Questions and answers relating to laser technology

Which materials are suitable for lasering?

In general, lasering suits all materials that are also recommended for conventional
chemical etching.

Aluminium is also good for lasering. All other non-ferrous metals on request.

Suitable materials include: 

Material no. Eschmann Name short name
40 CrMnNiMo 8-6-4 1.2738 EST ES Aktuell 1000
--- Special alloy ES Aktuell 1200 *) Standard for master pattern
40 CrMnMo 7 1.2311 EST ES Aktuell
--- Special alloy ES Multiform SL
X37 CrMoV 5-1 1.2343 ESU *) Limited as shown below ES Maximum 500
---- Special alloy *) Limited as shown below ES Primus SL


Special consideration of the material's suitability for graining must particularly  be taken into
account when combining laser technology and conventional chemical etching, e.g. with heavily
directionally orientated graining or the like. 

The same requirements apply here as for classic graining produced in an etching process.

Which data must be available?

Laser technology is a purely digital process chain. In addition to the graphical information
(greyscale) of the respective structure, the tool data is also used as a basis for the processing.
This must be provided in a .stp bzw..iges format and correspond to the final set of tool data.
We need the data solely for the contour area to be processed, i.e. without base plates, mould
frames and assemblies or the like. 

The graining direction (e.g. through the crosshair or the like) and also the graining limits should
be clearly defined in the data, particularly with directionally orientated structures.

An exchange of data is possible via the download portal of the Eschmann Textures Group or via
the data exchange platforms of the respective customers. 

The data should be made available to the processing location at least 3 weeks prior to delivery of
the tool.

Are special polishes required?

Areas to be provided with a lasered structure must have a certain surface quality (polish)
depending on the design.  

Requirements

  • General, 320 grain, groove-free
  • Fine structures, 400 grain, groove-free
  • Completely remove spark eroded residues, milling marks, etc.
  • Split lines must be aligned and free of burr
  • It is important to ensure that design and light edges and maintained
  • A test area sized 50x50 mm outside the split plane is recommended –
    as with conventional etching technology 

Lasering and high gloss! Excellent matt-gloss effects can be produced in combination
with highly polished surfaces, particularly when using suitable tool steels and plastics.

How are loose parts lasered?

Generally loose parts in the main visual area, such as sliders or inserts, should be
lasered in the assembly with the main mould (cavity).  Loose parts must be produced
from the same base material.


If loose parts cannot be lasered in the assembly, e.g.in an undercut situation or if there is restricted
access to the (slider) in build, a reference point system for the tool needs to be agreed with the
toolmaker, which ensures perfect laser control for separateprocessing. Fitting holes outside the
graining area, for example, which define the precise position in the X/Y/Z direction for the laser
process, suffice in this respect.   

What is meant by gloss level?
Photo source: BYK Gardner

"Gloss is a visual perception that occurs when viewing surfaces. The gloss perception is more
pronounced, the more directionally the light is reflected". The light is not only reflected in the
main direction of reflection but also reflected diffusely in other directions with rough – and thus
etched – surfaces. This reduces the reproduction accuracy of the surface: a reflected object is
no longer depicted as a brilliant image, but as a blurred image. The more uniform the diffusion
of light into the room, the lower the intensity of the directional component and the more matt
the surface. 


The gloss level is determined by: 

  • Surface roughness
  • Plastic reproduction accuracy  
  • Tool wall temperature  
  • Plastic and processing parameters
  • Wall thicknesses
  • Measuring angle (medium/matt gloss at a 60° - 85° angle of reflection)
  • Thermal conductivity of the steel used, etc. 

The gloss level can be measured reliably on flat surfaces. A specific gloss level for
the 
item cannot be guaranteed.

How do tools need to be delivered?




See the movement of goods flyer from Eschmann Textures International GmbH