Bas-relief production, how fast is my cnc router?

Have you ever wondered if your CNC machine is fast enough to perform a bas-relief?

Or why the execution times of the same bas-relief, on the same type of marble, with the same tool and with the same cutting feed differ from one machine to another?

And what if you could execute a bas-relief in three hours rather than in five?

What about the differences between an economic CNC and a more expensive one?

Just as in every sector, there are numerous manufacturers and various models of machines. You can create a bas-relief with any CNC machine but the time it takes and the quality of the final work will differ between each machine.

When we talk about Numerical Control Machines (CNC router or Machining Centers) both in the field of marble processing and in other sectors, a very important factor is the balance between quality of finish and execution time.

This ratio depends on the quality of the movement dynamics provided by the NC module that controls the CNC machine axes. When a part-program is loaded on a numerical control, in practice the machine only states the trajectories that the tool must perform. But the NC, internally, will calculate how to perform these trajectories in terms of speed, acceleration, and deceleration.

The machine with a “perfect” dynamic is a machine that has:

• Maximum machining precision
• Maximum quality of finish
• Minimum processing time
• Minimum stress on the mechanical components

Obviously, there are compromises that depend on the field of application of the machine: stone, wood, plastic, etc. The field of application, and therefore the final product, dictates a whole series of requirements that the machine must respect. Each application has its own different requirements in terms of processing speed, precision and finishing quality of the final product.

The calibration of the dynamics on a CNC router that works marble and granite is very different compared to the calibration on wood, forex, aluminium or plexiglass machines.

Therefore, based on the precision / minimum finish to be obtained, and the type of mechanics that moves the machine (ball screws, pinions, and racks, belts), the parameters of the dynamics have to be calibrated to minimize the execution time for completing a piece of work.

These parameters depend on the type of numerical control (CN) installed on the machine.

The more advanced the CN, the more parameters you will be able to control, which decreases the execution time of a given process. This will allow you to obtain a high precision finish in a shorter time.

Our CNC marble and granite pantograph Next is driven by the latest generation of powerful CN OSAI Open-Smart. We have chosen it for its reliability and for its range of parameters that allow us to manage many aspects in the processing cycle.

Here are some of the parameters that enable excellent speed performance in the execution of bas-reliefs on marble:

• Acceleration and deceleration of ramp type
  Parameter that defines the type of acceleration and deceleration of the axes. You can choose between linear ramp, non-linear S-ramp, trapezoidal ramp, and ramp with jerk limitation.

• DLA – Look ahead decelerations (See Next)
  Algorithm that considers the blocks of movement that make up the profile and that follow the block in execution, in order to recalculate the speed of exit from the various bodies, taking into account the type of profile to predict the deceleration on the corners.
  If the profile includes sudden changes in trajectory and the length of the bodies is not sufficient to guarantee the correct deceleration, it is essential to have the option to quickly predict these situations in advance in order to adjust the speed.

• Maximum speed jump on the corner
  Parameter that defines the maximum velocity jump for the axes at an edge.
  

• CRV – Speed optimization parameter
  This parameter is used to optimize the calculated speed value in the case of curved sections described by a sequence of very thick points or “noise”.

• MOA – Motion Auxiliary
  It allows the dynamic filtering of small movements in order to avoid delays and to guarantee the achievement of the programmed quota.
  

• ERF – Form error
  The ERF variable is used to check the shape error while a profile is running when there is an activated average point filter. The ERF algorithm, starting from the maximum error set with this parameter, calculates a given angle between two contiguous movements and the number of points of the filter, the speed with which the corner must be addressed.
• As mentioned above, these are just some of the parameters for managing the dynamics of the movement present in an OSAI numerical control.

Thanks to a CN of this level in the CNC Router Next you have the option of setting the configurations according to what you need and the material that you’re working with. For example, you can change configurations to suit stone or wood carving, or you can choose to prioritize accuracy over execution time.

The configuration of the standard dynamic present in our CNC router is optimized to minimize the processing times on marble and granite, with particular focus on the execution of low reliefs. Our CNC router Next is able to make a bas-relief of dimensions 140 x 160 mm, with a pitch of 0.3 mm and with a feed of 1000 mm / min in just 50 minutes.

Useful Links:

• 3 Axes CNC Router Amastone Next
• Configurator to create a quotation for a new CNC Router Amastone Next
• E-Shop for marble and granite tools