In this presentation I talk about who to successfully test materials with your laser. I also make sure you realize that the proper power is the first step in creating perfect images on your material

3. First Rule
 Number 1 rule of Laser is to always use
the least amount of power that you can
get away with
 The more power you use the more
issues you are going to have
 For example if you are engraving plastic
and you use to much power your
material warps and in some cases stains

4. Second Rule
 Never believe what the manufacturers
says is the proper power and speed.
 There are so many materials it is hard
for them to give you proper values
 Everyone is different. What you like is
not necessary what they like

5. Too much power can destroy an
image

6. Dot Gain – Printing
 It is defined as the increase in the
diameter of a halftone dot during the
prepress and printing processes. Total
dot gain is the difference between the
dot size on the film negative and the
corresponding printed dot size. For
example, a dot pattern that covers 30%
of the image area on film, but covers
50% when printed, is said to show a
total dot gain of 20%

7. Dot Gain Causes in Printing
 Dot gain is caused by ink spreading around halftone
dots. Several factors can contribute to the increase
in halftone dot area. Different paper types have
different ink absorption rates; uncoated papers can
absorb more ink than coated ones, and thus can
show more gain. As printing pressure can squeeze
the ink out of its dot shape causing gain, ink viscosity
is a contributing factor with coated papers; higher
viscosity inks can resist the pressure better. Halftone
dots can also be surrounded by a small
circumference of ink, in an effect called "rimming".
Each halftone dot has a microscopic relief, and ink
will fall off the edge before being eliminated entirely
by the fountain solution (in the case of offset
printing).

8. Dot Gain on a Laser
 All materials you laser will create a
certain amount of dot gain.
 As the laser burns a spot size the laser
dot becomes bigger and bigger.
 The more power you apply the wider the
dot

9. Dot Gain on a Laser
 The wider the dot the more dots start to
run into each other
 The more dots that run into each other
the more our material starts to look a big
“blob”

10. Black Granite – to much power

11. To Much Power 40 power 100
speed

12. 100 Speed 30 power

13. 100 power 20 speed

14. 100 speed 12 power

15. Zoomed in on the final
image

17. Laser Dot on anodized
metal

18. Notice how round the spot is
this is because of the optics
that are created by the
collimator

19. Lasered Dot on Metal

20. Testing our material
 When you are starting to use a different
material you should be trying to
establish an ideal power and speed.
Here is how I typically do it.

21. First of all draw a black square as
per figure 1 in CorelDraw.

22.  Send the job to your laser with settings
that should give you a good burn. For
example if I was doing laser plastic and I
had a 35 watt machine I would use a
speed of 100 percent and a power of 40.
Figure 2 shows the settings in my driver.

23. Driver setup – notice I am 400
DPI

24. You can adjust your speed

25. You can adjust your power

26.  With the job at the laser machine place your material
in the bed and focus out for the material.
 Next press the start button and let the machine start
to engrave.
 With the machine engraving press the “power” button
now press the down arrow button on your machine.
This will decrease the power of the machine. Keep
watching the black square on your machine until the
machine stops penetrating the top layer. Note: you
could press the stop button and open the lid to check
the engraving.
 Once you have reached the point where you stop
penetrating the top layer start increasing the power
again via the up arrow on the machine.

27. Sample material engraved

28.  I tend to increase the power maybe 3 percent past where
you are engraving out the entire area. I like to increase
the power a bit more because you will have a little lose of
power across the whole bed of the laser. For a lot of
lasers the top left hand corner represents not only the
starting position of the laser but also the closest distance
to the actual laser source. As you move away from the left
hand corner you will typically experience a drop in power.
Adding a few extra percentage points to your laser power
will help in combating any power drops you may have.
 Look at your machine and jot down the power (or speed)
that you are left with. Next go back to your print driver and
open it up. Select the arrow located beside the
configuration tab as per figure 3 and select “Save as”.

29. Save the settings

30.  You will be taken into an explorer dialogue box
as per figure 4. I have a folder created called
“Laser Settings”. It is good practice to make
sure that you save all your settings in one
directory so that they are easy to find. Note: If
you want you can also save the power and
speed savings with the CorelDraw job. Go to
FILE | SAVE and open the “Options” tab as
per figure 5. Located at the bottom you can
place in notes about the job. You will notice
that I have placed in a number of variables
about the job.

31. Give the File a Name

32. Save the File in CorelDraw -
XP

33. Save the File in CorelDraw – Win
7

34. Another way of adjusting your
figuring out your power and speed

35. Load up the settings as per
your job

37. Here is the test file on Glass
using Thermark

38. Here is a test piece using
Thermark on ceramic tile

40. Color Mapping
 The one important feature of a lot of laser
drivers is the ability to color map.
 For example color mapping allows us to
run a certain color and assign a power and
speed to that color. Thus when we run a
job we can have objects that can be
engraved at different power and speeds
 This is important as we may need one
power for certain (finer) objects and
another power for those (coarse) objects

41. Controlling Engraving order
 The other important feature of color
mapping is that we can speed certain jobs
such as columns that would be a lot slower
if we did a full bed engrave.
 We all know that engraving across the
table is the fastest way however if there is
a lot of white space in between objects
than we can have a lot of time that is
wasted moving to the next engraving object
 It is better than to place each set of objects
into a column as per the next slide

44. Things to remember when you
are lasering
 Am I doing photographs
 Do I have fine text
 Do I have bold text
 Do I have a combination of objects that are
fine and bold
 How fine does my power (speed) need to
be
 Do I need to color map
 What material am I lasering on