CNC Laser Cutting | What is Laser Cutting of sheet metal work?

WHAT IS CNC LASER CUTTING?

Sheet metal work with a CNC laser cutter

Computer numerically controlled (CNC) laser cutting is a sheet metal manufacturing process carried out by CNC laser cutters. The primary form of laser cutting for sheet metal is ‘vaporisation cutting’, in which the laser beam melts the material and a high pressure gas removes the molten material. The 3 main types of laser cutter are flying optic; moving material; and hybrid laser cutting. A flying optic laser cutter has a stationary bed for the cutting material, with the laser beam head (optic) moving in the X and Y directions above. The moving material works much like the standard punch presses, with the beam in a fixed position and the material moving in the X and Y directions beneath. The hybrid usually moves the work piece in one (X) direction, and the optic head/beam moves in the perpendicular (Y) direction.

The processing range for most CNC laser cutters is from 0.3mm up to 25mm for the higher powered models. The laser cutter can cut a variety of materials including mild steel, stainless steel, aluminium, zintec steel, pre-galvanised steel, copper, brass and more. CNC laser cutting use various gasses to aid the cutting process, which can include compressed air, nitrogen and oxygen.

While laser cutters are capable of creating more intricate shapes, they are limited in the way they can form the material. If you have a sheet metal design which needs material to be being formed then a CNC punch press is more suitable i.e. dimples, knockouts, louvres, countersinks, formed threads, etc. Combination (Combi) machines are available which have combined the laser cutter for intricate shapes and a punch press turret for simple shapes and form tools. Getting the best of both CNC laser cutting and CNC punching in the same machine cycle.

Laser cutters are generally faster than CNC punch presses when it comes to thinner gauge materials and that have fewer individual holes. This is due to the initial piercing of the material that slows the laser cutter down. This is also true for thicker gauges as more heat is required to melt through the material.

Programming components on a CNC laser cutter

Information about a design may be interpreted from a 2D file format such as DXF or DWG files or from a 3D file such as a STEP file, SAT file, etc. This information is then used to create the flat shape, altering the cut size for any bend allowances or anything that may affect the final component. Software packages can also be used to establish the most efficient layout of components from a given sheet size. This could be a standard sheet size such as 2M x 1M, 2.5M x 1.25M and 1.5M x 3.0M. It can also be off-cuts of materials from prevous jobs. This process is known as CNC nesting. Software packages like Radan® can automate this process to achieve the maximum yield from a single sheet metal panel, or even a selection of sizes of sheets as well as nesting a variety of different parts within the sheets. Creating groups of parts on the same sheet can increase the material usage efficiency.

CAM for laser cutting is generally more straight-forward than punch press programming. However, there are many factors to consider. Such as tag location, used to prevent the parts tipping in the nest; off-cutting, used to save the best size and shaped off-cut; and scrap-cutting, to turn the remnants into small sections that will fall between the slats of the laser cutter bed, to handle the whole laser cutting process.

Pros and Cons of laser cutting compared to CNC punching

Advantages of CNC laser cutting:

Quicker on thinner gauges (approx. up to 1.2mm) than punch presses, provided few lead-ins.

Can produce more intricate designs as well as holes thinner than the gauge, within reason, e.g. 2.5mm hole through
4.0mm steel.

Easier to program.

It doesn’t rely on having a wide range of tooling, which may not allow for certain sized cut-outs.

A cleaner cut through most* materials, without nibbles marks.

(*Aluminium is slightly more problematic)

Disadvantages of CNC laser cutting:

Slower than punch presses through mid-range to thick sheet thickness e.g. 2.0mm and up.

Added cost for nitrogen or oxygen on thicker gauges of metal.

Cannot form features; i.e. dimples, louvres, knockouts, countersinks and taps as there is no physical contact between the laser head and the surface of the metal sheet.

Cannot laser cut perforated/mesh sheets efficiently.

To see more information of our Trumpf 3030 3KW fibre laser take a look at our fibre laser plant page.

In conclusion

We use our Trumpf fibre CNC laser cutting machine in combination with our Trumpf CNC punch presses to enable us to offer the best process to suit the components being manufactured. Hopefully then the price and quality will be right for each customer’s parts and volumes required.

Using a fibre or fiber CNC laser cutting machine (depends whether you are in the UK or USA) is much quicker on thinner sheets of metal than a CO2 laser. With our customer base mainly looking for thin (under 3mm thick) components the fibre laser cutting machine is the one for us.

https://youtu.be/ltts7ocVv10

Gallery

Fibre laser cutting zintec sheet metal panels for lighting companies in the UK with our Trumpf 3030 3KW machine. This gauges can be cut very quickly with this machine and it has proved to be very productive in production and in producing samples.

