Off-Line Profilometer 3D (3DP) The Profilometer3D is the third-generation offline Profilometer from Starrett-Bytewise, and comes after 20 years of product experience. Profilometer3D is used to verify the accuracy of newly-cut dies by checking the extrusion dimensions. Its accuracy and speed helps reduce the number of die trials needed to approve a new die for production. Once the die is in production, Profilometer3D is used to check each run for overall quality, and to monitor for die wear. Under ideal conditions it is favorable to run tread extrusions so that the three main parameters – thickness, width and weight, are as near as possible to the lower control limits.This reduces the cost of the compound consumed. In practice extrusion lines normally operate with some if not all parameters above the limits. Since the tread measurements are used to tune the die dimensions, reductions to measurement uncertainty directly relate to improved die accuracy, which translates into less "running heavy". Profilometer3D is built on a monolithic granite superstructure in the "Academy Black" granite fabricated by Starrett Tru-Stone Technologies. This granite was selected due to its excellent properties for machinability, flatness, and coefficient of thermal expansion. Sensors are mounted to servo-motor controlled traversing slides mounted top and bottom. Linear travel is encoded to 5μm intervals. Profilometer3D is positioned on a wheel cart with locking casters. Sensor Technology Profilometer3D utilizes CrossCheck2T line laser sensors. These sensors project a laser line across the tread, and view the laser line with two CMOS cameras, one each side of the laser line.The resulting images are transformed into dimensional coordinates using triangulation methods. The two images are combined so that any data lost due to triangulation blockage of one camera can be augmented by data from the other camera. CrossCheck2T sensors employ high-speed CMOS detectors that run at frequencies 1,000 Hz and higher.The Starrett-Bytewise CMOS- based sensors were introduced in 2002 and there are over 3,000 sensors in use. Self-Calibra tion A multi-step certified gage block is mounted at the start position. At the beginning of each scan the gage block is measured. If the gage block measurements are inside the allowable range the measurement cycle is executed using the current calibration values. If the gage block measurement is outside the allowable tolerance the calibration offset is automatically adjusted. This means that the system is self-calibrating. This self-calibration compensates for error due primarily to temperature change in the environment.The gage block spans the entire width of the laser line.The calibration adjustments can be set to update automatically or to prompt the user to accept the changes.We log all calibration changes along with the temperature in the top and bottom chambers. Parameter µm Thickness Error of Measure (bias + 3σ) 25 Thickness Bias (typical) 15 Thickness Repeatability (typical) 1σ 3.3 Width Error of Measure (bias + 3σ) 250 Width Bias (typical) 100 Width Repeatability (typical) 1σ 50 3DP Measurement Capability No measurement system is exact, and all measurement systems have some degree of uncertainty, or error. We characterize measurement uncertainty by the Error of Measure method (EoM). EoM characterizes the inherent variation or capability of the equipment itself without regard to contributions from external sources. EoM is a means to express the capability of the measurement system that includes both the bias and repeatability components of variation. EoM encompasses the 99% confidence interval. ErrorofMeasure(EoM)isrepresentativeofthesystem's error in measuring a known value. It is calculated as the absolute value of the Bias plus 3σ for the measurement series. EoM is reported as two values - one for thickness and one for width. Bias is the average error from the known value. It is calculated as the absolute value of the average measurement minus the known value. Repeatability is representative of the system's ability to monitor process variation. It is calculated as the range (maximum minus minimum) divided by 6, and expressed as the 1-sigma standard deviation of the measurement series. Even if the measurement uncertainty is zero, there is measurand uncertainty – the uncertainty in how well the sample measured represents the overall tread. As measurementuncertaintyapproacheszero,themeasurand uncertainty can become the main source of variation. Profilometer3D acquires 512 tracks across 25mm width. Thispermitsonetoassessanareawideenoughtoaverage out variations and edge artifacts, something that can't be done with a single track area of interest. 540 L aser M easurement New!