Level 1 TrainingWelcome to Brown & Sharpes Telford Technical CentreDeveloped By:Ryan StaufferApplication EngineerCommercial OperationsMeasuring Systems GroupMetrology HouseHalesfield 13, TelfordShrops. TF7 4PL.eAdditional Information Peter HughesTraining OfficerMeasuring Systems Group
Course Objectives Understand why and how a Probe Qualification is performed Get a thorough understanding of how we create Part Alignments Understand how PC-DMIS handles Solid Geometry Learn how to Edit your part programs Write a logical, organized part program from beginning to end
The Cartesian Coordinate SystemXZYZXY
XZYThe Cartesian Coordinate SystemORIGINThe measurement VOLUME of a CMM can be represented by a cube. Each direction within the cube is an AXIS. The ORIGIN is the location where all three axes intersect.
XZThe Cartesian Coordinate SystemY | | | | | | | | 10
0105 5 105Each axis is divided into equal divisions, representing the units of measurement. Any point in the measurement cube can be defined in terms of a unique X, Y, and Z value.
XZThe Cartesian Coordinate System0What are thecoordinates of:X = 10Y = 5Z = 5X = 0Y = 0Z = 5X = 10Y = 10Z = 0
Probe Head (Wrist) & Touch Trigger Probe (Ttp)
Articulating Probe HeadThe A axis rotates from 0 to +105 in 7.5 increments
Articulating Probe HeadB axis rotates from -180 to +180 in 7.5 increments
Touch Trigger ProbesMechanical Probes such as the TP2 contain 3 electrical contacts. When the stylus is deflected, at least one of the contacts is broken. At this instant, the machines X, Y, and Z scales are read. These values represent the ball center position of the stylus at the time of contact.
Touch Trigger ProbesTouch Probe Example #1 :Measuring point on side of part
Touch Trigger ProbesTouch Probe Example #2 :Crashing into part with high velocity
Probe QualificationArtifact with Known Diameter, Traceable to National StandardsPROBE QUALIFICATION is the process of defining effective probe diameter and position of the probe tip for measurement. To accomplish this, a qualification artifact with a known diameter is measured with the probe tip to be qualified.Probe with Unknown Position and Diameter to be Qualified
Probe QualificationBall Centre coordinates at each measurement point around the artifact are compared to the known artifact diameter. The effective probe diameter is calculated from the difference between this diameter and the diameter of the spherical pattern of the measured points.
Building The Probe
Working Planes Of PcDmis
PC-DMIS Working PlanesXZYORIGINIn PC-DMIS, it is important that the correct WORKING PLANE is specified for measuring circles, calculating 2D distances, etc. The available working planes are:Y MINUSZ PLUSY PLUS XMINUS XPLUSZ MINUS
PC-DMIS Working Planes What Is A Working Plane The working plane is the view that you are currently looking from, for instance if you wish to measure the top surface of a part, then you are working in the ZPLUS working plane. If you are measuring features in the front face you are in the YMINUS working plane. This selection is important when you are working in polar co-ordinates, because PcDmis uses the working plane to decide where Zero Degrees (start point) is for that work plane.
PC-DMIS Working Planes * In the Zplus plane, zero deg is in the +X direction and 90 deg is in the +Y direction. * In the Xplus plane, zero deg is in the +Y direction and 90 deg is in the +Z direction. * In the Yplus plane, zero deg is in the -X direction and 90 deg is in the +Z direction.
+ X+Y0 deg 45 deg 90 deg 135 deg180 deg225 deg270 deg315 degCircle Measurement Direction
VectorsXZYDirections of features and directions for probe approach to a point are represented by VECTORS. A vector can be thought of as a line 1 unit long, pointing in the direction of the vector.(+I direction)(+J direction)(+K direction)The directions of a vector relate to the three axes of the coordinate system. The I direction is the direction of the X axis, J direction is the direction of Y, and K is the direction of the Z axis.
VectorsWhat is the vector direction of :I = 1.0J = 0.0K = 0.0I = 0.0J = 0.0K = -1.0I = 0.7071J = 0.7071K = 0.0
Cosine of 45o
Incorrect Vector = cosine error
Magnitude of error introduced by not probing normal to surface
AlignmentAlignment is the process of establishing a part coordinate system, where the Axes of the part and CMM are the same.Three things are needed to complete a part alignment: A LEVEL (Any measured feature with a vector direction). The level feature controls the orientation of the working plane. A ROTATE AXIS (Any measured feature with a vector direction). The rotate feature needs to be perpendicular to the level feature. This controls the timing or rotational position of the axes relative to the working plane. An ORIGIN (Any measured feature or features which define the X, Y, and Z zero point of the part).
