Laser Cutting Of Metals A Simple Explanation Of The Basics

Recently, many friends asked me privately in the background, besides sharing the knowledge of 3D printing every day, could you share a little knowledge of laser cutting?Can no problem, today to arrange the basic knowledge of laser cutting metal.

1. The laser

In short, a laser is a focused beam of light that concentrates a lot of energy on a very small area.When this happens, the material in front of the laser burns, melts or vaporizes, creating a hole.Add a few CNC's and you get a machine that can cut or carve very complex parts made of wood, plastic, rubber, metal, foam or other materials.

Each material has its limitations and advantages when laser cutting.

Not every material is suitable for laser cutting.Because materials have to cut a certain amount of energy.For example, cutting paper requires much less energy than 20 mm thick steel plates.The 40-watt laser cuts through paper, cardboard, foam and thin plastics, while the 300-watt laser cuts through thin steel and thicker plastics.If cutting through 2 mm or thicker steel plates, a minimum of 500W is required.

In the following, you will study whether to use personal equipment or laser cutting metal services, some design basics.

In this age of CNC machines, laser cutters that can cut through metal are still too expensive for the average hobbyist.

The metal-cutting laser must use a minimum power of 300W, and the metal-cutting machine also requires gas (usually oxygen) to cut.In addition, metal laser cutting machines are of very large dimensions and usually work in a workshop.

Laser cutting machines are getting cheaper and smaller, and we can expect desktop laser cutting machines for metals to become ubiquitous in the next few years.

Natural laser cutters are not toys, especially if you're doing metal cutting.May seriously harm our lives and property safety.

2. Design skills

Because laser cutting is a 2D technique, it is very easy to prepare the file.There are some guidelines to follow when designing parts, and I've collected some here:

1. Close the contour

All cutting profiles must be closed.This is the most important rule.If the contour remains open, the part cannot be removed from the original sheet metal.There are exceptions, if used for engraving or etching, which can be done without closing the contour.

2. The round hole

If you must have a small tolerance hole, be able to drill the hole with a laser first and then with a bit.The perforation creates a small hole in the material, which is then guided by the drill bit during the drilling process.The diameter of the perforation should be about 2-3 mm.In my experience, in this case, use the smallest possible hole, preferably one of the same thickness as the material if possible, and gradually drill larger and larger holes until the desired diameter is reached.

3. The screw holes

This is only for material thickness of at least 1.5 mm.For example, steel melts and evaporates during laser cutting.After cooling, the cut becomes hard and difficult to thread.So before thread cutting, it is best to laser the hole and then drill.

4. The Angle of fillet

Sheet metal parts may have sharp corners, but adding chamfering to each corner (at least half the thickness of the material) will make the part cheaper.

5. Gaps and lugs

The minimum width of the notch shall be at least 1 mm or the thickness of the material, whichever is greater.The length must not exceed five times the width.Lugs must be at least 3mm thick or twice the material thickness, whichever is greater.As with grooves, the length should be less than five times the width.

The distance between slots must be at least 3 mm, and the minimum distance between lugs must be 1 mm or greater in material thickness.Failure to follow this rule may cause parts to deform.

6. Multiple parts or thin parts

When cutting multiple parts on the same metal plate, a good rule of thumb is to make sure that the distance between them is no less than the thickness of the material.If the parts are too close to each other or the cut parts are too thin, the material between the two cutting lines may burn off.