Classifications

• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B19/00—Programme-control systems
  • G05B19/02—Programme-control systems electric
  • G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
  • G05B19/4097—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by using design data to control NC machines, e.g. CAD/CAM
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q1/00—Members which are comprised in the general build-up of a form of machine, particularly relatively large fixed members
  • B23Q1/03—Stationary work or tool supports
  • B23Q1/037—Stationary work or tool supports comprising series of support elements whose relative distance is adjustable
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q17/00—Arrangements for observing, indicating or measuring on machine tools
  • B23Q17/22—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring existing or desired position of tool or work
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q3/00—Devices holding, supporting, or positioning work or tools, of a kind normally removable from the machine
  • B23Q3/02—Devices holding, supporting, or positioning work or tools, of a kind normally removable from the machine for mounting on a work-table, tool-slide, or analogous part
  • B23Q3/06—Work-clamping means
  • B23Q3/08—Work-clamping means other than mechanically-actuated
  • B23Q3/088—Work-clamping means other than mechanically-actuated using vacuum means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
  • B23Q3/00—Devices holding, supporting, or positioning work or tools, of a kind normally removable from the machine
  • B23Q3/02—Devices holding, supporting, or positioning work or tools, of a kind normally removable from the machine for mounting on a work-table, tool-slide, or analogous part
  • B23Q3/10—Auxiliary devices, e.g. bolsters, extension members
  • B23Q3/103—Constructional elements used for constructing work holders
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
  • B25B11/00—Work holders not covered by any preceding group in the subclass, e.g. magnetic work holders, vacuum work holders
  • B25B11/005—Vacuum work holders
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
  • B25B5/00—Clamps
  • B25B5/006—Supporting devices for clamps
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/30—Nc systems
  • G05B2219/35—Nc in input of data, input till input file format
  • G05B2219/35025—Design and manufacture jig
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/30—Nc systems
  • G05B2219/50—Machine tool, machine tool null till machine tool work handling
  • G05B2219/50132—Jig, fixture
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P80/00—Climate change mitigation technologies for sector-wide applications
  • Y02P80/40—Minimising material used in manufacturing processes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P90/00—Enabling technologies with a potential contribution to greenhouse gas [GHG] emissions mitigation
  • Y02P90/02—Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Definitions

• the application relates to locators comprising a vacuum clamping surface for supporting and/or positioning an object as well as the use and manufacturing of such locators, and to supporting and/or reference structures comprising such locators.
• the supporting and/or reference structures described therein can be connected to a standard base structure and are manufactured via rapid prototyping techniques. Therefore, these reference structures can be produced fast and economically. However, the fixation of production parts to these reference structures often requires the presence of holes in the production parts, which is not always possible or desirable.
• clamps such as toggle clamps may result in unwanted deformation of the production part, and fixation and release of production parts using such clamps is time-consuming. Moreover, often a certain order of clamping needs to be respected. If an operator operates the clamps in a different order, or forgets certain clamps, the production part may not be held in the correct nominal position, resulting in an incorrect measurement or processing.
• the clamps may further block the visual range various scanning devices which are used for digitizing and measurement purposes.
• the application relates to locators comprising a vacuum clamping surface for supporting and/or positioning an object, to the use and manufacturing of such locators, and to supporting and/or reference structures comprising such locators.
• a first aspect provides in a method of manufacturing one or more locators for use on a base structure for supporting, positioning and/or calibrating an object, comprising the steps of:
• an internal channel for providing vacuum for said vacuum clamping surface wherein said channel is connected to two or more openings in said locator, whereby one of said openings allows connection of said locator to a vacuum unit, and one or more of said openings are provided on said vacuum clamping surface;
• the locator is designed to comprise a placement feature for attachment of said locator to said base structure or to a spacer attached to said base structure.
• the locator is designed to comprise a structural element connecting said vacuum clamping surface and said internal channel and optionally said placement feature.
• said internal channel has a wall thickness of more than 0.3 mm.
• the vacuum clamping surface is an object specific vacuum clamping surface complementary to at least part of the surface of said object.
• the locator comprises at least two vacuum clamping surfaces providing vacuum to two or more separate areas of said object.
• step iii) further comprises designing one or more mating surfaces on said one or more locators which mate specifically with a surface of said object, said surface not being addressed by a vacuum clamping surface from said locator.
• the method as described herein further comprises the step of at least partially coating the wall of said channel to increase the air tightness of said channel.
