and Aluminium.

Finishing.

We do not provide any finish directly online for our laser cut parts. But you can apply your own surface finish on your parts (painting, polishing…).

Do you want to learn more about our online laser cutting service?

Read our article on “How to use the interface for Laser Cutting?”, this will give you wider image to use our service. 

You can refer to our free tutorials for more precision and guidance for your vector construction, on Illustrator, Sketchup and Inkscape. 

Finally, you can also read our free ebook: The Ultimate Guide to Laser Cutting, for insights about how laser cutting works, what’s its history, its specific design guidelines, and our online service for laser cutting.