today is Sep 28, 2022

Clear acrylic panels have long been a mainstay of 3D printer enclosure designs, but they can also add significant cost in terms of money, shipping, weight, and hassle. An alternative material worth looking at is corrugated plastic (also known by its trade name coroplast) which is cheap, light, an excellent insulator, and easy to work with. Many enclosure designs can be refitted to use it instead of acrylic, so let’s take a closer look at what it has to offer.

What’s Wrong With Acrylic?

It’s not just the purchase price that makes acrylic a spendy option. Acrylic is fairly heavy, and shipping pieces the size of enclosure panels can be expensive. Also, cutting acrylic without special tools can be a challenge because it cracks easily if mishandled. Acrylic cuts beautifully in a laser cutter, but most laser cutters accessible to a hobbyist are not big enough to make enclosure-sized panels. If you are stuck with needing to cut acrylic by hand, here are some tips on how to get by with the tools you have.

It is best to source acrylic from a local shop that can also cut it to size with the right tools for a reasonable price, but it is still far from being a cheap material. There’s another option: corrugated plastic has quite a few properties that make it worth considering, especially for a hobbyist.

What’s Good About Corrugated Plastic?

Most of us know corrugated plastic as the stuff lawn signs are made of. Using it in enclosure design isn’t a new idea (here’s a printer enclosure made entirely from it, and here is a CNC mill enclosure using it as well) but instead of making an entire enclosure out of it, it can make more sense to use it only as a panel material. There is no need to design a new enclosure from scratch. One can use an existing design and swap the acrylic panels for corrugated plastic ones.

Corrugated plastic sheet, viewed on end Corrugated plastic, also known as Coroplast.

Corrugated plastic offers quite a few advantages:

  • It is a fraction of the cost of acrylic.
  • It is an excellent insulator.
  • It is lightweight.
  • Easily cuts with a sharp blade.
  • Available in fire retardant versions if needed.
  • Can be bent or folded along the corrugation, with or without scoring it first.

It can be easier to source than acrylic sheets, and is certainly much easier to work with. Any sign shop or plastics supplier likely has it on hand in a variety of colors.

There are a few disadvantages, however.

  • A standard thickness is 4 mm. Acrylic, however, is commonly used in 3 mm (or 1/8″) thickness.
  • It is not transparent (but windows can be cut easily.)
  • It is not fireproof. Like acrylic, it can burn if it gets hot enough. But compared to other plastics, combustion doesn’t spew a toxic mess, and is easily extinguished.

Corrugated plastic material being 4 mm thick instead of 3 mm means it is not necessarily a drop-in replacement for acrylic in existing designs. But not every enclosure is constrained by panel thickness.

Using Corrugated Plastic in Enclosures

The two easiest ways to use this material are: create an enclosure by adding panels to an existing structure, or use an existing design but replace the acrylic with corrugated plastic. Below are examples of both.

Make an Enclosure From an Existing Structure

Here is an enclosure I built into a metal IKEA BROR shelving unit, and it easily houses a Prusa Mini 3D printer. The BROR is made from angled metal pieces that contain regularly spaced holes. This makes it very convenient to turn a shelf section into an enclosure just by mounting a few side panels; the regular shelf surfaces provide a top and bottom.

Not only do corrugated plastic panels fit easily behind the angled metal posts, but a few short screws through the convenient holes is all it takes to fully secure them. Windows can be made by cutting a hole, and gluing or taping a clear plastic sheet to one or both sides. CA glue and most other adhesives work fine on corrugated plastic.

The only inconvenience I encountered was when it came to fashioning a door for the front. Instead of making cabinet-style doors with hinges, I took advantage of the lightweight nature of the material to create a simple removable cover. The shelf frame is steel, so I glued several strong magnets into a separate sheet to create a magnetically-attached removable front cover. I can close the front up completely, or leave a gap for airflow as needed. The result is simple, attractive, and cost very little apart from the shelf itself.

Corrugated plastic panels fit easily into the angled steel of an IKEA BROR shelf

Embedded magnets make a simple front cover instead of a door.

Replace the Acrylic in an Existing Enclosure Design

The only problem with refitting an existing enclosure designed for 3 mm acrylic sheets is that 4 mm corrugated plastic may not fit because they are slightly thicker. While it’s always possible to simply cut and peel away material until it fits, for best results, panel-retaining parts should be redesigned to accommodate the thicker material.

For example, I like the Prusa V2 LACK enclosure design and its 3D-printed parts, but the next time I build one I will use corrugated plastic panels instead of acrylic. In preparation for this, I have redesigned the necessary parts to accept 4 mm thick material.

Prusa’s original LACK enclosure design, intended for 3 mm thick acrylic panels. (Photo: Prusa Research)

Parts modified to accept 4 mm thick corrugated plastic instead of 3 mm acrylic.

Fortunately, Prusa provides not only STL files for their design, but also the CAD files. While it is possible to modify parts that exist only as STL files, in general having access to CAD format files makes this kind of task much easier.

An Under-Represented Material

For 3D printers, enclosure design is still a problem that isn’t entirely solved. “Soft” enclosure options like photo tents or fabric grow boxes meant for plants are an option for the cost-conscious, but there are also ways to reduce the cost of more traditional designs. Corrugated plastic offers a lot of advantages in that regard.

The idea of using corrugated plastic in enclosures isn’t new, but it does seem under-represented. Do you know of enclosures that make effective or particularly clever use of it, or do you have any tips of your own? We definitely want to hear about it, so share your thoughts in the comments.