Buttonius Puzzles & Plastics


Buttonius Puzzles & Plastics is a hobby of Peter Knoppers.

When you liberally translate the last name 'Knoppers' from Dutch to English and Latin-ize that, you could end up with 'Buttonius', hence the name.

Buttonius Puzzles & Plastics has a laser cutting and engraving machine that can cut certain plastics (non PVC), thin woods, thick paper, rubber, etc. All materials that can be cut can also be engraved. Additionally, there are some materials that can be engraved, but not cut. Some examples are: glass (some kinds) and most coated metals.

Laser cutting and engraving facility

The laser cutting and engraving machine can engrave the (horizontal) top surface of objects that are no larger than 30cm by 60cm (12" by 24"). The maximum height of objects to be engraved is about 15cm (6"). Planar objects (of compatible materials) can be cut with the machine. It is possible to combine engraving and cutting in one job.

The laser cutting machine is controlled at a maximum resolution of 1200DPI, this means that one step is about 0.02mm. The positioning accuracy is probably less, but not much. At the focal point, the (far infrared) laser beam has a thickness of about 0.1mm. Therefore the positioning resolution is about five times better than the thickness of the cut. The thickness of the laser beam increases above and below the focal point. This is not very noticeable when cutting material that is less then 10mm thick, but it will cause loss of precision when cutting thicker material.

Laser cutting and engraving acrylic

A very common material to laser engrave and cut is acrylic, also known under the brand names Plexiglas and Perspex, or the chemical name polymethyl-methacrylate (often abbreviated to PMMA). Acrylic is available in many colors and thicknesses, but very few combinations of these are commonly available. Transparant acrylic is readily available in many thicknesses, colored acrylic is readily available in 3mm thickness. Other combinations can only be ordered in very large quantities.

The actual thickness of acrylic can vary per batch, and even within a single sheet. In a nominally 8mm sheet I've observed the thickness vary between 7.2mm and 7.8mm. Designers of puzzles that are to be cut from acrylic should not rely on very accurate or constant thickness of the material.

If this cannot be avoided, extruded acrylic may be used, but this has much higher internal stresses than the (more expensive) cast acrylic. Extruded acrylic usually has more local differences in thickness, but the extremes (difference between thickest and thinnest parts) should be more limited.

Around the cut, the acrylic welds up and down a bit to the surface. This makes a cut out piece of acrylic slightly thicker around the cutting edges (about 0.1mm). An advantage of this effect is that a cut out piece on a flat surface is actually supported only on the edges and therefore much less likely to get scratched.

Normally, acrylic is cut on a vector grid (to prevent damage to the table on which the object is supported in the machine and to improve cooling and ventilation). The vector grid consist of thin metal plates at a 17.7mm (0.5") spacing in the X and Y directions. When the cutting laser beam crosses one of these grid plates, a slight imperfection is introduced where the laser light is reflected back into the acrylic.

I have developed a technique that avoids this. I support the acrylic that must be cut with small bits of acrylic at points where the laser will not pass in cutting mode. Laser cut acrylic does not normally require any further polishing to look and feel very smooth. If needed, slight torching (with a small buthane flame) can make the edges slightly more rounded.

Acrylic can also be engraved with the laser. Gray scale images and texts can be printed with a limited number of gray levels. Transparant acrylic is normally engraved from the back (which means that the image will have to be mirrored). Colored acrylic is more commonly engraved from the front, because it it not sufficiently transparant to observe the image through the material.

Text can be engraved using any MS-Windows font in any font size and direction.

Laser cutting and engraving wood

Virtually all fine-grained woods can be engraved with a laser. The grain of the wood will normally be visible through the engraved image. When the grain is finer, this effect becomes less disturbing.

Thin wood can be cut with the laser. Some charring will occur. This increases with the thickness of the wood, but it also depends on the kind of wood. Wooden sheets for laser-cutting or -engraving must be flat.

Preparing your CAD work

If you want me to laser-cut your CAD file read these instructions first. If you have suggestions to improve these instructions, please email me.

Cutting a mold for casting tin

I've made a copy of the Computers Choice Unique 10 Burr puzzle from tin. I have some photos and a description of the process.

Puzzles and other laser-cut objects for sale

Photo of 10x1 in a Cube bag and pieces10x1 in a Cube (G4G10 exchange)Peter Knoppers5mm sandblasted Blue Acrylic€ 1
 Big KnotOskar van DeventerClear 8mm Acrylic€ 25
 Big Knot VariationOskar van DeventerClear 8mm Acrylic€ 30
Photo of partly assembled Crazy Elephant Puzzle KitCrazy Elephant Dance kit (assembly required)Markus Götz4mm MDF€ 22
Photo of Di-Half-Hexes puzzleDi-Half-Hexes (IPP32 exchange), (the back of the tray has two more outlines)Peter KnoppersBlack and two other colors (various combinations available) Acrylic€ 20
Photo of slightly rotated EGGCentric puzzleEGGcentric (IPP26 exchange)Oskar van Deventer & Peter KnoppersBlack and Yellow Acrylic€ 30
Photo of Eighteen Eights puzzleEighteen Eights (IPP31 exchange)Peter KnoppersClear 8mm Acrylic€ 35
 Feed the cat (IPP28 exchange)Oskar van Deventer & Peter KnoppersClear and Black Acrylic€ 20
Photo of Knot Mass puzzleKnot MassOskar van DeventerClear 8mm Acrylic€ 99
Rendering by CAD software of Origami PuzzleOrigami Cube (assembly required) (G4G7 exchange)Oskar van Deventer200g/m2 Red paper€ 2
Photo of Polysquaretangles puzzlePolysquaretangles (IPP29 exchange)Peter Knoppers4mm MDF€ 15
 Quadraplank puzzle with parallel planksPeter KnoppersVarious types of wood€ 80
 Quadraplank puzzle with orthogonal planks (IPP23 exchange)Peter KnoppersVarious types of wood€ 80
Photo of Torus SliceformTorus SliceformPeter Knoppers200g/m2 Red and Yellow paper€ 15

Solutions to some puzzles that I have produced or designed


I have a blog (in Dutch) about traffic, money and communication systems (but I reserve to right to expand the subjects to anything I like).

Contact information

You can send email to info@buttonius.com, or write to

Peter Knoppers
Buttonius Puzzles & Plastics
Conradlaan 20
2627 BT  Delft
The Netherlands

Fax: +31 84 748 6536