On any laser cutting job, an etch takes a long time. Thousands of passes back and forth across the job occupies a significant proportion of the job run time. For this reason I was pretty pleased this week when I worked out a way to cut a 29 minute and 25 second job down to a 14 minute 50 second job.
It’s rather obvious when you think about it, but since laser cutters are usually charged for by the minute, plus the material, knowing how to drastically reduce etch time is really rather valuable!
This really, really quick trick will only work on jobs that contain multiples of the same item. The secret? Rotate! The following picture is of the job that I was running, a run of 10 scout woggles for a website that Steve and I set up to make use of our laser cutter. I’ll use this job as an example of how simply rotating it saves so much time.
When designing an item like the woggles above, I design the outline in my favourite drawing (well… okay, CAD) package, Alibre then export as a dxf. The image I then add within the laser cutting software. It of course feels natural to start with the woggle so that the text and picture is the right way up as I view it. This is fine if just cutting one woggle. If I want to run off a batch of 10, I get all the settings right for one, then step and repeat it to fit the material I’m using. In this case it was easiest to have 2 columns and 5 rows. The diagram below illustrates the flaw in just accepting this, since with 2 columns and 5 rows the laser cutter head has to traverse the distance between the items being etched before it can etch the second item.
In the diagram above, the green circles represent the area being etched on each woggle. The red rectangles are the outer cuts of the woggle. The black arrow shows the direction of etch; I am yet to find an option on our laser cutter or in the software that allows me to etch along the y axis, I only get the choice to etch along the x axis. The large blue rectangle represents wasted time. It takes time to get from the end of one etch across to the start of the next etch. The laser cutter starts at the bottom left, etches a line left to right on the bottom left green circle, then moves across to the bottom right circle and etches that. This takes time to traverse. It then moves up a step (in this case 0.1mm) then repeats this until it’s etched all of the text and images.
By rotating the above 10 items by 90 degrees, a far more optimal etch can be performed, as demonstrated by the diagram below.
This really simple rearrangement massively reduces the wasted travel time between etches. It could be further reduced by making the gap between the leather woggles smaller. I kept them at 1mm spacing rather than 0 since it stops the leather around them falling apart after being cut. This way I don’t have to pick up lots of small pieces from the bed of our laser cutter.
And here are some pictures of the job I was running, simply to plug our new website and because I’ve only used one photo so far: