Mark Boucher 6/24/24 Mark Boucher 6/24/24

Form Datum - Calypso

What the Form Datum does is establish a FUNCTIONAL Datum Reference Frame coordinate system, similar to if you were setting up the primary, secondary, and tertiary datums on a functional checking gage. This is ONLY for a datum reference frame and does not modify how the base and secondary alignments evaluate their respective coordinate system. In the screen shot below, you can notice the different origin points are for a base alignment and datum reference frame.

Below is an excerpt from the Calypso Handbook

To set the Form Datum correctly click on Extras/ Settings/ Measurement/ Form Datum, check both the Outer Tangential Element and the Re. Calculation as per ISO 5459 boxes.

What is happening?

When we create our base alignment the alignment uses the intersection point of your features as below.

This is based on the measurement of the actual features of the part.

Form Datum uses the highest contact points that would touch a Datum Feature Simulator, in order of primary, secondary, and tertiary features, establish a real coordinate system. Calypso will establish the proper location through the form datum reference calculation per ISO 5459. Again this is ONLY used for a Datum Reference Frame and does not affect the Base Alignment.

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Mark Boucher 6/19/24 Mark Boucher 6/19/24

Understanding the 6 Degrees of Freedom

Understanding the principle of the 6 degrees of freedom is essential to aligning your part correctly on the Coordinate Measuring Machine (CMM). When a part is placed on the CMM the location of the part is not known. It must be defined by using several features known as datums.

The following is an excerpt from The CMM Handbook

Using The Correct CMM Alignment Principles

These datums are defined on the blueprint and must be measured to define the part’s location to the CMM’s home position. If a program were written without a complete datum alignment all the linear locations in your program would come from the machines home position and not from the locations given on the blueprint. The subsequent parts would have to be placed in the exact location and alignment for your program to work. Writing a datum alignment routine at the beginning of your program will allow you to place the part anywhere on the CMM surface plate and will insure that your part will be aligned properly and your program will run correctly each time.

There will be three alignment functions used to define the datums (1) Orientation – this will use a 3d element to align the part to a spatial alignment. (2) Alignment – an element is used to align the part square to a CMM axis. (3) Origin – this will determine where the zero point is set. CMM softwares use alignment dialog boxes that allow you to set all the required datum elements at one time.

Words To Be Familiar With

Alignment – A part must be aligned to the CMM axes before you can begin to fully measure your part. The alignment is based on the datums specified on the blueprint. This alignment routine will square the part to the CMM and set the reference point (Origin) for all other dimensions to be referenced to.

Datum – A feature on the blueprint that is designated with a Datum letter. This feature is used to establish an origin that will be used to reference all other dimensions from.

Origin – The part’s zero point. The reference point on a part where the all the datums converge. The origin is where all other features are dimensioned from.

Coordinate System – After your alignment is complete and your origin is set this is known as a coordinate system.

Rotational – This degree of freedom allows the part to rotate about a given axis.

Translational – This degree of freedom allows the part to move transitional along an axis.

These principles constrain the 6 degrees of freedom.

6 Degrees of Freedom

When a part is held up in space it has “six degrees of freedom”, 3 Rotational and 3 Translational. The part can rotate about the X, Y, Z axes (rotational) and move along each of the three axes (translational). As shown below.

The part can rotate about the X, Y, Z axes and move along each of the three axes

In order to align a part to the CMM all degrees of freedom must be constrained, there are exceptions but, in our example, all must be constrained. For this example, we will place the part in a DRF, a datum reference frame. This will represent how we will constrain the degrees of freedom when we probe the part.

Placing the part on the surface plate or on a fixture constrains 3 degrees of freedom. The part can longer move up and down in Z (1 translation) or rotate about the X axis or about the Y axis (2 rotational).

As you can see, we can still rotate about Z and move the part back and forth in the X and Y axes.

Constraining one side of the block will limit 2 more degrees of freedom. Removing the ability to rotate in the Z axis (1 rotational) and constrains the ability to move in the X axis (1 translational). The part can still move back and forth in the Y axis.

Constraining the last degree of freedom requires restricting the back-and-forth motion of the last axis.

Now all 6 degrees of freedom have been constrained. You can see how this is accomplished on an open surface plate setup by merely pushing the part against a knee block or some sort of fixture. With CMM software the constraining of features is done with probing the part.

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Mark Boucher 6/14/24 Mark Boucher 6/14/24

Flexxbotics Integrates Hexagon Inspection Equipment

This integration of robot and in-line inspection capabilities reportedly enable continuous, unattended robot operations.

Flexxbotics, a supplier of workcell digitalization technologies for robot-driven manufacturing, has released FlexxCore, its advanced robotic machine tending in-line inspection connectivity compatible with Hexagon inspection equipment. This combination of technologies was developed to help manufacturers achieve precision quality with Six Sigma consistency and faster cycle times by delivering higher yields and greater throughput on complex parts for increased profit per part, according to Flexxbotics.

FlexxCore is designed to enable robots to securely connect and communicate with Hexagon machines, allowing the robots to receive closed-loop feedback based on automated inspection results enabling real-time adjustments to CNC machine programs for autonomous process control. Flexxbotics claims that, with this in-line inspection capability, it’s possible to orchestrate fleets of robots to achieve continuous, unattended operations.

The Hexagon inspection technologies that can be used with Flexxbotics include Hexagon’s PC-DMIS CMM (coordinate measuring machine) for bridge and gantry CMMs, the Tempo robotic-enabled CMM system, NC measuring software, and the Q-DAS product line for statistical process control and intelligent machine control (IMC).

“We believe in-line inspection technologies make autonomy in the smart factory possible, providing the closed-loop coordination necessary for autonomous process control,” said Tyler Modelski, chief technology officer and co-founder of Flexxbotics. “That’s why we have focused on making inspection equipment interoperable with CNC machines and the production robots which control and coordinate robot-driven manufacturing.”

Flexxbotics points out that its SaaS (software-as-a-service) robot operating software can operate online and offline, allowing production to continue with or without internet access. The company also promotes its ability to work with existing business systems such as CAD/CAM, DNC, SCADA/HMI, MES, ERP, PLM and others for process integration.

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Mark Boucher 5/21/24 Mark Boucher 5/21/24

Circular And Total Runout

Definition

A runout tolerance specifies how far the actual surface or feature is permitted to deviate from the desired form given in a drawing when you do a full rotation of the part on a datum axis. There are two types of runout: circular and total runout.

Tolerance Zone

A total width zone bounded by two boundaries of revolution within which:

– Circular Runout: all points of each circular element (cross-section) of the considered feature must lie regardless of the size of the considered feature.

- Total Runout: all points of the entire surface of the considered feature must lie

Circular Runout -