Computer aided generative design with tool size control to facilitate 2.5-axis subtractive manufacturing processes

A system comprising:

• a non-transitory storage medium having instructions of a computer aided design program stored thereon;
• and
• one or more data processing apparatus configured to run the instructions of the computer aided design program to cause the one or more data processing apparatus to
• obtain (i) a density-based representation of a modeled object for which a corresponding physical structure is to be manufactured using a 2.5-axis subtractive manufacturing process with one or more computer-controlled manufacturing systems, and (ii) data specifying a starting element for each of multiple different subsets of elements in the density-based representation of the modeled object,
• wherein each of the element subsets has a milling depth, which is one of three or more shared milling depths assigned respectively for three or more discrete layers, each of the three or more discrete layers being perpendicular to a milling direction of the 2.5-axis subtractive manufacturing process, and
• wherein the density-based representation specifies a three dimensional shape of the modeled object, which has been generatively designed using density-based topology optimization;
• process starting elements of the element subsets having milling depths associated with discrete layers below a top most layer of the three or more discrete layers, with respect to the milling direction, wherein the instructions cause the one or more data processing apparatus to process the starting elements of the element subsets by causing the one or more data processing apparatus to, for a current starting element of the starting elements being processed for a current layer,
• identify other starting elements that (i) have element subsets having milling depths associated with a layer above the current layer and (ii) are closer to the current starting element than an amount that is at least equal to a radius of a smallest milling tool available for use with the one or more computer-controlled manufacturing systems,
• calculate a maximum angular difference between the other starting elements with respect to the current starting element, and
• move the milling depth for the element subset of the current starting element to a layer above the current layer by at least changing density values for at least a portion of individual elements in the element subset, in response to the maximum angular difference being greater than a threshold value, to remove a non-manufacturable corner in the modeled object;
• and
• provide the three dimensional shape of the modeled object for use in manufacturing the physical structure using the one or more computer-controlled manufacturing systems that employ the 2.5-axis subtractive manufacturing process.

A non-transitory computer-readable medium encoding a program operable to cause one or more data processing apparatus to perform operations comprising:

• obtaining (i) a density-based representation of a modeled object for which a corresponding physical structure is to be manufactured using a 2.5-axis subtractive manufacturing process with one or more computer-controlled manufacturing systems, and (ii) data specifying a starting element for each of multiple different subsets of elements in the density-based representation of the modeled object,
• wherein each of the element subsets has a milling depth, which is one of three or more shared milling depths assigned respectively for three or more discrete layers, each of the three or more discrete layers being perpendicular to a milling direction of the 2.5-axis subtractive manufacturing process, and
• wherein the density-based representation specifies a three dimensional shape of the modeled object, which has been generatively designed using density-based topology optimization;
• processing starting elements of the element subsets having milling depths associated with discrete layers below a top most layer of the three or more discrete layers, with respect to the milling direction, the processing comprising, for a current starting element of the starting elements being processed for a current layer,
• identifying other starting elements that (i) have element subsets having milling depths associated with a layer above the current layer and (ii) are closer to the current starting element than an amount that is at least equal to a radius of a smallest milling tool available for use with the one or more computer-controlled manufacturing systems,
• calculating a maximum angular difference between the other starting elements with respect to the current starting element, and
• moving the milling depth for the element subset of the current starting element to a layer above the current layer by at least changing density values for at least a portion of individual elements in the element subset, in response to the maximum angular difference being greater than a threshold value, to remove a non-manufacturable corner in the modeled object;
• and
• providing the three dimensional shape of the modeled object for use in manufacturing the physical structure using the one or more computer-controlled manufacturing systems that employ the 2.5-axis subtractive manufacturing process.