• step iii) further comprises designing said placement feature such that it corresponds with the structure of said base structure, based on the information obtained from the desired position of said object relative to said base structure.
• a further aspect provides in a locator at least partially made via additive manufacturing, comprising:
• a vacuum clamping surface for attachment of said locator to an object, wherein said vacuum clamping surface is an object specific vacuum clamping surface complementary to at least part of the surface of said object.
• an internal channel for providing vacuum for said vacuum clamping surface wherein said channel is connected to two or more openings in said locator, whereby one of said openings allows connection of said locator to a vacuum unit, and one or more of said openings are provided on said vacuum clamping surface;
• the locator as envisaged herein is made as one integral piece.
• the vacuum clamping surface further comprises one or more sealing members.
• the wall thickness of said channel is more than 0.3 mm. In certain embodiments, the wall thickness of said channel is between 1 mm and 5 mm. In particular embodiments, the wall of said channel is at least partially coated to increase the air tightness of said channel. In particular embodiments, the channel is connected to a vacuum unit.
• the locator further comprises at least one surface which mates with a surface of said object based on a digital description of said object, said surface not being addressed by a vacuum clamping surface from said locator.
• the locator is reinforced at least in part with a layer of highly durable material or by local hardening.
• said locator comprises at least two vacuum clamping surfaces providing vacuum to two or more separate areas of said object.
• a further aspect provides in supporting and/or reference structures comprising a base structure and one or more locators connected or connectable to said base structure, wherein at least one of said locators is a locator according to one or more of the embodiments described herein.
• the position of said one or more locators in the supporting and/or reference structure is determined based on a digital description of said object and a desired positioning thereof relative to said base structure.
• the supporting and/or reference structure further comprises a means for indicating a positional deviation of said object relative to said supporting and/or reference structure.
• said means for indicating a positional deviation is a vacuum sensor.
• the supporting and/or reference structure further comprises a means to carry out a processing operation on said object, and a means to block or interrupt said operation upon an output of the means for indicating a positional deviation.
• a further aspect provides in the use of a locator as described herein, or a supporting and/or reference construction as described herein, for calibrating, inspecting, checking, assembling or any other processing of an object.
• the locators obtained by the method as described herein are suitable for releasable holding of an object in a supporting and/or reference structure, reduce the risk of deformation of the object to be held, do not require the presence of holes or other connection features in the object to be held, can be made via additive manufacturing, and facilitates checking if the object is held in the desired position.
• FIG. 1 Illustration of a supporting and reference structure (10) according to a particular embodiment as described herein, not holding an object.
• Figure 3 A Schematic view of a locator (22) according to a particular embodiment as described herein.
• B Sectional view of a locator (22) according to a particular embodiment as described herein.
• FIG. 4 Sectional view of a locator (40) according to a particular embodiment as described herein.
• Figure 5 Schematic top view of a supporting structure (10) with means for indicating a positional deviation of an object, according to a particular embodiment as described herein.
• a first aspect provides in an improved locator for supporting and positioning and/or calibrating an object.
• object relates to any piece or part thereof including prototyping, pre production and production parts.
• locator refers to an end component of a supporting and/or reference structure which is used to actually ensure contact with the object and to establish and maintain the position of an object in the supporting and/or reference structure by constraining the movement of the object.
• a locator is sometimes also referred to as end-affector, top-ends or precision-fixture. It is typically a device which consists of features for contacting and/or securing an object and optionally features for securing the locator to the remainder of the supporting and/or reference structure.
• it is essentially a mechanical piece, i.e. its main function of supporting the object is based on its three-dimensional structure and does not require electrical power.
• the embodiments envisaged herein are for use in combination with a unit to which the locator can be coupled which ensures vacuum pressure in at least part of the locator (as detailed below). Moreover it can be envisaged that it can be provided with electrical components such as sensors.
• the embodiments as described herein relate to devices for holding objects in a desired position at least partially via vacuum clamping, and to methods of manufacturing such devices.
• the supporting and/or reference structure as described herein is hereinafter also referred to as “supporting structure”.
• the supporting structure allows reversibly holding an object, herein also referred to as “object to be held”, optionally in a fixed position.
• the object to be held is typically held in a "target position", i.e. a certain predefined position where the object is going to be processed, measured, etc.
• the contact of the supporting and/or reference structure with the object is ensured by one of more locators present on the supporting and/or reference structure.