Laser cutting with our Trumpf 3030 3KW fibre laser. Stainless steel mounting plates cut from a 2mm think 2M x 1M 304 sheet. You can see from the photo how well the material has been used with very little waste.

Laser cutting aluminium housings for speed camera LED display signs. Each sign had a different hole pattern to correspond with the sigs output. Once programmed the laser is perfect for this job with no tooling needing to be changed.

Fibre laser cutting ornate patterns in plastic coated 314 stainless steel sheet metal. A special project to produce hand rails in a residential home. Again, a laser cutter is perfect for producing parts with odd shapes, letters, number and curves.

Laser cutting zintec coated mild steel gear trays for light fittings. On a job like this where it may take 10-15 minutes to laser cut the whole sheet the machine operator can be getting on with selecting material for the next job or deburring laser tags from a previous job.

Trumpf 3030 3KW fibre laser cutting 5mm thick mild steel brackets from material off-cuts. The thicker end of the type of work we produce at V and F Sheet Metal.

Small stainless steel brackets being laser cut from a 2M x 1M sheet of 0.9mm 304 material.

Laser cutting 0.9mm thick zintec sheet metal. These blanks will become light fitting recessing housings.

Can you find these parts above, laser cut from stainless steel.

Ornate shapes are easily programmed for laser cutting, Look above fro the finished laser cut stainless steel parts.

Automatic nesting of any shape to get the best from a sheet of metal.

A selection of parts all laser cut from the same sheet of metal. The ease of laser cutting is it's material handling capabilities.

Trumpf 3030 3KW fibre laser cut parts removed for inspection. You can stop the laser at any point and remove a finished part to double check the physical size to drawing and the quality of the cut edge. Adjustments can be made if required and then production can continue.

Laser cutting plastic coated brass sheet. These shapes were part of a one off special installation display in a TV studio. The laser is great for getting the most out of any size sheet.

Laser cutting 5mm thick mild steel sheet. Although our laser cutter is capably of cutting 20mm thick mild steel we stop at 6mm thick. This is purely a handling choice. The vast majority of our customers require thin sheet metal so the service we provide it a perfect match.

Laser cutting aluminium panels with pure nitrogen. These panels could have been produced by CNC punching or laser cutting. We have the option to go either way in house on some parts. This enables us to have the flexibility to produce the right parts at the right time for our customers.

Laser cut brass brackets are easy when you have a fibre laser cutting machine. The shape really lent itself to laser cutting with a series of curves blending together. Just a quick barrel deburr and the parts were complete.

Laser cutting 0.9mm zintec components using compressed air. Our laser cutter simply flys through this material at 0.9mm thick. Complex profiles and different holes sizes are no problem. The parts are also very easy to program and were cut with compressed air.

2M x 1M sheet of Zintec being laser cut with compressed air. If the edge finish is not so important and the material is thin then compressed air can be considered as the cutting gas. It’s cheaper than nitrogen and quite acceptable for many people.

Using an off cut of material to cut mild steel brackets. The laser cutter is a very flexibly option when it comes to using up off cuts of material from previous projects. Even the internal windows from previous jobs can be used up if they are larger enough.

Laser cut mild steel blanks used to produce formed and folded brackets. Laser cutting was ideal for these parts as although they were simple the outer profile had several different corner rads and edges joining at tangents.

Laser cut 304 stainless steel panels with ventilation grille sections. The inner squares were scrap and show nicely the start point of each window now being on the final component edge.

Laser cut stainless steel blanks still in their sheet nest. These blanks were then folded up to produce light fitting mounting brackets.

Mild steel ceiling mounted housings, laser cut, folded and with seam welded corner joints.

Customer Testimonials

“We have consistently used the services of V&F Sheet Metal since the late nineties to date and they are our prime supplier for sheet metal work. We are very satisfied with the levels of service and competitive pricing that we get from Ray & the Team.”

Director and owner of a Pump company in Hampshire

“The team at V&F Sheet Metal have helped us over the years with projects ranging from the sublime to the ridiculous! At either extreme we have always received fair pricing and excellent service.”

Director and owner of a Pump company in Hampshire

“V&F Sheet Metal is a key supplier to my fan manufacturing company. We know we can rely on them for a fast response to new inquiries and that they can assist us with the design, development and efficient manufacture of fabricated parts.”