Extrudate thickness, measure

Tx corroded finished thickness of extruded outlet, measured at a height equal to rx above the outside surface of the header... 

Fig. 8 Blown film line for PE-LD. 1 Extruders, 2 die head with air cooling ring, 3 sizing unit, 4 thickness measuring unit, 5 haul-off unit and collapsing boards, 6 reversing unit, 7 winder. (Reproduced with permission from Reifenhauser)...

Instead of the simultaneously extmded polymer film, a pre-extmded or laminated film can be laminated on the substrate (e.g., paper or paper board). In this case, the extruder can be used to extrude the polymer providing adhesion (e.g., Ecoflex ) in a thin layer between the polymer coating film or laminate and the substrate. Another option is to apply a dispersion or heat in the laminator (Fig. 10, 4) to obtain adhesion. After thickness measurement and second subsequent corona treatment, substrate and polymer coating are wound on a winder (Fig. 10, 6) in order to obtain rolls for transport to subsequent processes (e.g., printing, cutting, cup forming, box making). 

The extruder and die, as well as down-stream devices for the outside and inside calibration of the pipes cross sectional area, if required, use air pressure and/or vacuum to contain the pipe shape. Wall thickness measuring device, mandrel designs (such as while water cools outside ... 

Gawis-Std, Thickness measurement of plastic bottles and containers, TopWave International, Inc. Geartruder, Extruder and integral gear pump, Harrel... 

A variety of methods are available to measure extrudate thickness. The methods can be broadly classified into contacting and non-contacting techniques. The contacting thickness measurement techniques are generally simple and inexpensive however, the contact of the transducer with the extrudate can adversely affect the extrudate surface quality. In cases where the requirements for surface quality are very high, non-contacting thickness measurement is generally preferred. 

Movement of the core produces an AC output signal that reflects the amount and direction of movement. If an LVDT is used in thickness measurement, one has to check the effect of temperature on the accuracy because the extrudate is generally at an elevated temperature that may not be constant. The LVDT can be quite accurate it can measure to an accuracy of about 1 pm. 

Thus far, the discussion has dealt with contacting thickness measurements. In addition to the fact that there is contact between the sensor and the extrudate, there is another problem in that these methods cannot be applied to continuous thickness monitoring of annular profiles, i.e., tubes and pipes. In automated extrusion lines, non-contacting thickness measurement has become quite popular. Most of the noncontacting thickness measurement techniques are based on a radiation sensor picking up a signal from a radiation source. 

Dimension measuring devices are also necessary to control width and thickness of extrudates for most applications. In many cases it is also necessary to check weigh cut to length rubber sections. 

A number of issues relative to the prediction of solids conveying in smooth bore single-screw extruders are exposed from the theoretical fits to the data in Fig. 5.32. First, the data needed to carry out an effective simulation is difficult to take and is very time consuming, and only a few labs have the proper equipment that is, bulk density measurement, dynamic friction data, lateral stress, and solids conveying data. Moreover, care must be taken to develop an accurate representation of the surface temperature for the barrel and screw as a function of the axial position. This would be quite difficult in a traditional extruder with only a control thermocouple to measure the temperature at the midpoint of the barrel thickness. Second... 

In this application, the process analyzer is used in the vis-NIR spectral region to measure the clear top layer on a co-extruded polymer film. The bottom layer is pigmented to an opaque white color and its thickness cannot be determined by this method. Prior to the installation of the fiber-optic spectroscopy system, film samples were measured manually in the laboratory by a subtractive scheme. First, the total thickness of a sample was measured on a manual profilometer. The top layer of the polymer was removed with methylene chloride. The sample was then repositioned on the profilometer as closely as possible to the originally measured spot and the thickness of the second white layer was determined. The thickness of the top layer was then determined by difference. 

A first data set was measured on a heavy-duty diesel engine test bench. Extruded monoliths with 300 cpsi, a wall thickness of 0.32 mm and a diameter of 144 mm were used in these runs. By varying the number of monolith catalyst samples it was possible to test different catalyst volumes (25, 32 and 43 L). The complete SCR catalyst setup resulted in SVs ranging from 21,000 to... 

Understand and measuring melt flow or heat behavior of plastics during processing is important.487 It provides a means for determining whether a plastic can be fabricated into a useful product such as a usable extruded extrudate, completely fill a mold cavity, provide mixing action in a screw plasticator, meet product thickness tolerance requirements,... 

Using the cathetometer the force at initiation was measured on notched bars of % inch thick extruded Lexan polycarbonate sheet over the widest temperature range possible at one rate of deformation. These initiation forces and the forces at failure are shown in Figure 7a. Brittle failure parallels craze initiation in its temperature dependence. Yield force has a greater temperature dependence—one that approximately parallels the measured values of yield stress in linear tensile tests (data... 

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