Description

Auto bumper mould

Auto bumper mould is also named automotive bumper mould and car bumper mould.

there are also two different kinds of bumper – front bumper mould and rear bumper mould.

with more than 20 years experience on auto bumper mould, we are ready to help you with any new auto bumper mould.

With the development of the automotive industry, car bumpers have also entered the path of innovation as an important safety device. In addition to maintaining the original protective functions, the front and rear bumpers of today’s cars are also pursuing harmony and unity with the body shape, and pursuing their own lightweight. In order to achieve this goal, the front and rear bumpers of the car currently use plastic, which is called plastic bumper.

The main function of the auto bumper:

1. protection function – bumper should absorb part of the energy in the longitudinal and corner collision of the car to protect the body, vehicle lighting system, cooling system, engine cover, gift box cover, etc.; pedestrian protection function, in the bumper The lower part is equipped with a buffer block to better protect the calf injury value when a pedestrian collides.
2. device functions – on the bumper, some are equipped with lamps, license plates and license plates, etc., to give enough space and equipment conditions;
3. ventilation channel – providing ventilation channels for vehicle cooling systems
4. decoration function – the appearance decoration function integrated with the body shape
5. Improve aerodynamic characteristics ——The optimal design of the front bumper has obvious effect on reducing the front windward resistance coefficient and lift coefficient.

Design Concept :

1.  meet regulatory requirements
2. Collision performance requirements: 2.5MPH BUMPER (ECE R42);
3. Pedestrian protection performance requirements: EEC70/156;
4. External projection requirements: ECE R26. 01, EEC 79/488;
5. meet the effective air intake area of the cooling system
6. meets the modeling requirements, the overall appearance is smooth and coordinated
7. low cost, light weight, material recyclability
8. process feasibility, easy to disassemble principle

Material and structure of auto bumper

The auto bumper material is required to have good rigidity over a wide temperature range, good impact resistance, good dimensional stability, good solvent resistance and good coating performance. Commonly used >PP+EPDM-T20.

The auto bumper is composed of a buffer beam, an (energy absorbing) energy absorbing foam, a body and a connecting bracket, wherein the energy absorber is in the form of PP foaming.

Bumper body, upper and lower grille, tow hook cover, lower support guard material adopts PP+EPDM-T20: PP is the base of bumper cover, EPDM can improve the elasticity of bumper cover, and T20 means material Plus 20% talcum powder, mainly to improve the rigidity of the bumper cover.

The energy absorbing block generally adopts an EPP or a PP foaming structure to absorb the impact energy. The front/rear cushioning beam body material is made of cold-rolled high-strength structural steel B340/590DP, and the buffer beam bracket is made of B180P2 (relative to the material of the beam body, the material is low in strength but cheap), mainly to meet the requirements of European regulations. Front/rear collision requirements.

The bracket material on both sides adopts PP66+GF30%, and the material has the characteristics of good toughness and hard surface. The lower support guard mainly serves as a pedestrian protection function, and supports and protects the lower leg during collision, and plays a certain aesthetic effect.

The above-mentioned materials generally have an environmentally friendly effect of recycling and recycling, which can reduce environmental pollution. The structure of the bumper system is mainly composed of shape, wall thickness, demoulding angle, ribs, support surface, rounded corners, holes and so on.

The automotive bumper mask and the beam are large thin-walled injection molded parts, and the mask is also an appearance part. The material is required to have good fluidity, and has high precision of parts and ultraviolet stability. Generally, modified polypropylene is used. Pp+EPDM) material.

In the structural design, the geometric shape and the forming method should be designed. The mold parting surface should satisfy the forming process as well, and the parting line should be placed on the non-appearing surface as much as possible.

In the design of plastic parts, in order to avoid stress concentration at the corners, a circular arc transition should be used, which is very beneficial for the manufacturing life of the mold.

Generally, the joints of the plastic parts should be. Fillets of 5-1mm, and some rounded corners should be used at the corners to reduce stress and ensure consistent wall thickness.

Wall thickness

the wall thickness of the part is generally uniform, otherwise it will cause uneven shrinkage due to different curing or cooling speeds, resulting in internal force, resulting in warpage or shrinkage of the part.

Demoulding angle – Plastic parts must take into account the angle of release, avoiding zero or negative angles. The larger the demolding angle, the easier the part is to be demolded, but it is easy to cause uneven thickness of parts and affect manufacturing precision.

Reinforcing ribs

Plastic parts, especially large parts, can only guarantee the shape and size of the part if there is only a certain wall thickness, let alone a certain strength. Therefore, reinforcement must be applied at some points such as holes, large curved surfaces or mounting points to increase strength and rigidity.

The main surface of the exterior part (CLASSA) is generally not suitable for reinforcement. When the subsurface (CLASSB) is reinforced, the wall thickness of the root is not greater than 3/4 of the wall thickness, and the surface quality is low or non-visible (CLASS C&D).

Rounded corners

The minimum fillet for a typical part is R0.5, but the parting surface is not rounded, otherwise it will increase manufacturing costs and difficulty. The hole-hole shape should be as simple as possible, and the hole should be kept at a certain distance from the wall. The hole-to-boundary minimum is at least 1.5 times the aperture.

Inner parting structure

In the design of the auto bumper mold, in order to ensure the appearance quality of the product, the inner parting line is set on the invisible B side, so that the processing error or the flash produced by the mold after long-term production will not affect the appearance quality of the product.

In this way, the produced products not only meet the requirements of the customers, but also greatly improve the pass rate of the products, and use the inclined top block plus the lateral slider and use the variable rail to smoothly demold the product.