I have kicked around the idea of trying to buy or build a laser cutter for the past year. My primary reason for having one is to create acrylic boxes for electronics projects. Though I can 3D print project boxes, they really don’t look that polished.
I have seen several writers comment that it is more cost effective to simply have a third party company laser cut the acrylic. So I decided to look at what is necessary to design a box and have a third party do the cutting.
Designing the Box
I used the site www.makercase.com to design the box. It is a very simple process.
Fill in the dims of the box, and the type of edge joints – flat, finger, or T-slot. Then click on the Generate Laser Cutter Case Plans.
Further, you can add holes and text to the box using makercase.com.
Note: you are going to need to set the units to millimeters before you click on the Generate button. If you want to use inches when you enter the dims of the box, that is fine, just do that and then set them to millimeters before you click the Generate button.
Once you do, you will see the general layout of the box:
You need to make a few changes to the settings as required by Ponoko.com. Click on the vector cutting tab, set line stroke width to .01mm, and set line color to #0000ff (blue) like this:
Now click on the Laser Cutting Kerf tab and set the beam width to .1mm:
Now click on the Download Case plans. This will allow you to save the plans as an SVG file.
Tweaking the File
Unfortunately, the file, as created by MakerCase, is not quite useable by Ponoko. You will need to use Illustrator or InkScape (free) to edit the file. Using either of these programs is way beyond the scope of this document; however I will give a general explanation of what needs to be done.
First, you must download Ponoko’s template. This will create a work space the same size as the material you will be using. It also explains how to get the diagram set up properly.
Open the template. I use illustrator and I can use the place command to place the box plans on the template. I’ve also used cut and paste in the past as well. Your box design should now be in illustrator/inkscape and the lines must be blue.
The problem with makercase.com (at least as far as Ponoko is concerned) is there are some lines duplicated. This will cause the laser to go thru the same cut twice which is a bad thing. You have to get rid of those duplicate lines.
You will find the duplicated lines going down the center of the zig-zag cuts highlighted:
Again, it is really beyond the scope of this document to explain how to do this, but using the direct select tool, you must select all of these duplicated line segments and delete them one at a time (in this example, there are about 13 per each marked side, so there are quite a few).
See Apr 2015 update below for a work-around to having to select and delete.
Since the file is in an editor, you can easily add engraving here. Engraving is done with black lines, so create your design and fill it with black such something like this:
Send the Laser Cutting Plans to Ponoko
Take a look at the rest of the pre-quote checklist in the template to make sure the file is ready for Ponoko to process. Then upload the file for a quote if you are happy with everything, let them process it.
I sent in my 4x4x4″ test box and had it at my house in about a week. That included messing around deleting the duplicate lines (because I couldn’t see they were there, but Ponoko caught them and told me to fix them).
I assembled the box and glued it using acrylic cement from Tap Plastics. If you haven’t done this before, look at their video on using acrylic cement. It really helps, and it is very easy to make a mess of your box if you haven’t used acrylic cement before (I speak from experience).
Using cement rather than some kind of glue makes for almost invisible joins.
I used finger joints on my test box and they made aligning and cementing much easier than when I’ve made boxes with flat edges. Here is my final box:
My 4x4x4 box cost about $32 with tax. That was $10 for materials, $10 for labor, and $10 for shipping. Typically, when I have built a box in the past, I purchase acrylic from Tap Plastic (because I want something nicer than what I’m going to get at the big box hardware store like colored acrylic). So typically I end up spending $20 for a sheet of acrylic and shipping.
So really I only paid an extra $10 to get this box cut. Compare that to spending several hours trying to cut the box with a table saw, smooth the edges with a router, and even then I have never had one come out perfectly square. So for the extra $10 I STRONGLY recommend using a laser cutting service such as Ponoko!
Apr 2015 Update
Building a real project box today. As I’m following these instructions, I’ve found some optimizations that are good to know. The box I’m building was output like this:
This is really long and would only fit on a P3 sized piece of acrylic. With a little arranging, I selected each piece with illustrator’s selection tool, and move the pieces around until they fit on a P2 sized acrylic sheet:
I realized a fantastic side-effect of moving pieces like this – there is no overlap of lines so I don’t need to select and delete overlying lines (which is fantastic as this particular design was going to be difficult).
Mar 2016 Update:
Everytime I have done a lasercut with etching, I have had a heck of a time getting it submitted because of little formatting issues. Here are some notes that would have helped on this go around:
- Make sure all fonts are converted to outlines (their template tells you to do this).
- Next make sure that any etched object is converted to an outline. Select the object and do a Object | Path | outline stroke
- The cutting lines must be .01mm pure blue stroke with no fill. Once you’ve got your design done, select one line, verify it is set up like this then select | match | fill and stroke. This will select every blue line that is formatted correctly. You can hide those and see what is left and fix any that are.
- To etch an area, you must use .01mm pure red stroke with black fill. That was the only method I could find to get an etched area to pass their sanity check. I swear I didn’t use a red stroke in the past but I had to this time.