Thermally sprayed film forming method and device

摘要

An apparatus is provided to reduce the defect rate and decrease production yield by removing foreign objects even when the foreign objects are mixed in with the thermally sprayed film. The operation for forming thermally sprayed film on inner surface of cylinder bore is paused, and protrusions generated in the thermally sprayed film by foreign objects are detected by visual observation and removed by a manual operation. The thermal spraying operation is then performed until thermally sprayed film reaches the prescribed film thickness. After formation of the thermally sprayed film, a finishing operation is performed by means of honing.

主权项

1. A thermally sprayed film forming method comprising:
linearly driving a spraying gun having a thermal spraying nozzle along a path of travel between an open first end and an opposing second end of an inner surface of a cylinder of a workpiece wherein said workpiece is a cylinder block of an engine, and said inner surface of said cylinder is a cylinder bore inner surface of the cylinder block; and applying a plurality of layers of the thermally sprayed film to the inner surface of the cylinder by rotationally spraying a molten material towards the inner surface of the cylinder from the thermal spraying nozzle while linearly driving the spraying gun and then allowing said molten material to solidify attached to said inner surface wherein, when all layers of the plurality of layers are applied, a prescribed film thickness of the plurality of layers is formed that is a total thickness of all layers of the plurality of layers, by:
after applying at least one layer of the plurality of layers and before applying all layers of the plurality of layers, removing a protrusion formed of a foreign object as a nucleus mixed in with the at least one layer of said thermally sprayed film attached to the inner surface of the cylinder by contact of a tip of a cutting device with the protrusion while the tip of the cutting device is spaced apart from the prescribed film thickness, the protrusion having a form such that it projects beyond an exposed surface of the applied at least one layer surrounding it and leaves a recess within the exposed surface of the applied at least one layer when removed; andapplying remaining layers of all layers of the plurality of layers after removing the protrusion.