Machine Home PositionDesired Part Coordinate SystemAlignmentLevel Feature = PlaneRotate Axis Feature = LineOrigin Feature = CircleSTEP 1 : Level Z Axis to PlaneSTEP 2 : Rotate X Axis to LineXZYSTEP 5 : Translate Z Origin to Plane ALIGNMENT COMPLETED!!!!ALIGNMENT COMPLETED!!!!STEP 3 : Translate X Origin to CircleSTEP 4 : Translate Y Origin to Circle
Machine Home PositionRequired Part Origin PositionAlignmentLevel Feature = PlaneRotate Axis Feature = LineOrigin Feature = CornerSTEP 1 : Level Z Axis to PlaneSTEP 2 : Rotate X Axis to LineSTEP 5 : Translate Z Origin to Plane ALIGNMENT COMPLETED!!!!ALIGNMENT COMPLETED!!!!STEP 3 : Translate X Origin to PointSTEP 4 : Translate Y Origin to Line
How To Align a PartMeasure 3 Points To Create PlaneMeasure 2 Points To Create LineMeasure 1 Point On Side Face
Building The Alignment
Alignment How To Do ItClick The Utilities OptionAnd Then Select Alignment
Alignment How To Do ItFrom The Features List SelectPLN1LINE1PNT1Click On Auto AlignPcDmis will automatically align the part by Levelling and setting Z zero to PLN1Rotate and set Y zero to LINE1, and then set X zero to PNT1.Measured Features
Basic Geometric ElementsElement:POINTMin Points:1Position:XYZ locationVector:NoneForm:None2D/3D:3DEXAMPLEOutput X = 5 Y = 5 Z = 5
Basic Geometric ElementsElement:LINEMin Points:2Position:CentroidVector:From 1st to last pointForm:Straightness2D/3D:2D/3DEXAMPLEOutput X = 2.5 I = -1 Y = 0 J = 0 Z = 5 K = 012
Basic Geometric ElementsElement:CIRCLEMin Points:3Position:CentreVector*:Matches reference planeForm:Roundness2D/3D:2DEXAMPLEOutput X = 2 I = 0 D = 4 Y = 2 J = 0 R = 2 Z = 0 K = 1* The vector of a circle is only for measurement purposes, and does not uniquely describe the features geometry.
Basic Geometric ElementsElement:PLANEMin Points:3Position:CentroidVector:PerpendicularForm:Flatness2D/3D:3DEXAMPLEOutput X = 1.67 I = 0.707 Y = 2.50 J = 0.000 Z = 3.33 K = 0.707
Basic Geometric ElementsElement:CYLINDERMin Points:5Position:CentroidVector:From 1st level of hits to last levelForm:Cylindricity2D/3D:3DEXAMPLEY555ZXX = 2.0 I = 0 D = 4Y = 2.0 J = 0 R = 2Z = 2.5 K = 1
Basic Geometric ElementsElement:CONEMin Points:6Position:ApexVector:From 1st level of hits to last levelForm:Conicity2D/3D:3DEXAMPLEY555ZXX = 2.0 I = 0 A = 43degY = 2.0 J = 0 Z = 5.0 K = 1
Basic Geometric ElementsElement:SPHEREMin Points:4Position:CentreVector*:Toward North Pole of HitsForm:Sphericity2D/3D:3DEXAMPLEY555ZXX = 2.5 I = 0 D = 5.0Y = 2.5 J = 0 R = 2.5Z = 2.5 K = 1* The vector of a sphere is only for measurement purposes, and does not describe the features geometry.
Constructed FeaturesPOINT : AT ORIGINXZYA point is constructed at the origin of the current alignment system. Coordinates of the point will be 0, 0, 0.
Constructed FeaturesPOINT : CASTA point is created at the centroid of the selected feature. Its coordinates (x y z) are equal to that of the CircleINPUT : CIRCLE1CIRCLE1
Constructed FeaturesPOINT : CORNERA point is created at the intersection of three planes.INPUT : PLN1 PLN2 PLN3PLN1PLN2PLN3
Constructed FeaturesPOINT : PIERCEA point is created where feature