• the supporting structure as described herein comprises a base structure, which may vary in shape and form according to the specifications of the object.
• suitable base structures are those described in patent EP 1307317.
• the base structure comprises a plate and/or one or more bars.
• the base structure may be built up of modular standard components.
• the base structure is provided with means for fixation of the locator(s) on the base structure, either directly or via spacers (see further).
• the base structure may be a plate having a plurality of positions where a locator or spacer can be fixed. Fixation may be obtained via interlocking features, a snap-fit mechanism, screws, pins, etc.
• the supporting structure as described herein further comprises one or more locators, which are connected or connectable to the base structure.
• the locators allow reversibly holding an object, optionally in a fixed position.
• the supporting structure comprises two, three, four, five, six, seven, eight, nine, ten or more locators which are connected or connectable to the base structure.
• At least one locator is adapted for vacuum clamping an object.
• a locator is hereinafter also referred to as "vacuum clamp locator”.
• Vacuum clamping significantly reduces the risk of damaging the object, and reduces the risk of unwanted deformation of the object, compared to other clamp types such as toggle clamps.
• toggle clamps contact the object on at least two sides
• vacuum clamps only need to contact the object at one side. Therefore, variations in thickness of the object do not affect the operation of the vacuum clamps.
• vacuum clamps are less likely to block the visual range of scanning devices which may be used for digitizing and measurement purposes.
• the supporting structure comprises two, three, four, five, six, seven, eight, nine, ten or more vacuum clamp locators which are connected or connectable to the base structure.
• the supporting structure may further comprise one or more other locator types.
• all locators of the supporting structure are vacuum clamping locators as described herein.
• the base structure may have a plurality of positions where a locator or spacer can be reversibly fixed. In particular embodiments, the positions of the locators are determined based on a digital description of the object to be held, and the desired target position of that object relative to the base structure.
• the position of the locators is typically determined such that the object can be held in the target position without risk of moving and/or deformation of the object. Furthermore, the position (and shape) of the locators is preferably determined such that it becomes impossible to fit the object to be held onto the supporting structure in any other position than the target position.
• the vacuum clamping locator(s) of the support structure as envisaged herein are at least partially made via rapid prototyping, particularly additive manufacturing techniques.
• rapid Prototyping techniques including stereo lithography (SL), Laser Sintering (LS), Fused Deposition Modeling (FDM), foil-based techniques, Direct Metal Laser Sintering (DMLS) etc.
• a common feature of these techniques is that objects are typically built layer by layer.
• Stereo lithography presently the most common RP&M technique, utilizes a vat of liquid photopolymer "resin" to build an object a layer at a time.
• an electromagnetic ray e.g. one or several laser beams which are computer-controlled, traces a specific pattern on the surface of the liquid resin that is defined by the two- dimensional cross-sections of the object to be formed. Exposure to the electromagnetic ray cures, or, solidifies the pattern traced on the resin and adheres it to the layer below. After a coat had been polymerized, the platform descends by a single layer thickness and a subsequent layer pattern is traced, adhering to the previous layer. A complete 3-D object is formed by this process.
• Laser sintering uses a high power laser or another focused heat source to sinter or weld small particles of plastic, metal, or ceramic powders into a mass representing the 3- dimensional object to be formed.
• FDM Fused deposition modeling
• Foil-based techniques fix coats to one another by means of gluing or photo polymerization or other techniques and cut the object from these coats or polymerize the object. Such a technique is described in U.S. Pat. No. 5.192.539.
• RP&M techniques start from a digital representation of the 3-D object to be formed.
• the digital representation is sliced into a series of cross-sectional layers which can be overlaid to form the object as a whole.
• the RP&M apparatus uses this data for building the object on a layer-by-layer basis.
• the cross-sectional data representing the layer data of the 3-D object may be generated using a computer system and computer aided design and manufacturing (CAD/CAM) software.
• CAD/CAM computer aided design and manufacturing
• the locators as described herein may be manufactured in different materials.
• the locators comprise a polymer, for example a polyamide.
• typical materials include but are not limited to laser sinterable materials, pulvurent materials that can be used in an additive manufacturing technology, pulvurent thermoplastic materials with a sharp thermal transition, allowing the use in a laser sinter process, pulvurent thermoplastic materials with a sharp thermal transition, that can be selectively melted into a 3D object via a layer-wise partial or full melting process, thermoplastic materials suitable to be used in a Additive Manufacturing process via selective deposition of small extruded wires or wire-shaped thermoplastic materials that can be selectively deposited in an Additive Manufacturing process.
