Laser Marking Vs. Screen Printing
Contents
Introduction
Product manufacturers may wish to consider laser marking as an alternative to screen printing (also called silk screening) when looking to permanently mark a surface such as with a bar code, a serial number, a logo, or calibration settings. Depending on the application, laser marking and screen printing each have their pluses and minuses—although for most applications laser marking is faster, cleaner, easier to set up, more precise and more adaptable than screen printing.
How Each Method Works
Laser Marking
The marking results from the laser beam hitting the surface and oxidizing it at the point of contact. The oxidation causes a color change (from gray to black in stainless steel, for example). The shape of the marking can be virtually anything from simple numbers and barcodes to complex geometric shapes and depends on the movement of the laser beam relative to the marked surface—i.e., either the laser beam moves (as directed by mirrors) or the table moves that holds the object being marked. Depending on the power of the laser, the pattern can be a surface marking (i.e., no depression) or an etching (i.e., a depression).
Laser Marking
Screen Printing
The marking is essentially “painted on” the object. Five main players are involved: ink, a mesh, a squeegee, a stencil, and the marked surface. The mesh is soaked with ink which flows onto the surface as the squeegee moves across the back of the mesh, pressing the mesh and forcing the ink through openings in a stencil that is attached to the front of the mesh. This action leaves ink on the surface in a design that is a mirror image of the design cut out of the stencil. The name “silk screen” comes from the fact that these meshes once were made only from silk. Today, most meshes are made of polyester, although nylon and stainless steel meshes may also be used in certain applications.
Screen Printing
Comparing Laser Marking to Screen Printing
- Faster production, less prep work, no cleanup
- More environmentally friendly
- More precise—for smaller objects, tighter spaces
- More adaptable—e.g., can print on curved surfaces
- Permanent, won’t rub off
- Less possibility of contamination
- Control of etch depth
- Restoration of antique hand stamping
- Virtually any material can be marked
- More colors
- Lower equipment costs
Key criteria for comparing these two methods include:
Type of material: It is possible to screen print virtually any material, from tee shirts to stainless steel. But although laser marking is somewhat more limited in terms of materials that can be marked, it is nonetheless extremely wide-range, including most metals, glass, ceramics, polymers and plastics.
Colors: With silk screening, color is only limited by the color of the ink used. Multicolored patterns are also possible by applying different meshes with different color inks. Because laser marking is a subtractive process, there’s only one color available—i.e., the color that results from the reaction of the material to the heat of the laser.
Technical simplicity: Lasers cost more than screen printing machines and require more training to operate. That said, most product manufacturers will benefit from outsourcing the marking to a laser shop so they can benefit from the laser’s inherent speed advantages.
Production speed: A production run on a laser is measured in days versus the weeks typically required of screen printing. Laser marking is faster because there’s much
less prep work and no clean up: The marking itself is also faster. Once the job is “dialed in” to the machine, marking each piece takes only a few seconds.
Environmental impact: Screen printing requires ink and cleaning solvents—neither of which applies to laser marking, so laser marking is a much greener process.
Precision and uniformity: Light is inherently a more precise agent with which to mark than with a stencil, mesh or squeegee—all of which are much more vulnerable to variables such as the amount of pressure applied to the squeegee, the rate the squeegee passes across the back of the mesh, defects in the mesh material, variations in the stencil, and more. This makes laser marking the process of choice for very small barcodes and applications where there is not much room to mark.
Adaptability: Not only can you mark in very small spaces with a laser, you can also mark very large objects (at Accumet we mark objects up to 12-feet long). Lasers can also mark curved objects and other multidimensional surfaces that require the beam to move on the X, Y, and Z-axis simultaneously—which screen printing can’t.
Durability: Because ink bonds to the surface material, it can come off with continued rubbing—making it less suited than laser marking for applications like dials and switches.
Contamination: And because surface pigment can come off, it can contaminate its surrounding environment, which makes screen printing less suitable in “high purity” applications such as clean rooms, spacecraft and biomedical implants.
Conclusion
The best way to compare laser-processed ceramic substrates to more traditionally processed ceramic substrates is on the basis of your own product and production requirements. Are you looking for high-precision cuts so that your circuits can be smaller and more tightly packed? Do you know if your substrate needs to be cut or scribed? Have you discussed your fabrication needs with a manufacturer prior to design? If you’re uncertain about a design feature’s capacity to be fabricated contact us or upload a drawing on our support page.
