Summary for laser etch contrast Discussion
Improving laser etch contrast on brushed stainless steel was the core issue in this thread. Dean DiPietro explained that his consumer kitchen product could only be marked by laser, but the markings were too light and hard to read because the brushed surface was inconsistent and the cycle time was already about two minutes per item. He asked whether primers, reactive chemicals, or post-treatments could darken the etch. After sharing the machine specs for a TECH-H 50W laser marker, the only direct reply came from Brandon Martz, who said that on his diode laser the darkest stainless marks came from adjusting the mark properties rather than adding chemicals. He specifically recommended experimenting with power, passes, pulses, speed, frequency, and especially reducing step size and frequency, while noting that smaller step size can significantly increase marking time. His practical suggestion was to test settings in a grid to find the best contrast with minimal time penalty.
I have been developing a stainless steel consumer product for kitchen use that uses laser etched markings. Because of the shape and construction, laser marking is unfortunately the ONLY option available to us. The stainless surface is brushed albeit inconsistently due to geometric constraints. We have found that the laser markings are somewhat hard to read due to inconsistent, and insufficient contrast of the markings (ie, not dark enough). We have tried slowing the laser down, but since we have fairly elaborate markings, we are already at a 2 minute cycle time per item, so it’s not really practical for us to keep increasing the cycle time. I’ve asked for the make, model, and setup on the machine we’re using, will post when available.
So.. are there alternative ways to make laser etchings darker?
-can we prime the surface before?
-are there reactive chemicals that can work with the laser?
-is there a post-application?
-any guru you can refer me to? I’m not above bringing in a consultant.
help?!
Dean DiPietro
design engineer – consumer products – New York, New York
2005
I was able to get the machine info:
www.tec-h.com.cn/shop_view.asp?id=111
the entire site is in Chinese, so here are the general settings/specs I can translate from the site:
Name: TECH-H LASER MARKER
OUTPUT = 50W
LASER MARKING AREA = 200MMX200MM
FASTEST LASER MARKING SPEED = 7000MM/S
MINIMUM DISTANCE/HEIGHT FROM LASER LENS TO THE LASER SURFACE =
299MM
MINIMUM LINE THICKNESS TO BE LASERED = 0.05MM
MINIMUM SIZE OF THE LASER MARK = 0.2MM
Dean DiPietro
– New York, New York
A. Hello!
What kind of laser is it? Iuse a diode laser (RMI SymbolWriter) almost daily for work, much of which is on stainless steel. On the machine I use there are settings that control the nature of the mark (power, passes, pulses, speed, frequency, step size). I have found when trying to make a dark mark that step size and frequency decrease have provided the darkest marks, however decreasing step size increases the time to mark by a pretty substantial amount. Try exploring your laser’s properties by lasering a grid with the settings adjusted and see what darker marks take little time. Hope this helped!
Brandon Martz
– Lake Stevens, Washington, USA
July 3, 2012