• sharp thermal transition refers to a physical transition based upon a change in crystallinity and/or a change from glassy state to polymer melt that occurs over a limited temperature domain.
• the locators may comprise a polymer in which glass particles and/or metal particles are suspended.
• the metal and/or glass particles may enhance certain properties of the material (e.g. the stiffness, heat resistance and/or mechanical integrity), while retaining the material's compatibility with additive manufacturing techniques such as SLS.
• the polymer is a polyamide, e.g. nylon.
• the glass or metal particles typically have a size between 1 ⁇ and 100 ⁇ , for example 60 ⁇ .
• the metal particles are aluminium particles.
• Alumide ® available from EOS Gmbh, Germany.
• Alumide ® is made up of 50 (weight)% fine aluminium powder suspended in polyamide (Nylon 12).
• the particles are glass particles.
• An example of a polymer in which glass particles are suspended is DuraFormTM glass-filled (GF), available from 3D systems, USA. DuraFormTM GF is made up of glass particles suspended in polyamide.
• the (vacuum clamping) locators as described herein are produced by metal sintering.
• the vacuum clamping locator(s) as envisaged herein allow holding an object via application of a vacuum to a certain area of that object.
• the vacuum clamping locator(s) comprise one or more vacuum clamping surfaces, i.e. one or more surfaces on the external surface of the locator for attachment of the locator to an object, which allow the application of a vacuum to an object. This is ensured by the presence of one or more openings in said vacuum clamping surface which opening(s) is (are) connected to an inner channel through which a vacuum pressure is ensured.
• the vacuum clamping surface(s) provided on a vacuum clamping locator as described herein may have a fixed or variable position relative to the rest of the locator.
• the term “fixed vacuum clamping surface” refers to a vacuum clamping surface with a fixed position
• the term “movable vacuum clamping surface” refers to a vacuum clamping surface with a variable position.
• At least one locator comprises one or more movable vacuum clamping surfaces.
• at least one movable vacuum clamping surface comprises a resilient portion.
• at least one movable vacuum clamping surfaces is retractable. Locators comprising such movable vacuum clamping surfaces may be used to pull an object towards the desired target position as soon as the surface provides vacuum to the object. Accordingly, in particular embodiments, at least one movable vacuum clamping surface assumes a first position when not holding an object, and a second position different from said first position when holding an object.
• At least one locator comprises one or more fixed vacuum clamping surfaces.
• such locators when part of a supporting and/or reference structure) only apply vacuum to an object as soon as that object is within a certain tolerance of the target position.
• Fixed vacuum clamping surfaces can facilitate checking if the object is in the correct target position relative to the locator (see further).
• the vacuum clamping locator(s) comprise two vacuum clamping surfaces as described hereabove. This allows providing vacuum to two separate areas of the object to be held, which increases the capability of the locators to hold an object and further facilitates checking if the object to be held is in the target position.
• the two vacuum clamping surfaces may be located in the same plane or in different planes.
• the two vacuum clamping surfaces provide vacuum to two areas on different sides of the object to be held. This increases the stability of the object's position. In general, more vacuum clamping surfaces result in higher stability.
• the vacuum clamping locator(s) comprise three or more vacuum clamping surfaces, providing vacuum to three or more separate areas of the object.
• the vacuum clamping surface may have a planar shape, but the shape is not limited thereto. Indeed, the vacuum clamping surface may be a free-form surface, i.e. a surface having an irregular and/or asymmetrical flowing shape or contour. In preferred embodiments, the vacuum clamping surface is complementary to at least part of the surface of the object, which may or may not be a free-form surface. The complementary shape ensures a tight fit and reduces the risk of leaks which affect the vacuum quality.
• the supporting structure as described herein further comprises a means for indicating a positional deviation of the object relative to the supporting structure.
• the means for indicating a positional deviation comprises a pressure sensor, more particularly a vacuum sensor.
• the supporting structure comprises two or more pressure sensors.
• the supporting structure comprises one pressure sensor per (vacuum clamping) locator.
• the supporting structure comprises one pressure sensor per vacuum clamping surface.
