The Design of Dishwasher Polystyrene Foam Cushion Packaging

2. Determination of cushioning pad size

2.1 Because the dimensions of the outer box of the dishwasher have been determined, the thickness of the foam cushion can only be 30mm. In order to ensure the effectiveness of the cushion, low-density, medium-density, and high-density foams are used in sequence in the design process. After actual tests, it has been found that due to the strength of the product itself, the high-density foam cushioning effect is ideal. This is due to the large deformation of the medium- and low-density foams and the fact that the products are also easily deformed, so that it is impossible to effectively protect the product from deformation. The high-density foam itself has good strength and can better protect the product from deformation.

It is reasonable to use a polystyrene foam with a density of 0.025 as a liner according to the relevant standards when designing a cushion with a curved design. The buffer coefficient of this material = 8.8 corresponds to the minimum buffer coefficient C = 3.4, according to H = 46cm, G = 40 (check the standard, the estimated value) is calculated by the buffer pad size: = 3.4 × 46/40 = 3.91cm

2.2 Because of the heavy quality of the dishwasher, T=0.3mm thick plastic film was chosen as the design material for the single air cushion. The experimental results show that the lateral stretch rate of the material is 344.8%, the longitudinal stretch rate is 296.4%, the longitudinal heat seal strength is 28.4 (N) the transverse heat seal strength is 27.6 (N), it can be seen that the selected thickness is T=0.3mm The plastic film stretch rate is very good, but also has a good heat seal strength, as the monomer buffer material is the best choice.

3. Comparison of foam and air cushion cushioned packaging

3.1 Comparison of Vibration Tests for Foam and Air Mat Cushion Packages

Vibration is one of the main factors that cause damage to the goods in the circulation environment. The sinusoidal vibration test can be used to find the natural frequency of the product in order to avoid resonance at the natural frequency of the product when designing the package. The test block diagram is shown in Figure 4:

After making two kinds of buffer design, packing according to requirements, using Y50100-1A/ZF type 100kg mechanical vibration table, acceleration sensor, YE5850 charge amplifier and data acquisition and analysis system (all products of Northwest Machinery Factory), will pack The parts are fixed on the table of the vibration table and undergo sweeping vibrations of 3~50. The acceleration value at the corresponding frequency is recorded every 5th increment to determine the natural frequency and resonance frequency of the package.

As can be seen from the above figure, when the bare machine vibrates, the dishwasher has resonance at 35 o'clock; the first resonance frequency of the package when the foam is packaged appears at 30, which is lower than the natural frequency of the product, and there is no 35 Resonance occurs and can be used in actual circulation; low-frequency resonances occur at 25 and 35 when air cushions are used to package vibrations. It can be analyzed that the protective function of the foam packaging at low frequency is better than the air cushion, and the protection function at high frequency is not as good as the air cushion.

Air cushions generate resonance at 25 o'clock, so the excitation frequency at the natural frequency 35 does not destroy the product. Although the package still resonates at 35 o'clock, the peak acceleration here is significantly less than the peak acceleration of the foam. The package can be resonated in resonance for 15 minutes. If the product is not damaged, the package is considered acceptable. In addition, the buffer effect can be improved if the structure of the monomer or the amount of gas in the monomer is changed. (to be continued)