Comparison with other technologies
Tolerances
Borings
Threads
Male threads, like shaft undercuts, can be achieved by molding, thus eliminating secondary machining. The only problem may be due to flash along the parting line. This problem can be resolved by creating a cavity along the parting line.
Figure 1 shows how the parting line modifies the roundness of the cylinder (convexity), creating problems if it is to be mated with other parts: the same problem would occur in the case of a male thread.
Figure 2 shows how the parting line has been moved slightly inwards relative to the lateral surface of the cylinder, thus modifying the roundness of the shaft (concavity), and resolving the potential mating problem. In the case of female threads, the die must be equipped with a costly rotating/translating core, so that it may well be more convenient to use a secondary machining process to create them.
Uniform cross-sections
Injection
Surface finish
Assembly of green parts
Materials
Mechanical characteristics