Have you ever seen fire lighting experiments using a magnifying glass? This methodical principle also identically applies to Laser engraving systems - the Laser passes through a focal lens and converges at a single point, using this congregated energy to process and engrave designated working objects.
 
For that reason, the focal lens is considered a significant component of the laser. Informatively, there is a wide range of lens sizes to choose from in order to complement and support operations that differ in application requirements, and where different media is used.
LaserPro would also like to remind you that different media will generate different heat affects.
 
I. Specifications of Focal Lens
Three sizes of lens are available and extensively used by the Engrave series, namely 1.5", 2.0", and 4.0". From the table below, you will be able to depict that smaller lens converges laser at smaller spots and bigger lens yield bigger spots. Thus characteristically, small lenses will require less focal distance and larger lenses will call for a greater focal distance.
 
 
II. Comparison of Engraving Results
Model: Mercury 30W
Material: Acrylic
LaserPro will showcase 1.5", 2.0" , 2.5" and 4.0" lenses and exhibit with their actual application results.
 
I.Engraving Results-Graphics
 
From the comparison above we are able to depict an evident enlargement of spots when 4” lens were used, but no considerable changes when 1.5”~2.5” lens are used.
 
II. Engraving Result - Small Letterings
Engraving 1mm~0.2 mm sized letterings.
 
1.5" lens can engrave letters between 0.4 mm~0.5 mm, letters that are smaller than 0.3mm will be blurred and indistinguishable.
 
 
Engraving with a 2.0" lens will produce results that are similar to those produced by 1.5" lens; letterings are also sized between 0.4mm~0.5mm.
 
There is no significant difference in engraving results between 2.5” and 2.0” lens. However, when the 0.5mm lens is used, the engraved characters become blurred.
 
 
4.0"lens engrave letterings between 0.7 mm~0.8 mm given its bigger spot size; letterings that are smaller than 0.7 mm will be blurred.
 
III. Heat Affected
LaserPro will now test the actual engraving performance on paper, principally assessing the extent of heating effects using varied lens sizes, and also measure their resultant differences.
1.5" - engraves a spot of 0.4 mm in diameter, finishing at 11 mm
2.0" - engraves a spot of 0.4 mm in diameter, finishing at 12 mm
2.5” - engraves a spot of 10 mm in diameter, finishing at 12 mm
4.0” - engraves a spot of 10 mm in diameter, finishing at 13mm
LaserPro would also like to remind you that different media will generate different heat affects.
 
IV. Deep Cutting
Cutting test conducted using Spirit 100W.
For engraving/cutting operations on acrylics with considerable thickness, differences in performance between the lenses would be more evident as they differ in focus.
Comparative testing conducted using Spirit 100W adapting identical parameters.
From the comparative graphs shown above, we are able to depict that the 1.5” lens has a smaller focus, and evidently when cutting thicker acrylics actually produces more curved edges. This can be improved if bigger lenses are used as the edges produced would be straighter and smoother.
 
V.Options
Following the abovementioned comparisons, customers will become more aware of how different sized lenses can be utilized to complement differed applications. With continued practice and operation, one can better select the most suitable lens for production and elevate production efficiency. Based on our previous application experiences, here are some recommended lens applications:
 
1.5" Lens
Small spot sizes are more suitable for small lettering engraving applications, small circular shapes, and for drawing thin lines. It is most applicable for processing micro media, electronic parts and for accomplishing precision cutting.
2.0"&2.5" Lens
2.0”mm is currently the most commonly used lens on the market, popularly adapted for engraving images and other general applications. For example, it is generally used for engraving acrylic engravings, souvenirs, and cutting thin objects.
4.0" Lens
Bigger spot sizes are suitable for materials that are physically more substantial and thick, for example, wood chunks or thick acrylic sheets. Given the same wattage power, cutting with the assistance of bigger spots essentially gives faster cutting and maintains efficiency.