• some vacuum clamping locators may comprise two or more vacuum clamping surfaces. Again, the pressure at each of the vacuum clamping surfaces may be monitored individually, provided that the vacuum clamping locator comprises as many internal channels and openings for connection of a vacuum unit as it comprises vacuum clamping surfaces.
• the supporting structure as described herein further comprises a means to carry out a processing operation on the object (e.g. scanning, measuring, assembly, cutting, trimming, painting, coating, etc.) and a means to block or interrupt the operation upon an output of the means for indicating a positional deviation as described hereabove.
• a processing operation on the object e.g. scanning, measuring, assembly, cutting, trimming, painting, coating, etc.
• the vacuum clamping locator further comprises an internal channel, i.e. which passes through the structural element of the locator from the vacuum clamping surface to an opening which can be connected to a vacuum unit.
• Channels made via additive manufacturing typically have porous walls, which affects the obtainable vacuum quality.
• the size of the vacuum clamping surface of the locator and the strength of the vacuum required may affect the minimal wall thickness that can be used.
• a minimum wall thickness of 0.3 mm is preferred in order to obtain a vacuum of sufficient quality.
• the channel has a wall thickness of more than 0.3 mm, more than 0.5 mm, more than 0.8 mm, or even more than 1 mm.
• the channel wall thickness is between 1 and 5 mm.
• the channel is connected to two or more openings in the locator, whereby one opening allows connection of the locator to a vacuum unit, and one or more openings are provided on the vacuum clamping surface. In this way, the channel can provide vacuum for the locator's vacuum clamping surface.
• the shape of the channel is not limited to a particular shape. Typically, the channel closely follows the shortest path from the connection to the vacuum unit to the vacuum clamping surface, thereby avoiding other features of the fixture where appropriate.
• the channel may therefore have a curved or straight shape.
• the cross section of the channel may have various shapes, including but not limited to circular, square or rectangular. In particular embodiments, the cross section has a circular shape. For a given wall thickness, a circular cross section typically provides an optimal strength of the channel.
• a circular cross section provides a minimal surface to volume ratio, which decreases the risk of potential leakage.
• the shape and/or size of the cross section of the channel may change along the length of the channel.
• the channel extends directly and exclusively from a vacuum clamping surface to an external surface of the locator which is different from, most particularly opposite to, the vacuum clamping surface.
• the channel extends from a vacuum clamping surface to an external surface which is integrated in a placement feature, i.e. in a surface which is designed to allow connection with a base structure or spacer as detailed below.
• the base structure is typically also provided with a corresponding channel (comprising or consisting of tubing) which ensures connection of the internal channel of the locator to a vacuum unit.
• a corresponding channel comprising or consisting of tubing
• the internal channel extends to a surface which is different from the feature or surface designed for connection to the base structure.
• the channel wall is at least partially coated to increase the air tightness of the channel.
• the coating may be applied either on the inside or the outside of the channel.
• the channel is coated internally.
• the coating may consist of the same or a different material than the rest of the locator.
• the channel is coated with a polymer or copolymer, for example an acrylic copolymer.
• the channel is impregnated with a solution of a (co)polymer, followed by evaporation of the solvent.
• the channel is impregnated with an aqueous solution of a styrene-acrylic acid ester copolymer, followed by evaporation of the water.
• the channel is coated by passing hot air or steam or any other hot substance through the channel.
• the heat then seals the inside of the channel, which improves the air tightness of the channel, which in turn improves the obtainable vacuum quality.
• the channel is connected to a vacuum unit.
• the vacuum unit ensures that the channel provides vacuum to the vacuum clamping surface.
• the vacuum unit is not integrated in the locator but can be connected thereto e.g. by tubing.
• the locators as envisaged herein are generally defined by the structural element, i.e. the structure of the locator which, in addition to the vacuum clamp surface defines the three- dimensional shape of the locator.
• the overall size of the locators is typically determined by the one or more surfaces of the object that they are designed to mate with.
• the locators will have a general cuboid shape, with rounded edges to avoid damage to the object during placement on the locator.
• the rigidity and dimensions of the locators may thus depend on the weight of the objects it has to hold.
• additive manufacturing techniques are generally not suitable for manufacturing large surfaces and massive structures due to deformations caused by differential shrinking during the manufacturing process. Therefore, the structural element, which provides support for the locator's vacuum clamping surface(s) and the internal channel(s) (and optionally other features such as placement feature(s) described below) is typically at least in part hollow. It will be understood however by the skilled person that the internal structure of the structural element is independent of the features of the channel and vacuum clamping surface which it supports.
