3D metal cutting: how to choose the right technology for your production plant

If you are considering whether to buy a metal-cutting system, one of the most important decisions is which technology to focus on.

There is no best choice in absolute terms, but there is always one best suited to your needs. It depends on the type of machining and the objective you want to achieve: flexibility, productivity or quality of the produced parts.

Cutting metal with a five-axis machining center

How it works

A five-axis machining center allows you to cut complex geometries, as well as holes, slots, milling, traces of any shape on the part, literally sculpting the desired part from a block of raw material. This is a highly flexible chip removal system, but it is intended for machining solid or thick pieces (cubes or three-dimensional blanks).

Pros e cons

• Flexibility: CAD/CAM software allows you to program the work cycle off-line, simulate in and send it into production
  
  
• Productivity: cycle times are longer than other technologies. This is why stock removal processes are suitable for small-medium batches or prototypes
  
  
• The cutting edges, like the entire surface made by stock removal, can achieve degrees of roughness close to those obtained by grinding, but it is time consuming and requires specific tools
  
  
• Stock removal is not the right technology when the material thickness is reduced to a few millimeters. For this reason, five-axis machining centers are only used to process three-dimensional profiles, such as curved, hydroformed, molded or deep-drawn tubes.
  
  

There are many reasons for this:

• Tool wear, especially when processing hard materials, such as high-strenght steel or hot stamped parts. 
  
  
• Possible breakage of the tool, because:
  • It is forced to work in an "unnatural" way, concentrating wear only on one part of the cutting edge.
  • It is subject to vibration or seizure, which causes it to chip or break completely.
    
    
• Vibrations and deformations of the part or cutting edge cause by stresses that the tool generates on the workpiece by its nature.
  
  
• Difficulty in clamping the workpiece to compensare for the forces, produced by the tool. This is particularly difficult when it comes to a thin profile.

Blanking and punching

How it works
Mechanical profile cutting operations which use the combined action of a punch and a die to cut a desired shape/geometry out of a flat piece of sheet metal.

Example of punching machine

Pros and cons

• Flexibility: The need for punches, dies and punching blades in a shape dedicated to the type of hole or geometry you want to make means that this technology is not very flexible, especially when the final piece is particularly complicated.
  
  
• Productivity: In the processing of large production batches, this technology guarantees high productivity standards because the part is cut in a single stroke. It is not suitable for small production batches or prototypes, where making dedicated tools no longer becomes economical.
  
  
• The cutting edge created by blanking has several disadvantages, namely deformation due to entry of the tool, presence of burrs on the opposite edge, inclination of the cutting edge which is not parallel to the action of the tool. These issues can increase over time as tools wear.
  
  
• In order to ensure sufficient tool strength, the blades must respect certain minimum dimensions. This increases scrap volume, material waste and, in many cases, prevents thin cuts.

Plasma cutting

How it works
Plasma cutting is performed by a gas under pressure, transformed by an electric arc into plasma and projected onto the surface to be cut.

Pros and cons

• Flexibility: Plasma can only cut conductive materials and is mainly used for cutting thick sheet metal.
  
  
• Productivity: it offers good productivity on very thick sheets or profiles, however this advantage is quickly reduced with thinner materials, where the laser cutting is by far superior.
  
  
• Plasma cutting edges are not as precise as laser cutting, have poor perpendicularity, and increased cutting slag. These defects require labor intensive rework.

Five-axis laser cutting

How it works

When cutting 3D profiles, such as curved tubes, stamped, deep-drawn and hydroformed sheets, laser cutting can offer significant competitive advantages in terms of productivity, flexibility and precision.

Pros and cons

• Flexibility: With five-axis laser, you can cut a wide variety of three-dimensional shapes in different materials and thickness. The software can make a difference, allowing you to program the work cycle quickly and easily, greatly reducing production times. 
  
  
• Productivity: cutting speed is one of the main characteristics of the laser, especially on thin materials. Some systems are equipped with automatic loading or unloading systems, or solutions for loading in the background. The faster cutting speeds, combined with automatic material handling, offers significant advantages in terms of competitiveness.
  
  
• Accuracy: In laser cutting, the higher the finish of the edges, the lower the thickness to be cut. However, precision is much greater than that of plasma. The ability to concentrate a great deal of power in an extremely small area allows for a much thinner and faster cut. The surface of the cut edge is much less inclined than plasma and rework isn’t required. 
  
  
• Not all lasers are the same. To achieve a better cutting quality, you need a high-level system equipped with software solutions for the automatic optimization of technological parameters.

Discover LT-FREE: the 5-axis laser cutting machine for processing any 3D part

Finally, what technology will give you a competitive edge?

After this overview, it’s time to find out which technology is right for you.

When purchasing a new machine for cutting 3D metal profiles, such as curved, hydroformed, stamped and deep-drawn tubes, the main factors to consider are: 

• Lower cost per part
• Processing quality
• System features: performance footprint, power consumption operators, etc.

Choosing the right production system is a process that can take many months and involves many people in the company. However, there are a few steps that will ensure you make the right choice in the best possible way and help you evaluate the purchase in every angle:

• Go to trade fairs and visit manufacturers
  Trade fairs are an excellent opportunity to see a system at work and to be able to compare what technologies are available. Taking part in trade fairs and other events will help you understand what the market has to offer and will give you an idea of what you need, but given the large number of people and the short time that the exhibitor consultants have available, the next step is to schedule a visit directly with the manufacturer.This way, you can achieve a much clearer idea of the system and how it will meet the specific needs of your production.
  
  
• Test the system you want to buy
  When visiting a manufacturer, it is useful to prepare one or more challenging sample parts which are representative of your production and also those that you are planning to make in the future. This will give you an effective way of understanding how well that particular system is suited to your needs.
  
  
• Seek a reliable supplier, but not only…
  

  A renowned and well-known supplier in its field is certainly an added value, but sometimes the name is not everything. Before completely relying on a “name”, you should also ask yourself: "How important will I be to this supplier?"

  Especially when you choose a new system:
  
  
  1. Always make sure that the supplier can offer comprehensive service throughout the life cycle of your plant, such as maintenance plans, training, telephone support, spare parts, etc.
     
     
  2. Always make sure that the supplier is really dedicated to you and your business, offering a team of local, specialized technicians.
     
     

  Sometimes large multinational machine tool manufacturers tend to neglect small customers.

• Imagine your future work
  

  Evaluate how the introduction of the new system will revolutionize your manufacturing capabilities, both in terms of production and business dynamics. Always rememberthat development and change are the foundation of your competitiveness.