Diagnostic method for manufacturing processes

A method for identifying evidence of deviation from specification in a form produced in a workpiece by a manufacturing process, the manufacturing process being performed by respective manufacturing equipment, the method comprising the steps of:

• identifying a set of measurable forms associated with the workpiece, each form corresponding to an action of the manufacturing equipment;
• for each form, identifying a reference datum;
• for each form, making a set of measurements of the form relative to the respective datum;
• comparing each set of measurements to a respective target range of values;
• and
• based on the comparison, inferring the existence of evidence of an alert condition,
• wherein the hierarchic set of forms comprises two categories:
• a first category of forms characterizing the shape of a portion of the workpiece, and a second category of forms characterizing a set of portions of the workpiece.

A method for identifying evidence of deviation from specification in a workpiece produced by a manufacturing process, the manufacturing process being performed by respective manufacturing equipment, the method comprising the steps of:

• identifying a set of repeated portions of the workpiece, each instance of a repeated portion having a form, the form of one instance of a repeated portion being substantially similar to the form of the other instances;
• for each instance of the repeated portion, making a set of measurements of the reproducible part relative to a respective reference datum;
• comparing each set of measurements to a respective target range of values;
• and
• based on the comparison, inferring the existence of evidence of deviation from specification.

A method for assessing a condition of a workpiece acted upon by manufacturing equipment, comprising the steps of:

• identifying a set of forms, each form corresponding to an aspect of the action of the manufacturing equipment upon the workpiece;
• for each form, making a plurality of measurements;
• for each plurality of measurements, computing a respective deviation from a corresponding datum;
• defining a deviation threshold;
• and
• if a computed deviation exceeds the deviation threshold, inferring the existence of the condition attributable to the action of the manufacturing equipment on the workpiece associated with action corresponding to the form for which the deviation exceeds the threshold.

A method for detecting deviations from an intended form in a mechanical part, the deviations based upon computed differences between measured geometric properties with respect to a reference datum and defined threshold values, the deviations from an intended form caused by a machine tool operating on the mechanical part, the method comprising the steps of:

• a. identifying a hierarchic set of geometric forms characterizing the mechanical part, each form corresponding to an action of the machine tool on the part, wherein the hierarchic set of geometric forms comprises two categories:
• a first category of forms characterizing the shape of a portion of a workpiece forming the mechanical part, and a second category of forms characterizing one or more portions of the workpiece;
• b. categorizing the geometric forms from a lowest order to a highest order;
• c. making a plurality of measurements corresponding to the lowest order form, each plurality of measurements made relative to a reference datum;
• d. computing deviations based on differences between the plurality of measurements and the reference datum;
• e. comparing the deviations with respective threshold values, the deviations exceeding threshold values indicating an alert condition;
• and
• f. if an alert condition is present, inferring a deviation from the intended form.

A method for characterizing the ability of a machine tool to reproduce a product without deviating from a specification intended for at least a portion of the product, the characterization based upon taking geometric measurements, the method comprising the steps of:

• a. identifying a set of geometric forms present in the product;
• b. selecting a first of the set of geometric forms;
• c. making a plurality of measurements corresponding to the selected geometric form;
• d. for each plurality of measurements, computing a deviation from a respective reference datum;
• e. checking for an alert condition based on each of the respective deviations;
• f. if an alert condition is present, adjusting the machine tool and repeating the method from step c iteratively until no further alert condition is found;
• and
• g. if no alert condition is detected, repeating the method from step b and incrementing to the next form until all geometric forms have been selected.