• the use of a hollowed structural element significantly reduces the effects of differential shrinking and therefore increases the accuracy of the manufacturing process. Furthermore, the use of hollowed structural elements decreases the material consumption for producing the locators.
• the volume of the structural element is at least 50%, 60%, 70%, 80%, 90% hollow.
• the hollowed structural element comprises a framework, which may have an ordered or an unordered structure.
• the framework is a lattice structure.
• the lattice structure provides the required rigidity, and can be precisely manufactured via additive manufacturing.
• the lattice is typically a structure which consists of extended elements, for example made of strips, bars, girders, beams, plates or the like, which are contacting, crossing or overlapping in a regular pattern.
• the strips, bars, girders, beams, plates or the like may have a straight shape, but may also have a curved shape.
• the lattice may be an open or closed lattice.
• a closed lattice comprises cavities which are separated by walls, whereas an open lattice comprises interconnected cavities. Closed lattices are generally denser and stronger than open lattices.
• some or all locators are connected directly to the base structure.
• the target position of the object may require a considerable distance between the vacuum clamping surface and the base structure and thus the manufacture of large locators, which is expensive, time-consuming and difficult to manufacture with sufficient accuracy.
• the locators may be connected indirectly to the base structure, via spacers, which bridge the distance between the base structure and the locator.
• the spacers are preferably standard elements, i.e.
• the spacers may be column- or bar- shaped, and spacers with different lengths may be available.
• the spacers may comprise two or more pieces, which are connected to each other.
• the spacers are designed as modular building blocks, which can be connected in order to bridge larger distances.
• the locators are connected or connectable to the base structure or to a spacer attached to the base structure.
• the (vacuum clamping) locators may comprise a placement feature, for attachment of the locator to the base structure or to a spacer.
• the placement features correspond to one half of a set of interlocking features, a snap-fit mechanism, a dovetail system and/or a magnet-based system.
• the placement features may further comprise a hole or a threaded hole, to enable connection via a pin or screw.
• the placement feature may encompass one surface of the locator.
• the structure of the placement feature ensures a unique connection to the base structure or spacer. This may help to ensure (at least in part) the specific position of the locator on the base structure upon assembly. For instance, a groove fitting a ridge on the base structure may ensure a specific orientation but still allow flexibility in the exact position of the locator, while three-dimensional features may also determine the exact position of the locator relative to the base structure.
• the placement feature may be the same or different from placement features of other locators envisaged for use on the same base structure.
• the placement feature may comprise a hole, corresponding to the opening of the internal channel opposite from the clamping surface, which, by connection to the base structure or spacer corresponds to a channel (or tube) in the base structure which connects to a vacuum device.
• the separate placement feature and vacuum clamping surface provide a considerable flexibility in the locator design.
• the attachment of the placement feature and the vacuum clamping surface are designed such that they provide a certain angle relative to each other, so as to clamp to a surface which is not positioned parallel to the base structure.
• the vacuum clamping locator also comprises at least one mating surface which is not a vacuum clamping surface, and which mates with a surface of the object to be held based on a digital description of the object.
• the mating surface has several advantages. First, the mating surfaces facilitate obtaining the target position of the object, and allows checking if the object is in the target position.
• the mating surface of the locator may provide additional support for the object, thereby preventing movement or deformation of the object.
• the mating surface of the locator is designed based on a 3-dimensional image of the object to be held and its desired position on the fixture. Most particularly the surface is a surface which mates specifically with said object (i.e. does not mate with another surface of said object). Most particularly, the surface of the object which mates with the mating surface is specific or unique for the object, such that mating can be ensured only between the mating surface and its corresponding surface.
• the locators are provided with a protective coating which increases resistance against environmental factors and/or wear from use.
• a coating may cover all or part of the locator.
• Such coatings are especially advantageous on areas of the locator which contact the object to be held, such as the mating surfaces as described hereabove. Accordingly, in particular embodiments, the surface which mates with the object surface is provided with a protective coating.
• the coating may be obtained via local hardening of the material of which the locator is made. Additionally or alternatively, the coating can be of a different material than the locator itself.
• the (vacuum clamping) locator is reinforced with a sheath or insert of a highly durable material such as a metal plate or coated surface.
• a metal plated surface can be obtained by a metal plating process.
