Engineering Changes Made on the Line without a Notice
Unannounced line changes bypass engineering approvals to preserve local throughput, requiring physical tool audits and strict contract remedies to control.
Fixture Shim
Meaning
Thin metal or plastic plates compensate for small gaps and misalignments between a workpiece and its holding device during the machining or assembly process. A fixture shim is inserted to adjust the height and level of a component to ensure it meets the dimensional tolerances required by the engineering drawing. These spacers prevent the movement of the part under the pressure of cutting tools.
Adjustment Method
Technicians select specific thicknesses of material to fine-tune the orientation of the fixture on the machine bed. By placing a fixture shim at the contact points, the operator can correct for wear in the base plate or slight variations in the casting of the tool. This manual calibration is necessary when the automated settings of the machine cannot account for physical irregularities.
It is a fundamental step in the setup of jigs for welding and drilling where the repeatability of the part position determines the quality of the entire output. Operators often stack multiple thin layers to reach the precise thickness required for a specific setup.
Material Composition
Hardened steel or brass is commonly used to withstand the compressive forces of a production run without permanent deformation. A fixture shim must be resistant to the chemical solvents and coolants used in the factory environment. If the spacer material is too soft, it will compress over time and lead to a drift in the dimensions of the finished parts.
Dimensional Control
Validation of the setup involves the use of feeler gauges to verify that the spacing is exact. The fixture shim is considered a critical consumable because even a variation of one hundredth of a millimeter can result in a rejected batch of components. Regular inspection of these spacers ensures that the alignment remains stable throughout the life of the tool.