# US 5,349,746 A · Process for the manufacture of a force sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,349,746 A - Document ID: US5349746A - Status: Granted - Kind: A - Application number: 07/956,892 - Filed: 1992-11-30 - Granted: 1994-09-27 - Earliest claimed: 1990-05-07 - Assignees: Robert Bosch GmbH - Inventors: Werner Gruenwald; Kurt Schmid; Martin Mast - Web page: https://patentgrep.com/patent/US5349746A ## CPC - G01L 1/2287: {constructional details of the strain gauges (adjustable resistors H01C10/00)} - Y10T 29/49099: Coating resistive material on a base - Y10T 29/49103: Strain gauge making - G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A process and a device are proposed for manufacturing sensors, particularly those intended for the determination of pressure forces. In thick-film technology, initially at least one insulating layer (14) is produced on a pressure support (10), whereupon a pressure-sensitive resistance layer (12) and finally conductor paths (13) are applied. In a pressing tool (20-22), the layer arrangement (11-14) is then compressed together with a plastic pressure substance (15). Finally, the pressure support (10) is removed from the pressed article. ## Claims ### Claim 1 A process for manufacturing a sensor constructed in thick-film technology for the determination of forces acting on a surface of the sensor, the sensor including; at least one thick-film resistor which is applied to an insulating layer disposed on a metal pressure support, the latter having a smooth surface facing the layer arrangement; the resistor is electrically contacted at at least two spatially separated locations by means of conductor paths, with the surfaces of the layer arrangement being treated such that they are plane parallel to one another; and wherein the pressure support surface to be provided with the layer arrangement is polished smooth and the pressure support is removed once the production of the layer arrangement is completed. ### Claim 2 (depends on 1) A process according to claim 1, wherein the layer arrangement is treated by being compressed in a pressing tool together with a plastic pressing substance. ### Claim 3 (depends on 2) A process according to claim 2, wherein compressing takes place at an elevated temperature, with the temperature being selected, on the one hand, high enough that the plastic pressing substance becomes plastically deformable and, on the other hand, low enough that no carbonization occurs in the layer arrangement. ### Claim 4 (depends on 2) A process according to claim 2, wherein the pressed article produced during the compression is hardened at an elevated temperature of 120.degree. to 200.degree. Celsius. ### Claim 5 (depends on 1) A process according to claim 1, wherein the surface of the pressure support facing the layer arrangement was wetted with a release agent before the layer arrangement was applied. ### Claim 6 (depends on 1) A process according to claim 1, wherein pastes into which a release agent has been mixed are employed for the layer arrangement. ### Claim 7 In a process for manufacturing a sensor constructed in thick-film technology for the determination of forces acting on a surface of the sensor, said process including the steps of providing a metal pressure support having a substantially flat surface, applying a layer arrangement to the flat surface with the layer arrangement including at least one thick-film resistor layer disposed on at least one insulating layer which is disposed on the flat surface of the metal pressure support, electrically contacting the resistor layer at at least two spatially separated locations by means of conductor paths, and treating the opposed outer surfaces of the layer arrangement such that they are plane parallel to one another; the improvement comprising: polishing smooth the flat surface of the pressure support prior to the step of applying a layer arrangement; and removing the pressure support once the production of the layer arrangement is completed. ### Claim 8 (depends on 7) A process according to claim 7, wherein the step of treating includes pressing the layer arrangement in a pressing tool together with a plastic pressing substance. ### Claim 9 (depends on 8) A process according to claim 8, comprising carrying out the step of pressing at an elevated temperature, with the temperature being selected high enough that the plastic pressing substance becomes plastically deformable and low enough that no carbonization occurs in the layer arrangement. ### Claim 10 (depends on 9) A process according to claim 9, wherein the elevated temperature is between approximately 120.degree. and 180.degree. Celsius. ### Claim 11 (depends on 9) A process according to claim 9, further comprising hardening the pressed article produced during the step of pressing at a temperature of approximately 120.degree. to 200.degree. Celsius. ### Claim 12 (depends on 8) A process according to claim 8, further comprising hardening the pressed article produced during the step of pressing at a temperature of approximately 120.degree. to 200.degree. Celsius. ### Claim 13 (depends on 7) A process according to claim 7, further comprising the step of wetting the flat surface of the pressure support with a release agent before the step of applying a layer arrangement. ### Claim 14 (depends on 7) A process according to claim 7, wherein pastes into which a release agent has been mixed are employed for the layer arrangement during the step of applying.