Abstract: A coordinate measuring machine (CMM) is disclosed having improved manufacturability and low cost while maintaining high performance standards. The CMM includes a polymer composite gantry-style base incorporating a three-point support configuration in the X, Y, and Z axes. The X-beam is hollow, has a horizontal cross-sectional orientation, uses a passive ventilation technique, and is attached to the bearing at one end by a compliant mount. The Z-axis probe shaft incorporates a combined counterbalance/drive assembly and a compliant secondary rail guide mechanism. The X-axis and Y-axis drive screws have angular alignment capability using a spherical washer configuration. This combination of features serves to minimize non-repeatable errors and enhance the manufacturability of the CMM, providing substantial improvements in CMM design and construction.

Abstract: A coordinate measuring machine is described including a vertical probe shaft mounted on an X-axis carriage in turn mounted on a Y-axis carriage for movement along three orthogonal axes, in which the Y-axis carriage is guided and supported on a first guide beam fixed extending along one side of a machine base with air bearings mounted to the lower end of one upright engaging all four sides of the first guide beam. The Y-axis carriage is also supported on a second guide beam fixed extending along the other side of the base, with air bearings mounted to the lower end of the other upright engaging only the top and bottom surfaces. A lower crossmember beam connects the lower ends of the upright to increase stiffness of the Y-axis carriage. A cast aluminum table is supported on the base with three cast in support features projecting from the underside, configured to minimize thermal distortion, with a steel plate bonded into a recess in the upper surface.

Abstract: A coordinate measuring machine (10) having a horizontal probe shaft assembly (20) in which a cover system is provided for the X and Y axis ways (46, 108) and carriages (50, 106), including inwardly slanted X-axis cover members (26) mounted atop granite exposed way members (24) defining a gap through which the Y column (88) moves, a pair of upstanding side covers (32) mounted over the Y-axis column (88) defining a gap through which the probe shaft assembly (20) moves in its vertical movement. a recirculating cover belt (28) fills the X-axis gap and pleated upper and lower covers (34, 36) cover the vertical gap lying between the side covers (32) at the front and rear, while a top cap (38) atop side covers (32) and end caps (30) are fit over the X-axis cover members (26), X-axis way members (24) and base portion (18).

Abstract: A rotary workpiece support table (12) for a horizontal arm coordinate measuring machine (10) having a retractable datum ball (144) for determining the axis of rotation of a table top plate (36) on a table base (40). A frictional drive mechaism (38) has a drive wheel (72) urged into engagement with a perimeter surface (74) and rotates the table top plate (36), with a counterforce roller (98) neutralizing the side loading on an air spindle (116). The table base (40) is positioned on a machine base (30) and spacer (32) by a rotational connection (46) and a diametrically opposite block and cam follower connection (48) to avoid the effects of differential thermal expansion between the table base (40) and the machine base (30) and spacer (32).

Abstract: A bearing arrangement for a coordinate measuring machine having a horizontal probe arm assembly (16) extending to the front of the machine and supported for movement along X,Y, and Z orthogonal axes. The bearing arrangement comprised of opposing sets of supporting or guiding and preloading air bearings (48a,b; 46a,b; 66a,b; 64a,b; 76a,b; 78a,b) for the X carriage (40), the YZ carriage (17) (17a,b; 180a,b; 182a,b; 184a,b; 204a,b), and for the probe shaft (186) (188a,b; 190a,b; 192a,b194a,b). The air bearings each ride on way surfaces formed on the base (12) a column member 160, and the probe shaft (186) and are arranged to most efficiently distribute the load and minimize the effects of inaccuracies in the way surfaces, and make more efficient the accurate machining of the way surfaces.

Abstract: A coordinate measuring machine (10) of the horizontal arm type having an improved way arrangement for a carriage (40) mounted for movement along one of the orthogonal axes (X) of the machine including a pair of angled upstanding granite way members (24,26) detachably mounted spaced apart atop a granite base member (22), extending parallel to each other and the axis of movement. The way members (24, 26) have inwardly turned opposing overhang portions (28, 30) formed with upper horizontal way surfaces (32,34) and under way surfaces (36,38). The carriage (40) is received in the space between the way members (24,26) and is formed with flanges (42,44) extending over the upper way surfaces (32, 34) with pairs of air bearings (46a,b; 48a,b) interposed.