To design to meet the functional requirements of the connector, selection is very important, and the selection is based on full understanding of material performance, below connector plastic performance noun explanation, and they hope to help everyone.
One, the mechanical properties of 0
The impact strength of 1 (Impact Strength)
Impact strength is the maximum energy can bear external force impact of plastic.
Impact strength is the object by the impact force, resistance strength shows. It is not the material rupture stress (Kg/cm2) to represent the total energy, and to break can bear (Kgf-cm) absorption or sample units of basal area in the breaking energy (kgf-cm /cm2 or J/m) to represent.
Test methods are usually refer to the ASTM D256, it is the principle of using cantilever beam way, let the pendulum drop impact of unilateral fixation has notched plate, and then calculating the energy consumption (usually specified temperature).
Impact strength can be used as a reference level between different plastic toughness, in general, with high impact strength of plastic, says it has high intensity high ductility, high toughness is.
But do not suggest to bring it as the overall strength of plastic index, because some plastic on incision concentrated stress is very sensitive, strength performance can in no incision or very good, such as nylon and ethylene acetal plastic, to
In this type of plastic, it is recommended to avoid a sharp angle design, to avoid the possibility of stress concentration. In addition, some plastic supplier will provide no notch impact test value.
2 bending strength (Flexural Strength).
In the bending test, before the provisions of deflection or bending, the load reaches a maximum value of the stress is called the bending strength and bending moment, the unit is Mpa. it into flexural section modulus is proportional to the material is inversely proportional to.
Testing standards: ASTM D790.
Mainly used for the determination of folding endurance ability of plastic, expressed on a per unit area and how much force.
General plastics with PVC, beautiful La Ming resin, epoxy resin and polyester bending strength is better. Glass fiber is also used to enhance the plastic folding endurance. Bending elastic rate refers to the test piece bending (test methods such as bending strength), in the elastic range, unit deformation quantity generated by the bending stress. General bending elastic rate is bigger, the better the said rigid plastic material.
3 flexural modulus
Style to bear in the bending process of the maximum bending stress, unit Mpa. O: 'Q?
Modulus = stress / strain, bending modulus of bending stress ratio on the deformation caused by bending.
Tensile strength (4 Tensile Strength):
Also called tensile strength, refers to the test of plastic, tensile fracture or process to yield, the maximum tensile stress is called the tensile strength, the unit is Mpa.
5 tensile elongation (Tensile Elongation);
Some people call the elongation percentage, elongated length with the original length as a percentage (%) said.
6 compression strength (Compression Strength)
Also called compressive strength test, refers to the process of plastic, compressed to fracture or yield, the maximum compressive stress is called compression strength, unit
Two, processing properties
1 liquidity
Liquidity plastic materials generally with the melt index (MFI) to represent, melt index usually has two forms of expression:
Melt flow rate of g/10min;
Melt volume flow rate
Definition: the melt index of thermoplastics under certain temperature and pressure, melt by standard capillary weight or volume value in ten minutes of the time, with (g/10min or cm^3/10min) to represent.
The melt flow rate of raw materials has a direct impact on the effect of injection molding products, liquidity material too good, it will lead to some water, gas too late from the mold discharging took shape, will form a bubble, hollow, plastic into effect
Product strength; liquidity is too poor, it will lead to plastic mould is complex in the molding of plastic raw materials can not be timely flow to the corner and distant area, the formation of material shortage. The melt flow rate of accurate determination of plastic raw material value, and palm
Control, is crucial to the injection molding process of plastic.
Molding shrinkage for l2. (Mold Shrinkage)
Molding shrinkage rate refers to the corresponding volume products injection molding and mold when compared to what happened, shrink ratio. Heat melting plastic, caused by the heat expansion. In injection molding, injection pressure and compression for re contraction. Molding
In the mold internal cooling solidification shrinkage, once again, but when the die then due to pressure recovery and once again produce several expansion phenomenon. Summary of the volume difference, known as the molding shrinkage.
6 molding shrinkage can formula:
Molding shrinkage rate = size of die - molded product size / size of die
Into the shrinkage rate in percentage (%) to represent
The characteristics of:
The vertical direction of the flow of 81 resin shrinkage is big, and the direction of flow rate smaller shrinkage laws.
2 crystalline resin (PET, PA, POM, PP) than the non crystalline resin molding shrinkage rate.
3 non strengthened material than the molding shrinkage rate large hardening material. .
4 even the same kind of materials in different conditions, injection molding shrinkage rate also has the change, the effect of non crystalline resin under pressure, the influence of crystalline resin is easily affected by temperature conditions.
The influence factors of forming shrinkage:
1 strengthening factor
Many factors affect the forming law of shrinkage rate, can be divided into qualitative and qualitative factors of non -. Even if the same material, according to the enhancement factor to distinguish, the results are not the same. -6 materials such as nylon, strengthening under non, molding shrinkage rate
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