Commonly known as “bump stop”, the jounce bumpers are indispensable components in vehicle suspension systems where it’s used to prevent the abrupt and harsh bottoming-out of the suspension when under full compression. It absorbs impact and dampens noise, vibration and harshness by preventing the suspension components from fully compacting during shock impacts caused by heavy loads, potholes, curbs, or objects in the road. However, these repetitive impacts on the bumper, can cause deformation to the product.
Existing rubber products are thermally fragile and incompressible due to excessive damping, and this can cause unpleasant results in function and durability with the occurrence of large impacts and deformation. They are also relatively heavy. Although foamed products, on the other hand, can overcome these shortcomings of rubber, it is usually made through casting process which takes longer molding time/cycle and high investment/manufacturing costs.
Based on the current situation, a Korean manufacturer for automotive parts desires to develop an alternative material as well as a novel process for this, and now seeking partners for government funded joint R&D project. The expectations and goals for each are as follows :
1. Material Development
Unlike conventional polyurethane foaming in which polyol and is ocyanate react at the nozzle, it contains its own foaming agent and is suitable for bridging and foaming when injected into a mold at a high temperature.
TPE (Thermoplastic Elastomer) processed by a thermoplastic method, for example, TPU(Thermoplastic Poly Urethane) may be considered as a base material.
Functionally, a material that does not break even with high load and large deformation and has low permanent deformation
Environmental resistance such as moisture, oil, ozone, heat/cold resistance
Target foaming characteristics: Foaming rate 130%, Cell size 100um or less, Skin thickness 250um or less
2. Process Development
IP (Injection Phylon) equipment commonly used in the footwear industry may be considered but is not necessarily limited to IP equipment
It is also desirable to implement the above properties and foaming in a general thermoplastic resin injection machine, but a configuration in which a plurality of clamping devices is disposed in one injection machine is preferable to compensate for a long curing and cooling time (low production efficiency). For the configuration of Multi-Station, a rotary method or a linear movement method can be considered.
The mold opening and closing method can be either vertical or horizontal, but the horizontal method is advantageous to reduce runner loss in a multi-cavity mold. It is good if it is configured in consideration of automation.
For the injection method of the material in the mold, the injection method is preferable, unlike the pouring method of the existing MCU(Micro Cellular Urethane) in order to increase the degree of freedom in product design.
A method of foaming by injecting air such as nitrogen or carbon dioxide may be added as an option.
The injection molding process which is proceeded in a high temperature, allows higher level of freedom to implement the shape that results in high functionality as well. All the more, general or/and existing plastic molding machines can be retrofitted for this process thus it’s also cost efficient.
The Korean company, the owner of this profile has already formed a Korean consortium for a R&D cooperation, and now seeking global partners
*The expected outcome of R&D project will be as follows:
The Korean company is targeting EUREKA Network programme, therefore, is seeking partners from countries which have allocated funds to the Network Project programme. This profile is opened for EOIs until the 31st of August 2021, however, dates can be changed depending on the situation.