1. Flowchart
1.1 Raw material preparation: Select high-quality clean virgin pulp as the raw material, the fiber length should be appropriate, the ratio of long and short fibers to be appropriate, for easy pulping and dehydrating.
1.2 Pulping: Mix the pulp with water in a certain proportion, add an appropriate amount of dispersant and defoamer, oil proof and water proof agents, stir evenly, and make the pulp reach the appropriate concentration and beating degree, while removing any bubbles.
1.3 Forming: The stirred pulp is sucked into the mold, and vacuum adsorption dehydration is used to evenly cover on the forming mold, forming the products.
1.4 Drying and hot pressing: Transfer the dehydrated tableware items to the hot press mold, use vacuum, heat and dry to remove moisture from the wet products, and hot press at a certain temperature and pressure for a certain time to bond the pulp fibers and form a dry product with a certain strength.
1.5 Cooling: Take out the hot pressed pulp and cool it to room temperature (with fully automated die trimming and no cooling process). After cooling, the size and quality of die cutting and punching are more stable.
1.6 Trimming and punching: Trimming the cooled pulp tableware to remove burrs and defective products.
1.7 Post inspection processing: Select defective products and use laser engraving or printing.
1.8 Disinfection: Disinfect the finished pulp tableware with ultraviolet radiation.
1.9 Packaging: Package the disinfected pulp tableware to complete the entire process.
2. Key points of the processes
2.1 When mixing the pulp, it's necessary to control the ratio of pulp to water, the mixing time and speed, to ensure that the pulp is fully dispersed and remove bubbles.
2.2 When forming, it's necessary to ensure that the pulp evenly covers the forming mold and eliminate any bubbles inside.
2.3 When dehydrating, it's necessary to control the vacuum, pressure, and time to make the pulp more dense, uniform, and crack free.
2.4 When drying, it's necessary to control the temperature, pressure, and time to ensure that the pulp is completely dehydrated, as well as the hot pressing time, so that the pulp fibers adhere to each other and minimize the occurrence of defects such as cavitation and tearing.
2.5 Cutting and punching should ensure product quality and aesthetic appearance, and avoid reducing defects such as burrs.
3. Brief analysis of technological progress in pulp molded tableware equipment
3.1 In terms of raw materials, traditionally it mainly uses sugarcane pulp mixed with bamboo pulp. Currently the straw pulp (including wheat straw pulp and reed pulp) also becomes a trend. In addition, there are also requirements for the FSC properties and low-carbon demand for the raw materials.
3.2 Additives: Fluorine free requirements have become increasingly strict, and fluorine-free oil additives are not only expensive, but also have limitation. International brands of fluorine-free oil additives are being tested on a small scale, and domestic waxy fluorine-free oil additives are also being tested in batches by enterprises. To solve the unstable performance of fluorine-free oil additives, some enterprises have adopted fluorine-free coatings or film covering to partially meet market demand.
There are also some application scenarios that directly implement single waterproofing, which only uses fluorine free water proof without oil proof, to meet the fluorine free demand in the European and American markets.
Dyed tableware is also a highlight, and there are also non powdery tableware and extra hard tableware, especially for takeout applications. Dumpling pallets that are resistant to moisture, low temperature, and non sticky dough allowed for cold chain are rapidly entering the market.
3.3 The forming section is mainly focused on automation and energy saving. The energy management system is worth paying attention to. Reducing the moisture content of wet products and non cutting edge technology are also innovative directions worth paying attention to.
3.4 Drying and dehydration is mainly a research on process adjustment to achieve high efficiency and energy conservation.
3.5 Edge punching: Currently integration, automatic loading and unloading and high-speed punching machine are being researched and developed to improve efficiency and reduce costs.
3.6 The automation of post production inspection and packaging is a key focus of research and development. At present, specific products undergo high-speed punching and cutting, connected to automatic AI online detection, coupled with automated wiring and packaging, effectively reducing labor costs.
Youtube Video Links:
https://www.youtube.com/watch?v=EQpU4Wl8NVI&t=1s
https://www.youtube.com/watch?v=RT_tq5RAa4w&t=7s
https://www.youtube.com/watch?v=TEwvIqZGxy8
https://www.youtube.com/watch?v=jB11NKns27I