Fabrication materials
Most modern jigsaw puzzles are made of cardboard, so the cost is lower and the production process is simpler. The pattern of the jigsaw puzzle is a whole piece of art print pasted on the surface of the cardboard before cutting. The content of the picture can be an enlarged photographic work, painting, or other types of graphic art. The paperboard after mapping will be sent to a special press machine, which is equipped with a steel cutter set combined according to a predetermined pattern. The paperboard will be cut into pieces by the cutter set after being forcefully punched by the machine. This process is quite similar to the molding process of graphic biscuits, but the difference is that the impact force of jigsaw embossing machine is much higher. For example, for a typical 1000 piece jigsaw puzzle, in order to make the cutter set on the die completely cut through the cardboard, the machine tool is required to generate a pressure of up to 700 tons during operation. The die (printing plate) of the jigsaw puzzle is usually made of plywood. The die maker first carves or burns the groove on the template according to the assembly pattern of the pieces of the jigsaw puzzle, and then inserts the blade into the groove one by one to assemble the cutter group. The surface of the tool set is also covered with a layer of elastic material, usually foam rubber, which is used to eject cardboard pieces from the holes of the tool set after printing.
Pieces of jigsaw puzzle
There are various cutting methods for the joint line of the pieces of the jigsaw puzzle. The mainstream puzzle uses a piece edge style called "full interlocking". "Full interlock" refers to connecting several adjacent pieces together. If one piece is moved horizontally, all connected pieces will slide in the same direction without dispersion. Sometimes, the pieces are put together very closely, and the whole piece will not be separated.
A Close Look at the Joining of Puzzles
The interlocking of parts and pieces is usually realized by the bulges and depressions at the edges of parts and pieces, which is similar to the "mortise tenon joint" in furniture production. The main body of the piece is a rectangle with the same size and form. Suppose that the two pieces closely connected on the left and right are A and B, respectively. If the right edge of the piece has a bulge A extending to the right, then the left edge of the piece B must have a depression B with the shape consistent with A. In order to make A and B lock each other, it is also required that the end of the bulge A is wider than the end connected to the edge of the piece A. This kind of protrusion in the form of wide front and narrow back is called dovetail in traditional woodworking. We might as well call the bulge and depression of jigsaw pieces "tenon" and "mortise". However, if dovetail tenon with tip is made on cardboard, it is easy to layer and damage the parts, so the tenon and mortise in the puzzle are mostly circular.
In some jigsaw puzzles (perhaps the most common one), all parts have the same shape. Each part has an axisymmetric tenon and mortise, and the axes of the tenon and mortise cross, showing a "20" shape on the whole. In this way, parts and pieces are always crisscrossed. In some puzzles, the tenon and mortise structures of parts are different from each other, but usually the main body of parts is quadrilateral, with a tenon or mortise on each of the four sides.
Non interlocking jigsaw puzzle generally uses various forms of intersecting curves to segment parts, and the edge of parts is also a segment of the curve. In fact, this mode of jigsaw puzzle is relatively simple, because the matching between parts is mostly fixed, and it is easy to find adjacent parts according to the curve shape of the edge. However, players are required to be calm when putting together this kind of puzzle, otherwise it is easy to mess up the parts already put together.
The interlocking jigsaw puzzle with the same shape of parts and pieces is considered to be the most difficult one, especially the one with soft color and small contrast in design, because there are often only very subtle differences between parts and pieces.
Occasionally, there will be some jigsaw puzzles with very strange layout, which can bring more fun to players.
Rectangle is the most common overall picture frame of the jigsaw puzzle. The frame of the picture is either a straight line or a regular decorative curve. In this kind of jigsaw puzzle, there are always some pieces that either lack mortise and tenon on one side or have a right angle. Players can easily put out the frame, so they often start from the corners when putting together. Of course, there are also some jigsaw puzzles that deliberately make the parts of corners into mortise and tenon, to make the game more challenging. There are also some more childlike ideas, making the outline of the whole puzzle into small animals or other lovely shapes. Because the contour line is more tortuous and long, there are more pieces on the edge than the square puzzle, which makes it easier to put together. Of course, this kind of puzzle is more suitable for young players.
In recent years, computer and computer controlled laser and hydraulic cutting equipment have also been used in the design and production of jigsaw puzzle. The application of new technology has made the interlocking mechanism and pieces of jigsaw puzzle more sophisticated, and new and novel patterns emerge in endlessly.