Structural design and manufacture of the hottest p

Structural design and manufacture of packaging containers

Chapter 2 structural design and evaluation of packaging containers

section 1 overview

structural design of packaging containers is based on scientific principles, according to different packaging materials and different packaging container forming methods, from the internal and external structure of packaging containers. The design principles of scientificity, reliability, aesthetics and economy must be followed, and various contradictions must be considered to weigh the weight and achieve the best

section II packaging container structure design program

packaging container structure design is an important part of the whole packaging design system. And other packaging designs are interrelated, mutually restricted and mutually reinforcing. The general design process is shown in the figure

from the overall structure of the design process, it can be roughly divided into the following four stages:

1 In the stage of design condition analysis,

clarify the design requirements, investigate and study to master the necessary data; Analyze the category, physical state, physical, chemical and biological characteristics of the packaged products; Clarify the packaging environmental conditions, circulation conditions, market conditions, etc; Understand the packaging materials, container types and existing production conditions

2. Scheme design stage

in this stage, design parameters should be determined, such as the measurement value of packaged products, allowable deviation, etc; Design container modeling scheme; The best structural design scheme is determined through comparative analysis and evaluation of various structural design schemes of packaging containers

3. In the detailed structural design stage

convert the structural design scheme into specific and detailed structural expression, that is, analyze and calculate the strength, stiffness and stability of the structure, select materials, determine technical requirements, draw a full set of drawings, prepare instructions and relevant technical documents

4. Improvement design stage

according to sample test, use Identification, market feedback and other links "for the problems exposed by the low price of such bags, appropriate technical treatment should be made to the packaging container structure to ensure quality.

section III packaging container structure design content

I. specific design content

(1) Packaging container appearance structure design

is to design the three-dimensional appearance shape of the packaging container. The design should not only conform to the aesthetic principles of modeling design, but also consider the influence of packaging container molding process

(2) internal structure design of packaging container

that is to design the internal structure of packaging container, which includes container wall thickness design, local structure design, structural design calculation, etc. Among them, the design and calculation of container structure includes the design and calculation of structural size, the design and calculation of packaging container capacity, and the design and calculation of strength and stiffness

second, the design and optimization of structural dimensions

packaging containers are mostly geometric shapes. From the perspective of economy, it is always hoped that the material consumption of manufacturing containers can be minimized under the condition of meeting the packaged products, and the amount of materials consumed by containers is directly related to the wall thickness and external area of containers. Generally, the smaller the wall thickness is, the less consumables are used in the packaging container. Therefore, in the design of the wall thickness, the smaller value should be selected as far as possible under the condition of meeting the strength and stiffness. It can also be used in the production of handicrafts. When the wall thickness is determined, the optimization method can be used to optimize the design of the packaging container to obtain the best size of the packaging container

the basic idea of optimal design of this packaging container is summarized as follows:

Step 1 establish a mathematical model

A. determine the design variables

take the dimensions that must be determined in the structural design of the packaging container, such as the wall thickness, the external dimensions of the container that can be used to manufacture butyl rubber and styrene butadiene rubber, as the design variables. N design variables are often represented by

b. construct the objective function

for packaging containers, generally, the objective function can be constructed by taking the minimum material consumption or the cost of packaging containers as the objective. That is, the relational equation of the objective function is constructed based on the internal volume equation of the packaging container and the total area equation of the packaging material for the manufacturing container, which includes all variables (design variables) that determine the shape of the container

for a single objective function with n design variables, it can be written as:

f (x) =f (x1, X2, X3... Xn)......................... (4.1)

c. determine the constraint conditions

that is, determine the conditions that limit the value of design variables. There are requirements for the internal volume of the container, strength conditions, etc. for the packaging container

constraints are often expressed in the following form:

G (x) ≥ 0 i=1, 2................. M............. (4.2)

according to the above work, the mathematical model of the packaging container can be expressed as:

calculate the design variables... X=[x1, X2,... Xn]

minimize the objective function... Minf (external protection X of the testing machine)... (4.3)

meet the constraints... G (x) ≥ 0 i=1.2.3 M

Step 2 optimization design calculation

A. select optimization calculation method

optimization design method has been developed so far, many optimization calculation methods have been given, and many optimization calculation programs have been used in engineering. For the seen packaging container optimization mathematical model, select the appropriate optimization calculation method

b. calculation

choose the appropriate optimization calculation method, turn it into a mathematical model to solve the packaging container, and calculate the best size of the packaging container