2021-10-17 2154
Since the newly established pulp molding enterprise is not familiar with the pulp forming equipment and product technology,they tend to be misled to make wrong decisions.This paper discusses some phenomena encountered in pulp molding technology and production for the reference of new entrants:
1.Equipment capacity evaluation: misunderstandings of equipment productivity
(1) How to measure the production capacity of pulp molding equipment
The newly established pulp molding enterprise on the evaluation of the equipment production capacity is easy to produce the illusion. Pulp molding equipment produces different products and weight, and its production capacity varies.In order to facilitate the comparison of production capacity between different pulp molding equipment, the national industry standard uniformly calculates the capacity of the equipment by measuring the weight of the 10-inch daily production standard tray (21g).But in the actual production, the 10-inch tray weight is basically 20 grams, so the 20-gram standard 10-inch disk can generally be used as the measurement standard.
(2)The newly established pulp molding enterprise usually have below misunderstandings when they measure equipment capacities, so it is easily to have productivity illusions:
①, The same pulp molding equipment has a daily capacity of 600 kg at a standard 10 inch tray (20 g) and 1-1.2 tons daily capacity for 40 g box products.Capacity illusion is prone, before there is no distinction between measurement standards.
②, The increased weight of the 9-inch tray product is used to improve the production capacity of the pulp molding machine
On the market, 9-inch trays are also used to measure the production capacity of pulp molding machines. The standard weight of the 9-inch tray is 15 grams (14~15 grams) and the national industry standard allows weight deviation is ±5% .Then the standard weight deviation of the 9 inch tray is ± 0.75 g, and the maximum standard weight value of the 9 inch tray is 15.75 g.Some equipment salesmen, call the weight of the 9-inch tray 16 ± 2 grams.Raise the weight of the 9-inch tray to a maximum of 18 grams.
They used an 18-g 9-inch tray to boost the production capacity of their equipment.It was 3 grams more than the normal 15 grams, adding 20% more weight.Usually new companies don't pay attention to this problem.
This trick made his equipment production capacity of 20% higher than his normal production capacity.The 800 kg capacity equipment becomes a 1 ton capacity equipment.
③, Production ± 10% Tips
When the equipment quotation or contract, some equipment manufacturers will add this one: equipment production allowable deviation ± 10%. What the pulp molding industry says is equipment production capacity is the minimum production the device must achieve.Can only be a positive deviation, do not accept the negative deviation. But lots of clients always tend to ignore this.
(3)How to avoid productivity illusions?
①, The equipment capacity mentioned in this industry is equipment minimum daily output, whose acceptance criteria is standard 10 inches round tray (20g).No measurement and acceptance criteria are used for heavier box products, 10 inch round tray 22 grams, or 18 g 9 inch round tray.
②, Do not accept the agreement of ± 10% of equipment production, but only + 10% if required
2.Misunderstandings regard to edge-free energy saving and low cost
Which production cost is lower，Molded pulp products with trimming-free or margin trimming?
In fact, the trimming-free process consumes more energy than the margin trimming process.
According to 《Industry Standard of Paper Pulp(Plant Fiber) Mold Disposable Tableware Production Line》issued by Ministry of Industry and Information Technology of the People's Republic of China, the definition of trimming-free is :“Adopt special technology, but achieve the same effect as trimming production without blade or punching process.” The performance requirement of trimming-free is: “trimming-free product should not have crackles, missing edges, breakages; and no obvious whitish area or burrs surroundings when 100 pieces are stacked together, product edge deviation should not be more than ±0.5mm”.
The trimming-free issue has been explored for more than 20 years; relevant trimming-free patent was applied in 1998. According to theoretical calculations and practical conclusions, trimming-free process is more energy consumption than margin trimming process.trimming-free products have poor appearance effect and poor hygiene.
(1)According to trimming-free process, if pulp density is high, trimming-free production will have poor effect with serious burrs. So the pulp density is much lower than margin trimming process while producing trimming-free product. Generally, the pulp density of trimming product is 4-5% and of trimming-free product is 2-3%. At the same time, while producing 1t products by vacuum suction filtration molding technology, the water discharge volume increases a lot, which is almost up to 2 times and even more. In that case, producing trimming-free product consumes a lot more vacuum than producing trimming product. Vacuum and heating are main energy-consuming links during paper pulp molding production process.
(2)In hot pressing molding, virtual pressure process should take very long time to reduce burrs of molded pulp products during trimming-free process; The called "virtual pressure" is the thermal pressure closing mode without applying pressure. After a long time of "virtual pressure", the molded pulp "wet billet" is dried to a certain degree, then the clamping force of pulp molding is applied in hot pressing molding process.
The virtual pressing and drying process waste lots of heat, which leads to low density of products. Set an example, when 300 pieces same-sized 10 inches round plates are stacked together, trimming-free product is 30-50cm higher than normal product, in which way greatly increases packaging and transportation costs.
(3)Trimming-free product have very special requirements for raw materials, according to the feedback of several manufacturers who have produced pulp molding products using free-trimming methods, 100% bagass pulp or straw pulp is used to produce free-trimming products that produce many hairy edges. Thus, an amount of wood pulp should be mixed into them so that the edges of the product will be less hairy.
(4) Free-trimming molds for pulp molding equipment have high prices
(5)The yield of pulp molding free-trimming products is lower than those margin-trimming, as can be seen from the following points,, ①The slurry concentration of trimming-free process is low, large drainage, and long filter absorption time, resulting in a reduction in production capacity; ②Long time virtual pressure process leads to low production capacity.
(6)Because the thermal expansion of the mold is inevitable, the problem of uneven edge size of the products without edge cutting is also inevitable, especially free-trimming products produced with pulp molding equipment with large mold mounting plates (above 1500 panels).
In sum up, verified by practice, the production cost of free-trimming molded pulp products is 20% higher than margin-trimming products.
3.Before choosing pulp molding equipment, users need to clearly understand the "mold removal and cleaning cycle"
Wet pressure method pulp molding equipment, all need to regularly remove the mold to clean the carbon deposition.Fully automatic pulp molding equipment producing food packaging and tableware is different from the mold disassembly and cleaning cycle of fully automatic pulp molding equipment producing high-quality industrial packaging products.
Due to the high price of fine industrial packaging products, the appearance quality requirements are very strict and the production capacity requirements of the products are relatively low;and the production of food packaging and tableware is different, there is homogeneous competition, comparable, to win by production capacity, so we pay great attention to production costs.
Therefore, the production capacity of fully automatic pulp molding equipment producing food packaging and tableware is the key indicator.The mold removal and cleaning cycle shall not be too short,Generally speaking, the mold removal and cleaning cycle of fully automatic pulp molding equipment producing food packaging and tableware is about 30 days.If the mold removal and cleaning cycle is too short, it is not competitive.Before choosing the automatic pulp molding equipment to produce food packaging and tableware, users need to understand the problem of "mold removal and cleaning cycle".
to be continued
