Injection molding structuring

Injection molded Structural foam molded Compression molded... 

Injection-molded structural foams, 23 407 Injection molding, 19 549—554 of ABS, 1 424-426... 

Ultem PEI resins are amber and amorphous, with heat-distortion temperatures similar to polyethersulfone resins. Ultem resins exhibit high modulus and are stiff yet ductile. Light transmission is low. In spite of the high use temperature, they are processible by injection molding, structural foam molding, or extrusion techniques at moderate pressures between 340 and 425°C. They are inherently flame retardant and generate little smoke dimensional stabilities are excellent. Large flat parts such as circuit boards or hard disks for computers can be injection-molded to maintain critical dimensions. 

Of particular note to date are developments using ESI-based materials in foam applications. Novel foam structures offer attractive properties and characteristics including softness, esthetics and drape for a wide range of thermoplastic and crosslinked foam applications. Other product technologies of interest are as injection molded structural foams, as foamed layers in multilayer structures and as foamed blends of interpolymers with styrenic and olefinic polymers [77-79], Interpolymers also have potential for co-extruded film and sheet applications. 

As in injection molding of thermoplastics, the location of the sprue also influences the surface quality of injection-molded structural components made from phenolic resin molding compounds. 

Polystyrene. There are five basic types of polystyrene foams produced in a wide range of densities and employed in a wide variety of applications (1) extruded polystyrene board (2) extruded polystyrene sheet (3) expanded bead molding (4) injection-molded structural foam and (5) expanded polystyrene loose-fill packaging. 

If glass fibers are added to get reinforcement, the method is known as RRIM (Reinforced Reaction Injection Molding). Structural RIM (SRIM) is the process whereby the reinforcement fabric or mat (glass, carbon) are placed in the mold and the resin is injected to impregnate the reinforcement. 

In line with these four points, there is a need for know-how along the entire process chain from formulas for thermoplastics through injection molding, structuring, and metallization to final placement of the electronic components. Correspondingly, in-process quality assurance with defined interfaces between stakeholders is of tremendous importance. It is in this context that this book addresses each individual process step with the purpose of avoiding possible mistakes in MID projects. 

Process chain Injection molding Structuring Metallization Assembly (without OLED) OLED placement 2E mechatronic GmbH Co. KG 2E mechatronic GmbH Co. KG MID-Solutions GmbH/LaserMicronics GmbH 2E mechatronic GmbH Co. KG By customer... 

USE OF INJECTION SPEED PROFILE TO ACHIEVE A UNIFORM VOID FRACTION DISTRIBUTION IN INJECTION MOLDED STRUCTURAL FOAMS... 

The change in pressure drop and pressure drop rate at the gate of the mold during the structural foam molding process results in an inevitable nonuniform void fraction along the melt flow direction in injection molded structural foams. The nonuniform void fraction not only reduces the achievable void fraction but also can deteriorate the mechanical properties of structural foams. In this paper, an effort has been made to overcome this problem with various injection speed profiles. 

---