Introduction to finger processing technology

August 17, 2019

In response to the new life of wood waste, people have accepted this technology relatively slowly. Nowadays, due to the reduction of timber resources and the high yield and high yield brought by the processing of sawn timber, it has become inevitable. Common processing methods. Depending on the quality of the raw materials, finger joints can re-use 60% of the wood waste.

The joining process of short-sized wood is a combination of end-end processing methods, that is, the combination of tapered tapered finger-shaped enamels which are processed into the same pitch and section. Finger joints have many advantages, primarily at a reasonable cost, and can also utilize low grade and short size wood. By trimming the ends, the sides are planed and machined into high-grade end products such as furniture, table tops, and even structural products such as laminated beams and I-beams.

There are two main types of finger joints: vertical and flat connections, or docking. The difference between these two connections is: the difference in appearance shape characteristics, and the difference in the processing of the workpiece. Vertical finger joints, where the broad side of the wood is the visible surface of its shape, in contrast to the shape of the flat joint that can only be seen from the side of the sheet. Vertical connections are often popular in Europe and are used in the production of structural beams and are used extensively in the construction industry.

According to strict standards, finger joints used in engineering structures should have extremely high tensile strength. Finger joints have the advantage of being stronger than large solid wood pieces. Special applications for finger joints in other areas are also widely used on the surface of various products, mostly value-added products. For example: parts for doors and windows, cabinet parts, floor materials with beautiful surfaces and furniture parts.

Finger cutting

The strength of the wood parallel to the direction of the wood grain is the highest. This is an important theory of finger-joining technology. In addition to this basic factor, the finger-joining technology also contains other important contents. First of all, it is necessary to investigate the market situation of the final product of the finger joint. In order to obtain high value-added products, the wood used for finger joints must be intact, the joints are not frugal, and the cutting error should be controlled within the tolerance range. Only when these conditions are guaranteed can the factory produce useful value-added products.

In order to determine the investment in finger-joined equipment, the volume and type of raw materials must be determined in advance. Many Asian mills have a large number of low-grade raw materials suitable for finger joint processing, especially in Thailand and Malaysia. Rubber and pine woods are usually relatively short and can be processed into high quality specifications by finger joints. The raw material volume supplied must be measured once a week or monthly. In addition, the finger-joint production requires thousands of pieces of wool per hour.

In order to achieve a certain degree of mechanical connection, the processing accuracy, the moisture content of the wood and the amount of glue applied must be well controlled. Wood drying is also a major consideration for manufacturers, so investment in drying kilns is important. The average target moisture content of wood should be controlled at 10%. When the finger kiln is dry, its volatile organic compound has a low amount of divergence because the knots in the wood have been removed by the detector.

The adhesive used must undergo rigorous outdoor exposure and strength testing and can be cured quickly. Adhesives for structural materials are typically resorcinol, phenol and melamine adhesives. Adhesives for indoor, non-structural materials are typically melamine-urea, urea-formaldehyde and PVA. The dry condition is good, and there is a 87% success in fingering. If the drying condition is not good, it is to use the best adhesive in the world, and it is difficult to ensure the success of the finger joint.

From cutting to splicing

The finger-joining process is to first cut the end of the wood into a square right angle with a saw, and then cut the joint part with a high-speed milling head. The sawing determines the depth and length of the finger joint. The depth of the finger joint is very important. It is directly related to the strength of the finger joint. The number of wood for horizontal finger joints is small because wood workpieces need to be fed one by one, or their production capacity is low. Vertical finger joints can be fed in batches, allowing more parts to be cut at the same time.

The equipment operator must pre-select the wood used for finger jointing. The selected wood should be straight, the size is appropriate, and there are no defects that are easily broken, so as not to cause breakage at the joint of the finger joint. The bent wood segments are first machined into straight wooden segments before they can be finger-joined. The machining error at the joint should be controlled within the allowable range to ensure smooth application of the sizing pressurization process. Wood can be fed in a single feed or in batch feed. After cutting the ends of the wood into fingers, apply glue and then the ends of the two pieces of wood are relatively glued. The sizing is applied by a rotating rubber roller coater or by a specially shaped nozzle.

After the glue is applied, the workpieces are immediately placed in the finger-joined position and pressed to bond them together. The workpiece will continue to lengthen in the length direction until it reaches the desired length. These lengthened workpieces are sawn to a specific length, and then they are transported to the assembly table neatly placed, then glued, pressurized, and laterally assembled into sheets, which are then shaped and milled into the final product.

summary

Finger-jointing is an integral part of the wood industry's production and processing, providing the timber industry with an efficient and viable production method for reusing waste and being environmentally responsible. The strength and appearance quality of the wood has been improved by eliminating some undesired wood features. The maturity of finger-joining technology will give the world's timber resources and wood processing industry more benefits.

The surface of the Carton is waterproofed, and in addition to protecting the package from water, it is mainly to prevent the water from infiltrating the casing itself. When the carton is wetted by water, the compressive strength and bursting strength of the box will be greatly reduced, which will seriously affect the quality of the package. The surface of the carton is waterproofed, usually by applying a waterproofing agent. According to the action of the waterproofing agent, the processing method of the Waterproof Carton can be divided into: temporary waterproofing treatment and long-term waterproofing treatment.

I. Temporary Waterproof Treatment Corrugated board has a temporary waterproof function after being treated with a temporary waterproofing agent in the production process. When the water falls on it for a short time, it does not get wet and becomes a water droplet, which prevents water from penetrating the cardboard. Temporary water repellent treatment of paperboard has been applied in all major carton factories in China for nearly ten years. When it is in contact with water, the water does not wet on the cardboard, forming water droplets rolling down, thereby achieving waterproofing.

Second, long-term waterproof treatment The so-called long-term waterproof treatment, "even if the contact with water for a long time is almost impervious to water" treatment. In China, this method has been adopted for the waterproof treatment of cartons for a long time. The carton is hand-painted with a layer of waterproofing agent, which is bright, strong, and has good water resistance, and does not cause collapse after painting. Such water repellents are often solvent-type (or oily), which is harmful to the operator's body, pollutes the environment, and is also detrimental to the recycling of cartons, and has rarely been used in recent years. Instead of water or emulsion type waterproof coatings. Water-milk waterproofing coatings can meet the requirements of long-term contact with water and almost impervious to water. However, if the coating contains more water, it will naturally dry for a long time, which may cause collapse or separation of paper and corrugated.

Waterproof Carton


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Shenzhen Yanhua Packing Products Co., Ltd. , https://www.yhpackagingbox.com