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Five points of attention and precautions for newly pulp molding companies
1. evalsuation of equipment capacity: misunderstanding of equipment output
1.1 How to measure the capacity of pulp molding equipment
When producing different products, the output is different. In order to facilitate the comparison of the capacity of the equipment, the national industry standard uniformly stipulates that the Nissan standard 10-inch disc (21 grams) is used as the standard to calculate the equipment capacity, but the weight of the 10-inch disc in actual production Basically, it is 20 grams, so a 20-gram standard 10-inch disk is generally used as the measurement standard.
1.2 Newly entrant customers usually have the following misunderstandings when measuring equipment production capacity, which is prone to produce the illusion of production capacity:
①, the production capacity of the equipment is measured by square box products with higher gram weight. The same machine can produce 1 out of 9 20g 10-inch discs and 600 kg per day, or 1 out of 10 40g square box products per day. 1-1.2 tons. Before the measurement standards are distinguished, the illusion of capacity is easy to produce. Equipment with a daily production capacity of 600 kg will be mistaken for a 1 ton machine.
②, 9-inch disks are used as the measurement standard. Since 9-inch disks are slightly smaller than 10-inch disks, many pulp molding equipment can arrange 9-inch disks more economically, but the number of 10-inch disks decreases sharply. small.
③, the output trap of plus or minus 10%, the equipment capacity mentioned in this industry refers to the minimum output, usually not 10% less. When talking about output, the output is not allowed to be minus 10%, but many users generally do not take it seriously.
1.3 How to avoid the illusion of productivity
The equipment production capacity in this industry refers to the minimum daily output of equipment, which is based on a standard 10-inch disc (20 grams) as the acceptance standard. Any heavier square box products, 22 grams of 10-inch discs, or 17-gram 9-inch discs as the measurement standard and the allowable output of plus or minus 10%, will produce an illusion of capacity.
2. Misunderstandings about cutting-free energy saving and low cost
The “Industry Standard for Pulp (Plant Fiber) Molded Disposable Tableware Production Line” issued by the Ministry of Industry and Information Technology of the People’s Republic of China defines the edge-free cutting as: "Using a special process, no blade or punching process is used to achieve the same Process with the same effect". The performance requirements for the edge-free trimming: "The edge-free products should be free of cracks, missing edges, and no damage; and when 100 products are stacked together, there should be no obvious white areas and obvious burrs around the edges, and the edge deviation of the products should be no More than ±0.5mm".
The problem of edge-free trimming has been explored for more than 20 years, and a patent on edge-free trimming was applied for in 1998. From the theoretical calculation and the actual summary, the non-trimming process consumes more energy than the trimming process.
2.1 According to the non-trimming process, if the pulp concentration is high, the non-trimming effect will be poor and the burrs will be serious. Therefore, when producing non-trimmed products, the pulp concentration is much lower than that of trimmed products. Generally, the pulp concentration of trimmed products: 4-5%; non-trimmed products 2-3%. For the same production of 1 ton of products, the drainage volume during vacuum suction filtration molding has to be increased a lot, almost twice or more. That is to say, the amount of vacuum needed to produce non-trimmed products is much larger than that of trimmed products. Vacuum and heating are the main energy-consuming links in the pulp molding production process.
2.2 Edge-free cutting process In order to achieve the effect of reducing burrs, a relatively long period of virtual pressure must be passed during the hot-press mold clamping process, otherwise the phenomenon of "burst" or more burrs will occur. The so-called "virtual pressure" means that when the hot pressing mold is closed, the upper and lower hot pressing molds are not compressed when they are closed, and the "wet billet" in the mold is baked for a certain period of time, and the "wet billet" is baked until it is dry. After the temperature is reached, the clamping force is applied to heat and press the shape.
This process of under-pressure baking wastes a lot of heat, and another undesirable consequence is that the compactness of the product is very low. For example, the same 300 10-inch disc products are stacked together, and the edge-free products are 30-50CM higher than the normal products, which greatly increases the packaging and transportation costs.
2.3 The raw material problem of non-trimming products, according to the feedback of many manufacturers who have used the non-trimming production, the use of 100% straw pulp such as bagasse pulp and wheat straw pulp cannot achieve the same non-trimming effect, and a certain amount of wood pulp should be added for adjustment. Pulp can achieve a certain effect.
2.4 The price of forming molds without trimming is high
2.5 The output of non-cutting edge is lower than that of non-cutting edge. From the above points, it can be seen that
① the edge-free process has a large drainage capacity and a long suction filter time, which leads to a decrease in production capacity;
② a longer virtual pressure process leads to a decrease in production capacity.
2.6 The size and edge problem, because the thermal expansion of the mold is unavoidable, and the suction molding mold has no thermal expansion. Therefore, when the wet billet is transferred to the hot press mold, it will inevitably be offset, so the size and edge problem is inevitable. Especially large table (platen above 1500) equipment.
In summary and practical verification, the production cost of edge-free products is 20% higher than that of edge-cut products.
3. The user needs to understand clearly the "mold removal cleaning cycle" before selecting the equipment
The wet-pressing pulp molding equipment needs to remove the mold regularly to clean the carbon deposits. The automatic equipment for the production of meal bags and the automatic equipment for the production of high-quality work bags have a different mold removal and cleaning cycle. Due to the high price of high-quality work packages, the focus on quality and low output is often the goal of making ideal products; the production of meal packages is different, with homogeneous competition and comparability, winning by output, and paying great attention to production costs. Generally, the fully automatic equipment for producing meal packs usually takes about 30 days for mold removal and cleaning. However, due to different equipment processes, mold removal and cleaning cycles are also different. If the mold removal and cleaning cycle is too short, it will not be competitive. Before selecting equipment, users need to understand clearly the issue of "mold removal and cleaning cycle".
4. Back charcoal problem
The so-called "back charcoal" refers to the small carbonized particles that fall off the upper mold by hot pressing during the production of pulp molded products, and fall on the surface of the product (usually the back of the product) and adhere to the small carbonized black spots on the back of the product.
Due to the different production processes of the equipment, some equipment runs for about a week, and the product has "back charcoal". It can be eliminated only when the mold is removed and cleaned.
Before selecting equipment, users need to understand whether there will be a "back charcoal" problem.
5. The automation of pulp molding equipment must be combined with technology
It's like "washboard + manipulator ≠ washing machine". Good automatic pulp molding equipment is not just a simple "manual molding machine + manipulator" can be achieved.