Mold assembly

A mold assembly for insert-molding a heterogeneous object, comprising:

• an upper mold comprising a cavity for accommodating an insert object;
• and
• a lower mold comprising a rigid body and a resilient contact member, said upper mold being in direct contact with said rigid body, and said rigid body having two inner sidewalls and a bottom surface between said two inner sidewalls to thereby form a recess facing said upper mold, wherein the resilient contact member is fixed within the recess of the rigid body, the resilient contact member does not contact the upper mold, and wherein said inner sidewalls and said bottom surface conforms to and contacts two outer sidewalls and a bottom surface of the resilient contact member, wherein the insert object is disposed on the resilient contact member during an insert molding process, such that the resilient contact member absorbs dimensional variations of the insert object during the insert molding process.