Laser-cut score vs. pressure score

When having items laser cut you also have the option of adding laser score lines. By lowering the laser power the beam will cut partially into the paper instead of through it. I use laser scores for all Candyspotting greeting cards; however, they are not appropriate for every job.

Laser-cut score line on a card

Pros:

  • Precision: scores are computer controlled and will be parallel with the edge of the card.
  • No additional cost: the scores are fast straight lines
  • Time savings: card does not need to be scored afterwards.

Cons:

  • Potential weak point: if the cut is too deep or the card is flexed too many times it may tear. I err on the side of shallow rather than deep scores. I do not recommend laser scores for pocketfolds or other mailers without an external envelope.
  • Exposed fibers: when the card is folded the paper fibers will be exposed. Sometimes irregular fiber bumps can be seen and the score won’t look as nice as a pressure score. For troublesome papers I like to smooth over the exposed fold with a bone folder.
  • One-sided: for the most accuracy scores can only be all mountain or all valley, not a mix of the two.

How to improve a laser cut greeting card or stationery design

It’s surprising when a design that looks great on screen falls apart or looks completely different when laser cut. I hope you can learn from my overflowing “prototype” box by observing a few guidelines.

Print the design on paper.
When working on screen it is easy to lose touch with the scale of a design. Print it out and eliminate or thicken small design elements.

Imagine your design bending in the physical world.
Cardstock is flexible enough that thin or unsupported elements may bend or flop over. Watch for elements that can catch on envelopes or the laser bed.

The image below shows an example. When the design is first cut it looks fine. The second panel shows a weak spot; it is too easy for the design to bend out of shape. In the third panel the design has been improved by adding tiny bridges to the weak spot.

Adding small supports to a laser cut card will improve its robustness

Reduce the total line length.
Think of measuring the length of a coastline. If you drew it by walking the beach adding every detail you would end up with a distance many times greater than if you drew it from a birdseye view. Try smoothing out your lines or offsetting the path to remove excess detail. On an X-Y laser, the distance the laser head travels has a close correlation to the cost.

Shadows will change how your design appears.
Particularly, the contrast on small cut areas with be greatly reduced and lines will appear thicker than on screen. In the image below the small cutouts have lost their high-contrast effectiveness compared to the original art. The thicker the paper the more pronounced this effect becomes.

Small laser cut details can become obscured because of shadows

Check your compound paths & mind the kerf.
Releasing compound paths may reveal problem areas that need to be bridged. Precise designs should use offset paths to account for the kerf of the laser beam.

If lining your card, leave room for adhesive.
If your design has large cut areas, you will likely want to line it with paper to ensure that the writing on the inside of the card doesn’t show on the outside. If you are using glue or a tape gun make sure to leave the width of the tape line plus some slop.

Prepare for higher failure rates with many small cutouts.
The airflow in the system may cause small cutouts to blow onto uncut portions of the design. If the double thickness causes a skipped area then the small blip may be salvaged with an Xacto knife. Alternatively, if both layers are cut and smoke gets trapped you may try gently erasing the smoke.

Consult an expert
I have made hundreds of stationery designs laser ready. Sometimes the art just needs minor adjustments and other times cut & photographed prototypes are necessary. When working to a budget I can make suggestions early in the design phase.

Candyspotting specializes in laser-cut paperContact me for a free estimate.

Scherenschnitte template: Girl feeding a chicken

Papercut of a girl feeding a chicken

For the last two Fridays I’ve created new wall pieces, first a papercut with elephants (“Abatee”) and next a girl feeding a chicken (“Early Bird”).

For those of you interested in the craft of Scherenschnitte I thought you might enjoy cutting the main layer of Early Bird as a standalone piece.

Download zip of “Early Bird” in pdf & png formats.

Silhouette of girl feeding chicken - original design by Sarah Holbrook

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

Attribution required: “Early Bird” by Sarah Holbrook (http://candyspotting.com)

How to improve laser raster images with tuning

Adjusting the “tuning” in the Universal Control Panel (UCP) can make a dramatic difference in the clarity of raster images. For GCC/LaserPro machines this feature is also called tuning. On Epilog it is called “Laser Match.”

Last autumn I added a second laser to my shop. One day I saw a live auction listing and the next I was the slightly nervous and very excited owner of a machine that I’d never seen powered on. The first text tests were barely legible. One of the many steps to refine the output was to adjust the tuning.

The following diagram demonstrates the result we would like to achieve.

When a raster image is sent to the laser the driver splits it into horizontal slices. Each slice represents a pass that the laser head will make in the X direction of travel.

Tuning changes the distance that the X belt moves before the laser begins to pulse in each row. Poor tuning will cause a misalignment of an etched line in the right-to-left direction versus the left-to-right direction.

The fix is fairly straightforward. First, draw a solid, long thin rectangle. Change the raster settings to use the lowest image density (lines per inch). Etch on a material that has very high contrast. Anodized aluminum is fantastic; since I didn’t have any on hand I used a dark black paper that shows a nice mark.

The desired result is for the left and right edges of each line to be flush. The following image shows an example of running this test. The first column shows the original ragged line. Next, I moved the line over, adjusted the tuning, and ran the job again. This is the value I chose; the next two tests use different tuning values and are slightly ragged again.

After fixing the tuning my sample text was still slightly blurry compared to the results from my other laser. The accelerating/decelleration curve didn’t seem as good on the older model. That is; it wasn’t slowing down enough to give a really clean etch. By lowering the speed I finally saw the crisp text that I demand.

If the tuning value you need to use seems unusually high or low you should check the laser’s X belt; it may be too loose.

Freshly Cut: Thank You cards for Sense Labs

Cut from Neenah Oxford in Blue Chip

Check out the blog post over at Sense Labs about the custom thank you cards I cut for them. They requested a video so I tried to shine enough lights on the work area to make it visible. I also had to temporarily defeat the overlock so that I could film the work area directly instead of through the safety door’s glass.