• a Copper-Nickel (CuNi) alloy is applied to the locator using a metal plating process.
• a CuNi alloy has the potential to improve multiple meaningful characteristics of additive manufactured, especially of RP&M, supporting and/or reference structure, including an improved durability, an improved stiffness, hardness, resistance to humidity and thermal stability.
• a coated surface can be obtained in different ways known to the skilled person.
• the coating is obtained by the application of a thin layer of UV curable coating layer on the surface and hardening the coating layer using ultraviolet light.
• the coating is obtained via Atomic Layer Deposition (ALD), which allows the formation of conformal coatings on non-flat surfaces.
• ALD is especially advantageous for the production of metal oxide coatings, such as aluminium oxide.
• the vacuum clamping surface(s) of the vacuum clamping locators further comprise one or more sealing members.
• the sealing member is typically made of a softer material or a material with a higher flexibility, than the rest of the locator.
• the higher flexibility of the sealing member allows a certain adaptation of the shape of the sealing member to the shape of the object to be held, thereby ensuring an airtight fit.
• the sealing member may be for example a rubber sealing ring which is arranged around or incorporated in the vacuum clamping surface.
• the (vacuum clamping) locators are made of one integral piece. Additive manufacturing techniques are especially advantageous for producing objects which are made of one piece. Accordingly, in further embodiments, the (vacuum clamping) locators are at least in part, and more particularly in their entirety made by additive manufacturing techniques. Most particularly the locators are manufactured and thus provided as a single piece, i.e. one piece in which all features are homogenously integrated and irreversibly connected. In further embodiments, the (vacuum clamping) locators are made of a single material. However, additive manufacturing techniques may also be used for the production of composite objects, i.e.
• the Objet ConnexTM 3D printing system offers the ability to fabricate Digital MaterialsTM - composite materials with pre-determined mechanical properties.
• the use of such materials had various advantages. For example, this allows the manufacture of a locator with a sealing member as described hereabove, wherein the sealing member is made of a material which is softer or more flexible than the rest of the locator. Additionally or alternatively, this allows the manufacture of a vacuum locator with a movable vacuum clamping surface, wherein the movable vacuum clamping surface is made of a material with an adapted flexibility and/or resilience.
• the use of composite materials offers the ability to coat the channel walls with a material with a lower porosity than the rest of the channel. In this way, the whole channel is sufficiently airtight without compromising the strength of the channel.
• the locator as described herein is manufactured and thus provided as a single piece and comprises two or more materials with a different softness, resilience, porosity or flexibility.
• a further aspect provides in a (vacuum clamping) locator as described hereabove.
• the vacuum clamping locators as described herein are manufactured via the method of manufacturing as described below.
• a further aspect provides in methods of manufacturing one or more locators for use on a base structure for supporting, positioning and/or calibrating an object. Specifically, methods are provided for manufacturing one or more vacuum clamping locators as described hereabove. The methods as described herein comprise the following steps i)- iv)
• the object may be scanned using a 3D scanner, e.g. a laser scanner.
• the collected data can then be used to construct a digital, three dimensional model of the object, for example via the 3-maticTM computer program as provided by Materialise N.V., Leuven,
• ii) Selecting one or more surfaces of and/or locations on the object which are suitable for vacuum clamping the object.
• the surface of the object selected for mating with the locator is specific or unique for the object.
• At least one vacuum clamping surface for attachment of the locator to the object
• An internal channel for providing vacuum for the vacuum clamping surface preferably has a wall thickness of more than 0.3 mm.
• the channel is connected to two or more openings in said locator, whereby one of the openings allows connection of the locator to a vacuum unit, and one or more of the openings are provided on said vacuum clamping surface.
• the locator is designed to comprise a placement feature for attachment of said locator to said base structure or to a spacer attached to said base structure.
• the locator is designed to comprise a structural element connecting said vacuum clamping surface and said internal channel and optionally said placement feature.
• step iii) of the method as described herein further comprises designing one or more mating surfaces on the one or more locators, which mate specifically with a surface of the object, wherein these mating surfaces are not part of a vacuum clamping surface. This facilitates obtaining the object's target position and provides additional support.
• the method as described herein further comprises the step of (partially) coating the locator's channel wall in order to increase the air tightness of the channel.
• step iii) of the method as described herein further comprises designing the placement feature such that it corresponds with the structure of the base structure, based on the information obtained from the desired (target) position of the object relative to the base structure.
