1. Shape analysis of battery buckle plastic parts
The structure of this plastic part is relatively simple and the appearance is smooth, but the demoulding involved in the groove of the product must be pushed out twice, and there are four grooves on the plastic part.
2. Analysis of battery buckle material
The battery buckle material is PE, which is short for polyethylene. It is a polymer polymerized from ethylene. When used as plastic, its average relative molecular mass should be above 10000. Depending on the polymer conditions, the actual average relative molecular mass can vary from 10000 to several million. Most of the generated PE ethylene monomer is obtained by petroleum cracking. Polyethylene is the simplest molecular structure in the resin. It has rich raw material sources, low price, excellent electrical insulation and chemical stability, easy molding and processing, and There are many varieties that can meet different performance requirements. Therefore, it has developed rapidly since its inception and is currently the largest resin variety with a wide range of uses.
 
Performance characteristics of PE material:
Soft, poor mechanical properties, low surface hardness, good chemical stability, but not resistant to strong oxidants, good water resistance
 
PE molding features:
Can not be preheated before molding, shrinkage, easy deformation, long cooling time, molding efficiency is not high, plastic parts have shallow side concave can be forced demoulding.
 
PE material in the mold design should pay attention to matters: the gating system should be as soon as possible to ensure filling, cooling system, the use of temperature is generally <800 degrees Celsius.
There are many varieties of PE materials. According to the requirements and characteristics of plastic parts, low density polyethylene can be used as injection molding material.
There are many varieties of PE materials, and low density polyethylene (LDPE) is used as the injection molding material for plastic parts. LDPE is obtained by a typical radical polymerization process at high temperatures and particularly high pressures. As early as the early 1940 s, LDPE has been used for wire coating and is the earliest product in the PE family. LDPE combines many excellent properties, such as transparency, sealing, easy processing, is one of the most widely used materials in the polymer industry.
LDPE can usually be prepared by two production processes of tubular and kettle reactors. The pressure during polymerization is (150~350)Mpa, the polymerization temperature is between 150~260 ℃, and an appropriate amount of initiator is added.
Different from the linear PE obtained by other processes, the high-pressure free radical polymerization process is prone to chain transfer, and the obtained polymer has a large number of branched chain structures, which makes LDPE transparent, flexible, easy to extrude and other specific properties. By controlling the average relative molecular mass (MW), crystallinity and relative molecular mass distribution (MWD), a variety of applications can be obtained for LDPE resins.
The average relative molecular mass of a polymer is expressed in terms of the average size of all the molecular chains that make up the polymer. For convenience, the melt flow rate (MFR) is used in the plastics industry as a measure of the average relative molecular mass.
The crystallinity of LDPE is related to the content of short chain branches in the resin, and the crystallinity is usually 30% to 40%. The improvement of crystallinity is the increase of rigidity, chemical resistance, barrier property, tensile strength and heat resistance of LDPE. The impact strength, tear strength and stress cracking resistance were reduced.