一, Structural optimisation: the main way to make strength and accuracy better
1. Design of the hollow and vertical reinforcement: Finding the right balance between flexibility and strength
The packaging that protects electrical items needs to be able to withstand both impacts and distortion. In mould design, the hollow structure can make the product more elastic and absorb vibration energy during shipping. Reinforcing bars make the product more stiff and spread stress by making the fibre arrangement denser. For instance, Lenovo computers come in boxes with vertical corrugated ribs that make each box 20% stronger when it comes to compressive strength. The arc-shaped transition of the cavity also helps to spread out stress, which lowers the drop test damage rate from 8% to 0.3%.
2. Demoulding slope and rounded corner transition: a double guarantee of precision and yield
The slope of the demolding directly impacts the product's size and surface quality. Too much incline can make it hard to demold, which can leave tugging scars or cracks. Too much slope can also make packing less useful. To make sure that moisture-retaining paper blanks come out smoothly and that fibres don't break because of straight edges and right angles, electronic product packaging moulds usually have a demolding slope of 1 ° to 3 ° and rounded transitions of R0.5 to R2 mm. For instance, the packaging mould for Apple Beats Studio Pro earbuds has made the edges of the product 15% stronger and cut down on waste by making the corners rounder.
3. Controlling the thickness of the wall: the skill of finding the right balance between strength and cost
The strength of a product depends a lot on the thickness of the walls, yet making them too thick can need more raw materials and energy to dry. Most electronic device packaging moulds have walls that are 0.5 to 6 mm thick (adsorption forming method), and they make weak portions stronger by adding extra thickness to them. For instance, the Xiaomi phone packaging mould made the walls 0.3mm thicker in the camera module area, which made the local compressive strength 30% stronger, while the overall material use only went up by 5%.
二, Process adaptation: a technological leap from wet pressing to dry pressing
1. Process of wet pressing mould: making anything with a lot of detail and accuracy
The wet pressing method uses high-pressure moulding to make fibres denser, making it great for packing high-end electronics. There are two main problems that mould design needs to solve:
Fiber-oriented arrangement: The flow direction of fibres in the pressure field is regulated by carefully matching convex and concave moulds. The packaging mould for the Sony Xperia 1 V phone, for instance, uses zone pressure control technology to align the fibres with the direction of the impact. This enhances the energy absorption rate by 40% in drop tests.
Making a micro porous structure: The mould has to manufacture a micro porous array of 0.1–0.5mm in order to suit the buffering needs of precision instruments. A company produced a packaging mould for medical electronic equipment that uses laser engraving technology to evenly distribute 0.2mm micropores, keeping the product's density inaccuracy within ± 2%.
2. Dry process moulds: looking into low-cost, quick prototyping
Hot pressing moulding is part of the dry process, which lowers the need for moisture, energy use, and production costs. There are two big problems that mould design needs to solve:
Optimising heat conduction: The dry process needs to heat the fibres quickly to make them solid, and the mould needs to employ materials with high thermal conductivity (such aluminium alloy) and build a cooling water circuit that fits. For instance, a certain company made a dry pulp moulding mould that cut the moulding cycle from 120 seconds to 80 seconds by rearranging the cooling water circuit.
Better surface quality: Dry process technology often leaves burrs on surfaces, hence the mould needs to use nano coating technology. A titanium coating was put on a certain laptop packaging mould to make the surface of the product less rough, going from Ra3.2 μ m to Ra0.8 μ m. This met the appearance standards for high-end electronics.
三,Environmental Compliance: Trends in Sustainable Design in the Business World
1. Modular design: the best way to get more people to recycle
The EU WEEE rule says that electronic equipment must have a plastic recycling rate of at least 85%. However, classic integrated mould design packaging parts are hard to take apart and only have a recycling rate of 55%. Snap fasteners link modular moulds instead of glue, which makes it easy to take apart packing parts. For instance, one laptop maker altered the mould for the central frame from integrated to modular. This raised the rate of plastic recycling to 82% and cut mould expenses by 10%.
2. Changing biobased materials to lessen their impact on the environment
There are two big problems that need to be solved when making biobased materials like PLA and PHA into moulds:
Temperature resistance: The temperature of the injection should be kept between 180 and 220 degrees Celsius, and the mould should be coated with chromium to keep the PLA from sticking to it. A company has made a PLA mobile phone packaging mould that lasts 200,000 times longer than it did before by chrome plating it.
Optimising liquidity: PHA material is very thick, which can make filling uneven. Gradient flow channels must be used in the mould design. By optimising the flow channel section, a certain medical electronic packaging mould has made the fibre distribution of PHA goods 30% more even.
四, Industry Practice: From a big technological breakthrough to a wide use
Case 1: Lenovo's proposal to replace plastic
Lenovo will slowly switch from plastic cushioning in laptop packaging to pulp moulding starting in 2022. This will make the packaging stronger and more accurate by using new mould designs.
Increasing the amount of long fibres by 30% to build a skeleton structure and using high broom mechanical pulp (TMP) to improve the degree of fibre interweaving;
Using Enhancer: Adding 0.2% PAM solution to make a network membrane structure cuts down on chip shedding by 86%.
Improvement in the hot pressing process: The product is 20% tighter with a combination of 180 °C, 0.5 MPa, and 40 seconds, and the surface flatness error is smaller than 0.08 mm.
Lenovo has completely replaced pulp moulded packaging by 2024. This has cut the cost of shipping a single laptop by 15% and raised customer satisfaction by 12%.
Case 2: Apple's Fibre Aesthetics Innovation
The packaging for Apple Beats Studio Pro headphones is constructed of 100% fiber-based materials (bamboo fibre and sugarcane bagasse fibre). The following mould design strikes a compromise between strength and accuracy:
Adding nanocellulose (50–100 nm in diameter) to the material makes it 50% stronger, which is what precision equipment need to work properly.
Design of a micro porous structure: 0.3mm honeycomb cells are used to partition the region, which lowers the damage rate from 8% to 0.3% during drop testing.
Modular manufacturing: CNC precision machining moulds make sure that the packing size is accurate to within ± 0.05mm, which makes it easy to put together with the product.