• a final aspect provides in the use of a locator and/or a supporting structure as described herein, for calibrating, inspecting, checking, assembling or any other processing of an object. Such methods involve positioning the object such that the mating surfaces of one or more vacuum clamping locators (on the supporting structure) mate with the corresponding surface on the object and applying vacuum to the one or more locators such that the object is maintained in position.
• fixating component for fixtures and/or locators are described as examples only without intending to be limitative in any way.
• FIG 1 shows a supporting structure (10) according to a particular embodiment as described herein, while holding an object (24).
• the supporting structure (10) comprises a base structure (12) in the form of a frame and five locators (14, 16, 18, 20, 22).
• the locators are connected to the base structure via column-shaped spacers (13, 15, 17, 19, 21 ), wherein the longitudinal side of the column is positioned perpendicular to the surface of the base structure 12.
• the base structure has a plurality of positions where a spacer (or locator) can be fixed.
• the spacers are standard items that can be re-used for different objects (24) to be held.
• the object (24) is held in a target position by the locators (14, 16, 18, 20, 22).
• Figure 2 shows a supporting structure (10) according to a particular embodiment as described herein, not holding an object.
• Three locators (16, 18, 22) comprise a vacuum clamping surface (30).
• the object (24) is fixed to the vacuum clamping surfaces by vacuum.
• Some locators (14, 20) fix the object by other means, for example by a hole and a pin or a screw to provide an additional security of reversible positioning of the object.
• FIG. 3A shows a locator (16, 18, 22) according to a particular embodiment as described herein.
• the locator comprises two vacuum clamping surfaces (30) and an internal channel (28) which is connected to various openings.
• One of these openings is a connection point (32) which allows connection of the locator to a vacuum unit.
• More openings (31 ) are provided on the vacuum clamping surfaces (30).
• the vacuum clamping surfaces (30) are designed to provide vacuum to two separate areas of the object to be held.
• Figure 3B shows a sectional view of the locator (22) shown in Fig. 3A.
• the internal channel (28) is connected with the openings (31 ) provided on the vacuum clamping surface (30).
• the internal channel (28) further provides a connection point (32) to connect the internal channel (28) with a vacuum unit.
• the vacuum clamping surface (30) is provided with seal elements (34). The seal elements
• the locator (34) are rubber elements which are incorporated into the locator (22).
• the locator comprises a recessed placement feature (35) for attachment of the locator to a spacer.
• the sectional view further shows that the placement feature (35), the internal channel (28) and the vacuum clamping surfaces are connected via a lattice structure (37).
• FIG 4 shows a sectional view of a locator (40) according to a particular embodiment as described herein.
• the locator comprises a movable vacuum clamping surface (30).
• the movable vacuum clamping surface (30) has a flexible accordion-like structure, such that it can pull the object to be supported (not shown) towards the target position, as soon as it applies vacuum to the surface of the object.
• the movable vacuum clamping surface may comprise materials with a different flexibility than the other parts of the locator.
• the material of which the movable vacuum clamping surface is manufactured may be sufficiently flexible such that no separate seal elements are required.
• the locator further comprises a mating surface (39) which provides additional support and ensures that the object is not pulled further than the target position by the movable vacuum clamping surface (30).
• the locator (40) further comprises an internal channel (28) which is connected with the movable vacuum clamping surface (30) via an opening (31 ).
• the internal channel (28) further provides a connection point (32) to connect the internal channel (28) with a vacuum unit.
• the locator comprises a recessed placement feature
• the sectional view further shows that the placement feature (35), the internal channel (28) and the vacuum clamping surfaces are connected via a lattice structure (37). 3) Supporting structure with means for indicating a positional deviation of an object
• FIG. 5 is a top view of a supporting structure (10) with means for indicating a positional deviation of an object, according to a particular embodiment as described herein.
• Each locator (14, 16, 18, 20, 22) comprises a vacuum clamping surface and is linked with a collector (36).
• the collector (36) is linked with an pressure sensor (38).
• the pressure sensor (38) may then emit a (digital or analogue) warning signal.
• the pressure sensor (38) may emit a signal when the pressure is below a certain threshold value, i.e. when the object is in the target position.

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Cited By (10)

Citations (2)

• 2013
  • 2013-01-11 WO PCT/EP2013/050449 patent/WO2013104741A1/fr not_active Ceased

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