Described is a test head for a residual seal force (RSF) testing system. The test head includes a housing, an anvil, and a ball roller assembly. The housing defines a first cavity and the anvil is positioned at least partially within the first cavity. The ball roller assembly is configured to provide a point of contact between the housing and the anvil during a RSF test. The test head may further comprise a retaining ring configured to maintain the anvil at least partially within the first cavity.

A residual stress distribution measuring method of the present invention is characterized by comprising: by using an analytical model in which a cut-surface is interpolated to a cross section of a metal member, the step of calculating a residual force vector that is a sum of a load vector acting on a first metal piece at the cut-surface and a load vector acting on a second metal piece at the cut-surface; the step of calculating, as a modified displacement vector, an amount of movement at the cross section by interpolating the residual force vector as a forced load to the cross section of an analytical model of the metal member; by using an analytical model having the shape of a cut-surface of a measured first or second metal piece, the step of modifying the shape of the cut-surface of the first or the second metal piece on the basis of the calculated modified displacement vector; and by using the analytical model in which the shape of the cut-surface of the first or the second metal piece is modified, the step of calculating a residual stress distribution at the cross section by interpolating a forced displacement to the analytical model.

Techniques for producing a flat film surface in additive fabrication are provided. According to some aspects, a movable stage may be arranged beneath a container having a base that includes a flexible film. The movable stage may include a segmented member in which a number of segments are aligned along a common axis. The segmented member may maintain contact with the flexible film as the movable stage moves beneath the container, with the segmented member producing a flat surface of the flexible film, at least within a region above the movable stage. According to some embodiments, multiple segmented members may be provided within the movable stage, such as in parallel with one another.

Techniques for film tensioning in additive fabrication are provided. According to some aspects, a film forming part of a container in an additive fabrication device may be tensioned by different forces along different axes. According to some embodiments, an adjustable tensioning system may be provided within an additive fabrication device that may couple to one or more components of a removable container comprising a film. The tension of the film may be adjusted by the additive fabrication device via the adjustable tensioning system and its coupling to the container.

Multi-film containers for use in additive fabrication devices are provided. According to some aspects, a container may include multiple films that are at least partially detached from one another. In some embodiments, the multiple films may include films formed from different materials. As one example, an upper film may be formed so as to be relatively impermeable to substances within a source material of an additive fabrication device, whereas a lower film may be formed so as to provide desirable mechanical properties. In some cases, the multiple films may be commonly tensioned while being unattached to one another.

Techniques for directing light from a movable stage in an additive fabrication device are provided. According to some aspects, the movable stage may include a parabolic mirror onto which light may be directed at various different incident angles to produce light along different positions along an axis. In some cases, this axis may be perpendicular to a direction of motion of the movable stage.

Techniques for force sensing in additive fabrication are provided. According to some aspects, an additive fabrication device may include a force sensor configured to measure a force applied to a build platform during fabrication. A length of time taken for a layer of material to separate from a surface other than the build platform to which it is adhered may be determined based on measurements from the force sensor. Subsequent additive fabrication operations, such as subsequent motion of the build platform, may be adapted based on the determined length of time.

Systems and methods for prediction and measurement of overlay errors are disclosed. Process-induced overlay errors may be predicted or measured utilizing film force based computational mechanics models. More specifically, information with respect to the distribution of film force is provided to a finite element (FE) model to provide more accurate point-by-point predictions in cases where complex stress patterns are present. Enhanced prediction and measurement of wafer geometry induced overlay errors are also disclosed.

The present invention relates to a method and an apparatus for establishing residual stresses in objects, in particular in coated objects, and to a method and an apparatus for coating objects. The method comprises: impinging a surface (8) of the object (5) with laser light and generating a hole or a pattern of holes and/or locally heated points in the object (5); establishing the surface deformations by an optical deforming measuring method after the object (5) is impinged by laser light; establishing the residual stresses present in the object (5) from the measured surface deformations, wherein the generation of the hole pattern is carried out by an optical scanning apparatus which comprises an optical deflection and/or modulation arrangement for controllable deflection and/or modulation of the laser light, and/or a focusing arrangement for controllable focusing of the laser light.

A force dynamometer includes at least one plate, a controller with a memory and at least one force sensing resistor that senses a force exerted on the one or more plates. The controller receives a signal indicating magnitude of the force and transmits a signal to at least one color variable light emitting diode (LED) to change color of the color variable LED in response to the force sensing resistor changing magnitude of the force signal transmitted to the controller. The controller may transmit a signal to one or more piezoelectric sensors such that the controller controls intensity of vibrations and/or magnitude of frequency of the vibrations of the one or more piezoelectric sensors. A force dynamometer system includes a computing device that displays or controls speed of a variable motion speed image or object or displays or controls a direction controllable image or object via the force dynamometer.