Method of forming a flexure assembly
View Patent ↗A flexure assembly includes two metallic flexure arrays molded into a thermoplastic support base. The two flexure arrays are positioned in parallel in the thermoplastic support base to allow rotational movement about one axis while providing high stiffness with respect to off-axis movement. Flexible supports in the two flexure arrays may be interleaved to form a cross flexure configuration. Off-axis stiffness of the flexure assembly prevents harmonic resonance in directions that cannot be compensated for in a single-axis actuator.
1. A method of forming a flexure assembly, the method comprising:
providing a first metallic flexure array that includes a first base member and multiple flexible supports and a second metallic flexure array that includes a second base member and multiple flexible supports;
positioning the first metallic flexure array and the second metallic flexure array in an injection mold cavity; and
supplying a thermoplastic into the injection mold cavity to form a molded support base around the first base member and the second base member.
2. The method of claim 1 , wherein the first metallic flexure array and the second metallic flexure array are formed by removing material from a steel-containing sheet material.
3. The method of claim 1 , wherein the first metallic flexure array and the second metallic flexure array comprise a single component formed from a metallic sheet.
4. The method of claim 1 , further comprising:
prior to supplying a thermoplastic into the injection mold cavity, positioning a bottom support frame in the injection mold cavity, whereby the bottom support frame is integrated with the molded support base when the thermoplastic is supplied.
5. The method of claim 1 , further comprising, concurrently with forming the molded support base around the first base member and the second base member, forming a molded component that couples the multiple flexible supports in the first metallic flexure array to the multiple flexible supports in the second metallic flexure array.
6. The method of claim 1 , wherein positioning the first metallic flexure array and the second metallic flexure array in the injection mold cavity comprises interleaving the multiple flexible supports in the first metallic flexure array with the multiple flexible supports in the second metallic flexure array.
7. The method of claim 6 , wherein interleaving the multiple flexible supports in the first metallic flexure array with the multiple flexible supports in the second metallic flexure array comprises positioning the flexible supports in the first metallic flexure array within 100 microns of but not in contact with flexible supports in the second metallic flexure array.
8. The method of claim 1 , wherein a thickness of the steel-containing sheet material is selected so that flexion of the multiple flexible supports in normal operation of the flexure assembly produces an internal stress in the steel-containing material that does not exceed an endurance limit of the steel-containing sheet material.
9. The method of claim 1 , wherein positioning the first metallic flexure array and the second metallic flexure array in an injection mold cavity comprises contacting an interior surface of the injection mold cavity with the first metallic flexure array and contacting another interior surface of the injection mold cavity with the second metallic flexure array.
10. The method of claim 9 , wherein positioning the first metallic flexure array and the second metallic flexure array in an injection mold cavity further comprises mating an alignment feature of the first metallic flexure array or the second metallic flexure array with a corresponding feature associated with the injection mold cavity.