Wood is a natural resource that is very useful in our daily lives. In Indonesia, many woods are made into doors, chairs, tables, and many other objects that use wood as raw material in its manufacture. Apart from Indonesia, the country that uses the most wood in daily life is Japan. In Japan wood is often used as flooring and other household furniture. Seeing the many benefits that can be derived from wood, a lot of wood industry has begun to emerge in Indonesia. And one of the products produced is Plywood.
What exactly is called plywood? In Indonesian it is called plywood and in everyday language lay carpenters call it plywood, even though it is actually more than 3 layers. In other educational institutions call it a multiplex which means several layers.
Plywood is made of several thin sheets, or layers of which the direction of the fibers are arranged transversely between the bottom sheet and the top sheet together with special glue under great pressure so that a certain thickness is obtained. These sheets are usually obtained from a process of rotary stripping of logs. From this process obtained a wide and long sheet at a small thickness (0.3mm – 3 mm).
At first plywood was produced because of the need for a very large wide board and when using solid wood is very high risk for the effects of wood shrinkage (curved, twisted and cracked / cracked). However, plywood also has limitations in length and width.
The advantage of plywood is because of its durability against shrinkage of wood and the size of the length that is not possible to get from solid wood in the same quality position.
But that does not mean that plywood has the same strong resistance to the weather. This material is only recommended for furniture in the room (indoor). The biggest weakness in plywood is on the thick side. The thick side of plywood is the part that is the easiest to absorb water and the surface is very rough. To get a good smoothness must be added to the thick side cover.
In the Plywood industry besides woodworking machines, there is also a wood sheet cutting machine commonly called a rotary clipper. Rotary Clipper is a wood sheet cutting machine that has 1-2 blades that rotate cutting wood sheets according to the desired target length.
In general, Rotary Clipper simple components consist of 2 motors controlled by inverter, encoder, and PLC. But this system has several weaknesses. One weakness is the level of accuracy of the length of the piece. In the rotary clipper control system, the system generally has an accuracy of 5mm-10mm.
Therefore, in order to have high accuracy, we replace the system using PLC, 1 servo motor, 1 motor controlled by the inverter and 1 encoder. We use a servo motor as a drive for a wood cutting knife, while 1 motor that is driven by an inverter is used as a drive for the wood sheet feeder conveyor to be cut. We use servo with the brand DELTA type ASDA-A2. We use the DELTA type A2 servo because this Delta servo has the E-Cam facility. This E-Cam is an internal calculation in the servo drive that regulates at what distance the cutting motor starts moving at what speed so that when the length of the wooden layer passing on the feeder conveyor matches the cutting target, the cutting knife is also at the cutting point. This system can produce 1mm-2mm accuracy.