To change Fuji PXR-4 controller from F to C

Press and hold the SEL button for 3 seconds until you see P-nl in the top display (in red)

Then use the down arrow key until you get to: DSp 5

The Green display will show 20, (or some other value) you need to change this value to 16, to do this:

• Press SEL, and you will see the 20 value flashing - move the down arrow key till the value changes to 16
• Press SEL again to bring you back to the original temperature screen.
• Press SEL button for 2 seconds until you see P in the top display (in red)
• Press down key till you see P-F in Red

To change from F to C (you will see this in the Green display):

• Press SEL, then move up/down key until you see C.
• Then press SEL to lock in the change.

Important: You must change the set temperature to that value you want in C, the controller does NOT do this automatically.

Accuracy of Blending

We have been asked many times about the accuracy of our volumetric blending system compared to a gravimetric system. Our immediate response is that our system is as or more accurate compared to a gravimetric system on a shot-to-shot basis. Secondly, the question is always accuracy compared to what? The real question is what accuracy the customer needs and what other important features will make his operation more efficient.

Gravimetric systems meter fairly accurate amounts of components into a weigh scale. Most systems use time feed as a basis for feeding the correct amount of material and correct the next time cycle based on the weights of the prior components. Other systems feed the components into a live scale to control the amount of each component in an attempt to more accurately control the accuracy.

The problem with both systems is in the efficiency of mixing of the components that are layered during the feeding cycle. The design of the mixing blades and the time of mixing affect the homogeneity of the final blend. The blades must be designed to move material from the bottom and sides of the mixing chamber in a manner to blend the layers of material. The time of mixing is dependent upon the types and densities of the components and is not an exact science. This time has to be selected by the operator for each blend to maintain a homogeneous mixture.

With our blending system, all of the components are metered out at the same time into a stream of conveying air to our receiver. A fixed speed auger meters the major component with the other components metered by variable speed feeders. With this method, the components are mixed as they are fed into the air stream, resulting in a more accurate blend on a shot-to-shot basis. The resulting blend is also more homogeneous for accuracy of color of the final product.

Because the amount of each minor component is based on the major component, the operator does not have to make adjustments for changes in regrind percentage changes. The color amount is fixed to the major component that is the only component that needs the color. The percentage of regrind can now be changed on the fly to use the amount generated and increase efficiency.

A side benefit to blending just in time is that upon finishing the job, all components can be put into stock as their own identity rather than a mixture that may never be used again. Several of our customers have reduced their material costs because of this feature.

At what point should the material be blended, before or after drying? This is dependent upon how hygroscopic the resin is and how different the densities and sizes of the components are. Gravimetric blenders expose the dried material to ambient air for relatively long periods of time resulting in moisture pick up. conveying to and from the dryer. Also, the design of gravimetric hoppers do not provide for the proper material flow resulting in long residence times above the blending section. Different size and density components can be segregated during multiple conveying to and from the dryer further affecting the homogeneity of the mixture. In general, we prefer to dry before blending.

The accuracy of blenders is always a question. Do you look at the accuracy of each material or as a percentage of the mixture? How many customers can actually check the accuracy without manually separating the components and weighing them individually? The real test is the quality of the final product in terms of color or other dimensional or physical characteristics.

In summary, we contend that our system is as accurate on a shot-to-shot basis as a gravimetric system. The other features as noted above are many times the determining factor in the selection of equipment.